draft-ietf-mmusic-rfc2326bis-05.txt   draft-ietf-mmusic-rfc2326bis-06.txt 
Internet Engineering Task Force MMUSIC WG Internet Engineering Task Force MMUSIC WG
Internet Draft H. Schulzrinne Internet Draft H. Schulzrinne/Columbia U.
Columbia U. draft-ietf-mmusic-rfc2326bis-06.txt A. Rao/Cisco
A. Rao February 16, 2004 R. Lanphier/RealNetworks
Cisco Expires: August, 2004 M. Westerlund/Ericsson
R. Lanphier A. Narasimhan/Sun
RealNetworks
M. Westerlund
Ericsson
A. Narasimhan
Sun
draft-ietf-mmusic-rfc2326bis-05.txt
October 27, 2003
Expires: April, 2004
Real Time Streaming Protocol (RTSP) Real Time Streaming Protocol (RTSP)
STATUS OF THIS MEMO STATUS OF THIS MEMO
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
skipping to change at page 2, line 5 skipping to change at page 3, line 5
The Real Time Streaming Protocol, or RTSP, is an application-level The Real Time Streaming Protocol, or RTSP, is an application-level
protocol for control over the delivery of data with real-time protocol for control over the delivery of data with real-time
properties. RTSP provides an extensible framework to enable properties. RTSP provides an extensible framework to enable
controlled, on-demand delivery of real-time data, such as audio and controlled, on-demand delivery of real-time data, such as audio and
video. Sources of data can include both live data feeds and stored video. Sources of data can include both live data feeds and stored
clips. This protocol is intended to control multiple data delivery clips. This protocol is intended to control multiple data delivery
sessions, provide a means for choosing delivery channels such as UDP, sessions, provide a means for choosing delivery channels such as UDP,
multicast UDP and TCP, and provide a means for choosing delivery multicast UDP and TCP, and provide a means for choosing delivery
mechanisms based upon RTP (RFC 3550). mechanisms based upon RTP (RFC 3550).
Table of Contents
1 Introduction ........................................ 8
1.1 The Update of the RTSP Specification ................ 8
1.2 Purpose ............................................. 9
1.3 Notational Conventions .............................. 11
1.4 Terminology ......................................... 11
1.5 Protocol Properties ................................. 14
1.6 Extending RTSP ...................................... 16
1.7 Overall Operation ................................... 17
1.8 RTSP States ......................................... 18
1.9 Relationship with Other Protocols ................... 19
2 RTSP Use Cases ...................................... 19
2.1 On-demand Playback of Stored Content ................ 20
2.2 Unicast distribution of Live Content ................ 20
2.3 Inviting RTSP on-demand servers into a multicast
group ............................................... 20
2.4 On-demand Playback using Multicast .................. 20
3 Protocol Parameters ................................. 20
3.1 RTSP Version ........................................ 20
3.2 RTSP URL ............................................ 20
3.3 Session Identifiers ................................. 22
3.4 SMPTE Relative Timestamps ........................... 22
3.5 Normal Play Time .................................... 22
3.6 Absolute Time ....................................... 23
3.7 Feature-tags ........................................ 23
4 RTSP Message ........................................ 24
4.1 Message Types ....................................... 24
4.2 Message Headers ..................................... 24
4.3 Message Body ........................................ 25
4.4 Message Length ...................................... 25
5 General Header Fields ............................... 25
6 Request ............................................. 25
6.1 Request Line ........................................ 26
6.2 Request Header Fields ............................... 27
7 Response ............................................ 27
7.1 Status-Line ......................................... 28
7.1.1 Status Code and Reason Phrase ....................... 28
7.1.2 Response Header Fields .............................. 29
8 Entity .............................................. 30
8.1 Entity Header Fields ................................ 32
8.2 Entity Body ......................................... 32
9 Connections ......................................... 32
9.1 Pipelining .......................................... 33
9.2 Reliability and Acknowledgements .................... 33
9.3 Unreliable Transport ................................ 34
9.4 The usage of connections ............................ 34
9.5 Timing Out RTSP messages ............................ 36
9.6 Use of IPv6 ......................................... 36
10 Capability Handling ................................. 37
11 Method Definitions .................................. 38
11.1 OPTIONS ............................................. 39
11.2 DESCRIBE ............................................ 40
11.3 SETUP ............................................... 42
11.4 PLAY ................................................ 44
11.5 PAUSE ............................................... 48
11.6 TEARDOWN ............................................ 51
11.7 GET_PARAMETER ....................................... 52
11.8 SET_PARAMETER ....................................... 53
11.9 REDIRECT ............................................ 55
11.10 PING ................................................ 56
12 Embedded (Interleaved) Binary Data .................. 57
13 Status Code Definitions ............................. 59
13.1 Success 1xx ......................................... 59
13.1.1 100 Continue ........................................ 59
13.2 Success 2xx ......................................... 59
13.3 Redirection 3xx ..................................... 59
13.3.1 TBW ................................................. 60
13.3.2 301 Moved Permanently ............................... 60
13.3.3 302 Found ........................................... 60
13.3.4 303 See Other ....................................... 60
13.3.5 304 Not Modified .................................... 60
13.3.6 305 Use Proxy ....................................... 61
13.4 Client Error 4xx .................................... 61
13.4.1 400 Bad Request ..................................... 61
13.4.2 405 Method Not Allowed .............................. 61
13.4.3 451 Parameter Not Understood ........................ 61
13.4.4 452 reserved ........................................ 61
13.4.5 453 Not Enough Bandwidth ............................ 61
13.4.6 454 Session Not Found ............................... 62
13.4.7 455 Method Not Valid in This State .................. 62
13.4.8 456 Header Field Not Valid for Resource ............. 62
13.4.9 457 Invalid Range ................................... 62
13.4.10 458 Parameter Is Read-Only .......................... 62
13.4.11 459 Aggregate Operation Not Allowed ................. 62
13.4.12 460 Only Aggregate Operation Allowed ................ 62
13.4.13 461 Unsupported Transport ........................... 62
13.4.14 462 Destination Unreachable ......................... 63
13.5 Server Error 5xx .................................... 63
13.5.1 551 Option not supported ............................ 63
14 Header Field Definitions ............................ 63
14.1 Accept .............................................. 65
14.2 Accept-Encoding ..................................... 65
14.3 Accept-Language ..................................... 66
14.4 Accept-Ranges ....................................... 66
14.5 Allow ............................................... 66
14.6 Authorization ....................................... 66
14.7 Bandwidth ........................................... 66
14.8 Blocksize ........................................... 68
14.9 Cache-Control ....................................... 70
14.10 Connection .......................................... 72
14.11 Content-Base ........................................ 73
14.12 Content-Encoding .................................... 73
14.13 Content-Language .................................... 73
14.14 Content-Length ...................................... 73
14.15 Content-Location .................................... 73
14.16 Content-Type ........................................ 73
14.17 CSeq ................................................ 73
14.18 Date ................................................ 74
14.19 Expires ............................................. 74
14.20 From ................................................ 75
14.21 Host ................................................ 75
14.22 If-Match ............................................ 75
14.23 If-Modified-Since ................................... 75
14.24 Last-Modified ....................................... 76
14.25 Location ............................................ 76
14.26 Proxy-Authenticate .................................. 76
14.27 Proxy-Require ....................................... 76
14.28 Public .............................................. 77
14.29 Range ............................................... 77
14.30 Referer ............................................. 79
14.31 Retry-After ......................................... 79
14.32 Require ............................................. 79
14.33 RTP-Info ............................................ 80
14.34 Scale ............................................... 82
14.35 Speed ............................................... 82
14.36 Server .............................................. 83
14.37 Session ............................................. 83
14.38 Supported ........................................... 85
14.39 Timestamp ........................................... 86
14.40 Transport ........................................... 86
14.41 Unsupported ......................................... 92
14.42 User-Agent .......................................... 92
14.43 Vary ................................................ 93
14.44 Via ................................................. 93
14.45 WWW-Authenticate .................................... 93
15 Caching ............................................. 93
16 Examples ............................................ 94
16.1 Media on Demand (Unicast) ........................... 94
16.2 Streaming of a Container file ....................... 97
16.3 Single Stream Container Files ....................... 100
16.4 Live Media Presentation Using Multicast ............. 101
16.5 Capability Negotiation .............................. 103
17 Syntax .............................................. 104
17.1 Base Syntax ......................................... 104
17.2 RTSP Protocol Definition ............................ 105
17.2.1 Generic Protocol elements ........................... 105
17.2.2 Message Syntax ...................................... 106
17.2.3 Header Syntax ....................................... 110
18 Security Considerations ............................. 112
19 IANA Considerations ................................. 115
19.1 Feature-tags ........................................ 115
19.1.1 Description ......................................... 115
19.1.2 Registering New Feature-tags with IANA .............. 116
19.1.3 Registered entries .................................. 116
19.2 RTSP Methods ........................................ 116
19.2.1 Description ......................................... 116
19.2.2 Registering New Methods with IANA ................... 116
19.2.3 Registered Entries .................................. 117
19.3 RTSP Status Codes ................................... 117
19.3.1 Description ......................................... 117
19.3.2 Registering New Status Codes with IANA .............. 117
19.3.3 Registered Entries .................................. 117
19.4 RTSP Headers ........................................ 117
19.4.1 Description ......................................... 117
19.4.2 Registering New Headers with IANA ................... 118
19.4.3 Registered entries .................................. 118
19.5 Transport Header registries ......................... 118
19.5.1 Transport Protocols ................................. 119
19.5.2 Profile ............................................. 119
19.5.3 Lower Transport ..................................... 119
19.5.4 Transport modes ..................................... 120
19.6 Cache Directive Extensions .......................... 120
19.7 SDP attributes ...................................... 121
A RTSP Protocol State Machine ......................... 122
A.1 States .............................................. 122
A.2 State variables ..................................... 122
A.3 Abbreviations ....................................... 122
A.4 State Tables ........................................ 123
B Media Transport Alternatives ........................ 125
B.1 RTP ................................................. 126
B.1.1 AVP ................................................. 126
B.1.2 AVP/UDP ............................................. 127
B.1.3 AVP/TCP ............................................. 128
B.1.4 Handling NPT Jumps in the RTP Media Layer ........... 129
B.1.5 Handling RTP Timestamps after PAUSE ................. 131
B.1.6 RTSP / RTP Integration .............................. 133
B.1.7 Scaling with RTP .................................... 133
B.1.8 Maintaining NPT synchronization with RTP
timesatmps .......................................... 133
B.1.9 Continuous Audio .................................... 134
B.1.10 Multiple Sources in an RTP Session .................. 134
B.1.11 Usage of SSRCs and the RTCP BYE Message During a
RTSP Session ........................................ 134
B.2 Future Additions .................................... 134
C Use of SDP for RTSP Session Descriptions ............ 135
C.1 Definitions ......................................... 135
C.1.1 Control URL ......................................... 135
C.1.2 Media Streams ....................................... 136
C.1.3 Payload Type(s) ..................................... 137
C.1.4 Format-Specific Parameters .......................... 137
C.1.5 Range of Presentation ............................... 137
C.1.6 Time of Availability ................................ 138
C.1.7 Connection Information .............................. 138
C.1.8 Entity Tag .......................................... 139
C.2 Aggregate Control Not Available ..................... 139
C.3 Aggregate Control Available ......................... 140
C.4 RTSP external SDP delivery .......................... 141
D Minimal RTSP implementation ......................... 141
D.1 Client .............................................. 141
D.1.1 Basic Playback ...................................... 142
D.1.2 Authentication-enabled .............................. 142
D.2 Server .............................................. 143
D.2.1 Basic Playback ...................................... 143
D.2.2 Authentication-enabled .............................. 144
E Open Issues ......................................... 144
F Changes ............................................. 145
G Author Addresses .................................... 151
H Contributors ........................................ 152
I Acknowledgements .................................... 152
J Normative References ................................ 152
K Informative References .............................. 154
1 Introduction 1 Introduction
1.1 The Update of the RTSP Specification 1.1 The Update of the RTSP Specification
This is the draft to an update of RTSP which is currently a proposed This is the draft to an update of RTSP which is currently a proposed |
standard defined in RFC 2326 [21]. Many flaws have been found in standard defined in RFC 2326 [1]. Many flaws have been found in RTSP |
RTSP since it was published. While this draft tries to address the since it was published. While this draft tries to address the flaws, |
flaws, not all known issues have been resolved. not all known issues have been resolved. However in this version only |
a few remains, please see Open Issues in section E.
The goal of the current work on RTSP is to progress it to draft The goal of the current work on RTSP is to progress it to draft
standard status. Whether this is possible without first publishing standard status. Whether this is possible without first republishing
RTSP as a proposed standard depends on the changes necessary to make RTSP as a proposed standard depends on the changes necessary to make
the protocol work. The list of changes in chapter F indicates the the protocol work. The list of changes in appendix F indicates the
issues that have already been addressed. The currently open issues issues that have already been addressed. The currently open issues
are listed in chapter E. are listed in appendix E.
There is also a list of reported bugs available at There is also a list of reported bugs available at
"http://rtspspec.sourceforge.net". These bugs should be taken into "http://rtspspec.sourceforge.net". These bugs should be taken into
account when reading this specification. While a lot of these bugs account when reading this specification. While a lot of these bugs
are addressed, not all are yet accounted for in this specification. are addressed, not all are yet accounted for in this specification.
Input on the unresolved bugs and other issues can be sent via e-mail Input on the unresolved bugs and other issues can be sent via e-mail
to the MMUSIC WG's mailing list mmusic@ietf.org and the authors. to the MMUSIC WG's mailing list mmusic@ietf.org and the authors.
Take special notice of the following: Not all of the contents of RFC 2326 are part of this draft. In an |
attempt to prevent the draft from exploding in size, the |
o The example section 15 has not yet been revised since the specification has been reduced and split. The content of this draft |
changes to protocol have not been completed. is the core specification of the protocol. It contains the general |
idea behind RTSP and the basic functionality necessary to establish |
o The BNF chapter 16 has not been compiled completely. an on-demand play-back session. It also contains the mechanisms for |
extending the protocol. Any other functionality will be published as |
o Not all of the contents of RFC 2326 are part of this draft. extension documents. The Working group currently is working on: |
In an attempt to prevent the draft from exploding in size, the
specification has been reduced and split. The content of this
draft is the core specification of the protocol. It contains
the general idea behind RTSP and the basic functionality
necessary to establish an on-demand play-back session. It also
contains the mechanisms for extending the protocol. Any other
functionality will be published as extension documents. Two
proposals exist at this time:
o NAT and FW traversal mechanisms for RTSP are described in a o NAT and FW traversal mechanisms for RTSP are described in a |
document called "How to make Real-Time Streaming Protocol document called "How to make Real-Time Streaming Protocol |
(RTSP) traverse Network Address Translators (NAT) and interact (RTSP) traverse Network Address Translators (NAT) and interact |
with Firewalls." [33]. with Firewalls." [20]. |
o The MUTE extension [34] contains a proposal on adding There have also been discussion or proposals about the following |
functionality to mute and unmute media streams in an extensions to RTSP: |
aggregated media session without affecting the time-line of
the playback.
There have also been discussions about the following extensions to o Mute and Unmute Extension [21]. |
RTSP:
o Transport security for RTSP messages (rtsps). o RTSP Stream Switching [22]. |
o Unreliable transport of RTSP messages (rtspu). o Live Streaming Relays [23]. |
o The Record functionality. o Transport security for RTSP messages (rtsps). |
o Unreliable transport of RTSP messages (rtspu). |
o A text body type with suitable syntax for basic parameters to o The Record functionality. |
be used in SET_PARAMETER, and GET_PARAMETER. Including IANA
registry within the defined name space.
o A RTSP MIB. o A text body type with suitable syntax for basic parameters to |
be used in SET_PARAMETER, and GET_PARAMETER. Including IANA |
registry within the defined name space. |
However, so far, they have not become concrete proposals. o A RTSP MIB. |
1.2 Purpose 1.2 Purpose
The Real-Time Streaming Protocol (RTSP) establishes and controls The Real-Time Streaming Protocol (RTSP) establishes and controls
single or several time-synchronized streams of continuous media such single or several time-synchronized streams of continuous media such
as audio and video. Put simply, RTSP acts as a "network remote as audio and video. Put simply, RTSP acts as a "network remote
control" for multimedia servers. control" for multimedia servers.
There is no notion of a RTSP connection in the protocol. Instead, a | There is no notion of a RTSP connection in the protocol. Instead, a
RTSP server maintains a session labelled by an identifier to | RTSP server maintains a session labelled by an identifier to
associate groups of media streams and their states. A RTSP session is | associate groups of media streams and their states. A RTSP session is
not tied to a transport-level connection such as a TCP connection. | not tied to a transport-level connection such as a TCP connection.
During a session, a client may open and close many reliable transport | During a session, a client may open and close many reliable transport
connections to the server to issue RTSP requests for that session. connections to the server to issue RTSP requests for that session.
This memorandum describes the use of RTSP over a reliable connection This memorandum describes the use of RTSP over a reliable connection
based transport level protocol such as TCP. RTSP may be implemented based transport level protocol such as TCP. RTSP may be implemented
over an unreliable connectionless transport protocol such as UDP. over an unreliable connectionless transport protocol such as UDP.
While nothing in RTSP precludes this, additional definition of this While nothing in RTSP precludes this, additional definition of this
problem area must be handled as an extension to the core problem area must be handled as an extension to the core
specification. specification.
The mechanisms of RTSP's operation over UDP were left out The mechanisms of RTSP's operation over UDP were left out
of this spec. because they were poorly defined in RFC 2336 of this spec. because they were poorly defined in RFC 2326
[21] and the tradeoff in size and complexity of this spec. [1] and the tradeoff in size and complexity of this spec.
for a small gain in a targeted problem space was not deemed for a small gain in a targeted problem space was not deemed
justifiable. justifiable.
The set of streams to be controlled is defined by a presentation The set of streams to be controlled is defined by a presentation |
description. This memorandum does not define a format for the description. This memorandum does not define a format for the |
presentation description. The streams controlled by RTSP may use RTP presentation description. However appendix C defines how SDP [2] is |
[1] for their data transport, but the operation of RTSP does not used for this purpose. The streams controlled by RTSP may use RTP [3] |
depend on the transport mechanism used to carry continuous media. The for their data transport, but the operation of RTSP does not depend |
protocol is intentionally similar in syntax and operation to HTTP/1.1 on the transport mechanism used to carry continuous media. The |
[26] so that extension mechanisms to HTTP can in most cases also be protocol is intentionally similar in syntax and operation to HTTP/1.1 |
added to RTSP. However, RTSP differs in a number of important [4] so that extension mechanisms to HTTP can in most cases also be |
aspects from HTTP: added to RTSP. However, RTSP differs in a number of important aspects |
from HTTP:
o RTSP introduces a number of new methods and has a different o RTSP introduces a number of new methods and has a different
protocol identifier. protocol identifier.
o RTSP has the notion of a session built into the protocol. o RTSP has the notion of a session built into the protocol.
o A RTSP server needs to maintain state by default in almost all o A RTSP server needs to maintain state by default in almost all
cases, as opposed to the stateless nature of HTTP. cases, as opposed to the stateless nature of HTTP.
o Both a RTSP server and client can issue requests. o Both a RTSP server and client can issue requests.
o Data is usually carried out-of-band by a different protocol. o Data is usually carried out-of-band by a different protocol.
Session descriptions returned in a DESCRIBE response (see Session descriptions returned in a DESCRIBE response (see
Section 11.2) and interleaving of RTP with RTSP over TCP are Section 11.2) and interleaving of RTP with RTSP over TCP are
exceptions to this rule (see Section 11.11). exceptions to this rule (see Section 12). |
o RTSP is defined to use ISO 10646 (UTF-8) rather than ISO o RTSP is defined to use ISO 10646 (UTF-8) rather than ISO |
8859-1, consistent with current HTML internationalization 8859-1, consistent with HTML internationalization efforts |
efforts [3]. [24].
o The Request-URI always contains the absolute URI. Because of o The Request-URL always contains the absolute URL. Because of
backward compatibility with a historical blunder, HTTP/1.1 backward compatibility with a historical blunder, HTTP/1.1 [4]
[26] carries only the absolute path in the request and puts carries only the absolute path in the request and puts the
the host name in a separate header field. host name in a separate header field.
This makes "virtual hosting" easier, where a single This makes "virtual hosting" easier, where a single
host with one IP address hosts several document trees. host with one IP address hosts several document trees.
The protocol supports the following operations: The protocol supports the following operations:
Retrieval of media from media server: The client can request a Retrieval of media from media server: The client can either |
presentation description via HTTP or some other method. If request a presentation description via RTSP DESCRIBE, HTTP |
the presentation is being multicast, the presentation or some other method. If the presentation is being |
description contains the multicast addresses and ports to multicast, the presentation description contains the |
be used for the continuous media. If the presentation is multicast addresses and ports to be used for the continuous |
to be sent only to the client via unicast, the client media. If the presentation is to be sent only to the client |
provides the destination for security reasons. via unicast, the client provides the destination for |
security reasons.
Invitation of a media server to a conference: A media server can Invitation of a media server to a conference: A media server can
be "invited" to join an existing conference to play back be "invited" to join an existing conference to play back
media into the presentation. This mode is useful for media into the presentation. This mode is useful for
distributed teaching applications. Several parties in the distributed teaching applications. Several parties in the
conference may take turns "pushing the remote control conference may take turns "pushing the remote control
buttons". buttons".
Addition of media to an existing presentation: Particularly for
live presentations, it is useful if the server can tell the
client about additional media becoming available.
RTSP requests may be handled by proxies, tunnels and caches as in RTSP requests may be handled by proxies, tunnels and caches as in
HTTP/1.1 [26]. HTTP/1.1 [4].
1.3 Requirements 1.3 Notational Conventions |
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", Since many of the definitions and syntax are identical to HTTP/1.1, |
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this this specification only points to the section where they are defined |
document are to be interpreted as described in RFC 2119 [4]. rather than copying it. For brevity, [HX.Y] is to be taken to refer |
to Section X.Y of the current HTTP/1.1 specification (RFC 2616 [4]). |
All the mechanisms specified in this document are described in both |
prose and the augmented Backus-Naur form (BNF) described in detail in |
RFC 2234 [5]. |
In this specification, we use indented and smaller-type paragraphs to |
provide background and motivation. This is intended to give readers |
who were not involved with the formulation of the specification an |
understanding of why things are the way that they are in RTSP. |
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", |
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this |
document are to be interpreted as described in RFC 2119 [6]. |
This specification uses the word "Unspecified" to indicate |
functionality or features that are not defined in this specification, |
and therefore can't be used. Any such functionality or feature can in |
the future be evaluated and if technical sound be defined in |
specification extending RTSP.
1.4 Terminology 1.4 Terminology
Some of the terminology has been adopted from HTTP/1.1 [26]. Terms Some of the terminology has been adopted from HTTP/1.1 [4]. Terms not
not listed here are defined as in HTTP/1.1. listed here are defined as in HTTP/1.1.
Aggregate control: The concept of controlling multiple streams Aggregate control: The concept of controlling multiple streams
using a single timeline, generally maintained by the using a single timeline, generally maintained by the
server. A client, for example, uses aggregate control when server. A client, for example, uses aggregate control when
it issues a single play or pause message to simultaneously it issues a single play or pause message to simultaneously
control both the audio and video in a movie. control both the audio and video in a movie.
Aggregate control URI: The URI used in a RTSP request to refer Aggregate control URL: The URL used in a RTSP request to refer |
to and control an aggregated session. It normally, but not to and control an aggregated session. It normally, but not |
always, corresponds to the presentation URI specified in always, corresponds to the presentation URL specified in |
the session description. See Section 11.3 for more the session description. See Section 11.3 for more |
information. information.
Conference: a multiparty, multimedia presentation, where "multi" Conference: a multiparty, multimedia presentation, where "multi"
implies greater than or equal to one. implies greater than or equal to one.
Client: The client requests media service from the media server. Client: The client requests media service from the media server.
Connection: A transport layer virtual circuit established Connection: A transport layer virtual circuit established
between two programs for the purpose of communication. between two programs for the purpose of communication.
skipping to change at page 6, line 23 skipping to change at page 12, line 36
relationship is less strict. relationship is less strict.
Entity: The information transferred as the payload of a request Entity: The information transferred as the payload of a request
or response. An entity consists of meta-information in the or response. An entity consists of meta-information in the
form of entity-header fields and content in the form of an form of entity-header fields and content in the form of an
entity-body, as described in Section 8. entity-body, as described in Section 8.
Feature-tag: A tag representing a certain set of functionality, Feature-tag: A tag representing a certain set of functionality,
i.e. a feature. i.e. a feature.
Live: Normally used to describe a presentation or session with |
media coming from ongoing event. This generally results in |
that the session has a unbound or only loosely defined |
duration, and that no seek operations are possible.
Media initialization: Datatype/codec specific initialization. Media initialization: Datatype/codec specific initialization.
This includes such things as clockrates, color tables, etc. This includes such things as clockrates, color tables, etc.
Any transport-independent information which is required by Any transport-independent information which is required by
a client for playback of a media stream occurs in the media a client for playback of a media stream occurs in the media
initialization phase of stream setup. initialization phase of stream setup.
Media parameter: Parameter specific to a media type that may be Media parameter: Parameter specific to a media type that may be
changed before or during stream playback. changed before or during stream playback.
Media server: The server providing playback services for one or Media server: The server providing playback services for one or
skipping to change at page 6, line 46 skipping to change at page 13, line 16
the web server the presentation is invoked from. the web server the presentation is invoked from.
Media server indirection: Redirection of a media client to a Media server indirection: Redirection of a media client to a
different media server. different media server.
(Media) stream: A single media instance, e.g., an audio stream (Media) stream: A single media instance, e.g., an audio stream
or a video stream as well as a single whiteboard or shared or a video stream as well as a single whiteboard or shared
application group. When using RTP, a stream consists of all application group. When using RTP, a stream consists of all
RTP and RTCP packets created by a source within an RTP RTP and RTCP packets created by a source within an RTP
session. This is equivalent to the definition of a DSM-CC session. This is equivalent to the definition of a DSM-CC
stream([5]). stream([25]).
Message: The basic unit of RTSP communication, consisting of a Message: The basic unit of RTSP communication, consisting of a
structured sequence of octets matching the syntax defined structured sequence of octets matching the syntax defined
in Section 16 and transmitted via a connection or a in Section 17 and transmitted via a connection or a
connectionless protocol. connectionless protocol.
Non-Aggregated Control: Control of a single media stream. Only Non-Aggregated Control: Control of a single media stream. Only
possible in RTSP sessions with a single media. possible in RTSP sessions with a single media.
Participant: Member of a conference. A participant may be a Participant: Member of a conference. A participant may be a
machine, e.g., a playback server. machine, e.g., a playback server.
Presentation: A set of one or more streams presented to the Presentation: A set of one or more streams presented to the
client as a complete media feed, using a presentation client as a complete media feed, using a presentation
description as defined below. In most cases in the RTSP description as defined below. In most cases in the RTSP
context, this implies aggregate control of those streams, context, this implies aggregate control of those streams,
but does not have to. but does not have to.
Presentation description: A presentation description contains Presentation description: A presentation description contains
information about one or more media streams within a information about one or more media streams within a
presentation, such as the set of encodings, network presentation, such as the set of encodings, network
addresses and information about the content. Other IETF addresses and information about the content. Other IETF
protocols such as SDP (RFC 2327 [24]) use the term protocols such as SDP (RFC 2327 [2]) use the term "session"
"session" for a live presentation. The presentation for a presentation. The presentation description may take
description may take several different formats, including several different formats, including but not limited to the
but not limited to the session description format SDP. session description format SDP.
Response: A RTSP response. If an HTTP response is meant, that is Response: A RTSP response. If an HTTP response is meant, that is
indicated explicitly. indicated explicitly.
Request: A RTSP request. If an HTTP request is meant, that is Request: A RTSP request. If an HTTP request is meant, that is
indicated explicitly. indicated explicitly.
Request URL: The URL used in a request to indicate the resource |
which the request shall be performed on.
RTSP session: A stateful abstraction upon which the main control RTSP session: A stateful abstraction upon which the main control
methods of RTSP operate. A RTSP session is a server entity; methods of RTSP operate. A RTSP session is a server entity;
it is created, maintained and destroyed by the server. It it is created, maintained and destroyed by the server. It
is established by a RTSP server upon the completion of a is established by a RTSP server upon the completion of a
successful SETUP request (when 200 OK response is sent) and successful SETUP request (when 200 OK response is sent) and
is labelled by a session identifier at that time. The is labelled by a session identifier at that time. The
session exists until timed out by the server or explicitly session exists until timed out by the server or explicitly
removed by a TEARDOWN request. A RTSP session is also a removed by a TEARDOWN request. A RTSP session is also a
stateful entity; a RTSP server maintains an explicit stateful entity; a RTSP server maintains an explicit
session state machine (see Appendix A) where most state session state machine (see Appendix A) where most state
skipping to change at page 8, line 5 skipping to change at page 14, line 27
of a session implies the existence of state about the of a session implies the existence of state about the
session's media streams and their respective transport session's media streams and their respective transport
mechanisms. A given session can have zero or more media mechanisms. A given session can have zero or more media
streams associated with it. A RTSP server uses the session streams associated with it. A RTSP server uses the session
to aggregate control over multiple media streams. to aggregate control over multiple media streams.
Transport initialization: The negotiation of transport Transport initialization: The negotiation of transport
information (e.g., port numbers, transport protocols) information (e.g., port numbers, transport protocols)
between the client and the server. between the client and the server.
URI: Universal Resource Identifier, see RFC 2396 [12]. In RTSP |
the used URIs are as general rule in fact URL's as they |
gives an location for the resource. Therefore although RTSP |
URLs are a subset of URIs, they will be refered as URLs. |
URL: Universal Resource Locator, is an URI which identifies the |
resource through its primary access mechanism, rather than |
identifying the resource by name or by some other |
attribute(s) of that resource.
1.5 Protocol Properties 1.5 Protocol Properties
RTSP has the following properties: RTSP has the following properties:
Extendable: New methods and parameters can be easily added to Extendable: New methods and parameters can be easily added to
RTSP. RTSP.
Easy to parse: RTSP can be parsed by standard HTTP or MIME Easy to parse: RTSP can be parsed by standard HTTP or MIME
parsers. parsers.
Secure: RTSP re-uses web security mechanisms, either at the Secure: RTSP re-uses web security mechanisms, either at the
transport level (TLS, RFC 2246 [27]) or within the protocol transport level (TLS, RFC 2246 [26]) or within the protocol
itself. All HTTP authentication mechanisms such as basic itself. All HTTP authentication mechanisms such as basic
(RFC 2616 [26]) and digest authentication (RFC 2069 [6]) (RFC 2616 [4]) and digest authentication (RFC 2617 [7]) are
are directly applicable. directly applicable.
Transport-independent: RTSP does not preclude the use of an Transport-independent: RTSP does not preclude the use of an |
unreliable datagram protocol (UDP) (RFC 768 [7]), a unreliable datagram protocol (UDP) (RFC 768 [8]), a |
reliable datagram protocol (RDP, RFC 1151, not widely used reliable datagram protocol (RDP, RFC 1151, not widely used |
[8]) or a reliable stream protocol such as TCP (RFC 793 [27]) as it would be possible to implement application- |
[9]) as it implements application-level reliability. The level reliability. The use of a connectionless datagram |
use of a connectionless datagram protocol such as UDP or protocol such as UDP or RDP requires additional definition |
RDP requires additional definition that may be provided as that may be provided as extensions to the core RTSP |
extensions to the core RTSP specification. specification. The usage of the reliable stream protocol |
TCP (RFC 793 [9]) is what is currently defined as transport |
protocol of RTSP messages.
Multi-server capable: Each media stream within a presentation Multi-server capable: Each media stream within a presentation
can reside on a different server. The client automatically can reside on a different server. The client automatically
establishes several concurrent control sessions with the establishes several concurrent control sessions with the
different media servers. Media synchronization is different media servers. Media synchronization is
performed at the transport level. performed at the transport level.
Separation of stream control and conference initiation: Stream Separation of stream control and conference initiation: Stream
control is divorced from inviting a media server to a control is divorced from inviting a media server to a
conference. In particular, SIP [10] or H.323 [28] may be conference. In particular, SIP [28] or H.323 [29] may be
used to invite a server to a conference. used to invite a server to a conference.
Suitable for professional applications: RTSP supports frame- Suitable for professional applications: RTSP supports frame-
level accuracy through SMPTE time stamps to allow remote level accuracy through SMPTE time stamps to allow remote
digital editing. digital editing.
Presentation description neutral: The protocol does not impose a Presentation description neutral: The protocol does not impose a
particular presentation description or metafile format and particular presentation description or metafile format and
can convey the type of format to be used. However, the can convey the type of format to be used. However, the
presentation description must contain at least one RTSP presentation description must contain at least one RTSP
URI. URL.
Proxy and firewall friendly: The protocol should be readily Proxy and firewall friendly: The protocol should be readily |
handled by both application and transport-layer (SOCKS handled by both application and transport-layer (SOCKS |
[11]) firewalls. A firewall may need to understand the [30]) firewalls. A firewall may need to understand the |
SETUP method to open a "hole" for the UDP media stream. SETUP method to open a "hole" for the media stream.
HTTP-friendly: Where sensible, RTSP reuses HTTP concepts, so HTTP-friendly: Where sensible, RTSP reuses HTTP concepts, so
that the existing infrastructure can be reused. This that the existing infrastructure can be reused. This
infrastructure includes PICS (Platform for Internet Content infrastructure includes PICS (Platform for Internet Content
Selection [12,13]) for associating labels with content. Selection [31,32]) for associating labels with content.
However, RTSP does not just add methods to HTTP since the However, RTSP does not just add methods to HTTP since the
controlling continuous media requires server state in most controlling continuous media requires server state in most
cases. cases.
Appropriate server control: If a client can start a stream, it Appropriate server control: If a client can start a stream, it
must be able to stop a stream. Servers should not start must be able to stop a stream. Servers should not start
streaming to clients in such a way that clients cannot stop streaming to clients in such a way that clients cannot stop
the stream. the stream.
Transport negotiation: The client can negotiate the transport Transport negotiation: The client can negotiate the transport
skipping to change at page 10, line 5 skipping to change at page 16, line 42
Since not all media servers have the same functionality, media Since not all media servers have the same functionality, media
servers by necessity will support different sets of requests. For servers by necessity will support different sets of requests. For
example: example:
o A server may not be capable of seeking (absolute positioning) o A server may not be capable of seeking (absolute positioning)
if it is to support live events only. if it is to support live events only.
o Some servers may not support setting stream parameters and o Some servers may not support setting stream parameters and
thus not support GET_PARAMETER and SET_PARAMETER. thus not support GET_PARAMETER and SET_PARAMETER.
A server SHOULD implement all header fields described in Section 13. A server SHOULD implement all header fields described in Section 14.
It is up to the creators of presentation descriptions not to ask the It is up to the creators of presentation descriptions not to ask the
impossible of a server. This situation is similar in HTTP/1.1 [26], impossible of a server. This situation is similar in HTTP/1.1 [4],
where the methods described in [H19.5] are not likely to be supported where the methods described in [H19.5] are not likely to be supported
across all servers. across all servers.
RTSP can be extended in three ways, listed here in order of the RTSP can be extended in three ways, listed here in order of the
magnitude of changes supported: magnitude of changes supported:
o Existing methods can be extended with new parameters, as long o Existing methods can be extended with new parameters, e.g. |
as these parameters can be safely ignored by the recipient. headers, as long as these parameters can be safely ignored by |
(This is equivalent to adding new parameters to an HTML tag.) the recipient. (This is equivalent to adding new parameters to |
If the client needs negative acknowledgement when a method an HTML tag.) If the client needs negative acknowledgement |
extension is not supported, a tag corresponding to the when a method extension is not supported, a tag corresponding |
extension may be added in the Require: field (see Section to the extension may be added in the Require: field (see |
13.32). Section 14.32).
o New methods can be added. If the recipient of the message does o New methods can be added. If the recipient of the message does
not understand the request, it responds with error code 501 not understand the request, it responds with error code 501
(Not Implemented) and the sender should not attempt to use (Not Implemented) and the sender should not attempt to use
this method again. A client may also use the OPTIONS method this method again. A client may also use the OPTIONS method
to inquire about methods supported by the server. The server to inquire about methods supported by the server. The server
SHOULD list the methods it supports using the Public response SHOULD list the methods it supports using the Public response
header. header.
o A new version of the protocol can be defined, allowing almost o A new version of the protocol can be defined, allowing almost
all aspects (except the position of the protocol version all aspects (except the position of the protocol version
number) to change. number) to change.
The basic capability discovery mechanism can be used to both discover The basic capability discovery mechanism can be used to both discover
support for a certain feature and to ensure that a feature is support for a certain feature and to ensure that a feature is
available when performing a request. For detailed explanation of this available when performing a request. For detailed explanation of this
see chapter 10. see chapter 10.
1.7 Overall Operation 1.7 Overall Operation
Each presentation and media stream may be identified by a RTSP URL. Each presentation and media stream is identified by an RTSP URL. The
The overall presentation and the properties of the media the overall presentation and the properties of the media the presentation
presentation is made up of are defined by a presentation description is made up of are defined by a presentation description file, the
file, the format of which is outside the scope of this specification. format of which is outside the scope of this specification. The
The presentation description file may be obtained by the client using presentation description file may be obtained by the client using
HTTP or other means such as email and may not necessarily be stored HTTP or other means such as email and may not necessarily be stored
on the media server. on the media server.
For the purposes of this specification, a presentation description is For the purposes of this specification, a presentation description is
assumed to describe one or more presentations, each of which assumed to describe one or more presentations, each of which
maintains a common time axis. For simplicity of exposition and maintains a common time axis. For simplicity of exposition and
without loss of generality, it is assumed that the presentation without loss of generality, it is assumed that the presentation
description contains exactly one such presentation. A presentation description contains exactly one such presentation. A presentation
may contain several media streams. may contain several media streams.
skipping to change at page 12, line 25 skipping to change at page 19, line 15
REDIRECT: Indicates that the session should be moved to new REDIRECT: Indicates that the session should be moved to new
server / location server / location
PING: Prevents the identified session from being timed out. PING: Prevents the identified session from being timed out.
TEARDOWN: Frees resources associated with the stream. The RTSP TEARDOWN: Frees resources associated with the stream. The RTSP
session ceases to exist on the server. session ceases to exist on the server.
RTSP methods that contribute to state use the Session header field RTSP methods that contribute to state use the Session header field
(Section 13.37) to identify the RTSP session whose state is being (Section 14.37) to identify the RTSP session whose state is being
manipulated. The server generates session identifiers in response to manipulated. The server generates session identifiers in response to
SETUP requests (Section 11.3). SETUP requests (Section 11.3).
1.9 Relationship with Other Protocols 1.9 Relationship with Other Protocols
RTSP has some overlap in functionality with HTTP. It also may RTSP has some overlap in functionality with HTTP. It also may
interact with HTTP in that the initial contact with streaming content interact with HTTP in that the initial contact with streaming content
is often to be made through a web page. The current protocol is often to be made through a web page. The current protocol
specification aims to allow different hand-off points between a web specification aims to allow different hand-off points between a web
server and the media server implementing RTSP. For example, the server and the media server implementing RTSP. For example, the
skipping to change at page 13, line 8 skipping to change at page 19, line 45
been acknowledged. been acknowledged.
Re-using HTTP functionality has advantages in at least two Re-using HTTP functionality has advantages in at least two
areas, namely security and proxies. The requirements are areas, namely security and proxies. The requirements are
very similar, so having the ability to adopt HTTP work on very similar, so having the ability to adopt HTTP work on
caches, proxies and authentication is valuable. caches, proxies and authentication is valuable.
RTSP assumes the existence of a presentation description format that RTSP assumes the existence of a presentation description format that
can express both static and temporal properties of a presentation can express both static and temporal properties of a presentation
containing several media streams. Session Description Protocol (SDP) containing several media streams. Session Description Protocol (SDP)
[24] is generally the format of choice; however, RTSP is not bound to [2] is generally the format of choice; however, RTSP is not bound to
it. For data delivery, most real-time media will use RTP as a it. For data delivery, most real-time media will use RTP as a
transport protocol. While RTSP works well with RTP, it is not tied to transport protocol. While RTSP works well with RTP, it is not tied to
RTP. RTP.
2 Notational Conventions 2 RTSP Use Cases
This section describes some of the use cases RTSP can be used for. |
They are listed in descending order of importance in regards to |
ensuring that all necessary functionality is present. |
Since many of the definitions and syntax are identical to HTTP/1.1, TODO: Fill this headings with descriptions of the use cases. |
this specification only points to the section where they are defined
rather than copying it. For brevity, [HX.Y] is to be taken to refer
to Section X.Y of the current HTTP/1.1 specification (RFC 2616 [26]).
All the mechanisms specified in this document are described in both 2.1 On-demand Playback of Stored Content |
prose and an augmented Backus-Naur form (BNF) similar to that used in
[H2.1]. It is described in detail in RFC 2234 [14], with the
difference that this RTSP specification maintains the "#" notation
for comma-separated lists from [H2.1].
In this draft, we use indented and smaller-type paragraphs to provide 2.2 Unicast distribution of Live Content |
background and motivation. This is intended to give readers who were
not involved with the formulation of the specification an 2.3 Inviting RTSP on-demand servers into a multicast group |
understanding of why things are the way that they are in RTSP.
2.4 On-demand Playback using Multicast |
3 Protocol Parameters 3 Protocol Parameters
3.1 RTSP Version 3.1 RTSP Version
HTTP Specification Section [H3.1] applies, with HTTP replaced by HTTP Specification Section [H3.1] applies, with HTTP replaced by
RTSP. This specification defines version 1.0 of RTSP. RTSP. This specification defines version 1.0 of RTSP.
3.2 RTSP URL 3.2 RTSP URL
The "rtsp", "rtsps" and "rtspu" schemes are used to refer to network The "rtsp", "rtsps" and "rtspu" schemes are used to refer to network
resources via the RTSP protocol. This section defines the scheme- resources via the RTSP protocol. This section defines the scheme-
specific syntax and semantics for RTSP URLs. The RTSP URL is case specific syntax and semantics for RTSP URLs. The RTSP URL is case
sensitive. sensitive.
rtsp_URL = ( "rtsp:" / "rtspu:" / "rtsps:" ) Informative RTSP URL syntax:
"//" host [ ":" port ] [ abs_path [ "?" query ]]
host = As defined by RFC 2732 [30] rtsp[u|s]://host[:port]/abspath[?query]#fragment
abs_path = As defined by RFC 2396 [22]
port = *DIGIT See section 17.2.1 for the formal definition of the RTSP URL syntax.
query = As defined by RFC 2396 [22]
Note that fragment and query identifiers do not have a Note that fragment and query identifiers do not have a
well-defined meaning at this time, with the interpretation well-defined meaning at this time, i.e. their usage is
left to the RTSP server. unspecified, with the interpretation left to the RTSP
server.
The scheme rtsp requires that commands are issued via a reliable The URL scheme rtsp requires that commands are issued via a reliable
protocol (within the Internet, TCP), while the scheme rtspu protocol (within the Internet, TCP), while the scheme rtspu is
identifies an unreliable protocol (within the Internet, UDP). The intended to identify RTSP over an unreliable protocol (within the
scheme rtsps identifies a reliable transport using secure transport, Internet, UDP). The scheme rtsps is intended to identify a reliable
perhaps TLS [27]. The rtspu and rtsps is not defined in this transport using secure transport, perhaps TLS [26]. The rtspu and
specification, and are for future extensions of the protocol to rtsps is not defined in this specification, and are for future
define. extensions of the protocol to define how to use.
If the port is empty or not given, port 554 SHALL be assumed. The If the port is empty or not given, port 554 SHALL be assumed. The |
semantics are that the identified resource can be controlled by RTSP semantics are that the identified resource can be controlled by RTSP |
at the server listening for TCP (scheme "rtsp") connections or UDP at the server listening for TCP (scheme "rtsp") connections or UDP |
(scheme "rtspu") packets on that port of host, and the Request-URI (scheme "rtspu") packets on that port of host, and the Request-URL |
for the resource is rtsp_URL. for the resource is rtsp_URL. For the scheme rtsps the TCP and UDP |
port 322 is registered and SHALL be assumed.
The use of IP addresses in URLs SHOULD be avoided whenever possible The use of IP addresses in URLs SHOULD be avoided whenever possible
(see RFC 1924 [16]). Note: Using qualified domain names in any URL is (see RFC 1924 [10]). Note: Using qualified domain names in any URL is
one requirement for making it possible for RFC 2326 implementations one requirement for making it possible for RFC 2326 implementations
of RTSP to use IPv6. This specification is updated to allow for of RTSP to use IPv6. This specification is updated to allow for
literal IPv6 addresses in RTSP URLs using the host specification in literal IPv6 addresses in RTSP URLs using the host specification in
RFC 2732 [30]. RFC 2732 [11].
A presentation or a stream is identified by a textual media A presentation or a stream is identified by a textual media
identifier, using the character set and escape conventions [H3.2] of identifier, using the character set and escape conventions [H3.2] of
URLs (RFC 2396 [22]). URLs may refer to a stream or an aggregate of URLs (RFC 2396 [12]). URLs may refer to a stream or an aggregate of
streams, i.e., a presentation. Accordingly, requests described in streams, i.e., a presentation. Accordingly, requests described in
Section 11 can apply to either the whole presentation or an Section 11 can apply to either the whole presentation or an
individual stream within the presentation. Note that some request individual stream within the presentation. Note that some request
methods can only be applied to streams, not presentations and vice methods can only be applied to streams, not presentations and vice
versa. versa.
For example, the RTSP URL: For example, the RTSP URL:
rtsp://media.example.com:554/twister/audiotrack rtsp://media.example.com:554/twister/audiotrack
skipping to change at page 15, line 24 skipping to change at page 22, line 16
not imply any particular file system structure for the server. not imply any particular file system structure for the server.
This decoupling also allows presentation descriptions to be This decoupling also allows presentation descriptions to be
used with non-RTSP media control protocols simply by used with non-RTSP media control protocols simply by
replacing the scheme in the URL. replacing the scheme in the URL.
3.3 Session Identifiers 3.3 Session Identifiers
Session identifiers are strings of any arbitrary length. A session Session identifiers are strings of any arbitrary length. A session
identifier MUST be chosen randomly and MUST be at least eight identifier MUST be chosen randomly and MUST be at least eight
characters long to make guessing it more difficult. (See Section 17.) characters long to make guessing it more difficult. (See Section 18.)
session-id = 8*( ALPHA / DIGIT / safe )
3.4 SMPTE Relative Timestamps 3.4 SMPTE Relative Timestamps
A SMPTE relative timestamp expresses time relative to the start of A SMPTE relative timestamp expresses time relative to the start of
the clip. Relative timestamps are expressed as SMPTE time codes for the clip. Relative timestamps are expressed as SMPTE time codes for
frame-level access accuracy. The time code has the format frame-level access accuracy. The time code has the format
hours:minutes:seconds:frames.subframes, hours:minutes:seconds:frames.subframes,
with the origin at the start of the clip. The default smpte format with the origin at the start of the clip. The default smpte format
is"SMPTE 30 drop" format, with frame rate is 29.97 frames per second. is"SMPTE 30 drop" format, with frame rate is 29.97 frames per second.
Other SMPTE codes MAY be supported (such as "SMPTE 25") through the Other SMPTE codes MAY be supported (such as "SMPTE 25") through the
use of alternative use of "smpte time". For the "frames" field in the use of alternative use of "smpte time". For the "frames" field in the
time value can assume the values 0 through 29. The difference between time value can assume the values 0 through 29. The difference between
30 and 29.97 frames per second is handled by dropping the first two 30 and 29.97 frames per second is handled by dropping the first two
frame indices (values 00 and 01) of every minute, except every tenth frame indices (values 00 and 01) of every minute, except every tenth
minute. If the frame value is zero, it may be omitted. Subframes are minute. If the frame value is zero, it may be omitted. Subframes are
measured in one-hundredth of a frame. measured in one-hundredth of a frame.
smpte-range = smpte-type "=" smpte-range-spec
smpte-range-spec = ( smpte-time "-" [ smpte-time ] )
/ ( "-" smpte-time )
smpte-type = "smpte" / "smpte-30-drop" / "smpte-25"
; other timecodes may be added
smpte-time = 1*2DIGIT ":" 1*2DIGIT ":" 1*2DIGIT
[ ":" 1*2DIGIT [ "." 1*2DIGIT ] ]
Examples: Examples:
smpte=10:12:33:20- smpte=10:12:33:20-
smpte=10:07:33- smpte=10:07:33-
smpte=10:07:00-10:07:33:05.01 smpte=10:07:00-10:07:33:05.01
smpte-25=10:07:00-10:07:33:05.01 smpte-25=10:07:00-10:07:33:05.01
3.5 Normal Play Time 3.5 Normal Play Time
Normal play time (NPT) indicates the stream absolute position Normal play time (NPT) indicates the stream absolute position
relative to the beginning of the presentation, not to be confused relative to the beginning of the presentation, not to be confused
with the Network Time Protocol (NTP). The timestamp consists of a with the Network Time Protocol (NTP). The timestamp consists of a
decimal fraction. The part left of the decimal may be expressed in decimal fraction. The part left of the decimal may be expressed in
either seconds or hours, minutes, and seconds. The part right of the either seconds or hours, minutes, and seconds. The part right of the
decimal point measures fractions of a second. decimal point measures fractions of a second.
The beginning of a presentation corresponds to 0.0 seconds. Negative The beginning of a presentation corresponds to 0.0 seconds. Negative
values are not defined. The special constant now is defined as the values are not defined. The special constant now is defined as the
current instant of a live event. It MAY only be used for live events, current instant of a live type event. It MAY only be used for live
and SHALL NOT be used for on-demand content. type events, and SHALL NOT be used for on-demand content.
NPT is defined as in DSM-CC: "Intuitively, NPT is the clock the NPT is defined as in DSM-CC: "Intuitively, NPT is the clock the
viewer associates with a program. It is often digitally displayed on viewer associates with a program. It is often digitally displayed on
a VCR. NPT advances normally when in normal play mode (scale = 1), a VCR. NPT advances normally when in normal play mode (scale = 1),
advances at a faster rate when in fast scan forward (high positive advances at a faster rate when in fast scan forward (high positive
scale ratio), decrements when in scan reverse (high negative scale scale ratio), decrements when in scan reverse (high negative scale
ratio) and is fixed in pause mode. NPT is (logically) equivalent to ratio) and is fixed in pause mode. NPT is (logically) equivalent to
SMPTE time codes." [5] SMPTE time codes." [25]
npt-range = ["npt" "="] npt-range-spec
; implementations SHOULD use npt= prefix, but SHOULD
; be prepared to interoperate with RFC 2326
; implementations which don't use it
npt-range-spec = ( npt-time "-" [ npt-time ] ) / ( "-" npt-time )
npt-time = "now" / npt-sec / npt-hhmmss
npt-sec = 1*DIGIT [ "." *DIGIT ]
npt-hhmmss = npt-hh ":" npt-mm ":" npt-ss [ "." *DIGIT ]
npt-hh = 1*DIGIT ; any positive number
npt-mm = 1*2DIGIT ; 0-59
npt-ss = 1*2DIGIT ; 0-59
Examples: Examples:
npt=123.45-125 npt=123.45-125
npt=12:05:35.3- npt=12:05:35.3-
npt=now- npt=now-
The syntax conforms to ISO 8601. The npt-sec notation is The syntax conforms to ISO 8601. The npt-sec notation is
optimized for automatic generation, the ntp-hhmmss notation optimized for automatic generation, the ntp-hhmmss notation
for consumption by human readers. The "now" constant allows for consumption by human readers. The "now" constant allows
clients to request to receive the live feed rather than the clients to request to receive the live feed rather than the
stored or time-delayed version. This is needed since stored or time-delayed version. This is needed since
neither absolute time nor zero time are appropriate for neither absolute time nor zero time are appropriate for
this case. this case.
3.6 Absolute Time 3.6 Absolute Time
Absolute time is expressed as ISO 8601 timestamps, using UTC (GMT). Absolute time is expressed as ISO 8601 timestamps, using UTC (GMT).
Fractions of a second may be indicated. Fractions of a second may be indicated.
utc-range = "clock" "=" utc-range-spec
utc-range-spec = ( utc-time "-" [ utc-time ] ) / ( "-" utc-time )
utc-time = utc-date "T" utc-time "Z"
utc-date = 8DIGIT ; < YYYYMMDD >
utc-time = 6DIGIT [ "." fraction ] ; < HHMMSS.fraction >
fraction = 1*DIGIT
Example for November 8, 1996 at 14h37 and 20 and a quarter seconds Example for November 8, 1996 at 14h37 and 20 and a quarter seconds
UTC: UTC:
19961108T143720.25Z 19961108T143720.25Z
3.7 Feature-tags 3.7 Feature-tags
Feature-tags are unique identifiers used to designate features in Feature-tags are unique identifiers used to designate features in
RTSP. These tags are used in Require (Section 13.32), Proxy-Require RTSP. These tags are used in Require (Section 14.32), Proxy-Require
(Section 13.27), Unsupported (Section 13.41), and Supported (Section (Section 14.27), Unsupported (Section 14.41), and Supported (Section
13.38) header fields. 14.38) header fields.
Syntax:
feature-tag = token
Feature tag needs to indicate if they apply to servers only, proxies | Feature tag needs to indicate if they apply to servers only, proxies
only, or both server and proxies. only, or both server and proxies.
The creator of a new RTSP feature-tag should either prefix the The creator of a new RTSP feature-tag should either prefix the |
feature-tag with a reverse domain name (e.g., "com.foo.mynewfeature" feature-tag with a reverse domain name (e.g., |
is an apt name for a feature whose inventor can be reached at "com.example.mynewfeature" is an apt name for a feature whose |
"foo.com"), or register the new feature-tag with the Internet inventor can be reached at "example.com"), or register the new |
Assigned Numbers Authority (IANA), see IANA Section 18. feature-tag with the Internet Assigned Numbers Authority (IANA), see |
IANA Section 19.
4 RTSP Message 4 RTSP Message
RTSP is a text-based protocol and uses the ISO 10646 character set in RTSP is a text-based protocol and uses the ISO 10646 character set in
UTF-8 encoding (RFC 2279 [18]). Lines are terminated by CRLF, but UTF-8 encoding (RFC 2279 [13]). Lines are terminated by CRLF, but
receivers should be prepared to also interpret CR and LF by receivers should be prepared to also interpret CR and LF by
themselves as line terminators. themselves as line terminators.
Text-based protocols make it easier to add optional Text-based protocols make it easier to add optional
parameters in a self-describing manner. Since the number of parameters in a self-describing manner. Since the number of
parameters and the frequency of commands is low, processing parameters and the frequency of commands is low, processing
efficiency is not a concern. Text-based protocols, if done efficiency is not a concern. Text-based protocols, if done
carefully, also allow easy implementation of research carefully, also allow easy implementation of research
prototypes in scripting languages such as Tcl, Visual Basic prototypes in scripting languages such as Tcl, Visual Basic
and Perl. and Perl.
The 10646 character set avoids tricky character set switching, but is The 10646 character set avoids tricky character set switching, but is
invisible to the application as long as US-ASCII is being used. This invisible to the application as long as US-ASCII is being used. This
is also the encoding used for RTCP. ISO 8859-1 translates directly is also the encoding used for RTCP. ISO 8859-1 translates directly
into Unicode with a high-order octet of zero. ISO 8859-1 characters into Unicode with a high-order octet of zero. ISO 8859-1 characters
with the most-significant bit set are represented as 1100001x with the most-significant bit set are represented as 1100001x
10xxxxxx. (See RFC 2279 [18]) 10xxxxxx. (See RFC 2279 [13])
RTSP messages can be carried over any lower-layer transport protocol RTSP messages can be carried over any lower-layer transport protocol
that is 8-bit clean. RTSP messages are vulnerable to bit errors and that is 8-bit clean. RTSP messages are vulnerable to bit errors and
SHOULD NOT be subjected to them. SHOULD NOT be subjected to them.
Requests contain methods, the object the method is operating upon and Requests contain methods, the object the method is operating upon and
parameters to further describe the method. Methods are idempotent, parameters to further describe the method. Methods are idempotent,
unless otherwise noted. Methods are also designed to require little unless otherwise noted. Methods are also designed to require little
or no state maintenance at the media server. or no state maintenance at the media server.
skipping to change at page 19, line 28 skipping to change at page 25, line 21
When a message body is included with a message, the length of that When a message body is included with a message, the length of that
body is determined by one of the following (in order of precedence): body is determined by one of the following (in order of precedence):
1. Any response message which MUST NOT include a message body 1. Any response message which MUST NOT include a message body
(such as the 1xx, 204, and 304 responses) is always (such as the 1xx, 204, and 304 responses) is always
terminated by the first empty line after the header fields, terminated by the first empty line after the header fields,
regardless of the entity-header fields present in the regardless of the entity-header fields present in the
message. (Note: An empty line consists of only CRLF.) message. (Note: An empty line consists of only CRLF.)
2. If a Content-Length header field (section 13.14) is 2. If a Content-Length header field (section 14.14) is
present, its value in bytes represents the length of the present, its value in bytes represents the length of the
message-body. If this header field is not present, a value message-body. If this header field is not present, a value
of zero is assumed. of zero is assumed.
Note that RTSP does not (at present) support the HTTP/1.1 "chunked" Note that RTSP does not (at present) support the HTTP/1.1 "chunked"
transfer coding(see [H3.6.1]) and requires the presence of the transfer coding(see [H3.6.1]) and requires the presence of the
Content-Length header field. Content-Length header field.
Given the moderate length of presentation descriptions Given the moderate length of presentation descriptions
returned, the server should always be able to determine its returned, the server should always be able to determine its
length, even if it is generated dynamically, making the length, even if it is generated dynamically, making the
chunked transfer encoding unnecessary. chunked transfer encoding unnecessary.
5 General Header Fields 5 General Header Fields
See [H4.5], except that Pragma, Trailer, Transfer-Encoding, Upgrade, See [H4.5], except that Pragma, Trailer, Transfer-Encoding, Upgrade,
and Warning headers are not defined. RTSP further defines the CSeq, and Warning headers are not defined. RTSP further defines the CSeq,
and Timestamp: and Timestamp. The general headers are listed in table 1:
general-header = Cache-Control ; Section 13.9
/ Connection ; Section 13.10
/ CSeq ; Section 13.17
/ Date ; Section 13.18
/ Timestamp ; Section 13.39
/ Via ; Section 13.44
6 Request 6 Request
A request message from a client to a server or vice versa includes, A request message from a client to a server or vice versa includes, |
within the first line of that message, the method to be applied to within the first line (Request Line) of that message, the method to |
the resource, the identifier of the resource, and the protocol be applied to the resource, the identifier of the resource, and the |
version in use. protocol version in use. Then follows zero or more headers that can |
be of general (Section 5), request (Section 6.2), or entity (Section |
8.1) type. Then an empty line, i.e. a line with only the two |
characters Carriage Return (CR) and Line Feed (LF), indicates the end |
Header Name Comment
_________________________________
Cache-Control See section 14.9
Connection See section 14.10
CSeq See section 14.17
Date See section 14.18
Supported See section 14.38
Timestamp See section 14.39
Via See section 14.44
Request = Request-Line ; Section 6.1 Table 1: The General headers used in RTSP.
*( general-header ; Section 5
/ request-header ; Section 6.2
/ entity-header ) ; Section 8.1
CRLF
[ message-body ] ; Section 4.3
6.1 Request Line of the header part. Optionally a message body (entity) follows to the |
end of the message. The length of the message body is indicated |
through the entity headers. |
Request-Line = Method SP Request-URI SP RTSP-Version CRLF 6.1 Request Line |
Method = "DESCRIBE" ; Section 11.2 The request line, provides the most important things about the |
/ "GET_PARAMETER" ; Section 11.7 request: What method, on what resources and using which RTSP version. |
/ "OPTIONS" ; Section 11.1 The methods that is defined by this specification can be seen in |
/ "PAUSE" ; Section 11.5 Table 6.1. The resource is identified through an absolute RTSP URL |
/ "PLAY" ; Section 11.4 (see section 3.2.
/ "PING" ; Section 11.10
/ "REDIRECT" ; Section 11.9
/ "SETUP" ; Section 11.3
/ "SET_PARAMETER" ; Section 11.8
/ "TEARDOWN" ; Section 11.6
/ extension-method
extension-method = token <Method> SP <Request-URL> SP <RTSP-Version> CRLF
Request-URI = "*" / absolute_URI
RTSP-Version = "RTSP" "/" 1*DIGIT "." 1*DIGIT
6.2 Request Header Fields Please note: The request line's syntax can't be changed in future
request-header = Accept ; Section 13.1 versions of RTSP, as this line indicates the version of the messages
/ Accept-Encoding ; Section 13.2 and need to be parsable also by older versions.
/ Accept-Language ; Section 13.3
/ Authorization ; Section 13.6
/ Bandwidth ; Section 13.7
/ Blocksize ; Section 13.8
/ From ; Section 13.20
/ If-Modified-Since ; Section 13.23
/ Proxy-Require ; Section 13.27
/ Range ; Section 13.29
/ Referer ; Section 13.30
/ Require ; Section 13.32
/ Scale ; Section 13.34
/ Session ; Section 13.37
/ Speed ; Section 13.35
/ Supported ; Section 13.38
/ Transport ; Section 13.40
/ User-Agent ; Section 13.42
Note that in contrast to HTTP/1.1 [26], RTSP requests always contain Note that in contrast to HTTP/1.1 [4], RTSP requests always contain
the absolute URL (that is, including the scheme, host and port) the absolute URL (that is, including the scheme, host and port)
rather than just the absolute path. rather than just the absolute path.
HTTP/1.1 requires servers to understand the absolute URL, HTTP/1.1 requires servers to understand the absolute URL,
but clients are supposed to use the Host request header. but clients are supposed to use the Host request header.
This is purely needed for backward-compatibility with This is purely needed for backward-compatibility with
HTTP/1.0 servers, a consideration that does not apply to HTTP/1.0 servers, a consideration that does not apply to
RTSP. RTSP.
The asterisk "*" in the Request-URI means that the request does not The asterisk "*" in the Request-URL means that the request does not
apply to a particular resource, but to the server or proxy itself, apply to a particular resource, but to the server or proxy itself,
and is only allowed when the method used does not necessarily apply and is only allowed when the method used does not necessarily apply
Method Defined In Section
_________________________________
DESCRIBE Section 11.2
GET_PARAMETER Section 11.7
OPTIONS Section 11.1
PAUSE Section 11.5
PLAY Section 11.4
PING Section 11.10
REDIRECT Section 11.9
SETUP Section 11.3
SET_PARAMETER Section 11.8
TEARDOWN Section 11.6
Table 2: The RTSP Methods
to a resource. to a resource.
One example would be as follows: One example would be as follows:
OPTIONS * RTSP/1.0 OPTIONS * RTSP/1.0
An OPTIONS in this form will determine the capabilities of the server An OPTIONS in this form will determine the capabilities of the server
or the proxy that first receives the request. If one needs to address or the proxy that first receives the request. If one needs to address
the server explicitly, then one should use an absolute URL with the the server explicitly, then one should use an absolute URL with the
server's address. server's address.
OPTIONS rtsp://example.com RTSP/1.0 OPTIONS rtsp://example.com RTSP/1.0
7 Response 6.2 Request Header Fields
[H6] applies except that HTTP-Version is replaced by RTSP-Version. The RTSP headers in Table 6.2 can be included in a request with the
Also, RTSP defines additional status codes and does not define some purpose to give further define how the request should be fulfilled. A
HTTP codes. The valid response codes and the methods they can be used request header MAY also be response header, see section 7.1.2.
with are defined in Table 1.
After receiving and interpreting a request message, the recipient 7 Response
responds with an RTSP response message.
Response = Status-Line ; Section 7.1 [H6] applies except that HTTP-Version is replaced by RTSP-Version. |
*( general-header ; Section 5 Also, RTSP defines additional status codes and does not define some |
/ response-header ; Section 7.1.2 Header Defined in Section
/ entity-header ) ; Section 8.1 _____________________________________
CRLF Accept Section 14.1
[ message-body ] ; Section 4.3 Accept-Encoding Section 14.2
Accept-Language Section 14.3
Authorization Section 14.6
Bandwidth Section 14.7
Blocksize Section 14.8
From Section 14.20
If-Match Section 14.22
If-Modified-Since Section 14.23
Proxy-Require Section 14.27
Range Section 14.29
Referer Section 14.30
Require Section 14.32
Scale Section 14.34
Session Section 14.37
Speed Section 14.35
Supported Section 14.38
Transport Section 14.40
User-Agent Section 14.42
7.1 Status-Line Table 3: The RTSP request headers
The first line of a Response message is the Status-Line, consisting HTTP codes. The valid response codes and the methods they can be used |
of the protocol version followed by a numeric status code, and the with are defined in Table 4. |
textual phrase associated with the status code, with each element
separated by SP characters. No CR or LF is allowed except in the
final CRLF sequence.
Status-Line = RTSP-Version SP Status-Code SP Reason-Phrase CRLF After receiving and interpreting a request message, the recipient |
responds with an RTSP response message. |
7.1.1 Status Code and Reason Phrase 7.1 Status-Line |
The Status-Code element is a 3-digit integer result code of the The first line of a Response message is the Status-Line, consisting |
attempt to understand and satisfy the request. These codes are fully of the protocol version followed by a numeric status code, and the |
defined in Section 12. The Reason-Phrase is intended to give a short textual phrase associated with the status code, with each element |
textual description of the Status-Code. The Status-Code is intended separated by SP characters. No CR or LF is allowed except in the |
for use by automata and the Reason-Phrase is intended for the human final CRLF sequence. |
user. The client is not required to examine or display the Reason-
Phrase.
The first digit of the Status-Code defines the class of response. The <RTSP-Version> SP <Status-Code> SP <Reason-Phrase> CRLF |
last two digits do not have any categorization role. There are 5
values for the first digit:
o 1xx: Informational - Request received, continuing process 7.1.1 Status Code and Reason Phrase |
o 2xx: Success - The action was successfully received, The Status-Code element is a 3-digit integer result code of the |
understood, and accepted attempt to understand and satisfy the request. These codes are fully |
defined in Section 13. The Reason-Phrase is intended to give a short |
textual description of the Status-Code. The Status-Code is intended |
for use by automata and the Reason-Phrase is intended for the human |
user. The client is not required to examine or display the Reason- |
Phrase. |
o 3rr: Redirection - Further action must be taken in order to The first digit of the Status-Code defines the class of response. The |
complete the request last two digits do not have any categorization role. There are 5 |
values for the first digit: |
o 4xx: Client Error - The request contains bad syntax or cannot o 1xx: Informational - Request received, continuing process |
be fulfilled
o 5xx: Server Error - The server failed to fulfill an apparently o 2xx: Success - The action was successfully received, |
valid request understood, and accepted |
The individual values of the numeric status codes defined for o 3rr: Redirection - Further action must be taken in order to |
RTSP/1.0, and an example set of corresponding Reason-Phrase's, are complete the request |
presented below. The reason phrases listed here are only recommended
-- they may be replaced by local equivalents without affecting the
protocol. Note that RTSP adopts most HTTP/1.1 [26] status codes and
adds RTSP-specific status codes starting at x50 to avoid conflicts
with newly defined HTTP status codes.
Status-Code = "100" ; Continue o 4xx: Client Error - The request contains bad syntax or cannot |
/ "200" ; OK be fulfilled |
/ "201" ; Created
/ "250" ; Low on Storage Space
/ "300" ; Multiple Choices
/ "301" ; Moved Permanently
/ "302" ; Moved Temporarily
/ "303" ; See Other
/ "304" ; Not Modified
/ "305" ; Use Proxy
/ "350" ; Going Away
/ "351" ; Load Balancing
/ "400" ; Bad Request
/ "401" ; Unauthorized
/ "402" ; Payment Required
/ "403" ; Forbidden
/ "404" ; Not Found
/ "405" ; Method Not Allowed
/ "406" ; Not Acceptable
/ "407" ; Proxy Authentication Required
/ "408" ; Request Time-out
/ "410" ; Gone
/ "411" ; Length Required
/ "412" ; Precondition Failed
/ "413" ; Request Entity Too Large
/ "414" ; Request-URI Too Large
/ "415" ; Unsupported Media Type
/ "451" ; Parameter Not Understood
/ "452" ; reserved
/ "453" ; Not Enough Bandwidth
/ "454" ; Session Not Found
/ "455" ; Method Not Valid in This State
/ "456" ; Header Field Not Valid for Resource
/ "457" ; Invalid Range
/ "458" ; Parameter Is Read-Only
/ "459" ; Aggregate operation not allowed
/ "460" ; Only aggregate operation allowed
/ "461" ; Unsupported transport
/ "462" ; Destination unreachable
/ "500" ; Internal Server Error o 5xx: Server Error - The server failed to fulfill an apparently |
/ "501" ; Not Implemented valid request |
/ "502" ; Bad Gateway
/ "503" ; Service Unavailable
/ "504" ; Gateway Time-out
/ "505" ; RTSP Version not supported
/ "551" ; Option not supported
/ extension-code
extension-code = 3DIGIT
Reason-Phrase = *<TEXT, excluding CR, LF>
RTSP status codes are extensible. RTSP applications are not required The individual values of the numeric status codes defined for |
to understand the meaning of all registered status codes, though such RTSP/1.0, and an example set of corresponding Reason-Phrase's, are |
understanding is obviously desirable. However, applications MUST presented in table 4. The reason phrases listed here are only |
understand the class of any status code, as indicated by the first recommended they may be replaced by local equivalents without |
digit, and treat any unrecognized response as being equivalent to the affecting the protocol. Note that RTSP adopts most HTTP/1.1 [4] |
x00 status code of that class, with the exception that an status codes and adds RTSP-specific status codes starting at x50 to |
unrecognized response MUST NOT be cached. For example, if an avoid conflicts with newly defined HTTP status codes. |
unrecognized status code of 431 is received by the client, it can
safely assume that there was something wrong with its request and
treat the response as if it had received a 400 status code. In such
cases, user agents SHOULD present to the user the entity returned
with the response, since that entity is likely to include human-
readable information which will explain the unusual status.
7.1.2 Response Header Fields RTSP status codes are extensible. RTSP applications are not required |
to understand the meaning of all registered status codes, though such |
understanding is obviously desirable. However, applications MUST |
understand the class of any status code, as indicated by the first |
digit, and treat any unrecognized response as being equivalent to the |
x00 status code of that class, with the exception that an |
unrecognized response MUST NOT be cached. For example, if an |
unrecognized status code of 431 is received by the client, it can |
safely assume that there was something wrong with its request and |
treat the response as if it had received a 400 status code. In such |
cases, user agents SHOULD present to the user the entity returned |
with the response, since that entity is likely to include human- |
readable information which will explain the unusual status. |
The response-header fields allow the request recipient to pass 7.1.2 Response Header Fields |
additional information about the response which cannot be placed in The response-header fields allow the request recipient to pass |
the Status-Line. These header fields give information about the additional information about the response which cannot be placed in |
server and about further access to the resource identified by the the Status-Line. These header fields give information about the |
Request-URI. server and about further access to the resource identified by the |
Request-URL. All headers currently being classified as response |
headers are listed in table 7.1.2.
response-header = Accept-Ranges ; Section Header Defined in Section
13.4 ______________________________________
/ Location ; Section 13.25 Accept-Ranges Section 14.4
/ Proxy-Authenticate ; Section 13.26 Location Section 14.25
/ Public ; Section 13.28 Proxy-Authenticate Section 14.26
/ Range ; Section 13.29 Public Section 14.28
/ Retry-After ; Section 13.31 Range Section 14.29
/ RTP-Info ; Section 13.33 Retry-After Section 14.31
/ Scale ; Section 13.34 RTP-Info Section 14.33
/ Session ; Section 13.37 Scale Section 14.34
/ Server ; Section 13.36 Session Section 14.37
/ Speed ; Section 13.35 Server Section 14.36
/ Transport ; Section 13.40 Speed Section 14.35
/ Unsupported ; Section 13.41 Transport Section 14.40
/ Vary ; Section 13.43 Unsupported Section 14.41
/ WWW-Authenticate ; Section 13.45 Vary Section 14.43
WWW-Authenticate Section 14.45
Table 5: The RTSP response headers
Response-header field names can be extended reliably only in Response-header field names can be extended reliably only in
combination with a change in the protocol version. However, new or combination with a change in the protocol version. However, new or
experimental header fields MAY be given the semantics of response- experimental header fields MAY be given the semantics of response-
header fields if all parties in the communication recognize them to header fields if all parties in the communication recognize them to
be response-header fields. Unrecognized header fields are treated as be response-header fields. Unrecognized header fields are treated as
entity-header fields. entity-header fields.
8 Entity 8 Entity
Request and Response messages MAY transfer an entity if not otherwise Request and Response messages MAY transfer an entity if not otherwise |
restricted by the request method or response status code. An entity restricted by the request method or response status code. An entity |
consists of entity-header fields and an entity-body, although some consists of entity-header fields and an entity-body, although some |
responses will only include the entity-headers. responses will only include the entity-headers. |
In this section, both sender and recipient refer to either the client
or the server, depending on who sends and who receives the entity.
8.1 Entity Header Fields
Entity-header fields define optional meta-information about the
entity-body or, if no body is present, about the resource identified
by the request.
entity-header = Allow ; Section 13.5 The SET_PARAMETER, and GET_PARAMETER request and response, and |
DESCRIBE response MAY have an entity. All 4xx and 5xx responses MAY |
also have an entity. |
Code Reason Method Code Reason Method
_______________________________________________________ _______________________________________________________
100 Continue all 100 Continue all
_______________________________________________________ _______________________________________________________
200 OK all 200 OK all
201 Created RECORD 201 Created RECORD
250 Low on Storage Space RECORD 250 Low on Storage Space RECORD
_______________________________________________________ _______________________________________________________
300 Multiple Choices all 300 Multiple Choices all
skipping to change at page 26, line 35 skipping to change at page 31, line 35
403 Forbidden all 403 Forbidden all
404 Not Found all 404 Not Found all
405 Method Not Allowed all 405 Method Not Allowed all
406 Not Acceptable all 406 Not Acceptable all
407 Proxy Authentication Required all 407 Proxy Authentication Required all
408 Request Timeout all 408 Request Timeout all
410 Gone all 410 Gone all
411 Length Required all 411 Length Required all
412 Precondition Failed DESCRIBE, SETUP 412 Precondition Failed DESCRIBE, SETUP
413 Request Entity Too Large all 413 Request Entity Too Large all
414 Request-URI Too Long all 414 Request-URL Too Long all
415 Unsupported Media Type all 415 Unsupported Media Type all
451 Parameter Not Understood SET_PARAMETER 451 Parameter Not Understood SET_PARAMETER
452 reserved n/a 452 reserved n/a
453 Not Enough Bandwidth SETUP 453 Not Enough Bandwidth SETUP
454 Session Not Found all 454 Session Not Found all
455 Method Not Valid In This State all 455 Method Not Valid In This State all
456 Header Field Not Valid all 456 Header Field Not Valid all
457 Invalid Range PLAY, PAUSE 457 Invalid Range PLAY, PAUSE
458 Parameter Is Read-Only SET_PARAMETER 458 Parameter Is Read-Only SET_PARAMETER
459 Aggregate Operation Not Allowed all 459 Aggregate Operation Not Allowed all
460 Only Aggregate Operation Allowed all 460 Only Aggregate Operation Allowed all
461 Unsupported Transport all 461 Unsupported Transport all
462 Destination Unreachable all 462 Destination Unreachable all
_______________________________________________________ _______________________________________________________
500 Internal Server Error all 500 Internal Server Error all
501 Not Implemented all 501 Not Implemented all
502 Bad Gateway all 502 Bad Gateway all
503 Service Unavailable all 503 Service Unavailable all
504 Gateway Timeout all 504 Gateway Timeout all
505 RTSP Version Not Supported all 505 RTSP Version Not Supported all
Table 1: Status codes and their usage with RTSP methods Table 4: Status codes and their usage with RTSP methods
/ Content-Base ; Section 13.11 In this section, both sender and recipient refer to either the client |
/ Content-Encoding ; Section 13.12 or the server, depending on who sends and who receives the entity. |
/ Content-Language ; Section 13.13
/ Content-Length ; Section 13.14
/ Content-Location ; Section 13.15
/ Content-Type ; Section 13.16
/ Expires ; Section 13.19
/ Last-Modified ; Section 13.24
/ extension-header
extension-header = message-header
The extension-header mechanism allows additional entity-header fields 8.1 Entity Header Fields |
to be defined without changing the protocol, but these fields cannot
be assumed to be recognizable by the recipient. Unrecognized header
fields SHOULD be ignored by the recipient and forwarded by proxies.
8.2 Entity Body Entity-header fields define optional meta-information about the |
entity-body or, if no body is present, about the resource identified |
by the request. The entity header fields are listed in table 8.1. |
See [H7.2] with the addition that a RTSP message with an entity body Header Defined in Section
MUST include a Content-Type header. ____________________________________
Allow Section 14.5
Content-Base Section 14.11
Content-Encoding Section 14.12
Content-Language Section 14.13
Content-Length Section 14.14
Content-Location Section 14.15
Content-Type Section 14.16
Expires Section 14.19
Last-Modified Section 14.24
Table 6: The RTSP entity headers
The extension-header mechanism allows additional entity-header fields |
to be defined without changing the protocol, but these fields cannot |
be assumed to be recognizable by the recipient. Unrecognized header |
fields SHOULD be ignored by the recipient and forwarded by proxies. |
8.2 Entity Body |
See [H7.2] with the addition that a RTSP message with an entity body |
MUST include the Content-Type and Content-Length headers. |
9 Connections 9 Connections
RTSP requests can be transmitted in several different ways: RTSP requests can be transmitted in several different ways:
o persistent transport connections used for several request- o persistent transport connections used for several request-
response transactions; response transactions;
o one connection per request/response transaction; o one connection per request/response transaction;
o connectionless mode. o connectionless mode.
The type of transport connection is defined by the RTSP URI (Section The type of transport is defined by the RTSP URL (Section 3.2). For |
3.2). For the scheme "rtsp", a connection is assumed, while the the scheme "rtsp", a connection is assumed, while the scheme "rtspu" |
scheme "rtspu" calls for RTSP requests to be sent without setting up calls for RTSP requests to be sent without setting up a connection.
a connection.
Unlike HTTP, RTSP allows the media server to send requests to the Unlike HTTP, RTSP allows the media server to send requests to the
media client. However, this is only supported for persistent media client. However, this is only supported for persistent
connections, as the media server otherwise has no reliable way of connections, as the media server otherwise has no reliable way of
reaching the client. Also, this is the only way that requests from reaching the client. Also, this is the only way that requests from
media server to client are likely to traverse firewalls. media server to client are likely to traverse firewalls.
9.1 Pipelining 9.1 Pipelining
A client that supports persistent connections or connectionless mode A client that supports persistent connections or connectionless mode
MAY "pipeline" its requests (i.e., send multiple requests without MAY "pipeline" its requests (i.e., send multiple requests without
waiting for each response). A server MUST send its responses to those waiting for each response). A server MUST send its responses to those
requests in the same order that the requests were received. requests in the same order that the requests were received.
9.2 Reliability and Acknowledgements | 9.2 Reliability and Acknowledgements
The transmission of RTSP over UDP was optionally to implement and | The transmission of RTSP over UDP was optionally to implement and
specified in RFC 2326. However that definition was not satisfactory | specified in RFC 2326. However that definition was not satisfactory
for interoperable implementations. Due to lack of interest, this | for interoperable implementations. Due to lack of interest, this
specification does not specify how RTSP over UDP shall be | specification does not specify how RTSP over UDP shall be
implemented. However to maintain backwards compatibility in the | implemented. However to maintain backwards compatibility in the
message format certain RTSP headers must be maintained. These | message format certain RTSP headers must be maintained. These
mechanism are described below. The next section Unreliable Transport | mechanism are described below. The next section Unreliable Transport
(section 9.3) provides documentation of certain features that are | (section 9.3) provides documentation of certain features that are
necessary for transport protocols like UDP. | necessary for transport protocols like UDP.
Any RTSP request according to this specification SHALL NOT be sent to | Any RTSP request according to this specification SHALL NOT be sent to
a multicast address. Any RTSP request SHALL be acknowledged. If a | a multicast address. Any RTSP request SHALL be acknowledged. If a
reliable transport protocol is used to carry RTSP, requests MUST NOT | reliable transport protocol is used to carry RTSP, requests MUST NOT
be retransmitted; the RTSP application MUST instead rely on the | be retransmitted; the RTSP application MUST instead rely on the
underlying transport to provide reliability. | underlying transport to provide reliability.
If both the underlying reliable transport such as TCP and | If both the underlying reliable transport such as TCP and
the RTSP application retransmit requests, it is possible | the RTSP application retransmit requests, it is possible
that each packet loss results in two retransmissions. The | that each packet loss results in two retransmissions. The
receiver cannot typically take advantage of the | receiver cannot typically take advantage of the
application-layer retransmission since the transport stack | application-layer retransmission since the transport stack
will not deliver the application-layer retransmission | will not deliver the application-layer retransmission
before the first attempt has reached the receiver. If the | before the first attempt has reached the receiver. If the
packet loss is caused by congestion, multiple | packet loss is caused by congestion, multiple
retransmissions at different layers will exacerbate the | retransmissions at different layers will exacerbate the
congestion. | congestion.
Each request carries a sequence number in the CSeq header (Section | Each request carries a sequence number in the CSeq header (Section
13.17), which MUST be incremented by one for each distinct request | 14.17), which MUST be incremented by one for each distinct request
transmitted to the destination end-point. The initial sequence | transmitted to the destination end-point. The initial sequence
number MAY be chosen arbitrary, but is RECOMMENDED to begin with 0. | number MAY be chosen arbitrary, but is RECOMMENDED to begin with 0.
If a request is repeated because of lack of acknowledgement, the | If a request is repeated because of lack of acknowledgement, the
request MUST carry the original sequence number (i.e., the sequence | request MUST carry the original sequence number (i.e., the sequence
number is not incremented). | number is not incremented).
9.3 Unreliable Transport | 9.3 Unreliable Transport
This section provides some information to future specification of | This section provides some information to future specification of
RTSP over unreliable transport. | RTSP over unreliable transport.
Requests are acknowledged by the receiver unless they are sent to a |
multicast group. If there is no acknowledgement, the sender may |
resend the same message after a timeout of one round-trip time (RTT). |
The round-trip time is estimated as in TCP (RFC 1123) [15], with an |
initial round-trip value of 500 ms. An implementation MAY cache the |
last RTT measurement as the initial value for future connections. |
If RTSP is used over a small-RTT LAN, standard procedures for | Requests shall be acknowledged by the receiver. If there is no |
optimizing initial TCP round trip estimates, such as those used in | acknowledgement, the sender may resend the same message after a |
T/TCP (RFC 1644) [19], can be beneficial. | timeout of one round-trip time (RTT). The round-trip time is |
estimated as in TCP (RFC 1123) [14], with an initial round-trip value |
of 500 ms. An implementation MAY cache the last RTT measurement as |
the initial value for future connections.
The Timestamp header (Section 13.39) is used to avoid the | If RTSP is used over a small-RTT LAN, standard procedures for
retransmission ambiguity problem [20] and obviates the need for | optimizing initial TCP round trip estimates, such as those used in
Karn's algorithm. | T/TCP (RFC 1644) [33], can be beneficial.
If a request is repeated because of lack of acknowledgement, the | The Timestamp header (Section 14.39) is used to avoid the
request must carry the original sequence number (i.e., the sequence | retransmission ambiguity problem [34] and obviates the need for
number is not incremented). | Karn's algorithm.
A number of RTSP packets destined for the same control end point may | If a request is repeated because of lack of acknowledgement, the
be packed into a single lower-layer PDU or encapsulated into a TCP | request must carry the original sequence number (i.e., the sequence
stream. RTSP data MAY be interleaved with RTP and RTCP packets. | number is not incremented).
A number of RTSP messages destined for the same control end point may |
be packed into a single lower-layer PDU.
The default port for the RTSP server is 554 for UDP. The default port for the RTSP server is 554 for UDP.
9.4 The usage of connections 9.4 The usage of connections
Systems implementing RTSP MUST support carrying RTSP over TCP. The | Systems implementing RTSP MUST support carrying RTSP over TCP. The |
default port for the RTSP server is 554 for TCP. A number of RTSP | default port for the RTSP server is 554 for TCP. A number of RTSP |
packets destined for the same control end point may be encapsulated | packets destined for the same control end point may be encapsulated |
into a TCP stream. RTSP data MAY be interleaved with RTP and RTCP | into a TCP stream. RTSP data MAY be interleaved with RTP and RTCP |
packets. Unlike HTTP, an RTSP message MUST contain a Content-Length | packets, see section 12. Unlike HTTP, an RTSP message MUST contain a |
header field whenever that message contains a payload (entity). | Content-Length header field whenever that message contains a payload |
Otherwise, an RTSP packet is terminated with an empty line | (entity). Otherwise, an RTSP packet is terminated with an empty line |
immediately following the last message header. immediately following the last message header.
TCP can be used for both persistent connections and for one message TCP can be used for both persistent connections and for one message
exchange per connection, as presented above. This section gives exchange per connection, as presented above. This section gives
further rules and recommendations on how to handle these connections further rules and recommendations on how to handle these connections
so maximum interoperability and flexibility can be achieved. so maximum interoperability and flexibility can be achieved.
A server SHALL handle both persistent connections and one A server SHALL handle both persistent connections and one
request/response transaction per connection. A persistent connection request/response transaction per connection. A persistent connection
MAY be used for all transactions between the server and client, MAY be used for all transactions between the server and client,
skipping to change at page 30, line 15 skipping to change at page 35, line 28
message exchange or can be kept open for several messages, i.e. message exchange or can be kept open for several messages, i.e.
persistent. persistent.
A major motivation for allowing non-persistent connections are that A major motivation for allowing non-persistent connections are that
they ensure fault tolerance. A second one is to allow for application they ensure fault tolerance. A second one is to allow for application
layer mobility. A server and client supporting non-persistent layer mobility. A server and client supporting non-persistent
connection can survive a loss of a TCP connection, e.g. due to a NAT connection can survive a loss of a TCP connection, e.g. due to a NAT
timeout. When the client has discovered that the TCP connection has timeout. When the client has discovered that the TCP connection has
been lost, it can set up a new one when there is need to communicate. been lost, it can set up a new one when there is need to communicate.
The client MAY close the connection at any time when no outstanding The client MAY close the connection at any time when no outstanding |
request/response transactions exist. The server SHOULD NOT close the request/response transactions exist. The server SHOULD NOT close the |
connection unless at least one RTSP session timeout period has passed connection unless at least one RTSP session timeout period has passed |
without data traffic. A server MUST NOT initiate a close of a without data traffic. A server SHOULD NOT initiate a close of a |
connection directly after responding to a TEARDOWN request for the connection directly after responding to a TEARDOWN request for the |
whole session. A server MUST NOT close the connection as a result of whole session. A server SHOULD NOT close the connection as a result |
responding to a request with an error code. Doing this would prevent of responding to a request with an error code. Doing this would |
or result in extra overhead for the client when testing advanced or prevent or result in extra overhead for the client when testing |
special types of requests. advanced or special types of requests.
The client SHOULD NOT have more than one connection to the server at The client SHOULD NOT have more than one connection to the server at
any given point. If a client or proxy handles multiple RTSP sessions any given point. If a client or proxy handles multiple RTSP sessions
on the same server, it is RECOMMENDED to use only a single on the same server, it is RECOMMENDED to use only a single
connection. connection.
Older services which was implemented according to RFC 2326 sometimes Older services which was implemented according to RFC 2326 sometimes
requires the client to use persistent connection. The client closing requires the client to use persistent connection. The client closing
the connection may result in that the server removes the session. To the connection may result in that the server removes the session. To
achieve interoperability with old servers any client is strongly achieve interoperability with old servers any client is strongly
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A server implemented according to this specification MUST respond A server implemented according to this specification MUST respond
that it supports the "play.basic" feature-tag above. A client MAY that it supports the "play.basic" feature-tag above. A client MAY
send a request including the Supported header in a request to send a request including the Supported header in a request to
determine support of non-persistent connections. A server supporting determine support of non-persistent connections. A server supporting
non-persistent connections will return the "play.basic" feature-tag non-persistent connections will return the "play.basic" feature-tag
in its response. If the client receives the feature-tag in the in its response. If the client receives the feature-tag in the
response, it can be certain that the server handles non-persistent response, it can be certain that the server handles non-persistent
connections. connections.
9.5 Use of IPv6 9.5 Timing Out RTSP messages |
Receivers of a request (responder) SHOULD respond to requests in a |
timely manner even when a reliable transport such as TCP is used. |
Similarly, the sender of a request (requestor) SHOULD wait for a |
sufficient time for a response before concluding that the responder |
will not be acting upon its request. |
A responder SHOULD respond to all requests within 5 seconds. If the |
responder recognizes that processing of a request will take longer |
than 5 seconds, it SHOULD send a 100 response as soon as possible. It |
SHOULD continue sending a 100 response every 5 seconds thereafter |
until it is ready to send the final response to the requestor. After |
sending a 100 response, the receiver MUST send a final response |
indicating the success or failure of the request. |
A requestor SHOULD wait at least 10 seconds for a response before |
concluding that the responder will not be responding to its request. |
After receiving a 100 response, the requestor SHOULD continue waiting |
for further responses. If more than 10 seconds elapses without |
receiving any response, the requestor MAY assume the responder is |
unresponsive and abort the connection. |
A requestor SHOULD wait longer than 10 seconds for a response if it |
is experiencing significant transport delays on its connection to the |
responder. The requestor is capable of determining the RTT using the |
Timestamp header (section 14.39) in any RTSP request.
9.6 Use of IPv6
This specification has been updated so that it supports IPv6. This specification has been updated so that it supports IPv6.
However this support was not present in RFC 2326 therefore some However this support was not present in RFC 2326 therefore some
interoperability issues exist. A RFC 2326 implementation can support interoperability issues exist. A RFC 2326 implementation can support
IPv6 as long as no explicit IPv6 addresses are used within RTSP IPv6 as long as no explicit IPv6 addresses are used within RTSP
messages. This require that any RTSP URL pointing at a IPv6 host must messages. This require that any RTSP URL pointing at a IPv6 host must
use fully qualified domain name and not a IPv6 address. Further the use fully qualified domain name and not a IPv6 address. Further the
Transport header must not use the parameters source and destination. Transport header must not use the parameters source and destination.
Implementations according to this specification MUST understand IPv6 Implementations according to this specification MUST understand IPv6
skipping to change at page 31, line 36 skipping to change at page 37, line 29
mechanism is designed to handle these two cases. mechanism is designed to handle these two cases.
When a method is added the involved parties can use the OPTIONS When a method is added the involved parties can use the OPTIONS
method to discover if it is supported. This is done by issuing a method to discover if it is supported. This is done by issuing a
OPTIONS request to the other party. Depending on the URL it will OPTIONS request to the other party. Depending on the URL it will
either apply in regards to a certain media resource, the whole server either apply in regards to a certain media resource, the whole server
in general, or simply the next hop. The OPTIONS response will contain in general, or simply the next hop. The OPTIONS response will contain
a Public header which declares all methods supported for the a Public header which declares all methods supported for the
indicated resource. indicated resource.
It is not necessary to use OPTIONS to discover support of a method, | It is not necessary to use OPTIONS to discover support of a method,
the client could simply try the method. If the receiver of the | the client could simply try the method. If the receiver of the
request does not support the method it will respond with an error | request does not support the method it will respond with an error
code indicating the the method is either not implemented (501) or | code indicating the the method is either not implemented (501) or
does not apply for the resource (405). The choice between the two | does not apply for the resource (405). The choice between the two
discovery methods depends on the requirements of the service. discovery methods depends on the requirements of the service.
To handle functionality additions that are not new methods feature- To handle functionality additions that are not new methods feature-
tags are defined. Each feature-tag represents a certain block of tags are defined. Each feature-tag represents a certain block of
functionality. The amount of functionality that a feature-tag functionality. The amount of functionality that a feature-tag
represents can vary significantly. A simple feature-tag can simple represents can vary significantly. A simple feature-tag can simple
represent the functionality a single header gives. Another feature- represent the functionality a single header gives. Another feature-
tag is "play.basic" which represents the minimal playback tag is "play.basic" which represents the minimal playback
implementation according to the updated specification. implementation according to the updated specification.
The feature-tags are then used to determine if the client, server or The feature-tags are then used to determine if the client, server or
proxy supports the functionality that is necessary to achieve the proxy supports the functionality that is necessary to achieve the
desired service. To determine support of a feature-tag several desired service. To determine support of a feature-tag several
different headers can be used, each explained below: different headers can be used, each explained below:
Supported: The supported header is used to determine the Supported: The supported header is used to determine the
complete set of functionality that both client and server complete set of functionality that both client and server
has. The intended usage is to determine before one needs to has. The intended usage is to determine before one needs to
use a functionality that it is supported. If can be used in use a functionality that it is supported. It can be used in
any method however OPTIONS is the most suitable as one at any method however OPTIONS is the most suitable as one at
the same time determines all methods that are implemented. the same time determines all methods that are implemented.
When sending a request the requestor declares all its When sending a request the requestor declares all its
capabilities by including all supported feature-tags. The capabilities by including all supported feature-tags. This
results in that the receiver learns the requestors feature results in that the receiver learns the requestors feature
support. The receiver then includes its set of features in support. The receiver then includes its set of features in
the response. the response.
Require: The Require header can be included in any request where Require: The Require header can be included in any request where
the end point, i.e. the client or server, is required to the end point, i.e. the client or server, is required to
understand the feature to correctly perform the request. understand the feature to correctly perform the request.
This can for example be a SETUP request where the server This can for example be a SETUP request where the server
must understand a certain parameter to be able to set up must understand a certain parameter to be able to set up
the media delivery correctly. Ignoring this parameter would the media delivery correctly. Ignoring this parameter would
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Unsupported: This header is used in 551 error response to tell Unsupported: This header is used in 551 error response to tell
which feature(s) that was not supported. Such a response is which feature(s) that was not supported. Such a response is
only the result of the usage of the Require and/or Proxy- only the result of the usage of the Require and/or Proxy-
Require header where one or more feature where not Require header where one or more feature where not
supported. This information allows the requestor to make supported. This information allows the requestor to make
the best of situations as it knows which features that was the best of situations as it knows which features that was
not supported. not supported.
11 Method Definitions 11 Method Definitions
The method token indicates the method to be performed on the resource The method indicates what is to be performed on the resource |
identified by the Request-URI case-sensitive. New methods may be identified by the Request-URL. The method name is case-sensitive. |
defined in the future. Method names may not start with a $ character New methods may be defined in the future. Method names may not start |
(decimal 24) and must be a token as defined by the ABNF. Methods are with a $ character (decimal 24) and must be a token as defined by the |
summarized in Table 2. ABNF. Methods are summarized in Table 7.
Notes on Table 7: PAUSE is recommended, but not required in that a |
method direction object Server req. Client req. method direction object Server req. Client req.
___________________________________________________________________ ___________________________________________________________________
DESCRIBE C -> S P,S recommended recommended DESCRIBE C -> S P,S recommended recommended
GET_PARAMETER C -> S, S -> C P,S optional optional GET_PARAMETER C -> S, S -> C P,S optional optional
OPTIONS C -> S, S -> C P,S R=Req, Sd=Opt Sd=Req, R=Opt OPTIONS C -> S, S -> C P,S R=Req, Sd=Opt Sd=Req, R=Opt
PAUSE C -> S P,S recommended recommended PAUSE C -> S P,S recommended recommended
PING C -> S, S -> C P,S recommended optional PING C -> S, S -> C P,S recommended optional
PLAY C -> S P,S required required PLAY C -> S P,S required required
REDIRECT S -> C P,S optional optional REDIRECT S -> C P,S optional optional
SETUP C -> S S required required SETUP C -> S S required required
SET_PARAMETER C -> S, S -> C P,S optional optional SET_PARAMETER C -> S, S -> C P,S optional optional
TEARDOWN C -> S P,S required required TEARDOWN C -> S P,S required required
Table 2: Overview of RTSP methods, their direction, and what objects Table 7: Overview of RTSP methods, their direction, and what objects
(P: presentation, S: stream) they operate on. Legend: R=Responde to, (P: presentation, S: stream) they operate on. Legend: R=Responde to,
Sd=Send, Opt: Optional, Req: Required, Rec: Recommended Sd=Send, Opt: Optional, Req: Required, Rec: Recommended
Notes on Table 2: PAUSE is recommended, but not required in that a fully functional server can be built that does not support this |
fully functional server can be built that does not support this method, for example, for live feeds. If a server does not support a |
method, for example, for live feeds. If a server does not support a particular method, it MUST return 501 (Not Implemented) and a client |
particular method, it MUST return 501 (Not Implemented) and a client SHOULD NOT try this method again for this server and resource.
SHOULD NOT try this method again for this server.
11.1 OPTIONS 11.1 OPTIONS
The behavior is equivalent to that described in [H9.2]. An OPTIONS The behavior is equivalent to that described in [H9.2]. An OPTIONS
request may be issued at any time, e.g., if the client is about to request may be issued at any time, e.g., if the client is about to
try a nonstandard request. It does not influence the session state. try a nonstandard request. It does not influence the session state.
The Public header MUST be included in responses to indicate which The Public header MUST be included in responses to indicate which
methods that are supported by the server. To specify which methods methods that are supported by the server. To specify which methods
that are possible to use for the specified resource, the Allow MAY be that are possible to use for the specified resource, the Allow MAY be
used. By including in the OPTIONS request a Supported header, the used. By including in the OPTIONS request a Supported header, the
requester can determine which features the other part supports. requester can determine which features the other part supports.
The request URI determines which scope the OPTIONS request has. By The request URL determines which scope the OPTIONS request has. By
giving the URI of a certain media the capabilities regarding this giving the URL of a certain media the capabilities regarding this
media will be responded. By using the "*" URI the request regards the media will be responded. By using the "*" URL the request regards the
next hop only, while having a URL with only the host address regards next hop only, while having a URL with only the host address regards
the server without any media relevance. the server without any media relevance.
The OPTIONS method can be used for RTSP session keep alive The OPTIONS method can be used for RTSP session keep alive |
signalling, however this method is not the most recommended one, see signalling, however this method is not the most recommended one, see |
section 13.37 for a preference list. A keep alive OPTIONS request section 14.37 for a preference list. A keep alive OPTIONS request |
SHOULD use the media or aggregated control URI. SHOULD use the media or aggregated control URL. For options to |
function as session state keep-alive, it is REQUIRED that the session |
ID is included in the Session header.
Example: Example:
C->S: OPTIONS * RTSP/1.0 C->S: OPTIONS * RTSP/1.0
CSeq: 1 CSeq: 1
User-Agent: PhonyClient/1.2 User-Agent: PhonyClient/1.2
Require: Require:
Proxy-Require: gzipped-messages Proxy-Require: gzipped-messages
Supported: play-basic Supported: play-basic
skipping to change at page 34, line 29 skipping to change at page 40, line 27
Supported: play-basic, implicit-play, gzipped-messages Supported: play-basic, implicit-play, gzipped-messages
Server: PhonyServer/1.0 Server: PhonyServer/1.0
Note that some of the feature-tags in Require and Proxy-Require are Note that some of the feature-tags in Require and Proxy-Require are
necessarily fictional features (one would hope that we would not necessarily fictional features (one would hope that we would not
purposefully overlook a truly useful feature just so that we could purposefully overlook a truly useful feature just so that we could
have a strong example in this section). have a strong example in this section).
11.2 DESCRIBE 11.2 DESCRIBE
The DESCRIBE method retrieves the description of a presentation or The DESCRIBE method retrieves the description of a presentation or |
media object identified by the request URL from a server. It may use media object identified by the request URL from a server. The request |
the Accept header to specify the description formats that the client MAY use the Accept header to specify the description formats that the |
understands. The server responds with a description of the requested client understands. The server responds with a description of the |
resource. The DESCRIBE reply-response pair constitutes the media requested resource. The DESCRIBE reply-response pair constitutes the |
initialization phase of RTSP. media initialization phase of RTSP.
Example: Example:
C->S: DESCRIBE rtsp://server.example.com/fizzle/foo RTSP/1.0 C->S: DESCRIBE rtsp://server.example.com/fizzle/foo RTSP/1.0
CSeq: 312 CSeq: 312
User-Agent: PhonyClient 1.2 User-Agent: PhonyClient 1.2
Accept: application/sdp, application/rtsl, application/mheg Accept: application/sdp, application/rtsl, application/mheg
S->C: RTSP/1.0 200 OK S->C: RTSP/1.0 200 OK
CSeq: 312 CSeq: 312
skipping to change at page 36, line 14 skipping to change at page 42, line 9
media initialization format). media initialization format).
It is RECOMMENDED that minimal servers support the DESCRIBE method, It is RECOMMENDED that minimal servers support the DESCRIBE method,
and highly recommended that minimal clients support the ability to and highly recommended that minimal clients support the ability to
act as a "helper application" that accepts a media initialization act as a "helper application" that accepts a media initialization
file from standard input, command line, and/or other means that are file from standard input, command line, and/or other means that are
appropriate to the operating environment of the client. appropriate to the operating environment of the client.
11.3 SETUP 11.3 SETUP
The SETUP request for a URI specifies the transport mechanism to be | The SETUP request for a URL specifies the transport mechanism to be
used for the streamed media. The SETUP method may be used in two | used for the streamed media. The SETUP method may be used in two
different cases; Create a RTSP session or add a media to a session, | different cases; Create a RTSP session or add a media to a session,
and change the transport parameters of already set up media stream. | and change the transport parameters of already set up media stream.
Using SETUP to create or add media to a session when in PLAY state | Using SETUP to create or add media to a session when in PLAY state is
are not allowed. Otherwise SETUP can be used in all three states; | unspecified. Otherwise SETUP can be used in all three states; INIT,
INIT, and READY, for both purposes and in PLAY to change the | and READY, for both purposes and in PLAY to change the transport
transport parameters. | parameters.
The Transport header, see section 13.40, specifies the transport | The Transport header, see section 14.40, specifies the transport |
parameters acceptable to the client for data transmission; the | parameters acceptable to the client for data transmission; the |
response will contain the transport parameters selected by the | response will contain the transport parameters selected by the |
server. This allows the client to enumerate in priority order the | server. This allows the client to enumerate in priority order the |
transport mechanisms and parameters acceptable to it, while the | transport mechanisms and parameters acceptable to it, while the |
server can select the most appropriate. All transport parameters | server can select the most appropriate. It is expected that the |
SHOULD be included in the Transport header, the use of other headers | session description format used will enable the client to select a |
for this purpose is discouraged due to middle boxes. | limited number possible configurations that are offered to the server |
to choose from. All transport parameters SHOULD be included in the |
For the benefit of any intervening firewalls, a client SHOULD | Transport header, the use of other headers for this purpose is |
indicate the transport parameters even if it has no influence over | discouraged due to middle boxes.
these parameters, for example, where the server advertises a fixed |
multicast address. |
Since SETUP includes all transport initialization | For the benefit of any intervening firewalls, a client SHOULD
information, firewalls and other intermediate network | indicate the transport parameters even if it has no influence over
devices (which need this information) are spared the more | these parameters, for example, where the server advertises a fixed
arduous task of parsing the DESCRIBE response, which has | multicast address.
been reserved for media initialization. |
In a SETUP response the server SHOULD include the Accept-Ranges | Since SETUP includes all transport initialization
header (see section 13.4 to indicate which time formats that are | information, firewalls and other intermediate network
acceptable to use for this media resource. | devices (which need this information) are spared the more
arduous task of parsing the DESCRIBE response, which has
been reserved for media initialization.
C->S: SETUP rtsp://example.com/foo/bar/baz.rm RTSP/1.0 | In a SETUP response the server SHOULD include the Accept-Ranges
CSeq: 302 | header (see section 14.4 to indicate which time formats that are
Transport: RTP/AVP;unicast;client_port=4588-4589, | acceptable to use for this media resource.
RTP/AVP/TCP;unicast;interleave=0-1 |
S->C: RTSP/1.0 200 OK | C->S: SETUP rtsp://example.com/foo/bar/baz.rm RTSP/1.0
CSeq: 302 | CSeq: 302
Date: 23 Jan 1997 15:35:06 GMT | Transport: RTP/AVP;unicast;client_port=4588-4589,
Server: PhonyServer 1.0 | RTP/AVP/TCP;unicast;interleave=0-1
Session: 47112344 | S->C: RTSP/1.0 200 OK
Transport: RTP/AVP;unicast;client_port=4588-4589; | CSeq: 302
server_port=6256-6257;ssrc=2A3F93ED | Date: 23 Jan 1997 15:35:06 GMT
Accept-Ranges: NPT | Server: PhonyServer 1.0
Session: 47112344
Transport: RTP/AVP;unicast;client_port=4588-4589;
server_port=6256-6257;ssrc=2A3F93ED
Accept-Ranges: NPT
In the above example the client want to create a RTSP session | In the above example the client want to create a RTSP session
containing the media resource "rtsp://example.com/foo/bar/baz.rm". | containing the media resource "rtsp://example.com/foo/bar/baz.rm".
The transport parameters acceptable to the client is either | The transport parameters acceptable to the client is either
RTP/AVP/UDP (UDP per default) to be received on client port 4588 and | RTP/AVP/UDP (UDP per default) to be received on client port 4588 and
4589 or RTP/AVP interleaved on the RTSP control channel. The server | 4589 or RTP/AVP interleaved on the RTSP control channel. The server
selects the RTP/AVP/UDP transport and adds the ports it will send and | selects the RTP/AVP/UDP transport and adds the ports it will send and
received RTP and RTCP from, and the RTP SSRC that will be used by the | received RTP and RTCP from, and the RTP SSRC that will be used by the
server. | server.
The server MUST generate a session identifier in response to a | The server MUST generate a session identifier in response to a
successful SETUP request, unless a SETUP request to a server includes | successful SETUP request, unless a SETUP request to a server includes
a session identifier, in which case the server MUST bundle this setup | a session identifier, in which case the server MUST bundle this setup
request into the existing session (aggregated session) or return | request into the existing session (aggregated session) or return
error 459 (Aggregate Operation Not Allowed) (see Section 12.4.11). | error 459 (Aggregate Operation Not Allowed) (see Section 13.4.11).
An Aggregate control URI MUST be used to control an aggregated | An Aggregate control URL MUST be used to control an aggregated
session. This URI MUST be different from the stream control URIs of | session. This URL MUST be different from the stream control URLs of
the individual media streams included in the aggregate. The Aggregate | the individual media streams included in the aggregate. The Aggregate
control URI is to be specified by the session description if the | control URL is to be specified by the session description if the
server supports aggregated control and aggregated control is desired | server supports aggregated control and aggregated control is desired
for the session. However even if aggregated control is offered the | for the session. However even if aggregated control is offered the
client MAY chose to not set up the session in aggregated control. | client MAY chose to not set up the session in aggregated control. If
an Aggregate control URL is not specified in the session description,
it is normally an indication that non-aggregated control should be |
used. The SETUP of media streams in an aggregate which has not been |
given an aggregated control URL is unspecified.
If an Aggregate control URI is not specified in the session | While the session ID sometimes has enough information for
description, it is probably a indication that non-aggregated control | aggregate control of a session, the Aggregate control URL
should be used. However a client MAY try to SETUP the session in | is still important for some methods such as SET_PARAMETER
aggregated control. If the server refuse to aggregate the specified | where the control URL enables the resource in question to
media, the server SHALL use the 459 error code. If the server allows | be easily identified. The Aggregate control URL is also
the aggregation, then the client MUST create an URI for aggregate | useful for proxies, enabling them to route the request to
control of the session. This URI MUST contain the servers host | the appropriate server, and for logging, where it is useful
address and MUST contain the port, if applicable (e.g. not default | to note the actual resource that a request was operating
port). Once an URI is used to refer to an aggregation for a given | on. Finally, presence of the Aggregate control URL allows
session, that URI MUST be used to refer to that aggregation for the | for backwards compatibility with RFC 2326 [1].
duration of the session. |
While the session ID sometimes has enough information for |
aggregate control of a session, the Aggregate control URI |
is still important for some methods such as SET_PARAMETER |
where the control URI enables the resource in question to |
be easily identified. The Aggregate control URI is also |
useful for proxies, enabling them to route the request to |
the appropriate server, and for logging, where it is useful |
to note the actual resource that a request was operating |
on. Finally, presence of the Aggregate control URI allows |
for backwards compatibility with RFC 2326 [21].
A session will exist until it is either removed by a TEARDOWN request A session will exist until it is either removed by a TEARDOWN request
or is timed-out by the server. The server MAY remove a session that or is timed-out by the server. The server MAY remove a session that
has not demonstrated liveness signs from the client within a certain has not demonstrated liveness signs from the client within a certain
timeout period. The default timeout value is 60 seconds; the server timeout period. The default timeout value is 60 seconds; the server
MAY set this to a different value and indicate so in the timeout MAY set this to a different value and indicate so in the timeout
field of the Session header in the SETUP response. For further field of the Session header in the SETUP response. For further
discussion see chapter 13.37. Signs of liveness for a RTSP session discussion see chapter 14.37. Signs of liveness for a RTSP session
are: are:
o Any RTSP request from a client which includes a Session header o Any RTSP request from a client which includes a Session header
with that session's ID. with that session's ID.
o If RTP is used as a transport for the underlying media o If RTP is used as a transport for the underlying media
streams, an RTCP sender or receiver report from the client for streams, an RTCP sender or receiver report from the client for
any of the media streams in that RTSP session. any of the media streams in that RTSP session.
If a SETUP request on a session fails for any reason, the session | If a SETUP request on a session fails for any reason, the session
state, as well as transport and other parameters for associated | state, as well as transport and other parameters for associated
streams SHALL remain unchanged from their values as if the SETUP | streams SHALL remain unchanged from their values as if the SETUP
request had never been received by the server. | request had never been received by the server.
A client MAY issue a SETUP request for a stream that is already set | A client MAY issue a SETUP request for a stream that is already set
up or playing in the session to change transport parameters, which a | up or playing in the session to change transport parameters, which a
server MAY allow. If it does not allow this, it MUST respond with | server MAY allow. If it does not allow this, it MUST respond with
error 455 (Method Not Valid In This State). Reasons to support | error 455 (Method Not Valid In This State). Reasons to support
changing transport parameters, is to allow for application layer | changing transport parameters, is to allow for application layer
mobility and flexibility to utilize the best available transport as | mobility and flexibility to utilize the best available transport as
it becomes available. | it becomes available.
In a SETUP response for a request to change the transport parameters | In a SETUP response for a request to change the transport parameters
while in Play state, the server SHOULD include the Range to indicate | while in Play state, the server SHOULD include the Range to indicate
from what point the new transport parameters are used. Further if RTP | from what point the new transport parameters are used. Further if RTP
is used for delivery the server SHOULD also include the RTP-Info | is used for delivery the server SHOULD also include the RTP-Info
header to indicate from what timestamp and RTP sequence number the | header to indicate from what timestamp and RTP sequence number the
change has taken place. If both RTP-Info and Range is included in the | change has taken place. If both RTP-Info and Range is included in the
response the "rtp_time" parameter and range MUST be for the | response the "rtp_time" parameter and range MUST be for the
corresponding time, i.e. be used in the same way as for PLAY to | corresponding time, i.e. be used in the same way as for PLAY to
ensure the correct synchronization information is present. | ensure the correct synchronization information is present.
If the transport parameter change while in PLAY state results in a | If the transport parameter change while in PLAY state results in a
change of synchronization related information, for example changing | change of synchronization related information, for example changing
RTP SSRC, the server MUST provide in the SETUP response the necessary | RTP SSRC, the server MUST provide in the SETUP response the necessary
synchronization information. However the server is RECOMMENDED to | synchronization information. However the server is RECOMMENDED to
avoid changing the synchronization information if possible. | avoid changing the synchronization information if possible.
11.4 PLAY 11.4 PLAY
The PLAY method tells the server to start sending data via the | The PLAY method tells the server to start sending data via the
mechanism specified in SETUP. A client MUST NOT issue a PLAY request | mechanism specified in SETUP. A client MUST NOT issue a PLAY request
until any outstanding SETUP requests have been acknowledged as | until any outstanding SETUP requests have been acknowledged as
successful. PLAY requests are valid when the session is in READY | successful. PLAY requests are valid when the session is in READY
state; the use of PLAY requests when the session is in PLAY state is | state; the use of PLAY requests when the session is in PLAY state is
deprecated. A PLAY request MUST include a Session header to indicate | deprecated. A PLAY request MUST include a Session header to indicate
which session the request applies to. which session the request applies to.
In an aggregated session the PLAY request MUST contain an aggregated In an aggregated session the PLAY request MUST contain an aggregated
control URL. A server SHALL responde with error 460 (Only Aggregate control URL. A server SHALL responde with error 460 (Only Aggregate
Operation Allowed) if the client PLAY request URI is for one of the Operation Allowed) if the client PLAY request URL is for one of the
media. The media in an aggregate SHALL be played in sync. If a client media. The media in an aggregate SHALL be played in sync. If a client
want individual control of the media it must use separate RTSP want individual control of the media it must use separate RTSP
sessions for each media. sessions for each media.
The PLAY request SHALL position the normal play time to the beginning | The PLAY request SHALL position the normal play time to the beginning
of the range specified by the Range header and delivers stream data | of the range specified by the Range header and delivers stream data
until the end of the range if given, else to the end of the media is | until the end of the range if given, else to the end of the media is
reached. To allow for precise composition multiple ranges MAY be | reached. To allow for precise composition multiple ranges MAY be
specified in one PLAY Request. The range values are valid if all | specified in one PLAY Request. The range values are valid if all
given ranges are part of any media within the aggregate. If a given | given ranges are part of any media within the aggregate. If a given
range value points outside of the media, the response SHALL be the | range value points outside of the media, the response SHALL be the
457 (Invalid Range) error code. 457 (Invalid Range) error code.
The below example will first play seconds 10 through 15, then, The below example will first play seconds 10 through 15, then,
immediately following, seconds 20 to 25, and finally seconds 30 immediately following, seconds 20 to 25, and finally seconds 30
through the end. through the end.
C->S: PLAY rtsp://audio.example.com/audio RTSP/1.0 C->S: PLAY rtsp://audio.example.com/audio RTSP/1.0
CSeq: 835 CSeq: 835
Session: 12345678 Session: 12345678
Range: npt=10-15, npt=20-25, npt=30- Range: npt=10-15, npt=20-25, npt=30-
skipping to change at page 40, line 4 skipping to change at page 45, line 35
457 (Invalid Range) error code. 457 (Invalid Range) error code.
The below example will first play seconds 10 through 15, then, The below example will first play seconds 10 through 15, then,
immediately following, seconds 20 to 25, and finally seconds 30 immediately following, seconds 20 to 25, and finally seconds 30
through the end. through the end.
C->S: PLAY rtsp://audio.example.com/audio RTSP/1.0 C->S: PLAY rtsp://audio.example.com/audio RTSP/1.0
CSeq: 835 CSeq: 835
Session: 12345678 Session: 12345678
Range: npt=10-15, npt=20-25, npt=30- Range: npt=10-15, npt=20-25, npt=30-
See the description of the PAUSE request for further examples. See the description of the PAUSE request for further examples.
A PLAY request without a Range header is legal. It SHALL start | A PLAY request without a Range header is legal. It SHALL start
playing a stream from the beginning (npt=0-) unless the stream has | playing a stream from the beginning (npt=0-) unless the stream has
been paused. If a stream has been paused via PAUSE, stream delivery | been paused. If a stream has been paused via PAUSE, stream delivery
resumes at the pause point. The stream SHALL play until the end of | resumes at the pause point. The stream SHALL play until the end of
the media. the media.
The Range header MUST NOT contain a time parameter. The usage of time The Range header MUST NOT contain a time parameter. The usage of time |
in PLAY method has been deprecated. in PLAY method has been deprecated. If a request with time parameter |
is received the server SHOULD respond with a 457 (Invalid Range) to |
indicate that the time parameter is not supported. |
Server MUST include a "Range" header in any PLAY response. The | Server MUST include a "Range" header in any PLAY response. The |
response MUST use the same format as the request's range header | response MUST use the same format as the request's range header |
contained. If no Range header was in the request, the NPT time format | contained. If no Range header was in the request, the NPT time format |
SHOULD be used unless the client showed support for an other format. | SHOULD be used unless the client showed support for an other format |
Also for a session with live media streams the Range header MUST | more appropriate. Also for a session with live media streams the |
indicate a valid time. It is RECOMMENDED that normal play time is | Range header MUST indicate a valid time. It is RECOMMENDED that |
used, either the "now" indicator, for example "npt=now-", or the time | normal play time is used, either the "now" indicator, for example |
since session start as an open interval, e.g. "npt=96.23-". An | "npt=now-", or the time since session start as an open interval, e.g. |
absolute time value (clock) for the corresponding time MAY be given, | "npt=96.23-". An absolute time value (clock) for the corresponding |
i.e. "clock=20030213T143205Z-". The UTC clock format SHOULD only be | time MAY be given, i.e. "clock=20030213T143205Z-". The UTC clock |
used if client has shown support for it. | format SHOULD only be used if client has shown support for it.
A media server only supporting playback MUST support the npt format | A media server only supporting playback MUST support the npt format
and MAY support the clock and smpte formats. | and MAY support the clock and smpte formats.
For a on-demand stream, the server MUST reply with the actual range | For a on-demand stream, the server MUST reply with the actual range
that will be played back. This may differ from the requested range if | that will be played back. This may differ from the requested range if
alignment of the requested range to valid frame boundaries is | alignment of the requested range to valid frame boundaries is
required for the media source. If no range is specified in the | required for the media source. If no range is specified in the
request, the start position SHALL still be returned in the reply. If | request, the start position SHALL still be returned in the reply. If
the medias that are part of an aggregate has different lengths, the | the medias that are part of an aggregate has different lengths, the
PLAY request SHALL be performed as long as the given range is valid | PLAY request SHALL be performed as long as the given range is valid
for any media, for example the longest media. Media will be sent | for any media, for example the longest media. Media will be sent
whenever it is available for the given play-out point. | whenever it is available for the given play-out point.
After playing the desired range, the presentation is NOT | After playing the desired range, the presentation is NOT |
automatically paused, media delivery simply stops. A PAUSE request | automatically paused, media delivery simply stops. A PAUSE request |
MUST be issued before another PLAY request can be issued. Note: This | MUST be issued before another PLAY request can be issued. Note: This |
is one change resulting in a non-operability with RFC 2326 | is one change resulting in a non-operability with RFC 2326 |
implementations. A client not issuing a PAUSE request before a new | implementations. A client not issuing a PAUSE request before a new |
PLAY will be stuck in PLAY state. | PLAY will be stuck in PLAY state. To mitigate this backwards |
compatibility issue the following behavior is recommended. If a |
server receives a PLAY request when in play state and all media has |
finished the requested playout, the server MAY interpret this as a |
PLAY request received in ready state. However the server SHALL NOT do |
this if the client has shown any support for this specification, for |
example by sending a Supported header with the play.basic feature |
tag.
A client desiring to play the media from the beginning MUST send a | A client desiring to play the media from the beginning MUST send a
PLAY request with a Range header pointing at the beginning, e.g. | PLAY request with a Range header pointing at the beginning, e.g.
npt=0-. If a PLAY request is received without a Range header when | npt=0-. If a PLAY request is received without a Range header when
media delivery has stopped at the end, the server SHOULD respond with | media delivery has stopped at the end, the server SHOULD respond with
a 457 "Invalid Range" error response. In that response the current | a 457 "Invalid Range" error response. In that response the current
pause point in a Range header SHALL be included. pause point in a Range header SHALL be included.
The following example plays the whole presentation starting at SMPTE The following example plays the whole presentation starting at SMPTE
time code 0:10:20 until the end of the clip. Note: The RTP-Info time code 0:10:20 until the end of the clip. Note: The RTP-Info
headers has been broken into several lines to fit the page. headers has been broken into several lines to fit the page.
C->S: PLAY rtsp://audio.example.com/twister.en RTSP/1.0 C->S: PLAY rtsp://audio.example.com/twister.en RTSP/1.0 |
CSeq: 833 CSeq: 833 |
Session: 12345678 Session: 12345678 |
Range: smpte=0:10:20- Range: smpte=0:10:20- |
S->C: RTSP/1.0 200 OK S->C: RTSP/1.0 200 OK |
CSeq: 833 CSeq: 833 |
Date: 23 Jan 1997 15:35:06 GMT Date: 23 Jan 1997 15:35:06 GMT |
Server: PhonyServer 1.0 Server: PhonyServer 1.0 |
Range: smpte=0:10:22- Range: smpte=0:10:22-0:15:45 |
RTP-Info:url=rtsp://example.com/twister.en; RTP-Info:url=rtsp://example.com/twister.en; |
seq=14783;rtptime=2345962545 seq=14783;rtptime=2345962545 |
For playing back a recording of a live presentation, it may be For playing back a recording of a live presentation, it may be
desirable to use clock units: desirable to use clock units:
C->S: PLAY rtsp://audio.example.com/meeting.en RTSP/1.0 C->S: PLAY rtsp://audio.example.com/meeting.en RTSP/1.0
CSeq: 835 CSeq: 835
Session: 12345678 Session: 12345678
Range: clock=19961108T142300Z-19961108T143520Z Range: clock=19961108T142300Z-19961108T143520Z
S->C: RTSP/1.0 200 OK S->C: RTSP/1.0 200 OK
skipping to change at page 42, line 7 skipping to change at page 47, line 42
RTP-Info:url=rtsp://example.com/meeting.en; RTP-Info:url=rtsp://example.com/meeting.en;
seq=53745;rtptime=484589019 seq=53745;rtptime=484589019
All range specifiers in this specification allow for ranges with All range specifiers in this specification allow for ranges with
unspecified begin times (e.g. "npt=-30"). When used in a PLAY unspecified begin times (e.g. "npt=-30"). When used in a PLAY
request, the server treats this as a request to start/resume playback request, the server treats this as a request to start/resume playback
from the current pause point, ending at the end time specified in the from the current pause point, ending at the end time specified in the
Range header. If the pause point is located later than the given end Range header. If the pause point is located later than the given end
value, a 457 (Invalid Range) response SHALL be given. value, a 457 (Invalid Range) response SHALL be given.
The queued play functionality described in RFC 2326 [21] is removed The queued play functionality described in RFC 2326 [1] is removed |
and multiple ranges can be used to achieve a similar performance. If and multiple ranges can be used to achieve a similar functionality. |
a server receives a PLAY request while in the PLAY state, the server If a server receives a PLAY request while in the PLAY state, the |
SHALL responde using the error code 455 (Method Not Valid In This server SHALL responde using the error code 455 (Method Not Valid In |
State). This will signal the client that queued play are not This State). This will signal the client that queued play are not |
supported. supported.
The use of PLAY for keep-alive signaling, i.e. PLAY request without a | The use of PLAY for keep-alive signaling, i.e. PLAY request without a
range header in PLAY state, has also been depreciated. Instead a | range header in PLAY state, has also been depreciated. Instead a
client can use, PING, SET_PARAMETER or OPTIONS for keep alive. A | client can use, PING, SET_PARAMETER or OPTIONS for keep alive. A
server receiving a PLAY keep alive SHALL respond with the 455 error | server receiving a PLAY keep alive SHALL respond with the 455 error
code. code.
11.5 PAUSE 11.5 PAUSE
The PAUSE request causes the stream delivery to be interrupted The PAUSE request causes the stream delivery to be interrupted
(halted) temporarily. A PAUSE request MUST be done with the (halted) temporarily. A PAUSE request MUST be done with the
aggregated control URI for aggregated sessions, resulting in all aggregated control URL for aggregated sessions, resulting in all
media being halted, or the media URI for non-aggregated sessions. media being halted, or the media URL for non-aggregated sessions.
Any attempt to do muting of a single media with an PAUSE request in Any attempt to do muting of a single media with an PAUSE request in
an aggregated session SHALL be responded with error 460 (Only an aggregated session SHALL be responded with error 460 (Only
Aggregate Operation Allowed). After resuming playback, Aggregate Operation Allowed). After resuming playback,
synchronization of the tracks MUST be maintained. Any server synchronization of the tracks MUST be maintained. Any server
resources are kept, though servers MAY close the session and free resources are kept, though servers MAY close the session and free
resources after being paused for the duration specified with the resources after being paused for the duration specified with the
timeout parameter of the Session header in the SETUP message. timeout parameter of the Session header in the SETUP message.
Example: | Example:
C->S: PAUSE rtsp://example.com/fizzle/foo RTSP/1.0 | C->S: PAUSE rtsp://example.com/fizzle/foo RTSP/1.0
CSeq: 834 | CSeq: 834
Session: 12345678 | Session: 12345678
S->C: RTSP/1.0 200 OK | S->C: RTSP/1.0 200 OK
CSeq: 834 | CSeq: 834
Date: 23 Jan 1997 15:35:06 GMT | Date: 23 Jan 1997 15:35:06 GMT
Range: npt=45.76- | Range: npt=45.76-
The PAUSE request MAY contain a Range header specifying when the The PAUSE request MAY contain a Range header specifying when the
stream or presentation is to be halted. We refer to this point as the stream or presentation is to be halted. We refer to this point as the
"pause point". The time parameter in the Range MUST NOT be used. The "pause point". The time parameter in the Range MUST NOT be used. The
Range header MUST contain a single value, expressed as the beginning Range header MUST contain a single value, expressed as the beginning
value an open range. For example, the following clip will be played value an open range. For example, the following clip will be played
from 10 seconds through 21 seconds of the clip's normal play time, from 10 seconds through 21 seconds of the clip's normal play time,
under the assumption that the PAUSE request reaches the server within under the assumption that the PAUSE request reaches the server within
11 seconds of the PLAY request. Note that some lines has been broken 11 seconds of the PLAY request. Note that some lines has been broken
in an non-correct way to fit the page: in an non-correct way to fit the page:
skipping to change at page 44, line 8 skipping to change at page 49, line 45
If the Range header specifies a time outside any range from the PLAY If the Range header specifies a time outside any range from the PLAY
request, the error 457 (Invalid Range) SHALL be returned. If a media request, the error 457 (Invalid Range) SHALL be returned. If a media
unit (such as an audio or video frame) starts presentation at exactly unit (such as an audio or video frame) starts presentation at exactly
the pause point, it is not played. If the Range header is missing, the pause point, it is not played. If the Range header is missing,
stream delivery is interrupted immediately on receipt of the message stream delivery is interrupted immediately on receipt of the message
and the pause point is set to the current normal play time. However, and the pause point is set to the current normal play time. However,
the pause point in the media stream MUST be maintained. A subsequent the pause point in the media stream MUST be maintained. A subsequent
PLAY request without Range header SHALL resume from the pause point PLAY request without Range header SHALL resume from the pause point
and play until media end. and play until media end.
If the server has already sent data beyond the time specified in the | If the server has already sent data beyond the time specified in the
PAUSE request's Range header, a PLAY without range SHALL resume at | PAUSE request's Range header, a PLAY without range SHALL resume at
the point in time specified by the PAUSE request's Range header, as | the point in time specified by the PAUSE request's Range header, as
it is assumed that the client has discarded data after that point. | it is assumed that the client has discarded data after that point.
This ensures continuous pause/play cycling without gaps. | This ensures continuous pause/play cycling without gaps.
The pause point after any PAUSE request SHALL be returned to the | The pause point after any PAUSE request SHALL be returned to the
client by adding a Range header with what remains unplayed of the | client by adding a Range header with what remains unplayed of the
PLAY request's ranges, i.e. including all the remaining ranges part | PLAY request's ranges, i.e. including all the remaining ranges part
of multiple range specification. If one desires to resume playing a | of multiple range specification. If one desires to resume playing a
ranged request, one simple included the Range header from the PAUSE | ranged request, one simply includes the Range header from the PAUSE
response. Note that this server behavior was not mandated previously | response. Note that this server behavior was not mandated previously
and servers implementing according to RFC 2326 will probably not | and servers implementing according to RFC 2326 will probably not
return the range header. | return the range header.
For example, if the server have a play request for ranges 10 to 15 | For example, if the server have a play request for ranges 10 to 15
and 20 to 29 pending and then receives a pause request for NPT 21, it | and 20 to 29 pending and then receives a pause request for NPT 21, it
would start playing the second range and stop at NPT 21. If the pause | would start playing the second range and stop at NPT 21. If the pause
request is for NPT 12 and the server is playing at NPT 13 serving the | request is for NPT 12 and the server is playing at NPT 13 serving the
first play request, the server stops immediately. If the pause | first play request, the server stops immediately. If the pause
request is for NPT 16, the server returns a 457 error message. To | request is for NPT 16, the server returns a 457 error message. To
prevent that the second range is played and the server stops after | prevent that the second range is played and the server stops after
completing the first range, a PAUSE request for 20 must be issued. | completing the first range, a PAUSE request for 20 must be issued.
As another example, if a server has received requests to play ranges | As another example, if a server has received requests to play ranges
10 to 15 and then 13 to 20 (that is, overlapping ranges), the PAUSE | 10 to 15 and then 13 to 20 (that is, overlapping ranges), the PAUSE
request for NPT=14 would take effect while the server plays the first | request for NPT=14 would take effect while the server plays the first
range, with the second range effectively being ignored, assuming the | range, with the second range effectively being ignored, assuming the
PAUSE request arrives before the server has started playing the | PAUSE request arrives before the server has started playing the
second, overlapping range. Regardless of when the PAUSE request | second, overlapping range. Regardless of when the PAUSE request
arrives, it sets the pause point to 14. The below example messages is | arrives, it sets the pause point to 14. The below example messages is
for the above case when the PAUSE request arrives before the first | for the above case when the PAUSE request arrives before the first
occurrence of NPT=14. | occurrence of NPT=14.
C->S: PLAY rtsp://example.com/fizzle/foo RTSP/1.0 | C->S: PLAY rtsp://example.com/fizzle/foo RTSP/1.0
CSeq: 834
Session: 12345678
Range: npt=10-15, npt=13-20
S->C: RTSP/1.0 200 OK
CSeq: 834
Date: 23 Jan 1997 15:35:06 GMT
Server: PhonyServer 1.0
Range: npt=10-15, npt=13-20
RTP-Info:url=rtsp://example.com/fizzle/audiotrack;
seq=5712;rtptime=934207921,
url=rtsp://example.com/fizzle/videotrack;
seq=57654;rtptime=2792482193
Session: 12345678
C->S: PAUSE rtsp://example.com/fizzle/foo RTSP/1.0
CSeq: 835
Session: 12345678
Range: npt=14-
S->C: RTSP/1.0 200 OK
CSeq: 835
Date: 23 Jan 1997 15:35:09 GMT
Server: PhonyServer 1.0
Range: npt=14-15, npt=13-20
Session: 12345678
If a client issues a PAUSE request and the server acknowledges and
enters the READY state, the proper server response, if the player
issues another PAUSE, is still 200 OK. The 200 OK response MUST
include the Range header with the current pause point, even if the
PAUSE request is asking for some other pause point. See examples
below:
Examples: |
C->S: PAUSE rtsp://example.com/fizzle/foo RTSP/1.0 |
CSeq: 834 | CSeq: 834 |
Session: 12345678 | Session: 12345678 |
Range: npt=10-15, npt=13-20 |
S->C: RTSP/1.0 200 OK | S->C: RTSP/1.0 200 OK |
CSeq: 834 | CSeq: 834 |
Date: 23 Jan 1997 15:35:06 GMT |
Server: PhonyServer 1.0 |
Range: npt=10-15, npt=13-20 |
RTP-Info:url=rtsp://example.com/fizzle/audiotrack; |
seq=5712;rtptime=934207921, |
url=rtsp://example.com/fizzle/videotrack; |
seq=57654;rtptime=2792482193 |
Session: 12345678 | Session: 12345678 |
Date: 23 Jan 1997 15:35:06 GMT |
Range: npt=45.76-98.36 |
C->S: PAUSE rtsp://example.com/fizzle/foo RTSP/1.0 | C->S: PAUSE rtsp://example.com/fizzle/foo RTSP/1.0 |
CSeq: 835 | CSeq: 835 |
Session: 12345678 | Session: 12345678 |
Range: npt=14- | Range: 86- |
S->C: RTSP/1.0 200 OK | S->C: RTSP/1.0 200 OK |
CSeq: 835 | CSeq: 835 |
Date: 23 Jan 1997 15:35:09 GMT |
Server: PhonyServer 1.0 |
Range: npt=14-15, npt=13-20 |
Session: 12345678 | Session: 12345678 |
Date: 23 Jan 1997 15:35:07 GMT |
If a client issues a PAUSE request and the server acknowledges and | Range: npt=45.76-98.36 |
enters the READY state, the proper server response, if the player |
issues another PAUSE, is still 200 OK. The 200 OK response MUST |
include the Range header with the current pause point, even if the |
PAUSE request is asking for some other pause point. See examples |
below:
Examples:
C->S: PAUSE rtsp://example.com/fizzle/foo RTSP/1.0
CSeq: 834
Session: 12345678
S->C: RTSP/1.0 200 OK
CSeq: 834
Session: 12345678
Date: 23 Jan 1997 15:35:06 GMT
Range: npt=45.76-
C->S: PAUSE rtsp://example.com/fizzle/foo RTSP/1.0
CSeq: 835
Session: 12345678
Range: 86-
S->C: RTSP/1.0 200 OK
CSeq: 835
Session: 12345678
Date: 23 Jan 1997 15:35:07 GMT
Range: npt=45.76-
11.6 TEARDOWN 11.6 TEARDOWN
The TEARDOWN client to server request stops the stream delivery for | The TEARDOWN client to server request stops the stream delivery for
the given URI, freeing the resources associated with it. TEARDOWN | the given URL, freeing the resources associated with it. TEARDOWN
MAY be done using either an aggregated or a media control URI. | MAY be done using either an aggregated or a media control URL.
However some restrictions apply depending on the current state. The |
TEARDOWN request SHALL contain a Session header indicating what |
session the request applies to. |
A TEARDOWN using the aggregated control URI or the media URI in a | However some restrictions apply depending on the current state. The
session under non-aggregated control MAY be done in any state (Ready, | TEARDOWN request SHALL contain a Session header indicating what
and Play). A successful request SHALL result in that media delivery | session the request applies to.
is immediately halted and the session state is destroyed. This SHALL |
be indicated through the lack of a Session header in the response. |
A TEARDOWN using a media URI in an aggregated session MAY only be | A TEARDOWN using the aggregated control URL or the media URL in a
session under non-aggregated control MAY be done in any state (Ready,
and Play). A successful request SHALL result in that media delivery
is immediately halted and the session state is destroyed. This SHALL
be indicated through the lack of a Session header in the response.
A TEARDOWN using a media URL in an aggregated session MAY only be |
done in Ready state. Such a request only removes the indicated media | done in Ready state. Such a request only removes the indicated media |
stream and associated resources from the session. This may result in | stream and associated resources from the session. This may result in |
that a session returns to non-aggregated control. In the response to | that a session returns to non-aggregated control, due to that it only |
TEARDOWN request resulting in that the session still exist SHALL | contains a single media. In the response to TEARDOWN request |
contain a Session header to indicate this. | resulting in that the session still exist SHALL contain a Session |
header to indicate this.
Note, the indication with the session header if sessions state remain | Note, the indication with the session header if sessions state remain
may not be done correctly by a RFC 2326 client, but will be for any | may not be done correctly by a RFC 2326 client, but will be for any
server signalling the "play.basic" tag. server signalling the "play.basic" tag.
Example: Example:
C->S: TEARDOWN rtsp://example.com/fizzle/foo RTSP/1.0 C->S: TEARDOWN rtsp://example.com/fizzle/foo RTSP/1.0
CSeq: 892 CSeq: 892
Session: 12345678 Session: 12345678
S->C: RTSP/1.0 200 OK S->C: RTSP/1.0 200 OK
CSeq: 892 CSeq: 892
Server: PhonyServer 1.0 Server: PhonyServer 1.0
11.7 GET_PARAMETER 11.7 GET_PARAMETER
The GET_PARAMETER request retrieves the value of a parameter of a The GET_PARAMETER request retrieves the value of a parameter or |
presentation or stream specified in the URI. If the Session header is parameters for a presentation or stream specified in the URL. If the |
present in a request, the value of a parameter MUST be retrieved in Session header is present in a request, the value of a parameter MUST |
the sessions context. The content of the reply and response is left be retrieved in the specified session context. The content of the |
to the implementation. GET_PARAMETER with no entity body may be used reply and response is left to the implementation. |
to test client or server liveness ("ping").
The method MAY also be used without a body (entity). If the this |
request is successful, i.e. a 200 OK response is received, then the |
keep-alive time has been updated. Any non-required header present in |
such a request, may or may not been processed. The allow a client to |
determine if any such header has been processed, it is necessary to |
use a feature tag and the Require header. Due to this reason it is |
RECOMMENDED that any parameters to be retrieved are sent in the body, |
rather than using any header.
Example: Example:
S->C: GET_PARAMETER rtsp://example.com/fizzle/foo RTSP/1.0 S->C: GET_PARAMETER rtsp://example.com/fizzle/foo RTSP/1.0
CSeq: 431 CSeq: 431
Content-Type: text/parameters Content-Type: text/parameters
Session: 12345678 Session: 12345678
Content-Length: 15 Content-Length: 15
packets_received packets_received
skipping to change at page 47, line 40 skipping to change at page 53, line 34
packets_received: 10 packets_received: 10
jitter: 0.3838 jitter: 0.3838
The "text/parameters" section is only an example type for The "text/parameters" section is only an example type for
parameter. This method is intentionally loosely defined parameter. This method is intentionally loosely defined
with the intention that the reply content and response with the intention that the reply content and response
content will be defined after further experimentation. content will be defined after further experimentation.
11.8 SET_PARAMETER 11.8 SET_PARAMETER
This method requests to set the value of a parameter for a This method requests to set the value of a parameter or a set of |
presentation or stream specified by the URI. parameters for a presentation or stream specified by the URL. The |
method MAY also be used without a body (entity). If the this request |
is successful, i.e. a 200 OK response is received, then the keep- |
alive time has been updated. Any non-required header present in such |
a request, may or may not been processed. The allow a client to |
determine if any such header has been processed, it is necessary to |
use a feature tag and the Require header. Due to this reason it is |
RECOMMENDED that any parameters are sent in the body, rather than |
using any header.
A request is RECOMMENDED to only contain a single parameter to allow A request is RECOMMENDED to only contain a single parameter to allow
the client to determine why a particular request failed. If the the client to determine why a particular request failed. If the
request contains several parameters, the server MUST only act on the request contains several parameters, the server MUST only act on the
request if all of the parameters can be set successfully. A server request if all of the parameters can be set successfully. A server
MUST allow a parameter to be set repeatedly to the same value, but it MUST allow a parameter to be set repeatedly to the same value, but it
MAY disallow changing parameter values. If the receiver of the MAY disallow changing parameter values. If the receiver of the
request does not understand or can locate a parameter error 451 request does not understand or can locate a parameter error 451
(Parameter Not Understood) SHALL be used. In the case a parameter is (Parameter Not Understood) SHALL be used. In the case a parameter is
not allowed to change the error code 458 (Parameter Is Read-Only). not allowed to change the error code 458 (Parameter Is Read-Only).
skipping to change at page 49, line 4 skipping to change at page 55, line 6
Content-type: text/parameters Content-type: text/parameters
barparam barparam
The "text/parameters" section is only an example type for The "text/parameters" section is only an example type for
parameter. This method is intentionally loosely defined parameter. This method is intentionally loosely defined
with the intention that the reply content and response with the intention that the reply content and response
content will be defined after further experimentation. content will be defined after further experimentation.
11.9 REDIRECT 11.9 REDIRECT
A redirect request informs the client that it MUST connect to another |
server location. The REDIRECT request MAY contain the header |
Location, which indicates that the client should issue requests for |
that URL. The lack of a Location header in the response SHALL be |
interpreted as that the server can't any longer fulfill the current |
request, but has no alternative at the present where the client |
continue. |
If a REDIRECT request contains a Session header, it is end-to-end and | A redirect request informs the client that it MUST connect to another
applies only to the given session. If there are proxies in the | server location. The REDIRECT request MAY contain the header
request chain, they SHOULD NOT disconnect the control channel unless | Location, which indicates that the client should issue requests for
there are no remaining sessions. If the Location header is included | that URL. The lack of a Location header in the response SHALL be
it SHALL contain a full absolute URI pointing out the resource to | interpreted as that the server can't any longer fulfill the current
reconnect too, i.e. the Location SHALL NOT contain only host and | request, but has no alternative at the present where the client can
port. | continue.
If a REDIRECT request does not contain a Session header, it is next- | If a REDIRECT request contains a Session header, it is end-to-end and
hop and applies also to the control connection. If the Location | applies only to the given session. If there are proxies in the
header is included it SHOULD only contain an absolute URI containing | request chain, they SHOULD NOT disconnect the control channel unless
the host address and OPTIONAL the port number. If there are proxies | there are no remaining sessions. If the Location header is included
in the request chain, they SHOULD do all of the following: (1) | it SHALL contain a full absolute URL pointing out the resource to
respond to the REDIRECT request, (2) disconnect the control channel | reconnect too, i.e. the Location SHALL NOT contain only host and
from the requestor, (3) reconnect to the given host address, and (4) | port.
pass the request to each applicable client (typically those clients |
with an active session or unanswered request from the requestor). | If a REDIRECT request does not contain a Session header, it is next-
Note that the proxy is responsible for accepting the REDIRECT | hop and applies also to the control connection. If the Location
response from its clients and these responses MUST NOT be passed on | header is included it SHOULD only contain an absolute URL containing
the host address and OPTIONAL the port number. If there are proxies
in the request chain, they SHOULD do all of the following: (1)
respond to the REDIRECT request, (2) disconnect the control channel
from the requestor, (3) reconnect to the given host address, and (4)
pass the request to each applicable client (typically those clients
with an active session or unanswered request from the requestor).
Note that the proxy is responsible for accepting the REDIRECT
response from its clients and these responses MUST NOT be passed on
to either the requesting or the destination server. to either the requesting or the destination server.
A REDIRECT request with a Session header MAY only be received by a |
client when it has the established session. A REDIRECT request |
without a Session MAY be received at any time communication is |
established with the server.
The redirect request MAY contain the header Range, which indicates The redirect request MAY contain the header Range, which indicates
when the redirection takes effect. If the Range contains a "time=" when the redirection takes effect. If the Range contains a "time="
value that is the wall clock time that the redirection MUST at the value that is the wall clock time that the redirection MUST at the
latest take place. When the "time=" parameter is present the range latest take place. When the "time=" parameter is present the range
value MUST be ignored. However the range entered MUST be syntactical value MUST be ignored. However the range entered MUST be syntactical
correct and SHALL point at the beginning of any on-demand content. If correct and SHALL point at the beginning of any on-demand content. If
no time parameter is part of the Range header then redirection SHALL no time parameter is part of the Range header then redirection SHALL
take place when the media playout from the server reaches the given take place when the media playout from the server reaches the given
time. The range value MUST be a single value in the open ended form, time. The range value MUST be a single value in the open ended form,
e.g. npt=59-. e.g. npt=59-.
A server upon receiving a successful (2xx) response for a REDIRECT | A server upon receiving a successful (2xx) response for a REDIRECT
request without any Range header SHALL consider the session as | request without any Range header SHALL consider the session as
removed and can free any session state. For this type of requests the | removed and can free any session state. For this type of requests
rest of this paragraph applies. The server MAY close the signalling | the rest of this paragraph applies. The server MAY close the
connection upon receiving the response for REDIRECT requests without | signalling connection upon receiving the response for REDIRECT
a Session header. The client SHOULD close the signaling connection | requests without a Session header. The client SHOULD close the
after having given the 2xx response to a REDIRECT response, unless it | signaling connection after having given the 2xx response to a
has several sessions on the server. If the client has multiple | REDIRECT response, unless it has several sessions on the server. If
session on the server it SHOULD close the connection when it has | the client has multiple session on the server it SHOULD close the
received and responded to REDIRECT requests for all sessions. | connection when it has received and responded to REDIRECT requests
for all sessions.
A client receiving a REDIRECT request with a Range header SHALL issue | A client receiving a REDIRECT request with a Range header SHALL issue
a TEARDOWN request when the in indicated redirect point is reached. | a TEARDOWN request when the in indicated redirect point is reached.
The client SHOULD for REDIRECT requests with Range header close the | The client SHOULD for REDIRECT requests with Range header close the
signalling connection after a 2xx response on its TEARDOWN request. | signalling connection after a 2xx response on its TEARDOWN request.
The normal connection considerations apply for the server. This | The normal connection considerations apply for the server. This
differentiation from REDIRECT requests without range headers is to | differentiation from REDIRECT requests without range headers is to
allow clear an explicit state handling. As the state in the server | allow clear an explicit state handling. As the state in the server
needs to be kept until the point of redirection, the handling becomes | needs to be kept until the point of redirection, the handling becomes
more clear if the client is required to tear down the session at that | more clear if the client is required to tear down the session at that
point. | point.
If the client wants to continue to send or receive media for this | If the client wants to continue to send or receive media for this
resource, the client will have to establish a new session with the | resource, the client will have to establish a new session with the
designated host. A client SHOULD issue a new DESCRIBE request with | designated host. A client SHOULD issue a new DESCRIBE request with
the URL given in the Location header, unless the URL only contains a | the URL given in the Location header, unless the URL only contains a
host address. In the cases the Location only contains a host address | host address. In the cases the Location only contains a host address
the client MAY assume that the media on the server it is redirected | the client MAY assume that the media on the server it is redirected
to is identical. Identical media means that all media configuration | to is identical. Identical media means that all media configuration
information from the old session still is valid except for the host | information from the old session still is valid except for the host
address. In the case of absolute URLs in the location header the | address. In the case of absolute URLs in the location header the
media redirected to can be either identical, slightly different or | media redirected to can be either identical, slightly different or
totally different. This is the reason why a new DESCRIBE request | totally different. This is the reason why a new DESCRIBE request
SHOULD be issued. SHOULD be issued.
This example request redirects traffic for this session to the new This example request redirects traffic for this session to the new
server at the given absolute time: server at the given absolute time:
S->C: REDIRECT rtsp://example.com/fizzle/foo RTSP/1.0 S->C: REDIRECT rtsp://example.com/fizzle/foo RTSP/1.0
CSeq: 732 CSeq: 732
Location: rtsp://bigserver.com:8001 Location: rtsp://s2.example.com:8001
Range: npt=0- ;time=19960213T143205Z Range: npt=0- ;time=19960213T143205Z
Session: uZ3ci0K+Ld-M Session: uZ3ci0K+Ld-M
11.10 PING 11.10 PING
This method is a bi-directional mechanism for server or client This method is a bi-directional mechanism for server or client
liveness checking. It has no side effects. The issuer of the request liveness checking. It has no side effects. The issuer of the request
MUST include a session header with the session ID of the session that MUST include a session header with the session ID of the session that
is being checked for liveness. is being checked for liveness.
Prior to using this method, an OPTIONS method is RECOMMENDED to be Prior to using this method, an OPTIONS method is RECOMMENDED to be
issued in the direction which the PING method would be used. This issued in the direction which the PING method would be used. This
method MUST NOT be used if support is not indicated by the Public method MUST NOT be used if support is not indicated by the Public
header. Note: That an 501 (Not Implemented) response means that the header. Note: That an 501 (Not Implemented) response means that the
keep-alive timer has not been updated. keep-alive timer has not been updated.
skipping to change at page 51, line 23 skipping to change at page 57, line 29
Example: Example:
C->S: PING * RTSP/1.0 C->S: PING * RTSP/1.0
CSeq: 123 CSeq: 123
Session:12345678 Session:12345678
S->C: RTSP/1.0 200 OK S->C: RTSP/1.0 200 OK
CSeq: 123 CSeq: 123
Session:12345678 Session:12345678
11.11 Embedded (Interleaved) Binary Data 12 Embedded (Interleaved) Binary Data
Certain firewall designs and other circumstances may force a server Certain firewall designs and other circumstances may force a server
to interleave RTSP messages and media stream data. This interleaving to interleave RTSP messages and media stream data. This interleaving
should generally be avoided unless necessary since it complicates should generally be avoided unless necessary since it complicates
client and server operation and imposes additional overhead. Also client and server operation and imposes additional overhead. Also
head of line blocking may cause problems. Interleaved binary data head of line blocking may cause problems. Interleaved binary data
SHOULD only be used if RTSP is carried over TCP. SHOULD only be used if RTSP is carried over TCP.
Stream data such as RTP packets is encapsulated by an ASCII dollar Stream data such as RTP packets is encapsulated by an ASCII dollar
sign (24 decimal), followed by a one-byte channel identifier, sign (24 decimal), followed by a one-byte channel identifier,
followed by the length of the encapsulated binary data as a binary, followed by the length of the encapsulated binary data as a binary,
two-byte integer in network byte order. The stream data follows two-byte integer in network byte order. The stream data follows
immediately afterwards, without a CRLF, but including the upper-layer immediately afterwards, without a CRLF, but including the upper-layer
protocol headers. Each $ block contains exactly one upper-layer protocol headers. Each $ block SHALL contain exactly one upper-layer
protocol data unit, e.g., one RTP packet. protocol data unit, e.g., one RTP packet.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| "$" = 24 | Channel ID | Length in bytes | | "$" = 24 | Channel ID | Length in bytes |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: Length number of bytes of binary data : : Length number of bytes of binary data :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The channel identifier is defined in the Transport header with the The channel identifier is defined in the Transport header with the
interleaved parameter(Section 13.40). interleaved parameter(Section 14.40).
When the transport choice is RTP, RTCP messages are also interleaved When the transport choice is RTP, RTCP messages are also interleaved
by the server over the TCP connection. The usage of RTCP messages is by the server over the TCP connection. The usage of RTCP messages is
indicated by including a range containing a second channel in the indicated by including a range containing a second channel in the
interleaved parameter of the Transport header, see section 13.40. If interleaved parameter of the Transport header, see section 14.40. If
RTCP is used, packets SHALL be sent on the first available channel RTCP is used, packets SHALL be sent on the first available channel
higher than the RTP channel. The channels are bi-directional and higher than the RTP channel. The channels are bi-directional and
therefore RTCP traffic are sent on the second channel in both therefore RTCP traffic are sent on the second channel in both
directions. directions.
RTCP is needed for synchronization when two or more streams RTCP is needed for synchronization when two or more streams
are interleaved in such a fashion. Also, this provides a are interleaved in such a fashion. Also, this provides a
convenient way to tunnel RTP/RTCP packets through the TCP convenient way to tunnel RTP/RTCP packets through the TCP
control connection when required by the network control connection when required by the network
configuration and transfer them onto UDP when possible. configuration and transfer them onto UDP when possible.
C->S: SETUP rtsp://foo.com/bar.file RTSP/1.0 C->S: SETUP rtsp://example.com/bar.file RTSP/1.0 |
CSeq: 2 CSeq: 2 |
Transport: RTP/AVP/TCP;unicast;interleaved=0-1 Transport: RTP/AVP/TCP;unicast;interleaved=0-1 |
S->C: RTSP/1.0 200 OK S->C: RTSP/1.0 200 OK |
CSeq: 2 CSeq: 2 |
Date: 05 Jun 1997 18:57:18 GMT Date: 05 Jun 1997 18:57:18 GMT |
Transport: RTP/AVP/TCP;unicast;interleaved=5-6 Transport: RTP/AVP/TCP;unicast;interleaved=5-6 |
Session: 12345678 Session: 12345678 |
C->S: PLAY rtsp://foo.com/bar.file RTSP/1.0 C->S: PLAY rtsp://example.com/bar.file RTSP/1.0 |
CSeq: 3 CSeq: 3 |
Session: 12345678 Session: 12345678 |
S->C: RTSP/1.0 200 OK S->C: RTSP/1.0 200 OK |
CSeq: 3 CSeq: 3 |
Session: 12345678 Session: 12345678 |
Date: 05 Jun 1997 18:59:15 GMT Date: 05 Jun 1997 18:59:15 GMT |
RTP-Info: url=rtsp://foo.com/bar.file; RTP-Info: url=rtsp://example.com/bar.file; |
seq=232433;rtptime=972948234 seq=232433;rtptime=972948234 |
S->C: $005{2 byte length}{"length" bytes data, w/RTP header}
S->C: $005{2 byte length}{"length" bytes data, w/RTP header}
S->C: $006{2 byte length}{"length" bytes RTCP packet}
12 Status Code Definitions S->C: $005{2 byte length}{"length" bytes data, w/RTP header} |
S->C: $005{2 byte length}{"length" bytes data, w/RTP header} |
S->C: $006{2 byte length}{"length" bytes RTCP packet} |
13 Status Code Definitions
Where applicable, HTTP status [H10] codes are reused. Status codes Where applicable, HTTP status [H10] codes are reused. Status codes
that have the same meaning are not repeated here. See Table 1 for a that have the same meaning are not repeated here. See Table 4 for a
listing of which status codes may be returned by which requests. All listing of which status codes may be returned by which requests. All
error messages, 4xx and 5xx MAY return a body containing further error messages, 4xx and 5xx MAY return a body containing further
information about the error. information about the error.
12.1 Success 1xx 13.1 Success 1xx
12.1.1 100 Continue 13.1.1 100 Continue
See, [H10.1.1]. See, [H10.1.1].
12.2 Success 2xx 13.2 Success 2xx
12.2.1 250 Low on Storage Space
The server returns this warning after receiving a RECORD request that
it may not be able to fulfill completely due to insufficient storage
space. If possible, the server should use the Range header to
indicate what time period it may still be able to record. Since other
processes on the server may be consuming storage space
simultaneously, a client should take this only as an estimate.
12.3 Redirection 3xx 13.3 Redirection 3xx
The notation "3rr" indicates response codes from 300 to 399 inclusive The notation "3rr" indicates response codes from 300 to 399 inclusive
which are meant for redirection. The response code 304 is excluded which are meant for redirection. The response code 304 is excluded
from this set, as it is not used for redirection. from this set, as it is not used for redirection.
See [H10.3] for definition of status code 300 to 305. However See [H10.3] for definition of status code 300 to 305. However
comments are given for some to how they apply to RTSP. comments are given for some to how they apply to RTSP.
Within RTSP, redirection may be used for load balancing or Within RTSP, redirection may be used for load balancing or
redirecting stream requests to a server topologically closer to the redirecting stream requests to a server topologically closer to the
client. Mechanisms to determine topological proximity are beyond the client. Mechanisms to determine topological proximity are beyond the
scope of this specification. scope of this specification.
If the the Location header is used in a response it SHALL contain an | A 3rr code MAY be used to respond to any request. It is RECOMMENDED |
absolute URI pointing out the media resource the client is redirected | that they are used if necessary before a session is established, i.e. |
to, the URI SHALL NOT only contain the host name. in response to DESCRIBE or SETUP. However in cases where a server is |
not able to send a REDIRECT request to the client, the server MAY |
need to resort to using 3rr responses to inform a client with a |
established session about the need for redirecting the session. If an |
3rr response is received for an request in relation to a established |
session, the client SHOULD send a TEARDOWN request for the session, |
and MAY reestablish the session using the resource indicated by the |
Location.
12.3.1 300 Multiple Choices If the the Location header is used in a response it SHALL contain an
absolute URL pointing out the media resource the client is redirected
to, the URL SHALL NOT only contain the host name.
12.3.2 301 Moved Permanently 13.3.1 300 Multiple Choices
The request resource are moved permanently and resides now at the URI 13.3.2 301 Moved Permanently
The request resource are moved permanently and resides now at the URL
given by the location header. The user client SHOULD redirect given by the location header. The user client SHOULD redirect
automatically to the given URI. This response MUST NOT contain a automatically to the given URL. This response MUST NOT contain a
message-body. message-body.
12.3.3 302 Found 13.3.3 302 Found
The requested resource reside temporarily at the URI given by the The requested resource reside temporarily at the URL given by the
Location header. The Location header MUST be included in the Location header. The Location header MUST be included in the
response. Is intended to be used for many types of temporary response. Is intended to be used for many types of temporary
redirects, e.g. load balancing. It is RECOMMENDED that one set the redirects, e.g. load balancing. It is RECOMMENDED that one set the
reason phrase to something more meaningful than "Found" in these reason phrase to something more meaningful than "Found" in these
cases. The user client SHOULD redirect automatically to the given cases. The user client SHOULD redirect automatically to the given
URI. This response MUST NOT contain a message-body. URL. This response MUST NOT contain a message-body.
12.3.4 303 See Other 13.3.4 303 See Other
This status code SHALL NOT be used in RTSP. However as it was allowed This status code SHALL NOT be used in RTSP. However as it was allowed |
to use in RFC 2326 it is possible that such response may be received. to use in RFC 2326 it is possible that such response may be received, |
in which case the behavior is undefined.
12.3.5 304 Not Modified 13.3.5 304 Not Modified
If the client has performed a conditional DESCRIBE or SETUP (see If the client has performed a conditional DESCRIBE or SETUP (see
12.23) and the requested resource has not been modified, the server 12.23) and the requested resource has not been modified, the server
SHOULD send a 304 response. This response MUST NOT contain a SHOULD send a 304 response. This response MUST NOT contain a
message-body. message-body.
The response MUST include the following header fields: The response MUST include the following header fields:
o Date o Date
skipping to change at page 55, line 5 skipping to change at page 61, line 13
o Expires, Cache-Control, and/or Vary, if the field-value might o Expires, Cache-Control, and/or Vary, if the field-value might
differ from that sent in any previous response for the same differ from that sent in any previous response for the same
variant. variant.
This response is independent for the DESCRIBE and SETUP requests. This response is independent for the DESCRIBE and SETUP requests.
That is, a 304 response to DESCRIBE does NOT imply that the resource That is, a 304 response to DESCRIBE does NOT imply that the resource
content is unchanged and a 304 response to SETUP does NOT imply that content is unchanged and a 304 response to SETUP does NOT imply that
the resource description is unchanged. The ETag and If-Match headers the resource description is unchanged. The ETag and If-Match headers
may be used to link the DESCRIBE and SETUP in this manner. may be used to link the DESCRIBE and SETUP in this manner.
12.3.6 305 Use Proxy 13.3.6 305 Use Proxy
See [H10.3.6]. See [H10.3.6].
12.4 Client Error 4xx 13.4 Client Error 4xx
12.4.1 400 Bad Request 13.4.1 400 Bad Request
The request could not be understood by the server due to malformed The request could not be understood by the server due to malformed
syntax. The client SHOULD NOT repeat the request without syntax. The client SHOULD NOT repeat the request without
modifications [H10.4.1]. If the request does not have a CSeq header, modifications [H10.4.1]. If the request does not have a CSeq header,
the server MUST NOT include a CSeq in the response. the server MUST NOT include a CSeq in the response.
12.4.2 405 Method Not Allowed 13.4.2 405 Method Not Allowed
The method specified in the request is not allowed for the resource The method specified in the request is not allowed for the resource
identified by the request URI. The response MUST include an Allow identified by the request URL. The response MUST include an Allow
header containing a list of valid methods for the requested resource. header containing a list of valid methods for the requested resource.
This status code is also to be used if a request attempts to use a This status code is also to be used if a request attempts to use a
method not indicated during SETUP, e.g., if a RECORD request is method not indicated during SETUP, e.g., if a RECORD request is
issued even though the mode parameter in the Transport header only issued even though the mode parameter in the Transport header only
specified PLAY. specified PLAY.
12.4.3 451 Parameter Not Understood 13.4.3 451 Parameter Not Understood
The recipient of the request does not support one or more parameters The recipient of the request does not support one or more parameters
contained in the request.When returning this error message the sender contained in the request.When returning this error message the sender
SHOULD return a entity body containing the offending parameter(s). SHOULD return a entity body containing the offending parameter(s).
12.4.4 452 reserved 13.4.4 452 reserved
This error code was removed from RFC 2326 [21] and is obsolete. This error code was removed from RFC 2326 [1] and is obsolete.
12.4.5 453 Not Enough Bandwidth 13.4.5 453 Not Enough Bandwidth
The request was refused because there was insufficient bandwidth. The request was refused because there was insufficient bandwidth.
This may, for example, be the result of a resource reservation This may, for example, be the result of a resource reservation
failure. failure.
12.4.6 454 Session Not Found 13.4.6 454 Session Not Found
The RTSP session identifier in the Session header is missing, The RTSP session identifier in the Session header is missing,
invalid, or has timed out. invalid, or has timed out.
12.4.7 455 Method Not Valid in This State 13.4.7 455 Method Not Valid in This State
The client or server cannot process this request in its current The client or server cannot process this request in its current
state. The response SHOULD contain an Allow header to make error state. The response SHOULD contain an Allow header to make error
recovery easier. recovery easier.
12.4.8 456 Header Field Not Valid for Resource 13.4.8 456 Header Field Not Valid for Resource
The server could not act on a required request header. For example, The server could not act on a required request header. For example,
if PLAY contains the Range header field but the stream does not allow if PLAY contains the Range header field but the stream does not allow
seeking. This error message may also be used for specifying when the seeking. This error message may also be used for specifying when the
time format in Range is impossible for the resource. In that case the time format in Range is impossible for the resource. In that case the
Accept-Ranges header SHOULD be returned to inform the client of which Accept-Ranges header SHOULD be returned to inform the client of which
format(s) that are allowed. format(s) that are allowed.
12.4.9 457 Invalid Range 13.4.9 457 Invalid Range
The Range value given is out of bounds, e.g., beyond the end of the The Range value given is out of bounds, e.g., beyond the end of the
presentation. presentation.
12.4.10 458 Parameter Is Read-Only 13.4.10 458 Parameter Is Read-Only
The parameter to be set by SET_PARAMETER can be read but not The parameter to be set by SET_PARAMETER can be read but not
modified. When returning this error message the sender SHOULD return modified. When returning this error message the sender SHOULD return
a entity body containing the offending parameter(s). a entity body containing the offending parameter(s).
12.4.11 459 Aggregate Operation Not Allowed 13.4.11 459 Aggregate Operation Not Allowed
The requested method may not be applied on the URL in question since The requested method may not be applied on the URL in question since
it is an aggregate (presentation) URL. The method may be applied on a it is an aggregate (presentation) URL. The method may be applied on a
media URL. media URL.
12.4.12 460 Only Aggregate Operation Allowed 13.4.12 460 Only Aggregate Operation Allowed
The requested method may not be applied on the URL in question since The requested method may not be applied on the URL in question since
it is not an aggregate control (presentation) URL. The method may be it is not an aggregate control (presentation) URL. The method may be
applied on the aggregate control URL. applied on the aggregate control URL.
12.4.13 461 Unsupported Transport 13.4.13 461 Unsupported Transport
The Transport field did not contain a supported transport The Transport field did not contain a supported transport
specification. specification.
12.4.14 462 Destination Unreachable 13.4.14 462 Destination Unreachable
The data transmission channel could not be established because the The data transmission channel could not be established because the
client address could not be reached. This error will most likely be client address could not be reached. This error will most likely be
the result of a client attempt to place an invalid Destination the result of a client attempt to place an invalid Destination
parameter in the Transport field. parameter in the Transport field.
12.5 Server Error 5xx 13.5 Server Error 5xx
12.5.1 551 Option not supported 13.5.1 551 Option not supported
An feature-tag given in the Require or the Proxy-Require fields was An feature-tag given in the Require or the Proxy-Require fields was
not supported. The Unsupported header SHOULD be returned stating the not supported. The Unsupported header SHOULD be returned stating the
feature for which there is no support. feature for which there is no support.
13 Header Field Definitions 14 Header Field Definitions
method direction object acronym Body method direction object acronym Body
_________________________________________________ _________________________________________________
DESCRIBE C -> S P,S DES r DESCRIBE C -> S P,S DES r
GET_PARAMETER C -> S, S -> C P,S GPR R,r GET_PARAMETER C -> S, S -> C P,S GPR R,r
OPTIONS C -> S P,S OPT OPTIONS C -> S P,S OPT
S -> C S -> C
PAUSE C -> S P,S PSE PAUSE C -> S P,S PSE
PING C -> S, S -> C P,S PNG PING C -> S, S -> C P,S PNG
PLAY C -> S P,S PLY PLAY C -> S P,S PLY
REDIRECT S -> C P,S RDR REDIRECT S -> C P,S RDR
SETUP C -> S S STP SETUP C -> S S STP
SET_PARAMETER C -> S, S -> C P,S SPR R,r SET_PARAMETER C -> S, S -> C P,S SPR R,r
TEARDOWN C -> S P,S TRD TEARDOWN C -> S P,S TRD
Table 3: Overview of RTSP methods, their direction, and what objects Table 8: Overview of RTSP methods, their direction, and what objects
(P: presentation, S: stream) they operate on. Body notes if a method (P: presentation, S: stream) they operate on. Body notes if a method
is allowed to carry body and in which direction, R = Request, is allowed to carry body and in which direction, R = Request,
r=response. Note: It is allowed for all error messages 4xx and 5xx to r=response. Note: It is allowed for all error messages 4xx and 5xx to
have a body have a body
The general syntax for header fields is covered in Section 4.2 This The general syntax for header fields is covered in Section 4.2 This
section lists the full set of header fields along with notes on section lists the full set of header fields along with notes on
syntax, meaning, and usage. Throughout this section, we use [HX.Y] meaning, and usage. The syntax definition for headers are present in
to refer to Section X.Y of the current HTTP/1.1 specification RFC section 17.2.3. Throughout this section, we use [HX.Y] to refer to
2616 [26]. Examples of each header field are given. Section X.Y of the current HTTP/1.1 specification RFC 2616 [4].
Examples of each header field are given.
Information about header fields in relation to methods and proxy Information about header fields in relation to methods and proxy
processing is summarized in Table 4 and Table 5. processing is summarized in Table 9 and Table 10.
The "where" column describes the request and response types in which The "where" column describes the request and response types in which
the header field can be used. Values in this column are: the header field can be used. Values in this column are:
R: header field may only appear in requests; R: header field may only appear in requests;
r: header field may only appear in responses; r: header field may only appear in responses;
2xx, 4xx, etc.: A numerical value or range indicates response 2xx, 4xx, etc.: A numerical value or range indicates response
codes with which the header field can be used; codes with which the header field can be used;
skipping to change at page 58, line 23 skipping to change at page 64, line 34
present. present.
m: A proxy can modify an existing header field value. m: A proxy can modify an existing header field value.
d: A proxy can delete a header field value. d: A proxy can delete a header field value.
r: A proxy must be able to read the header field, and thus this r: A proxy must be able to read the header field, and thus this
header field cannot be encrypted. header field cannot be encrypted.
The rest of the columns relate to the presence of a header field in a The rest of the columns relate to the presence of a header field in a
method. The method names when abbreviated, are according to table 3: method. The method names when abbreviated, are according to table 8:
c: Conditional; requirements on the header field depend on the c: Conditional; requirements on the header field depend on the
context of the message. context of the message.
m: The header field is mandatory. m: The header field is mandatory.
m*: The header field SHOULD be sent, but clients/servers need to m*: The header field SHOULD be sent, but clients/servers need to
be prepared to receive messages without that header field. be prepared to receive messages without that header field.
o: The header field is optional. o: The header field is optional.
*: The header field is required if the message body is not *: The header field is required if the message body is not
empty. See sections 13.14, 13.16 and 4.3 for details. empty. See sections 14.14, 14.16 and 4.3 for details.
-: The header field is not applicable. -: The header field is not applicable.
"Optional" means that a Client/Server MAY include the header |
"Optional" means that a Client/Server MAY include the header field in field in a request or response. The Client/Server behavior when |
a request or response, and a Client/Server MAY ignore the header receiving such headers varies, for some it may ignore the header |
field if present in the request or response (The exception to this field, in other case it is request to process the header. This |
rule is the Require header field discussed in 13.32). A "mandatory" is regulated by the method and header descriptions. Example of |
header field MUST be present in a request, and MUST be understood by such headers that require processing are the Require and Proxy- |
the Client/Server receiving the request. A mandatory response header Require header fields discussed in 14.32 and 14.27. A |
field MUST be present in the response, and the header field MUST be "mandatory" header field MUST be present in a request, and MUST |
understood by the Client/Server processing the response. "Not be understood by the Client/Server receiving the request. A |
applicable" means that the header field MUST NOT be present in a mandatory response header field MUST be present in the response, |
request. If one is placed in a request by mistake, it MUST be ignored and the header field MUST be understood by the Client/Server |
by the Client/Server receiving the request. Similarly, a header field processing the response. "Not applicable" means that the header |
labeled "not applicable" for a response means that the Client/Server field MUST NOT be present in a request. If one is placed in a |
MUST NOT place the header field in the response, and the request by mistake, it MUST be ignored by the Client/Server |
Client/Server MUST ignore the header field in the response. receiving the request. Similarly, a header field labeled "not |
applicable" for a response means that the Client/Server MUST NOT |
place the header field in the response, and the Client/Server |
MUST ignore the header field in the response.
A Client/Server SHOULD ignore extension header parameters that are A Client/Server SHOULD ignore extension header parameters that are
not understood. not understood.
The From, Location, and RTP-Info header fields contain a URI. If the The From, Location, and RTP-Info header fields contain a URL. If the
URI contains a comma, or semicolon, the URI MUST be enclosed in URL contains a comma, or semicolon, the URL MUST be enclosed in
double quotas ("). Any URI parameters are contained within these double quotas ("). Any URL parameters are contained within these
quotas. If the URI is not enclosed in double quotas, any semicolon- quotas. If the URL is not enclosed in double quotas, any semicolon-
delimited parameters are header-parameters, not URI parameters. delimited parameters are header-parameters, not URL parameters.
13.1 Accept 14.1 Accept
The Accept request-header field can be used to specify certain The Accept request-header field can be used to specify certain
presentation description content types which are acceptable for the presentation description content types which are acceptable for the
response. response.
The "level" parameter for presentation descriptions is The "level" parameter for presentation descriptions is
properly defined as part of the MIME type registration, not properly defined as part of the MIME type registration, not
here. here.
See [H14.1] for syntax. See [H14.1] for syntax.
Example of use: Example of use: |
Accept: application/rtsl q=1.0, application/sdp;level=2
13.2 Accept-Encoding Accept: application/rtsl q=1.0, application/sdp |
14.2 Accept-Encoding
See [H14.3] See [H14.3]
13.3 Accept-Language 14.3 Accept-Language
See [H14.4]. Note that the language specified applies to the See [H14.4]. Note that the language specified applies to the
presentation description and any reason phrases, not the media presentation description and any reason phrases, not the media
content. content.
13.4 Accept-Ranges 14.4 Accept-Ranges
The Accept-Ranges response-header field allows the server to indicate The Accept-Ranges response-header field allows the server to indicate
its acceptance of range requests and possible formats for a resource: | its acceptance of range requests and possible formats for a resource:
Accept-Ranges = "Accept-Ranges" ":" acceptable-ranges |
acceptable-ranges = 1#range-unit / "none" |
range-unit = NPT / SMPTE / UTC / extension-format |
extension-format = token |
This header has the same syntax as [H14.5]. However new range-units | Accept-Ranges: NPT, SMPTE
are defined. Inclusion of any of the time formats indicates |
acceptance by the server for PLAY and PAUSE requests with this |
format. The headers value is valid for the resource specified by the |
URI in the request, this response corresponds to. A server is SHOULD |
to use this header in SETUP responses to indicate to the client which |
range time formats the media supports. The header SHOULD also be |
included in "456" responses which is a result of use of unsupported |
range formats. |
13.5 Allow This header has the same syntax as [H14.5] and the syntax is defined
in 17.2.3. However new range-units are defined. Inclusion of any of
the time formats indicates acceptance by the server for PLAY and
PAUSE requests with this format. The headers value is valid for the
resource specified by the URL in the request, this response
corresponds to. A server SHOULD use this header in SETUP responses to
indicate to the client which range time formats the media supports.
The header SHOULD also be included in "456" responses which is a
result of use of unsupported range formats.
14.5 Allow
The Allow entity-header field lists the methods supported by the The Allow entity-header field lists the methods supported by the
resource identified by the request-URI. The purpose of this field is resource identified by the request-URL. The purpose of this field is
to strictly inform the recipient of valid methods associated with the to strictly inform the recipient of valid methods associated with the
resource. An Allow header field MUST be present in a 405 (Method Not resource. An Allow header field MUST be present in a 405 (Method Not
Allowed) response. See [H14.7] for syntax definition. Allowed) response. See [H14.7] for syntax definition.
Example of use: Example of use:
Allow: SETUP, PLAY, SET_PARAMETER Allow: SETUP, PLAY, SET_PARAMETER
13.6 Authorization 14.6 Authorization
See [H14.8] See [H14.8]
13.7 Bandwidth 14.7 Bandwidth
The Bandwidth request-header field describes the estimated bandwidth
available to the client, expressed as a positive integer and measured
in bits per second. The bandwidth available to the client may change
during an RTSP session, e.g., due to modem retraining.
Bandwidth = "Bandwidth" ":" 1*DIGIT
Example:
Header Where Proxy DES OPT SETUP PLAY PAUSE TRD Header Where Proxy DES OPT SETUP PLAY PAUSE TRD
_____________________________________________________________ _____________________________________________________________
Accept R o - - - - - Accept R o - - - - -
Accept-Encoding R r o - - - - - Accept-Encoding R r o - - - - -
Accept-Language R r o - - - - - Accept-Language R r o - - - - -
Accept-Ranges r r - - o - - - Accept-Ranges r r - - o - - -
Accept-Ranges 456 r - - - o o - Accept-Ranges 456 r - - - o o -
Allow r - o - - - - Allow r - o - - - -
Allow 405 - - - m m - Allow 405 m m m m m m
Authorization R o o o o o o Authorization R o o o o o o
Bandwidth R o o o o - - Bandwidth R o o o o - -
Blocksize R o - o o - - Blocksize R o - o o - -
Cache-Control r - - o - - - Cache-Control r - - o - - -
Connection o o o o o o Connection o o o o o o
Content-Base r o - - - - - Content-Base r o - - - - -
Content-Base 4xx o o o o o o Content-Base 4xx o o o o o o
Content-Encoding R r - - - - - - Content-Encoding R r - - - - - -
Content-Encoding r r o - - - - - Content-Encoding r r o - - - - -
Content-Encoding 4xx r o o o o o o Content-Encoding 4xx r o o o o o o
skipping to change at page 62, line 27 skipping to change at page 68, line 27
Unsupported r c c c c c c Unsupported r c c c c c c
User-Agent R m* m* m* m* m* m* User-Agent R m* m* m* m* m* m*
Vary r c c c c c c Vary r c c c c c c
Via R amr o o o o o o Via R amr o o o o o o
Via c dr m m m m m m Via c dr m m m m m m
WWW-Authenticate 401 m m m m m m WWW-Authenticate 401 m m m m m m
_________________________________________________________ _________________________________________________________
Header Where Proxy DES OPT SETUP PLAY PAUSE TRD Header Where Proxy DES OPT SETUP PLAY PAUSE TRD
Table 4: Overview of RTSP header fields related to methods DESCRIBE, Table 9: Overview of RTSP header fields related to methods DESCRIBE,
OPTIONS, SETUP, PLAY, PAUSE, and TEARDOWN. OPTIONS, SETUP, PLAY, PAUSE, and TEARDOWN.
The Bandwidth request-header field describes the estimated bandwidth
available to the client, expressed as a positive integer and measured
in bits per second. The bandwidth available to the client may change
during an RTSP session, e.g., due to modem retraining.
Example:
Bandwidth: 4000 Bandwidth: 4000
13.8 Blocksize 14.8 Blocksize
The Blocksize request-header field is sent from the client to the The Blocksize request-header field is sent from the client to the
media server asking the server for a particular media packet size. media server asking the server for a particular media packet size.
This packet size does not include lower-layer headers such as IP, This packet size does not include lower-layer headers such as IP,
UDP, or RTP. The server is free to use a blocksize which is lower UDP, or RTP. The server is free to use a blocksize which is lower
than the one requested. The server MAY truncate this packet size to than the one requested. The server MAY truncate this packet size to
the closest multiple of the minimum, media-specific block size, or the closest multiple of the minimum, media-specific block size, or
override it with the media-specific size if necessary. The block size override it with the media-specific size if necessary. The block size
MUST be a positive decimal number, measured in octets. The server MUST be a positive decimal number, measured in octets. The server
only returns an error
(400) if the value is syntactically invalid.
Blocksize = "Blocksize" ":" 1*DIGIT
Header Where Proxy GPR SPR RDR PNG Header Where Proxy GPR SPR RDR PNG
__________________________________________________ __________________________________________________
Allow 405 m m m m
Allow 405 - - - -
Authorization R o o o o Authorization R o o o o
Bandwidth R - o - - Bandwidth R - o - -
Blocksize R - o - - Blocksize R - o - -
Connection o o o - Content- Connection o o o -
Base R o o - - Content- Content-Base R o o - -
Base r o o - - Content- Content-Base r o o - -
Base 4xx o o o - Content- Content-Base 4xx o o o -
Encoding R r o o - - Content- Content-Encoding R r o o - -
Encoding r r o o - - Content- Content-Encoding r r o o - -
Encoding 4xx r o o o - Content- Content-Encoding 4xx r o o o -
Language R r o o - - Content- Content-Language R r o o - -
Language r r o o - - Content- Content-Language r r o o - -
Language 4xx r o o o - Content- Content-Language 4xx r o o o -
Length R r * * - - Content- Content-Length R r * * - -
Length r r * * - - Content- Content-Length r r * * - -
Length 4xx r * * * - Content- Content-Length 4xx r * * * -
Location R o o - - Content- Content-Location R o o - -
Location r o o - - Content- Content-Location r o o - -
Location 4xx o o o - Content- Content-Location 4xx o o o -
Type R * * - - Content- Content-Type R * * - -
Type r * * - - Content- Content-Type r * * - -
Type 4xx * * * - Content-Type 4xx * * * -
CSeq Rc m m m m CSeq Rc m m m m
Date am o o o o Date am o o o o
From R r o o o o From R r o o o o
Host - - - - Last- Host - - - -
Modified R r - - - - Last- Last-Modified R r - - - -
Modified r r o - - - Last-Modified r r o - - -
Location 3rr o o o o Location 3rr o o o o
Location R - - m - Proxy- Location R - - m -
Authenticate 407 amr m m m m Proxy- Proxy-Authenticate 407 amr m m m m
Require R ar o o o o Proxy-Require R ar o o o o
Public 501 admr m* m* m* m* Public 501 admr m* m* m* m*
Range R - - o - Range R - - o -
Referer R o o o - Referer R o o o -
Require R o o o o Retry- Require R o o o o
After 3rr,503 o o - - Retry-After 3rr,503 o o - -
Scale - - - - Scale - - - -
Session R o o o m Session R o o o m
Session r c c o m Session r c c o m
Server R o o o o Server R o o o o
Server r o o - o Server r o o - o
Timestamp R o o o o Supported R o o o o
Timestamp c m m m m Timestamp c m m m m
Unsupported r c c c c User- Unsupported r c c c c
Agent R m* m* - m* User- User-Agent R m* m* - m*
Agent r - - m* - User-Agent r - - m* -
Vary r c c - - Vary r c c - -
Via R amr o o o o Via R amr o o o o
Via c dr m m m m WWW- Via c dr m m m m
Authenticate 401 m m m m WWW-Authenticate 401 m m m m
__________________________________________________ __________________________________________________
Header Where Proxy GPR SPR RDR PNG Header Where Proxy GPR SPR RDR PNG
Table 5: Overview of RTSP header fields related to methods Table 10: Overview of RTSP header fields related to methods
GET_PARAMETER, SET_PARAMETER,REDIRECT, and PING. GET_PARAMETER, SET_PARAMETER,REDIRECT, and PING.
13.9 Cache-Control only returns an error (4xx) if the value is syntactically invalid.
14.9 Cache-Control
The Cache-Control general-header field is used to specify directives The Cache-Control general-header field is used to specify directives
that MUST be obeyed by all caching mechanisms along the that MUST be obeyed by all caching mechanisms along the
request/response chain. request/response chain.
Cache directives must be passed through by a proxy or gateway Cache directives must be passed through by a proxy or gateway
application, regardless of their significance to that application, application, regardless of their significance to that application,
since the directives may be applicable to all recipients along the since the directives may be applicable to all recipients along the
request/response chain. It is not possible to specify a cache- request/response chain. It is not possible to specify a cache-
directive for a specific cache. directive for a specific cache.
Cache-Control should only be specified in a SETUP request and its Cache-Control should only be specified in a SETUP request and its |
response. Note: Cache-Control does not govern the caching of response. Note: Cache-Control does not govern the caching of |
responses as for HTTP, but rather of the stream identified by the responses as for HTTP, instead it applies to the media stream |
SETUP request. Responses to RTSP requests are not cacheable, except identified by the SETUP request. The caching of RTSP requests are |
for responses to DESCRIBE. generally not cacheable, for further information see 15. Below is the |
description of the cache directives that can be included in the |
Cache-Control = "Cache-Control" ":" 1#cache-directive Cache-Control header.
cache-directive = cache-request-directive
/ cache-response-directive
cache-request-directive = "no-cache"
/ "max-stale" ["=" delta-seconds]
/ "min-fresh" "=" delta-seconds
/ "only-if-cached"
/ cache-extension
cache-response-directive = "public"
/ "private"
/ "no-cache"
/ "no-transform"
/ "must-revalidate"
/ "proxy-revalidate"
/ "max-age" "=" delta-seconds
/ cache-extension
cache-extension = token [ "=" ( token / quoted-string ) ]
delta-seconds = 1*DIGIT
no-cache: Indicates that the media stream MUST NOT be cached no-cache: Indicates that the media stream MUST NOT be cached
anywhere. This allows an origin server to prevent caching anywhere. This allows an origin server to prevent caching
even by caches that have been configured to return stale even by caches that have been configured to return stale
responses to client requests. responses to client requests.
public: Indicates that the media stream is cacheable by any public: Indicates that the media stream is cacheable by any
cache. cache.
private: Indicates that the media stream is intended for a private: Indicates that the media stream is intended for a
single user and MUST NOT be cached by a shared cache. A single user and MUST NOT be cached by a shared cache. A
private (non-shared) cache may cache the media stream. private (non-shared) cache may cache the media stream.
no-transform: An intermediate cache (proxy) may find it useful no-transform: An intermediate cache (proxy) may find it useful
to convert the media type of a certain stream. A proxy to convert the media type of a certain stream. A proxy
might, for example, convert between video formats to save might, for example, convert between video formats to save
cache space or to reduce the amount of traffic on a slow cache space or to reduce the amount of traffic on a slow
link. Serious operational problems may occur, however, when link. Serious operational problems may occur, however,
these transformations have been applied to streams intended when these transformations have been applied to streams
for certain kinds of applications. For example, intended for certain kinds of applications. For example,
applications for medical imaging, scientific data analysis applications for medical imaging, scientific data analysis
and those using end-to-end authentication all depend on and those using end-to-end authentication all depend on
receiving a stream that is bit-for-bit identical to the receiving a stream that is bit-for-bit identical to the
original entity-body. Therefore, if a response includes the original media stream. Therefore, if a response includes
no-transform directive, an intermediate cache or proxy MUST the no-transform directive, an intermediate cache or proxy
NOT change the encoding of the stream. Unlike HTTP, RTSP MUST NOT change the encoding of the stream. Unlike HTTP,
does not provide for partial transformation at this point, RTSP does not provide for partial transformation at this
e.g., allowing translation into a different language. point, e.g., allowing translation into a different
language.
only-if-cached: In some cases, such as times of extremely poor only-if-cached: In some cases, such as times of extremely poor
network connectivity, a client may want a cache to return network connectivity, a client may want a cache to return
only those media streams that it currently has stored, and only those media streams that it currently has stored, and
not to receive these from the origin server. To do this, not to receive these from the origin server. To do this,
the client may include the only-if-cached directive in a the client may include the only-if-cached directive in a
request. If it receives this directive, a cache SHOULD request. If it receives this directive, a cache SHOULD
either respond using a cached media stream that is either respond using a cached media stream that is
consistent with the other constraints of the request, or consistent with the other constraints of the request, or
respond with a 504 (Gateway Timeout) status. However, if a respond with a 504 (Gateway Timeout) status. However, if a
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its now validated copy to the client with a 200 (OK) its now validated copy to the client with a 200 (OK)
response. If the server replies with a new entity and cache response. If the server replies with a new entity and cache
validator, however, the intermediate cache can compare the validator, however, the intermediate cache can compare the
returned validator with the one provided in the client's returned validator with the one provided in the client's
request, using the strong comparison function. If the request, using the strong comparison function. If the
client's validator is equal to the origin server's, then client's validator is equal to the origin server's, then
the intermediate cache simply returns 304 (Not Modified). the intermediate cache simply returns 304 (Not Modified).
Otherwise, it returns the new entity with a 200 (OK) Otherwise, it returns the new entity with a 200 (OK)
response. response.
13.10 Connection 14.10 Connection
See [H14.10]. The use of the connection option "close" in RTSP See [H14.10]. The use of the connection option "close" in RTSP
messages SHOULD be limited to error messages when the server is messages SHOULD be limited to error messages when the server is
unable to recover and therefore see it necessary to close the unable to recover and therefore see it necessary to close the
connection. The reason is that the client shall have the choice of connection. The reason is that the client shall have the choice of
continue using a connection indefinitely as long as it sends valid continue using a connection indefinitely as long as it sends valid
messages. messages.
13.11 Content-Base 14.11 Content-Base
The Content-Base entity-header field may be used to specify the base The Content-Base entity-header field may be used to specify the base
URI for resolving relative URLs within the entity. URL for resolving relative URLs within the entity.
Content-Base = "Content-Base" ":" absoluteURI Content-Base: rtsp://media.example.com/movie/twister
If no Content-Base field is present, the base URI of an entity is If no Content-Base field is present, the base URL of an entity is
defined either by its Content-Location (if that Content-Location URI defined either by its Content-Location (if that Content-Location URL
is an absolute URI) or the URI used to initiate the request, in that is an absolute URL) or the URL used to initiate the request, in that
order of precedence. Note, however, that the base URI of the contents order of precedence. Note, however, that the base URL of the contents
within the entity-body may be redefined within that entity-body. within the entity-body may be redefined within that entity-body.
13.12 Content-Encoding 14.12 Content-Encoding
See [H14.11] See [H14.11]
13.13 Content-Language 14.13 Content-Language
See [H14.12] See [H14.12]
13.14 Content-Length 14.14 Content-Length
The Content-Length general-header field contains the length of the The Content-Length general-header field contains the length of the
content of the method (i.e. after the double CRLF following the last content of the method (i.e. after the double CRLF following the last
header). Unlike HTTP, it MUST be included in all messages that carry header). Unlike HTTP, it MUST be included in all messages that carry
content beyond the header portion of the message. If it is missing, a content beyond the header portion of the message. If it is missing, a
default value of zero is assumed. It is interpreted according to default value of zero is assumed. It is interpreted according to
[H14.13]. [H14.13].
13.15 Content-Location 14.15 Content-Location
See [H14.14] See [H14.14]
13.16 Content-Type 14.16 Content-Type
See [H14.17]. Note that the content types suitable for RTSP are See [H14.17]. Note that the content types suitable for RTSP are
likely to be restricted in practice to presentation descriptions and likely to be restricted in practice to presentation descriptions and
parameter-value types. parameter-value types.
13.17 CSeq 14.17 CSeq
The CSeq general-header field specifies the sequence number for an The CSeq general-header field specifies the sequence number for an |
RTSP request-response pair. This field MUST be present in all RTSP request-response pair. This field MUST be present in all |
requests and responses. For every RTSP request containing the given requests and responses. For every RTSP request containing the given |
sequence number, the corresponding response will have the same sequence number, the corresponding response will have the same |
number. Any retransmitted request must contain the same sequence number. Any retransmitted request must contain the same sequence |
number as the original (i.e. the sequence number is not incremented number as the original (i.e. the sequence number is not incremented |
for retransmissions of the same request). For each new RTSP request for retransmissions of the same request). For each new RTSP request |
the CSeq value SHALL be incremented by one. The initial sequence the CSeq value SHALL be incremented by one. The initial sequence |
number MAY be any number. Each sequence number series is unique number MAY be any number, however it is RECOMMENDED to start at 1. |
between each requester and responder, i.e. the client has one series Each sequence number series is unique between each requester and |
for its request to a server and the server has another when sending responder, i.e. the client has one series for its request to a server |
request to the client. Each requester and responder is identified and the server has another when sending request to the client. Each |
with its network address. requester and responder is identified with its network address.
CSeq = "Cseq" ":" 1*DIGIT Example:
13.18 Date CSeq: 239
14.18 Date
See [H14.18]. An RTSP message containing a body MUST include a Date See [H14.18]. An RTSP message containing a body MUST include a Date
header if the sending host has a clock. Servers SHOULD include a Date header if the sending host has a clock. Servers SHOULD include a Date
header in all other RTSP messages. header in all other RTSP messages.
13.19 Expires 14.19 Expires
The Expires entity-header field gives a date and time after which the The Expires entity-header field gives a date and time after which the
description or media-stream should be considered stale. The description or media-stream should be considered stale. The
interpretation depends on the method: interpretation depends on the method:
DESCRIBE response: The Expires header indicates a date and time DESCRIBE response: The Expires header indicates a date and time
after which the description should be considered stale. after which the description SHOULD be considered stale.
SETUP response: The Expires header indicate a date and time
after which the media stream SHOULD be considered stale.
A stale cache entry may not normally be returned by a cache (either a A stale cache entry may not normally be returned by a cache (either a
proxy cache or an user agent cache) unless it is first validated with proxy cache or an user agent cache) unless it is first validated with
the origin server (or with an intermediate cache that has a fresh the origin server (or with an intermediate cache that has a fresh
copy of the entity). See section 14 for further discussion of the copy of the entity). See section 15 for further discussion of the
expiration model. expiration model.
The presence of an Expires field does not imply that the original The presence of an Expires field does not imply that the original
resource will change or cease to exist at, before, or after that resource will change or cease to exist at, before, or after that
time. time.
The format is an absolute date and time as defined by HTTP-date in The format is an absolute date and time as defined by HTTP-date in
[H3.3]; it MUST be in RFC1123-date format: [H3.3]; it MUST be in RFC1123-date format:
Expires = "Expires" ":" HTTP-date
An example of its use is An example of its use is
Expires: Thu, 01 Dec 1994 16:00:00 GMT Expires: Thu, 01 Dec 1994 16:00:00 GMT
RTSP/1.0 clients and caches MUST treat other invalid date formats, RTSP/1.0 clients and caches MUST treat other invalid date formats,
especially including the value "0", as having occurred in the past especially including the value "0", as having occurred in the past
(i.e., already expired). (i.e., already expired).
To mark a response as "already expired," an origin server should use To mark a response as "already expired," an origin server should use
an Expires date that is equal to the Date header value. To mark a an Expires date that is equal to the Date header value. To mark a
response as "never expires," an origin server SHOULD use an Expires response as "never expires," an origin server SHOULD use an Expires
date approximately one year from the time the response is sent. date approximately one year from the time the response is sent.
RTSP/1.0 servers SHOULD NOT send Expires dates more than one year in RTSP/1.0 servers SHOULD NOT send Expires dates more than one year in
the future. the future.
The presence of an Expires header field with a date value of some The presence of an Expires header field with a date value of some
time in the future on a media stream that otherwise would by default time in the future on a media stream that otherwise would by default
be non-cacheable indicates that the media stream is cacheable, unless be non-cacheable indicates that the media stream is cacheable, unless
indicated otherwise by a Cache-Control header field (Section 13.9). indicated otherwise by a Cache-Control header field (Section 14.9).
13.20 From 14.20 From
See [H14.22]. See [H14.22].
13.21 Host 14.21 Host
The Host HTTP request header field [H14.23] is not needed for RTSP, | The Host HTTP request header field [H14.23] is not needed for RTSP,
and SHALL NOT be sent. It SHALL be silently ignored if received. and SHALL NOT be sent. It SHALL be silently ignored if received.
13.22 If-Match 14.22 If-Match
See [H14.24]. See [H14.24].
The If-Match request-header field is especially useful for ensuring The If-Match request-header field is especially useful for ensuring
the integrity of the presentation description, in both the case where the integrity of the presentation description, in both the case where
it is fetched via means external to RTSP (such as HTTP), or in the it is fetched via means external to RTSP (such as HTTP), or in the
case where the server implementation is guaranteeing the integrity of case where the server implementation is guaranteeing the integrity of
the description between the time of the DESCRIBE message and the the description between the time of the DESCRIBE message and the
SETUP message. SETUP message.
The identifier is an opaque identifier, and thus is not specific to The identifier is an opaque identifier, and thus is not specific to
any particular session description language. any particular session description language.
13.23 If-Modified-Since 14.23 If-Modified-Since
The If-Modified-Since request-header field is used with the DESCRIBE The If-Modified-Since request-header field is used with the DESCRIBE
and SETUP methods to make them conditional. If the requested variant and SETUP methods to make them conditional. If the requested variant
has not been modified since the time specified in this field, a has not been modified since the time specified in this field, a
description will not be returned from the server (DESCRIBE) or a description will not be returned from the server (DESCRIBE) or a
stream will not be set up (SETUP). Instead, a 304 (Not Modified) stream will not be set up (SETUP). Instead, a 304 (Not Modified)
response will be returned without any message-body. response SHALL be returned without any message-body.
If-Modified-Since = "If-Modified-Since" ":" HTTP-date
An example of the field is: An example of the field is:
If-Modified-Since: Sat, 29 Oct 1994 19:43:31 GMT If-Modified-Since: Sat, 29 Oct 1994 19:43:31 GMT
13.24 Last-Modified 14.24 Last-Modified
The Last-Modified entity-header field indicates the date and time at The Last-Modified entity-header field indicates the date and time at
which the origin server believes the presentation description or which the origin server believes the presentation description or
media stream was last modified. See [H14.29]. For the methods media stream was last modified. See [H14.29]. For the methods
DESCRIBE, the header field indicates the last modification date and DESCRIBE, the header field indicates the last modification date and
time of the description, for SETUP that of the media stream. time of the description, for SETUP that of the media stream.
13.25 Location 14.25 Location
See [H14.30]. See [H14.30].
13.26 Proxy-Authenticate 14.26 Proxy-Authenticate
See [H14.33]. See [H14.33].
13.27 Proxy-Require 14.27 Proxy-Require
The Proxy-Require request-header field is used to indicate proxy- | The Proxy-Require request-header field is used to indicate proxy-
sensitive features that MUST be supported by the proxy. Any Proxy- | sensitive features that MUST be supported by the proxy. Any Proxy-
Require header features that are not supported by the proxy MUST be | Require header features that are not supported by the proxy MUST be
negatively acknowledged by the proxy to the client using the | negatively acknowledged by the proxy to the client using the
Unsupported header. Any feature tag included in the Proxy-Require | Unsupported header. The proxy SHALL use the 551 (Option Not
does not apply to the server. To ensure that a feature is supported | Supported) status code in the response. Any feature tag included in
by both proxies and servers the tag must be included in also a | the Proxy-Require does not apply to the server. To ensure that a
Require header. feature is supported by both proxies and servers the tag must be
included in also a Require header.
See Section 13.32 for more details on the mechanics of this message See Section 14.32 for more details on the mechanics of this message
and a usage example. and a usage example.
Proxy-Require = "Proxy-Require" ":" 1#feature-tag | Example of use:
Example of use: |
Proxy-Require: play.basic | Proxy-Require: play.basic
13.28 Public 14.28 Public
The Public response-header field lists the set of methods supported The Public response-header field lists the set of methods supported
by the server. The purpose of this field is strictly to inform the by the server. The purpose of this field is strictly to inform the
recipient of the capabilities of the server regarding unusual recipient of the capabilities of the server regarding unusual
methods. The methods listed may or may not be applicable to the methods. The methods listed may or may not be applicable to the
Request-URI; the Allow header field (section 14.7) MAY be used to Request-URL; the Allow header field (section 14.7) MAY be used to
indicate methods allowed for a particular URI. indicate methods allowed for a particular URL.
Public = "Public" ":" 1#method
Example of use: Example of use:
Public: OPTIONS, SETUP, PLAY, PAUSE, TEARDOWN Public: OPTIONS, SETUP, PLAY, PAUSE, TEARDOWN
This header field applies only to the server directly connected to the This header field applies only to the server directly connected to
client (i.e., the nearest neighbor in a chain of connections). If the the client (i.e., the nearest neighbor in a chain of connections).
response passes through a proxy, the proxy MUST either remove the Public If the response passes through a proxy, the proxy MUST either remove
header field or replace it with one applicable to its own capabilities. the Public header field or replace it with one applicable to its own
capabilities.
13.29 Range 14.29 Range
The Range request and response header field specifies a range of The Range request and response header field specifies a range of |
time. The range can be specified in a number of units. This time. The header is used in PLAY request to indicate the range of |
specification defines the smpte (Section 3.4), npt (Section 3.5), and time the client desires the server to play back. The Range header in |
clock (Section 3.6) range units. Within RTSP, byte ranges [H14.35.1] a PLAY indicates what range of time that is actually being played. In |
are normally not meaningful. The header MAY contain a time parameter a SETUP response the header MAY be used, to ensure correct |
in UTC, specifying the time at which the operation is to be made synchronization information after changes of transport parameters. |
effective. This functionality SHALL only be used with the REDIRECT
method. Servers supporting the Range header MUST understand the NPT The range can be specified in a number of units. This specification |
range format and SHOULD understand the SMPTE range format. The Range defines the smpte (Section 3.4), npt (Section 3.5), and clock |
response header indicates what range of time is actually being (Section 3.6) range units. Within RTSP, byte ranges [H14.35.1] are |
played. If the Range header is given in a time format that is not normally not meaningful, and the behavior is unspecified, but they |
understood, the recipient should return 501 (Not Implemented). and other extended units MAY be used. Servers supporting the Range |
header MUST understand the NPT range format and SHOULD understand the |
SMPTE range format. If the Range header is given in a time format |
that is not understood, the recipient should return 456 (Header Field |
Not Valid for Resource) and include a Accept-Ranges header indicating |
which time format that is supported for this resource.
The header MAY contain a time parameter in UTC, specifying the time
at which the operation is to be made effective. This functionality
SHALL only be used with the REDIRECT method.
Ranges are half-open intervals, including the first point, but Ranges are half-open intervals, including the first point, but
excluding the second point. In other words, a range of A-B starts excluding the second point. In other words, a range of A-B starts
exactly at time A, but stops just before B. Only the start time of a exactly at time A, but stops just before B. Only the start time of a
media unit such as a video or audio frame is relevant. As an example, media unit such as a video or audio frame is relevant. As an example,
assume that video frames are generated every 40 ms. A range of assume that video frames are generated every 40 ms. A range of
10.0-10.1 would include a video frame starting at 10.0 or later time 10.0-10.1 would include a video frame starting at 10.0 or later time
and would include a video frame starting at 10.08, even though it and would include a video frame starting at 10.08, even though it
lasted beyond the interval. A range of 10.0-10.08, on the other hand, lasted beyond the interval. A range of 10.0-10.08, on the other hand,
would exclude the frame at 10.08. would exclude the frame at 10.08.
Range = "Range" ":" 1#ranges-specifier [ ";" "time" "=" utc-time ]
ranges-specifier = npt-range / utc-range / smpte-range
Example: Example:
Range: clock=19960213T143205Z-;time=19970123T143720Z Range: clock=19960213T143205Z-;time=19970123T143720Z
The notation is similar to that used for the HTTP/1.1 [26] The notation is similar to that used for the HTTP/1.1 [4]
byte-range header. It allows clients to select an excerpt byte-range header. It allows clients to select an excerpt
from the media object, and to play from a given point to from the media object, and to play from a given point to
the end as well as from the current location to a given the end as well as from the current location to a given
point. The start of playback can be scheduled for any time point. The start of playback can be scheduled for any time
in the future, although a server may refuse to keep server in the future, although a server may refuse to keep server
resources for extended idle periods. resources for extended idle periods.
By default, range intervals increase, where the second point is By default, range intervals increase, where the second point is
larger than the first point. larger than the first point.
Example: Example:
Range: npt=10-15 Range: npt=10-15
However, range intervals can also decrease if the Scale header (see However, range intervals can also decrease if the Scale header (see
section 13.34) indicates a negative scale value. For example, this section 14.34) indicates a negative scale value. For example, this
would be the case when a playback in reverse is desired. would be the case when a playback in reverse is desired.
Example: Example:
Scale: -1 Scale: -1
Range: npt=15-10 Range: npt=15-10
Decreasing ranges are still half open intervals as described above. Decreasing ranges are still half open intervals as described above.
Thus, For range A-B, A is closed and B is open. In the above example, Thus, For range A-B, A is closed and B is open. In the above example,
15 is closed and 10 is open. An exception to this rule is the case 15 is closed and 10 is open. An exception to this rule is the case
skipping to change at page 73, line 40 skipping to change at page 79, line 15
Example: Example:
Scale: -1 Scale: -1
Range: npt=15-0 Range: npt=15-0
In this range both 15 and 0 are closed. In this range both 15 and 0 are closed.
A decreasing range interval without a corresponding negative Scale A decreasing range interval without a corresponding negative Scale
header is not valid. header is not valid.
13.30 Referer 14.30 Referer
See [H14.36]. The URL refers to that of the presentation description, See [H14.36]. The URL refers to that of the presentation description,
typically retrieved via HTTP. typically retrieved via HTTP.
13.31 Retry-After 14.31 Retry-After
See [H14.37]. See [H14.37].
13.32 Require 14.32 Require
The Require request-header field is used by clients or servers to The Require request-header field is used by clients or servers to
ensure that the other end-point supports features that are required ensure that the other end-point supports features that are required
in respect to this request. It can also be used to query if the in respect to this request. It can also be used to query if the other
other end-point supports certain features, however the use of the end-point supports certain features, however the use of the Supported
Supported (Section 13.38) is much more effective in this purpose. (Section 14.38) is much more effective in this purpose. The server
The server MUST respond to this header by using the Unsupported MUST respond to this header by using the Unsupported header to
header to negatively acknowledge those feature-tags which are NOT negatively acknowledge those feature-tags which are NOT supported.
supported. The response SHALL use the error code 551 (Option Not The response SHALL use the error code 551 (Option Not Supported).
Supported). This header does not apply to proxies, for the same This header does not apply to proxies, for the same functionality in
functionality in respect to proxies see, header Proxy-Require respect to proxies see, header Proxy-Require (Section 14.27).
(Section 13.27).
This is to make sure that the client-server interaction This is to make sure that the client-server interaction
will proceed without delay when all features are understood will proceed without delay when all features are understood
by both sides, and only slow down if features are not by both sides, and only slow down if features are not
understood (as in the example below). For a well-matched understood (as in the example below). For a well-matched
client-server pair, the interaction proceeds quickly, client-server pair, the interaction proceeds quickly,
saving a round-trip often required by negotiation saving a round-trip often required by negotiation
mechanisms. In addition, it also removes state ambiguity mechanisms. In addition, it also removes state ambiguity
when the client requires features that the server does not when the client requires features that the server does not
understand. understand.
Require = "Require" ":" feature-tag *("," feature-tag)
Example: Example:
C->S: SETUP rtsp://server.com/foo/bar/baz.rm RTSP/1.0 C->S: SETUP rtsp://server.com/foo/bar/baz.rm RTSP/1.0
CSeq: 302 CSeq: 302
Require: funky-feature Require: funky-feature
Funky-Parameter: funkystuff Funky-Parameter: funkystuff
S->C: RTSP/1.0 551 Option not supported S->C: RTSP/1.0 551 Option not supported
CSeq: 302 CSeq: 302
Unsupported: funky-feature Unsupported: funky-feature
C->S: SETUP rtsp://server.com/foo/bar/baz.rm RTSP/1.0
CSeq: 303
S->C: RTSP/1.0 200 OK
CSeq: 303
In this example, "funky-feature" is the feature-tag which indicates In this example, "funky-feature" is the feature-tag which indicates
to the client that the fictional Funky-Parameter field is required. to the client that the fictional Funky-Parameter field is required.
The relationship between "funky-feature" and Funky-Parameter is not The relationship between "funky-feature" and Funky-Parameter is not
communicated via the RTSP exchange, since that relationship is an communicated via the RTSP exchange, since that relationship is an
immutable property of "funky-feature" and thus should not be immutable property of "funky-feature" and thus should not be
transmitted with every exchange. transmitted with every exchange.
Proxies and other intermediary devices SHOULD ignore features that Proxies and other intermediary devices SHOULD ignore features that
are not understood in this field. If a particular extension requires are not understood in this field. If a particular extension requires
that intermediate devices support it, the extension should be tagged that intermediate devices support it, the extension should be tagged
in the Proxy-Require field instead (see Section 13.27). in the Proxy-Require field instead (see Section 14.27).
13.33 RTP-Info 14.33 RTP-Info
The RTP-Info response-header field is used to set RTP-specific The RTP-Info response-header field is used to set RTP-specific |
parameters in the PLAY response. For streams using RTP as transport parameters in the PLAY response. These parameters correspond to the |
protocol the RTP-Info header SHALL be part of a 200 response to PLAY. synchronization source identified by the ssrc parameter of the |
Transport response header in the SETUP reponse. For streams using RTP |
as transport protocol the RTP-Info header SHOULD be part of a 200 |
response to PLAY. |
The RTP-Info response-header field is used to set RTP-specific The exclusion of the RTP-Info in a PLAY response for RTP |
parameters in the PLAY response. These parameters correspond to the transported media will result in that a client needs to |
synchronization source identified by the ssrc parameter of the synchronize the media streams using RTCP. This may have |
Transport response header in the SETUP reponse. For streams using RTP negative impact as the RTCP can be lost, and does not need |
as transport protocol the RTP-Info header SHALL be part of a 200 to be particulary timely in their arrival. Also |
response to PLAY. functionality as informing the client from which packet a |
seek has occurred is affected. |
The RTP-Info MAY also be included in SETUP responses to provide |
synchronization information when changing transport parameters, see |
11.3. |
The header can carry the following parameters:
url: Indicates the stream URL which for which the following RTP url: Indicates the stream URL which for which the following RTP
parameters correspond, this URL MUST be the same used in parameters correspond, this URL MUST be the same used in
the SETUP request for this media stream. Any relative URL the SETUP request for this media stream. Any relative URL
SHALL use the request URL as base URL. SHALL use the request URL as base URL.
seq: Indicates the sequence number of the first packet of the seq: Indicates the sequence number of the first packet of the
stream. This allows clients to gracefully deal with packets stream. This allows clients to gracefully deal with packets
when seeking. The client uses this value to differentiate when seeking. The client uses this value to differentiate
packets that originated before the seek from packets that packets that originated before the seek from packets that
skipping to change at page 76, line 24 skipping to change at page 81, line 39
seek), and that it is delivered reliably, this mapping seek), and that it is delivered reliably, this mapping
is placed in the RTSP control channel. is placed in the RTSP control channel.
In order to compensate for drift for long, uninterrupted In order to compensate for drift for long, uninterrupted
presentations, RTSP clients should additionally map NPT to presentations, RTSP clients should additionally map NPT to
NTP, using initial RTCP sender reports to do the mapping, NTP, using initial RTCP sender reports to do the mapping,
and later reports to check drift against the mapping. and later reports to check drift against the mapping.
Additionally, the RTP-Info header parameter fields only apply to a | Additionally, the RTP-Info header parameter fields only apply to a |
single SSRC within a stream (the SSRC reported in the transport | single SSRC within a stream (the SSRC reported in the transport |
response header; see section 13.40). If there are multiple | response header; see section 14.40). If there are multiple |
synchronization sources (SSRCs) present within a RTP session, RTCP | synchronization sources (SSRCs) present within a RTP session |
must be used to map RTP and NTP timestamps for those sources, for | transmitting media, RTCP must be used to map RTP and NTP timestamps |
both synchronization and drift-checking. for those sources, for both synchronization and drift-checking. Due |
to backwards compatibility reasons these shortcomings can't be fixed |
Syntax: without defining a new header, which is for future work if needed.
RTP-Info = "RTP-Info" ":" 1#rtsp-info-spec
rtsp-info-spec = stream-url 1*parameter
stream-url = quoted-url / unquoted-url
unquoted-url = "url" "=" safe-url
quoted-url = "url" "=" <"> needquote-url <">
safe-url = url
needquote-url = url //That contains ; or ,
url = ( absoluteURI / relativeURI )
parameter = ";" "seq" "=" 1*DIGIT
/ ";" "rtptime" "=" 1*DIGIT
Additional constraint: safe-url MUST NOT contain the semicolon (";")
or comma (",") characters. The quoted-url form SHOULD only be used
when a URL does not meet the safe-url constraint, in order to ensure
compatibility with implementations conformant to RFC 2326 [21].
absoluteURI and relativeURI are defined in RFC 2396 [22] with RFC Additional constraint: The syntax element "safe-url" (see section
2732 [30] applied. 17.2.3) MUST NOT contain the semicolon (";") or comma (",")
characters. The quoted-url form SHOULD only be used when a URL does
not meet the safe-url constraint, in order to ensure compatibility
with implementations conformant to RFC 2326 [1].
Example: Example: |
RTP-Info: url=rtsp://foo.com/bar.avi/streamid=0;seq=45102, RTP-Info: url=rtsp://example.com/bar.avi/streamid=0;seq=45102, |
url=rtsp://foo.com/bar.avi/streamid=1;seq=30211 url=rtsp://example.com/bar.avi/streamid=1;seq=30211 |
13.34 Scale 14.34 Scale
A scale value of 1 indicates normal play at the normal forward A scale value of 1 indicates normal play at the normal forward |
viewing rate. If not 1, the value corresponds to the rate with viewing rate. If not 1, the value corresponds to the rate with |
respect to normal viewing rate. For example, a ratio of 2 indicates respect to normal viewing rate. For example, a ratio of 2 indicates |
twice the normal viewing rate ("fast forward") and a ratio of 0.5 twice the normal viewing rate ("fast forward") and a ratio of 0.5 |
indicates half the normal viewing rate. In other words, a ratio of 2 indicates half the normal viewing rate. In other words, a ratio of 2 |
has normal play time increase at twice the wallclock rate. For every has normal play time increase at twice the wallclock rate. For every |
second of elapsed (wallclock) time, 2 seconds of content will be second of elapsed (wallclock) time, 2 seconds of content will be |
delivered. A negative value indicates reverse direction. delivered. A negative value indicates reverse direction. For certain |
media transports this may require certain considerations to work |
consistent, see section B.1 for description on how RTP handles this.
Unless requested otherwise by the Speed parameter, the data rate Unless requested otherwise by the Speed parameter, the data rate
SHOULD not be changed. Implementation of scale changes depends on the SHOULD not be changed. Implementation of scale changes depends on the
server and media type. For video, a server may, for example, deliver server and media type. For video, a server may, for example, deliver
only key frames or selected key frames. For audio, it may time-scale only key frames or selected key frames. For audio, it may time-scale
the audio while preserving pitch or, less desirably, deliver the audio while preserving pitch or, less desirably, deliver
fragments of audio. fragments of audio.
The server should try to approximate the viewing rate, but may The server should try to approximate the viewing rate, but may
restrict the range of scale values that it supports. The response restrict the range of scale values that it supports. The response
MUST contain the actual scale value chosen by the server. MUST contain the actual scale value chosen by the server.
If the server does not implement the possibility to scale, it will If the server does not implement the possibility to scale, it will
not return a Scale header. A server supporting Scale operations for not return a Scale header. A server supporting Scale operations for
PLAY SHALL indicate this with the use of the "play.scale" feature- PLAY SHALL indicate this with the use of the "play.scale" feature-
tags. tags.
Scale = "Scale" ":" [ "-" ] 1*DIGIT [ "." *DIGIT ]
When indicating a negative scale for a reverse playback, the Range When indicating a negative scale for a reverse playback, the Range
header must indicate a decreasing range as described in section header must indicate a decreasing range as described in section
13.29. 14.29.
Example of playing in reverse at 3.5 times normal rate: Example of playing in reverse at 3.5 times normal rate:
Scale: -3.5 Scale: -3.5
Range: npt=15-10 Range: npt=15-10
13.35 Speed 14.35 Speed
The Speed request-header field requests the server to deliver data to The Speed request-header field requests the server to deliver data to
the client at a particular speed, contingent on the server's ability the client at a particular speed, contingent on the server's ability
and desire to serve the media stream at the given speed. and desire to serve the media stream at the given speed.
Implementation by the server is OPTIONAL. The default is the bit rate Implementation by the server is OPTIONAL. The default is the bit rate
of the stream. of the stream.
The parameter value is expressed as a decimal ratio, e.g., a value of The parameter value is expressed as a decimal ratio, e.g., a value of
2.0 indicates that data is to be delivered twice as fast as normal. A 2.0 indicates that data is to be delivered twice as fast as normal. A
speed of zero is invalid. All speeds may not be possible to support. speed of zero is invalid. All speeds may not be possible to support.
Therefore the actual used speed MUST be included in the response. Therefore the actual used speed MUST be included in the response. The
The lack of a response header is indication of lack of support from lack of a response header is indication of lack of support from the
the server of this functionality. Support of the speed functionality server of this functionality. Support of the speed functionality are
are indicated by the "play.speed" feature-tag. indicated by the "play.speed" featuretag.
Speed = "Speed" ":" 1*DIGIT [ "." *DIGIT ]
Example: Example:
Speed: 2.5 Speed: 2.5
Use of this field changes the bandwidth used for data delivery. It is | Use of this field changes the bandwidth used for data delivery. It is
meant for use in specific circumstances where preview of the | meant for use in specific circumstances where preview of the
presentation at a higher or lower rate is necessary. Implementors | presentation at a higher or lower rate is necessary. Implementors
should keep in mind that bandwidth for the session may be negotiated | should keep in mind that bandwidth for the session may be negotiated
beforehand (by means other than RTSP), and therefore re-negotiation | beforehand (by means other than RTSP), and therefore re-negotiation
may be necessary. When data is delivered over UDP, it is highly | may be necessary. When data is delivered over UDP, it is highly
recommended that means such as RTCP be used to track packet loss | recommended that means such as RTCP be used to track packet loss
rates. If the data transport is performed over public best-effort | rates. If the data transport is performed over public best-effort
networks the sender SHOULD perform congestion control of the | networks the sender SHOULD perform congestion control of the
stream(s). This can result in that the communicated speed is | stream(s). This can result in that the communicated speed is
impossible to maintain. impossible to maintain.
13.36 Server 14.36 Server
See [H14.38], however the header syntax is here corrected. See [H14.38], however the header syntax is corrected in section
17.2.3.
Server = "Server" ":" ( product / comment ) *(SP (product / comment)) 14.37 Session
13.37 Session The Session request-header and response-header field identifies an
The Session request-header and response-header field identifies an | RTSP session. An RTSP session is created by the server as a result of
RTSP session. An RTSP session is created by the server as a result of | a successful SETUP request and in the response the session identifier
a successful SETUP request and in the response the session identifier | is given to the client. The RTSP session exist until destroyed by a
is given to the client. The RTSP session exist until destroyed by a | TEARDOWN or timed out by the server.
TEARDOWN or timed out by the server. |
The session identifier is chosen by the server (see Section 3.3) and | The session identifier is chosen by the server (see Section 3.3) and
MUST be returned in the SETUP response. Once a client receives a | MUST be returned in the SETUP response. Once a client receives a
session identifier, it SHALL be included in any request related to | session identifier, it SHALL be included in any request related to
that session. This means that the Session header MUST be included in | that session. This means that the Session header MUST be included in
a request using the following methods: PLAY, PAUSE, PING, and | a request using the following methods: PLAY, PAUSE, PING, and
TEARDOWN, and MAY be included in SETUP, OPTIONS, SET_PARAMETER, | TEARDOWN, and MAY be included in SETUP, OPTIONS, SET_PARAMETER,
GET_PARAMETER, and REDIRECT, and SHALL NOT be included in DESCRIBE. | GET_PARAMETER, and REDIRECT, and SHALL NOT be included in DESCRIBE.
In a RTSP response the session header SHALL be included in methods, | In a RTSP response the session header SHALL be included in methods,
SETUP, PING, PLAY, and PAUSE, and MAY be included in methods, | SETUP, PING, PLAY, and PAUSE, and MAY be included in methods,
TEARDOWN, and REDIRECT, and if included in the request of the | TEARDOWN, and REDIRECT, and if included in the request of the
following methods it SHALL also be included in the response, OPTIONS, | following methods it SHALL also be included in the response, OPTIONS,
GET_PARAMETER, and SET_PARAMETER, and SHALL NOT be included in | GET_PARAMETER, and SET_PARAMETER, and SHALL NOT be included in
DESCRIBE. | DESCRIBE.
Note that RFC 2326 servers and client may in some cases not include | Note that RFC 2326 servers and client may in some cases not include
or return a Session header when expected according to the above text. | or return a Session header when expected according to the above text.
Any client or server is RECOMMENDED to be forgiving of this error if | Any client or server is RECOMMENDED to be forgiving of this error if
possible (which it is in many cases). possible (which it is in many cases).
Session = "Session" ":" session-id [ ";" "timeout" "=" delta-seconds ] The timeout parameter MAY be included in a SETUP response, and SHALL |
NOT be included in requests. The server uses it to indicate to the |
The timeout parameter MAY be included in a response, and SHALL NOT be | client how long the server is prepared to wait between RTSP commands |
included in requests. The server uses it to indicate to the client | or other signs of life before closing the session due to lack of |
how long the server is prepared to wait between RTSP commands or |
other signs of life before closing the session due to lack of |
activity (see below and Section A). The timeout is measured in | activity (see below and Section A). The timeout is measured in |
seconds, with a default of 60 seconds (1 minute). | seconds, with a default of 60 seconds (1 minute). The length of the |
session timeout SHALL NOT be changed in a established session.
The mechanisms for showing liveness of the client is, any RTSP | The mechanisms for showing liveness of the client is, any RTSP
request with a Session header, if RTP & RTCP is used an RTCP message, | request with a Session header, if RTP & RTCP is used an RTCP message,
or through any other used media protocol capable of indicating | or through any other used media protocol capable of indicating
liveness of the RTSP client. It is RECOMMENDED that a client does not | liveness of the RTSP client. It is RECOMMENDED that a client does not
wait to the last second of the timeout before trying to send a | wait to the last second of the timeout before trying to send a
liveness message. The RTSP message may be lost or when using reliable | liveness message. The RTSP message may be lost or when using reliable
protocols, such as TCP, the message may take some time to arrive | protocols, such as TCP, the message may take some time to arrive
safely at the receiver. To show liveness between RTSP request issued | safely at the receiver. To show liveness between RTSP request issued
to accomplish other things, the following mechanisms can be used, in | to accomplish other things, the following mechanisms can be used, in
descending order of preference: | descending order of preference:
RTCP: If RTP is used for media transport RTCP SHOULD be used. If | RTCP: If RTP is used for media transport RTCP SHOULD be used. If
RTCP is used to report transport statistics, it SHALL also | RTCP is used to report transport statistics, it SHALL also
work as keep alive. The server can determine the client by | work as keep alive. The server can determine the client by
used network address and port together with the fact that | used network address and port together with the fact that
the client is reporting on the servers SSRC(s). A downside | the client is reporting on the servers SSRC(s). A downside
of using RTCP is that it only gives statistical guarantees | of using RTCP is that it only gives statistical guarantees
to reach the server. However that probability is so low | to reach the server. However that probability is so low
that it can be ignored in most cases. For example, a | that it can be ignored in most cases. For example, a
session with 60 seconds timeout and enough bitrate assigned | session with 60 seconds timeout and enough bitrate assigned
to RTCP messages to send a message from client to server on | to RTCP messages to send a message from client to server on
average every 5 seconds. That client have for a network | average every 5 seconds. That client have for a network
with 5 % packet loss, the probability to fail showing | with 5 % packet loss, the probability to fail showing
liveness sign in that session within the timeout interval | liveness sign in that session within the timeout interval
of 2.4*E-16. In sessions with shorter timeout times, or | of 2.4*E-16. In sessions with shorter timeout times, or
much higher packet loss, or small RTCP bandwidths SHOULD | much higher packet loss, or small RTCP bandwidths SHOULD
also use any of the mechanisms below. | also use any of the mechanisms below.
PING: The use of the PING method is the best of the RTSP based | PING: The use of the PING method is the best of the RTSP based
methods. It has no other effects than updating the timeout | methods. It has no other effects than updating the timeout
timer. In that way it will be a minimal message, that also | timer. In that way it will be a minimal message, that also
does not cause any extra processing for the server. The | does not cause any extra processing for the server. The
downside is that it may not be implemented. A client SHOULD | downside is that it may not be implemented. A client SHOULD
use a OPTIONS request to verify support of the PING at the | use a OPTIONS request to verify support of the PING at the
server. It is also possible to detect support by sending a | server. It is also possible to detect support by sending a
PING to the server. If a 200 (OK) message is received the | PING to the server. If a 200 (OK) message is received the
server supports it. In case a 501 (Not Implemented) is | server supports it. In case a 501 (Not Implemented) is
received it does not support PING and there is no meaning | received it does not support PING and there is no meaning
in continue trying. Also the reception of a error message | in continue trying. Also the reception of a error message
will also mean that the liveness timer has not been | will also mean that the liveness timer has not been
updated. | updated.
SET_PARAMETER: When using SET_PARAMETER for keep alive, no body | SET_PARAMETER: When using SET_PARAMETER for keep alive, no body
SHOULD be included. This method is basically as good as | SHOULD be included. This method is basically as good as
PING, however the implementation support of the method is | PING, however the implementation support of the method is
today limited. The same considerations as for PING apply | today limited. The same considerations as for PING apply
regarding checking of support in server and proxies. | regarding checking of support in server and proxies.
OPTIONS: This method does also work. However it causes the | OPTIONS: This method does also work. However it causes the
server to perform unnecessary processing and result in | server to perform unnecessary processing and result in
bigger responses than necessary for the task. The reason | bigger responses than necessary for the task. The reason
for this is that the Public is always included creating | for this is that the Public is always included creating
overhead. | overhead.
Note that a session identifier identifies an RTSP session across | Note that a session identifier identifies an RTSP session across
transport sessions or connections. RTSP requests for a given session | transport sessions or connections. RTSP requests for a given session
can use different URIs (Presentation and media URIs). Note, that | can use different URLs (Presentation and media URLs). Note, that
there are restrictions depending on the session which URIs that are | there are restrictions depending on the session which URLs that are
acceptable for a given method. However, multiple "user" sessions for | acceptable for a given method. However, multiple "user" sessions for
the same URI from the same client will require use of different | the same URL from the same client will require use of different
session identifiers. | session identifiers.
The session identifier is needed to distinguish several | The session identifier is needed to distinguish several
delivery requests for the same URL coming from the same | delivery requests for the same URL coming from the same
client. | client.
The response 454 (Session Not Found) SHALL be returned if the session | The response 454 (Session Not Found) SHALL be returned if the session
identifier is invalid. identifier is invalid.
13.38 Supported 14.38 Supported
The Supported header field enumerates all the extensions supported by The Supported header field enumerates all the extensions supported by
the client or server. When offered in a request, the receiver MUST the client or server. When offered in a request, the receiver MUST
respond with its corresponding Supported header. respond with its corresponding Supported header.
The Supported header field contains a list of feature-tags, described The Supported header field contains a list of feature-tags, described
in Section 3.7, that are understood by the client or server. in Section 3.7, that are understood by the client or server.
Supported = "Supported" ":" [feature-tag *("," feature-tag)]
Example: Example:
C->S: OPTIONS rtsp://example.com/ RTSP/1.0 C->S: OPTIONS rtsp://example.com/ RTSP/1.0
Supported: foo, bar, blech Supported: foo, bar, blech
S->C: RTSP/1.0 200 OK S->C: RTSP/1.0 200 OK
Supported: bar, blech, baz Supported: bar, blech, baz
13.39 Timestamp 14.39 Timestamp
The Timestamp general-header field describes when the client sent the The Timestamp general-header field describes when the client sent the
request to the server. The value of the timestamp is of significance request to the server. The value of the timestamp is of significance
only to the client and may use any timescale. The server MUST echo only to the client and may use any timescale. The server MUST echo
the exact same value and MAY, if it has accurate information about the exact same value and MAY, if it has accurate information about
this, add a floating point number indicating the number of seconds this, add a floating point number indicating the number of seconds
that has elapsed since it has received the request. The timestamp is that has elapsed since it has received the request. The timestamp is
used by the client to compute the round-trip time to the server so used by the client to compute the round-trip time to the server so
that it can adjust the timeout value for retransmissions. It also that it can adjust the timeout value for retransmissions. It also
resolves retransmission ambiguities for unreliable transport of RTSP. resolves retransmission ambiguities for unreliable transport of RTSP.
Timestamp = "Timestamp" ":" *(DIGIT) [ "." *(DIGIT) ] [ delay ] 14.40 Transport
delay = *(DIGIT) [ "." *(DIGIT) ]
13.40 Transport
The Transport request- and response- header field indicates which The Transport request and response header field indicates which
transport protocol is to be used and configures its parameters such transport protocol is to be used and configures its parameters such
as destination address, compression, multicast time-to-live and as destination address, compression, multicast time-to-live and
destination port for a single stream. It sets those values not destination port for a single stream. It sets those values not
already determined by a presentation description. already determined by a presentation description.
Transports are comma separated, listed in order of preference. Transports are comma separated, listed in order of preference. |
Parameters may be added to each transport, separated by a semicolon. Parameters may be added to each transport, separated by a semicolon. |
The server SHOULD return a Transport response-header field in the |
The Transport header field MAY also be used to change certain response to indicate the values actually chosen. The Transport header |
transport parameters. A server MAY refuse to change parameters of an field MAY also be used to change certain transport parameters. A |
existing stream. server MAY refuse to change parameters of an existing stream. |
The server MAY return a Transport response-header field in the A Transport request header field MAY contain a list of transport |
response to indicate the values actually chosen. options acceptable to the client, in the form of multiple |
transportspec entries. In that case, the server MUST return the |
single option (transport-spec) which was actually chosen. The number |
of transportspec entries is expected to be limited as the client will |
get guidance on what configurations that are possible from the |
presentation description.
A Transport request header field MAY contain a list of transport A transport-spec transport option may only contain one of any given |
options acceptable to the client, in the form of multiple parameter within it. Parameters may be given in any order. |
transportspec entries. In that case, the server MUST return the Additionally, it may only contain the unicast or multicast transport |
single option (transport-spec) which was actually chosen. parameter. Unknown transport parameters SHALL be ignored. The |
requester need to ensure that the responder understands the |
parameters through the use of feature tags and the Require header. |
A transport-spec transport option may only contain one of any given The usage of any parameter that was not defined in RFC 2326 or in an |
parameter within it. Parameters may be given in any order. extended way requires that request or response contains a Require |
Additionally, it may only contain the unicast or multicast transport header with the "play.basic" feature tag.
parameter.
The Transport header field is restricted to describing a The Transport header field is restricted to describing a
single media stream. (RTSP can also control multiple single media stream. (RTSP can also control multiple
streams as a single entity.) Making it part of RTSP rather streams as a single entity.) Making it part of RTSP rather
than relying on a multitude of session description formats than relying on a multitude of session description formats
greatly simplifies designs of firewalls. greatly simplifies designs of firewalls.
The syntax for the transport specifier is The syntax for the transport specifier is
transport/profile/lower-transport. transport/profile/lower-transport.
The default value for the "lower-transport" parameters is specific to The default value for the "lower-transport" parameters is specific to
the profile. For RTP/AVP, the default is UDP. the profile. For RTP/AVP, the default is UDP.
There is three different methods for how to specify where the media |
should be delivered: |
o The presence of this parameter and its values indicates |
address and port pairs for one or more IP flow necessary for |
the media transport. This is an improved version of the |
Destination parameter. |
o The presence of this parameter and its value indicates what IP |
address the media shall be delivered to. This method is kept |
for backwards compatibility reasons, dest_addr is a better |
choice. |
o The lack of of both of the above parameters indicates that the |
server SHALL send media to same address for which the RTSP |
messages originates. |
The choice of method for indicating where the media shall be |
delivered depends on the use case. In many case the only allowed |
method will be to use no explicit indication and have the server |
deliver media to the source of the RTSP messages. |
An RTSP proxy will also need to take care. If the media is not |
desired to be routed through the proxy, the proxy will need to |
introduce the destination indication.
Below are the configuration parameters associated with transport: Below are the configuration parameters associated with transport:
General parameters: General parameters:
unicast / multicast: This parameter is a mutually exclusive unicast / multicast: This parameter is a mutually exclusive
indication of whether unicast or multicast delivery will be indication of whether unicast or multicast delivery will be
attempted. One of the two values MUST be specified. Clients attempted. One of the two values MUST be specified. Clients
that are capable of handling both unicast and multicast that are capable of handling both unicast and multicast
transmission MUST indicate such capability by including two transmission MUST indicate such capability by including two
full transport-specs with separate parameters for each. full transport-specs with separate parameters for each.
skipping to change at page 83, line 44 skipping to change at page 89, line 5
recipient itself and the credentials passed along to the recipient itself and the credentials passed along to the
server. However, in certain cases, such as when recipient server. However, in certain cases, such as when recipient
address is a multicast group, or when the recipient is address is a multicast group, or when the recipient is
unable to communicate with the server in an out-of-band unable to communicate with the server in an out-of-band
manner, this may not be possible. In these cases server may manner, this may not be possible. In these cases server may
chose another method such as a server-resident chose another method such as a server-resident
authorization list to ensure that the request originator authorization list to ensure that the request originator
has the proper credentials to request stream delivery to has the proper credentials to request stream delivery to
the recipient. the recipient.
This parameter SHALL NOT be used when src_addr and dst_addr | This parameter SHALL NOT be used when src_addr and
is used in a transport declaration. For IPv6 addresses it | dest_addr is used in a transport declaration. For IPv6
is RECOMMENDED that they be given as fully qualified domain | addresses it is RECOMMENDED that they be given as fully
to make it backwards compatible with RFC 2326 | qualified domain to make it backwards compatible with RFC
implementations. 2326 implementations.
source: If the source address for the stream is different than source: If the source address for the stream is different than
can be derived from the RTSP endpoint address (the server can be derived from the RTSP endpoint address (the server
in playback), the source address SHOULD be specified. To in playback), the source address SHOULD be specified. To
maintain backwards compatibility with RFC 2326, any IPv6 maintain backwards compatibility with RFC 2326, any IPv6
host's address must be given as a fully qualified domain host's address must be given as a fully qualified domain
name. This parameter SHALL NOT be used when src_addr and name. This parameter SHALL NOT be used when src_addr and
dst_addr is used in a transport declaration. dest_addr is used in a transport declaration.
This information may also be available through SDP. This information may also be available through SDP.
However, since this is more a feature of transport However, since this is more a feature of transport
than media initialization, the authoritative source than media initialization, the authoritative source
for this information should be in the SETUP response. for this information should be in the SETUP response.
layers: The number of multicast layers to be used for this media layers: The number of multicast layers to be used for this media
stream. The layers are sent to consecutive addresses stream. The layers are sent to consecutive addresses
starting at the destination address. starting at the destination address.
dest_addr: A general destination address parameter that can dest_addr: A general destination address parameter that can |
contain one or more address and port pair. For each contain one or more address and port pair. For each |
combination of Protocol/Profile/Lower Transport the combination of Protocol/Profile/Lower Transport the |
interpretation of the address or addresses needs to be interpretation of the address or addresses needs to be |
defined. The client or server SHALL NOT use this parameter defined. The host address part of the tuple MAY be empty, |
unless both client and server has shown support. This for example ":8000", in cases when only destination port is |
parameter MUST be supported by client and servers that desired to be specified.
implements this specification. Support is indicated by the
use of the feature-tag "play.basic". This parameter SHALL The client or server SHALL NOT use this parameter unless
NOT be used in the same transport specification as any of both client and server has shown support. This parameter
the parameters "destination", "source", "port", MUST be supported by client and servers that implements
"client_port", and "server_port". this specification. Support is indicated by the use of the
feature-tag "play.basic". This parameter SHALL NOT be used
in the same transport specification as any of the
parameters "destination", "source", "port", "client_port",
and "server_port".
The same security consideration that are given for the The same security consideration that are given for the
"Destination" parameter does also applies to this "Destination" parameter does also applies to this
parameter. This parameter can be used for redirecting parameter. This parameter can be used for redirecting
traffic to recipient not desiring the media traffic. traffic to recipient not desiring the media traffic.
src_addr: A General source address parameter that can contain src_addr: A General source address parameter that can contain
one or more address and port pair. For each combination of one or more address and port pair. For each combination of
Protocol/Profile/Lower Transport the interpretation of the Protocol/Profile/Lower Transport the interpretation of the
address or addresses needs to be defined. The client or address or addresses needs to be defined. The client or
server SHALL NOT use this parameter unless both client and server SHALL NOT use this parameter unless both client and
server has shown support. This parameter MUST be supported server has shown support. This parameter MUST be supported
by client and servers that implements this specification. by client and servers that implements this specification.
Support is indicated by the use the feature-tag Support is indicated by the use the feature-tag
"play.basic". This parameter SHALL NOT be used in the same "play.basic". This parameter SHALL NOT be used in the same
transport specification as any of the parameters transport specification as any of the parameters
"destination", "source", "port", "client_port", and "destination", "source", "port", "client_port", and
"server_port". "server_port".
The address or addresses indicated in the src_addr This parameter MUST be specified by the server if it |
parameter SHOULD be used both for sending and receiving of transmits media packets from another address than the one |
the media streams data packet. The main reasons are two: RTSP messages are sent to. This will allow the client to |
First by sending from the indicated ports the source verify source address and give it a destination address for |
address will be known by the receiver of the packet. its RTCP feedback packets if RTP is used. The address or |
Secondly, in the presence of NATs some traversal mechanism addresses indicated in the src_addr parameter SHOULD be |
requires either knowledge from which address and port a used both for sending and receiving of the media streams |
packet flow is coming, or having the possibility to send data packets. The main reasons are three: First by sending |
data to the sender port. from the indicated ports the source address will be known |
by the receiver of the packet. Secondly, in the presence of |
NATs some traversal mechanism requires either knowledge |
from which address and port a packet flow is coming, or |
having the possibility to send data to the sender port.
mode: The mode parameter indicates the methods to be supported mode: The mode parameter indicates the methods to be supported
for this session. Valid values are PLAY and RECORD. If not for this session. Valid values are PLAY and RECORD. If not
provided, the default is PLAY. The RECORD value was provided, the default is PLAY. The RECORD value was
defined in RFC 2326 and is deprecated in this defined in RFC 2326 and is deprecated in this
specification. specification.
append: The append parameter was used together with RECORD and append: The append parameter was used together with RECORD and
is now deprecated. is now deprecated.
interleaved: The interleaved parameter implies mixing the media interleaved: The interleaved parameter implies mixing the media
stream with the control stream in whatever protocol is stream with the control stream in whatever protocol is
being used by the control stream, using the mechanism being used by the control stream, using the mechanism
defined in Section 11.11. The argument provides the channel defined in Section 12. The argument provides the channel
number to be used in the $ statement and MUST be present. number to be used in the $ statement and MUST be present.
This parameter MAY be specified as a range, e.g., This parameter MAY be specified as a range, e.g.,
interleaved=4-5 in cases where the transport choice for the interleaved=4-5 in cases where the transport choice for the
media stream requires it, e.g. for RTP with RTCP. The media stream requires it, e.g. for RTP with RTCP. The
channel number given in the request are only a guidance channel number given in the request are only a guidance
from the client to the server on what channel number(s) to from the client to the server on what channel number(s) to
use. The server MAY set any valid channel number in the use. The server MAY set any valid channel number in the
response. The declared channel(s) are bi-directional, so response. The declared channel(s) are bi-directional, so
both end-parties MAY send data on the given channel. One both end-parties MAY send data on the given channel. One
example of such usage is the second channel used for RTCP, example of such usage is the second channel used for RTCP,
skipping to change at page 86, line 12 skipping to change at page 91, line 28
These parameters are MAY only be used if the media transport protocol These parameters are MAY only be used if the media transport protocol
is RTP. is RTP.
port: This parameter provides the RTP/RTCP port pair for a port: This parameter provides the RTP/RTCP port pair for a
multicast session. It is should be specified as a range, multicast session. It is should be specified as a range,
e.g., port=3456-3457 e.g., port=3456-3457
client_port: This parameter provides the unicast RTP/RTCP port client_port: This parameter provides the unicast RTP/RTCP port
pair on the client where media data and control information pair on the client where media data and control information
is to be sent. It is specified as a range, e.g., is to be sent. It is specified as a range, e.g.,
port=3456-3457 is used in a transport declaration. port=3456-3457. This parameter SHALL NOT be used when
src_addr and dest_addr is used in a transport declaration.
server_port: This parameter provides the unicast RTP/RTCP port server_port: This parameter provides the unicast RTP/RTCP port
pair on the server where media data and control information pair on the server where media data and control information
is to be sent. It is specified as a range, e.g., is to be sent. It is specified as a range, e.g.,
port=3456-3457 is used in a transport declaration. port=3456-3457. This parameter SHALL NOT be used when
src_addr and dest_addr is used in a transport declaration.
ssrc: The ssrc parameter, if included in a SETUP response, ssrc: The ssrc parameter, if included in a SETUP response,
indicates the RTP SSRC [23] value that will be used by the indicates the RTP SSRC [15] value that will be used by the
media server for RTP packets within the stream. It is media server for RTP packets within the stream. It is
expressed as an eight digit hexadecimal value. If the expressed as an eight digit hexadecimal value. If the
server does not act as a synchronization source for stream server does not act as a synchronization source for stream
data (for instance, server is a translator, reflector, data (for instance, server is a translator, reflector,
etc.) the value will be the "packet sender's SSRC" that etc.) the value will be the "packet sender's SSRC" that
would have been used in the RTCP Receiver Reports generated would have been used in the RTCP Receiver Reports generated
by the server, regardless of whether the server actually by the server, regardless of whether the server actually
generates RTCP RRs. If there are multiple sources within generates RTCP RRs. If there are multiple sources within
the stream, the ssrc parameter only indicates the value for the stream, the ssrc parameter only indicates the value for
a single synchronization source. Other sources must be a single synchronization source. Other sources must be
deduced from the actual RTP/RTCP stream. deduced from the actual RTP/RTCP stream.
The functionality of specifying the ssrc parameter in a The functionality of specifying the ssrc parameter in a
SETUP request is deprecated as it is incompatible with the SETUP request is deprecated as it is incompatible with the
specification of RTP in RFC 3550. If the parameter is specification of RTP in RFC 3550 [15]. If the parameter is
included in the transport header of a SETUP request, the included in the transport header of a SETUP request, the
server MAY ignore it, and choose an appropriate SSRC for server MAY ignore it, and choose an appropriate SSRC for
the stream. The server MAY set the ssrc parameter in the the stream. The server MAY set the ssrc parameter in the
transport header of the response. transport header of the response.
Transport = "Transport" ":" 1#transport-spec
transport-spec = transport-id *parameter
transport-id = transport-protocol "/" profile ["/" lower-transport]
; no LWS is allowed inside transport-id
transport-protocol = "RTP" / token
profile = "AVP" / token
lower-transport = "TCP" / "UDP" / token
parameter = ";" ( "unicast" / "multicast" )
/ ";" "source" "=" host
/ ";" "destination" [ "=" host ]
/ ";" "interleaved" "=" channel [ "-" channel ]