draft-ietf-mmusic-rfc2326bis-02.txt   draft-ietf-mmusic-rfc2326bis-03.txt 
skipping to change at page 1, line 13 skipping to change at page 1, line 13
Internet Engineering Task Force MMUSIC WG Internet Engineering Task Force MMUSIC WG
Internet Draft H. Schulzrinne Internet Draft H. Schulzrinne
Columbia U. Columbia U.
A. Rao A. Rao
Cisco Cisco
R. Lanphier R. Lanphier
RealNetworks RealNetworks
M. Westerlund M. Westerlund
Ericsson Ericsson
draft-ietf-mmusic-rfc2326bis-02.txt draft-ietf-mmusic-rfc2326bis-03.txt
November 01, 2002 March 3, 2003
Expires: April, 2003 Expires: September, 2003
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 1, line 57 skipping to change at page 1, line 57
ties. RTSP provides an extensible framework to enable controlled, on- ties. RTSP provides an extensible framework to enable controlled, on-
demand delivery of real-time data, such as audio and video. Sources demand delivery of real-time data, such as audio and video. Sources
of data can include both live data feeds and stored clips. This pro- of data can include both live data feeds and stored clips. This pro-
tocol is intended to control multiple data delivery sessions, provide tocol is intended to control multiple data delivery sessions, provide
a means for choosing delivery channels such as UDP, multicast UDP and a means for choosing delivery channels such as UDP, multicast UDP and
TCP, and provide a means for choosing delivery mechanisms based upon TCP, and provide a means for choosing delivery mechanisms based upon
RTP (RFC 1889). RTP (RFC 1889).
1 Introduction 1 Introduction
1.1 The Update of the Specification | 1.1 The Update of the RTSP Specification
This is the draft to an update of the RTSP which currently is a pro- | This is the draft to an update of the RTSP which currently is a pro-
posed standard defined in [21]. During the years since RTSP was pub- | posed standard defined in [21]. During the years since RTSP was pub-
lished many flaws has been found. This draft tries to address these. | lished many flaws has been found. This draft tries to address these.
The work is not yet completed to get all known issues resolved. | The work is not yet completed to get all known issues resolved.
The goal is to progress RTSP to draft standard. If that is possible | The goal is to progress RTSP to draft standard. If that is possible
without first publishing it as a proposed standard is not yet deter- | without first publishing it as a proposed standard is not yet deter-
mined, as it depends on the changes necessary to make the protocol | mined, as it depends on the changes necessary to make the protocol
work. | work.
See the list of changes in chapter F to see what has been addressed. | See the list of changes in chapter F to see what has been addressed.
The currently open issues are listed in chapter E | The currently open issues are listed in chapter E.
There is currently a list of reported bugs available at "http://rtsp- | There is currently a list of reported bugs available at "http://rtsp-
spec.sourceforge.net". This list should be taken into account when | spec.sourceforge.net". This list should be taken into account when
reading this specification. A lot of these bugs are addressed but not | reading this specification. A lot of these bugs are addressed but not
yet all. Please comment on unresolved ones to give your view. | yet all. Please comment on unresolved ones to give your view.
Another way of giving input on this work is to send e-mail to the | Another way of giving input on this work is to send e-mail to the
MMUSIC WG's mailing list mmusic@ietf.org and the authors. | MMUSIC WG's mailing list mmusic@ietf.org and the authors.
Take special notice of the following: | Take special notice of the following:
+ The example section 14 has not yet been revised as the changes | + The example section 15 has not yet been revised as the changes
to protocol has not been completed. | to protocol has not been completed.
+ The BNF chapter 16 has neither been compiled completely. | + The BNF chapter 16 has neither been compiled completely.
All of the contents of RFC 2326 is not longer part of this draft. In |
an attempt to prevent the draft from becoming to thick for its own |
good, the specification has been reduced and split. The content of |
this draft is the core specification of the protocol. It contains |
the basic idea behind RTSP, the basic and general functionality nec- |
essary to establish on-demand a play-back session, and the protocol |
extension mechanisms. This allow us too keep this draft as short as |
possible, it is however still a rather thick document. |
Any other functionality will be published as extension documents. So |
far there exist two proposals: |
+ NAT and FW traversal mechanisms for RTSP are described in a docu- |
ment called "How to make Real-Time Streaming Protocol (RTSP) tra- |
verse Network Address Translators (NAT) and interact with Fire- |
walls." [33]. |
+ The MUTE extension [34] contains a proposal on how to add the |
possibility to MUTE and UNMUTE media streams in a aggregated |
media session without affecting the time-line of the playback. |
Unfortunately the draft has expired in IETF's repository. |
There has been discussion about the following extensions to RTSP, |
they have however so far not become concrete proposals: |
+ Transport security for RTSP messages (rtsps). |
+ Unreliable transport of RTSP messages (rtspu). |
+ The Record functionality. |
+ 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. |
+ An 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
either a single or several time-synchronized streams of continuous either a single or several time-synchronized streams of continuous
media such as audio and video. It does not typically deliver the con- media such as audio and video. It does not typically deliver the con-
tinuous streams itself, although interleaving of the continuous media tinuous streams itself, although interleaving of the continuous media
stream with the control stream is possible (see Section 10.13). In stream with the control stream is possible (see Section 11.11). In
other words, RTSP acts as a "network remote control" for multimedia other words, RTSP acts as a "network remote control" for multimedia
servers. servers.
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 a presenta- description. This memorandum does not define a format for a presenta-
tion description. tion description.
There is no necessity for a notion of an RTSP connection; instead, a There is no necessity for a notion of an RTSP connection; instead, a
server maintains a session labeled by an identifier. An RTSP session server maintains a session labeled by an identifier. An RTSP session
is in normally not tied to a transport-level connection such as a TCP is in normally not tied to a transport-level connection such as a TCP
skipping to change at page 1, line 150 skipping to change at page 1, line 186
The protocol supports the following operations: The protocol supports the following operations:
Retrieval of media from media server: The client can request a pre- Retrieval of media from media server: The client can request a pre-
sentation description via HTTP or some other method. If the sentation description via HTTP or some other method. If the
presentation is being multicast, the presentation description presentation is being multicast, the presentation description
contains the multicast addresses and ports to be used for the contains the multicast addresses and ports to be used for the
continuous media. If the presentation is to be sent only to continuous media. If the presentation is to be sent only to
the client via unicast, the client provides the destination the client via unicast, the client provides the destination
for security reasons. for security reasons.
Invitation of a media server to a conference: A media server can be Invitation of a media server to a conference: A media server can be |
"invited" to join an existing conference, either to play back "invited" to join an existing conference to play back media |
media into the presentation or to record all or a subset of into the presentation. This mode is useful for distributed |
the media in a presentation. This mode is useful for dis- teaching applications. Several parties in the conference may |
tributed teaching applications. Several parties in the confer- take turns "pushing the remote control buttons".
ence may take turns "pushing the remote control buttons".
Addition of media to an existing presentation: Particularly for Addition of media to an existing presentation: Particularly for
live presentations, it is useful if the server can tell the live presentations, it is useful if the server can tell the
client about additional media becoming available. 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 [26].
1.3 Requirements 1.3 Requirements
skipping to change at page 1, line 178 skipping to change at page 1, line 213
document are to be interpreted as described in RFC 2119 [4]. document are to be interpreted as described in RFC 2119 [4].
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 [26]. Terms
not listed here are defined as in HTTP/1.1. not listed here are defined as in HTTP/1.1.
Aggregate control: The control of the multiple streams using a sin- Aggregate control: The control of the multiple streams using a sin-
gle timeline by the server. For audio/video feeds, this means gle timeline by the server. For audio/video feeds, this means
that the client may issue a single play or pause message to that the client may issue a single play or pause message to
control both the audio and video feeds. | control both the audio and video feeds.
Aggregate control URI: The URI that represents the whole aggregate. | Aggregate control URI: The URI that represents the whole aggregate.
Normally specified in the session description. Normally specified in the session description.
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 between Connection: A transport layer virtual circuit established between
two programs for the purpose of communication. two programs for the purpose of communication.
Container file: A file which may contain multiple media streams Container file: A file which may contain multiple media streams
which often comprise a presentation when played together. RTSP which often comprise a presentation when played together. RTSP
servers may offer aggregate control on these files, though the servers may offer aggregate control on these files, though the
concept of a container file is not embedded in the protocol. concept of a container file is not embedded in the protocol.
Continuous media: Data where there is a timing relationship between Continuous media: Data where there is a timing relationship between
skipping to change at page 1, line 209 skipping to change at page 1, line 244
ples of continuous media are audio and motion video. Continu- ples of continuous media are audio and motion video. Continu-
ous media can be real-time (interactive), where there is a ous media can be real-time (interactive), where there is a
"tight" timing relationship between source and sink, or "tight" timing relationship between source and sink, or
streaming (playback), where the relationship is less strict. streaming (playback), where the relationship is less strict.
Entity: The information transferred as the payload of a request or Entity: The information transferred as the payload of a request or
response. An entity consists of metainformation in the form of response. An entity consists of metainformation in the form of
entity-header fields and content in the form of an entity- entity-header fields and content in the form of an entity-
body, as described in Section 8. 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.
Media initialization: Datatype/codec specific initialization. This Media initialization: Datatype/codec specific initialization. This
includes such things as clockrates, color tables, etc. Any includes such things as clockrates, color tables, etc. Any
transport-independent information which is required by a transport-independent information which is required by a
client for playback of a media stream occurs in the media ini- client for playback of a media stream occurs in the media ini-
tialization phase of stream setup. tialization 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 or recording services Media server: The server providing playback services for one or |
for one or more media streams. Different media streams within more media streams. Different media streams within a presenta- |
a presentation may originate from different media servers. A tion may originate from different media servers. A media |
media server may reside on the same or a different host as the server may reside on the same or a different host as the web |
web server the presentation is invoked from. server the presentation is invoked from.
Media server indirection: Redirection of a media client to a dif- Media server indirection: Redirection of a media client to a dif-
ferent media server. ferent media server.
(Media) stream: A single media instance, e.g., an audio stream or a (Media) stream: A single media instance, e.g., an audio stream or a
video stream as well as a single whiteboard or shared applica- video stream as well as a single whiteboard or shared applica-
tion group. When using RTP, a stream consists of all RTP and tion group. When using RTP, a stream consists of all RTP and
RTCP packets created by a source within an RTP session. This RTCP packets created by a source within an RTP session. This
is equivalent to the definition of a DSM-CC stream([5]). is equivalent to the definition of a DSM-CC stream([5]).
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 in structured sequence of octets matching the syntax defined in
Section 16 and transmitted via a connection or a connection- Section 16 and transmitted via a connection or a connection-
less protocol. less 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 media record or playback server. machine, e.g., a playback server.
Presentation: A set of one or more streams presented to the client Presentation: A set of one or more streams presented to the client
as a complete media feed, using a presentation description as as a complete media feed, using a presentation description as
defined below. In most cases in the RTSP context, this implies defined below. In most cases in the RTSP context, this implies
aggregate control of those streams, but does not have to. aggregate control of those streams, 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 presenta- information about one or more media streams within a presenta-
tion, such as the set of encodings, network addresses and tion, such as the set of encodings, network addresses and
information about the content. Other IETF protocols such as information about the content. Other IETF protocols such as
skipping to change at page 1, line 271 skipping to change at page 1, line 306
Response: An RTSP response. If an HTTP response is meant, that is Response: An RTSP response. If an HTTP response is meant, that is
indicated explicitly. indicated explicitly.
Request: An RTSP request. If an HTTP request is meant, that is Request: An RTSP request. If an HTTP request is meant, that is
indicated explicitly. indicated explicitly.
RTSP session: A state established on a RTSP server by a client with | RTSP session: A state established on a RTSP server by a client with |
an SETUP request. The RTSP session exist until it either time- | an SETUP request. The RTSP session exist until it either time- |
outs or is explicitly removed by a TEARDOWN request. The ses- | outs or is explicitly removed by a TEARDOWN request. The ses- |
sion contains state about which media resources that can be | sion contains state about which media resources that can be |
played or recorded, and their transport. played and their transport.
Transport initialization: The negotiation of transport information Transport initialization: The negotiation of transport information
(e.g., port numbers, transport protocols) between the client (e.g., port numbers, transport protocols) between the client
and the server. and the server.
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 RTSP. Extendable: New methods and parameters can be easily added to RTSP.
skipping to change at page 1, line 363 skipping to change at page 1, line 398
ble. The protocol would not address how several clients nego- ble. The protocol would not address how several clients nego-
tiate access; this is left to either a "social protocol" or tiate access; this is left to either a "social protocol" or
some other floor control mechanism. some other floor control mechanism.
1.6 Extending RTSP 1.6 Extending RTSP
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:
+ A server may only be capable of playback thus has no need to sup-
port the RECORD request.
+ A server may not be capable of seeking (absolute positioning) if + A server may not be capable of seeking (absolute positioning) if
it is to support live events only. it is to support live events only.
+ Some servers may not support setting stream parameters and thus + Some servers may not support setting stream parameters and thus
not support GET_PARAMETER and SET_PARAMETER. not support GET_PARAMETER and SET_PARAMETER.
A server SHOULD implement all header fields described in Section 12. A server SHOULD implement all header fields described in Section 13.
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 [26],
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 mag- RTSP can be extended in three ways, listed here in order of the mag-
nitude of changes supported: nitude of changes supported:
+ Existing methods can be extended with new parameters, as long as + Existing methods can be extended with new parameters, as long as
these parameters can be safely ignored by the recipient. (This is these parameters can be safely ignored by the recipient. (This is
equivalent to adding new parameters to an HTML tag.) If the equivalent to adding new parameters to an HTML tag.) If the
client needs negative acknowledgement when a method extension is client needs negative acknowledgement when a method extension is
not supported, a tag corresponding to the extension may be added not supported, a tag corresponding to the extension may be added
in the Require: field (see Section 12.32). in the Require: field (see Section 13.32).
+ New methods can be added. If the recipient of the message does + New methods can be added. If the recipient of the message does
not understand the request, it responds with error code 501 (Not not understand the request, it responds with error code 501 (Not
Implemented) and the sender should not attempt to use this method Implemented) and the sender should not attempt to use this method
again. A client may also use the OPTIONS method to inquire about again. A client may also use the OPTIONS method to inquire about
methods supported by the server. The server SHOULD list the meth- methods supported by the server. The server SHOULD list the meth-
ods it supports using the Public response header. ods it supports using the Public response header.
+ A new version of the protocol can be defined, allowing almost all + A new version of the protocol can be defined, allowing almost all
aspects (except the position of the protocol version number) to aspects (except the position of the protocol version number) to
change. change.
The basic capability discovery mechanism can be used to both discover
support for a certain feature and to ensure that a feature is avail-
able when performing a request. For detailed explanation of this see
chapter 10.
1.7 Overall Operation 1.7 Overall Operation
Each presentation and media stream may be identified by an RTSP URL. Each presentation and media stream may be identified by an RTSP URL.
The overall presentation and the properties of the media the presen- The overall presentation and the properties of the media the presen-
tation is made up of are defined by a presentation description file, tation is made up of are defined by a presentation description file,
the format of which is outside the scope of this specification. The the format of which is outside the scope of this specification. 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.
skipping to change at page 1, line 460 skipping to change at page 1, line 497
RTSP controls a stream which may be sent via a separate protocol, RTSP controls a stream which may be sent via a separate protocol,
independent of the control channel. For example, RTSP control may independent of the control channel. For example, RTSP control may
occur on a TCP connection while the data flows via UDP. Thus, data occur on a TCP connection while the data flows via UDP. Thus, data
delivery continues even if no RTSP requests are received by the media delivery continues even if no RTSP requests are received by the media
server. Also, during its lifetime, a single media stream may be con- server. Also, during its lifetime, a single media stream may be con-
trolled by RTSP requests issued sequentially on different TCP connec- trolled by RTSP requests issued sequentially on different TCP connec-
tions. Therefore, the server needs to maintain "session state" to be tions. Therefore, the server needs to maintain "session state" to be
able to correlate RTSP requests with a stream. The state transitions able to correlate RTSP requests with a stream. The state transitions
are described in Appendix A. are described in Appendix A.
Many methods in RTSP do not contribute to state. However, the follow- Many methods in RTSP do not contribute to state. However, the follow- |
ing play a central role in defining the allocation and usage of ing play a central role in defining the allocation and usage of |
stream resources on the server: SETUP, PLAY, RECORD, PAUSE, and TEAR- stream resources on the server: SETUP, PLAY, PAUSE, REDIRECT and |
DOWN. TEARDOWN.
SETUP: Causes the server to allocate resources for a stream and SETUP: Causes the server to allocate resources for a stream and
create an RTSP session. create an RTSP session.
PLAY and RECORD: Starts data transmission on a stream allocated via PLAY: Starts data transmission on a stream allocated via SETUP. |
SETUP.
PAUSE: Temporarily halts a stream without freeing server resources. PAUSE: Temporarily halts a stream without freeing server resources.
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 RTSP methods that contribute to state use the Session header
field (Section 12.37) to identify the RTSP session whose state field (Section 13.37) to identify the RTSP session whose state
is being manipulated. The server generates session identifiers is being manipulated. The server generates session identifiers
in response to SETUP requests (Section 10.4). in response to 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 inter- RTSP has some overlap in functionality with HTTP. It also may inter-
act with HTTP in that the initial contact with streaming content is act with HTTP in that the initial contact with streaming content is
often to be made through a web page. The current protocol specifica- often to be made through a web page. The current protocol specifica-
tion aims to allow different hand-off points between a web server and tion aims to allow different hand-off points between a web server and
the media server implementing RTSP. For example, the presentation the media server implementing RTSP. For example, the presentation
description can be retrieved using HTTP or RTSP, which reduces description can be retrieved using HTTP or RTSP, which reduces
roundtrips in web-browser-based scenarios, yet also allows for stan- roundtrips in web-browser-based scenarios, yet also allows for
dalone RTSP servers and clients which do not rely on HTTP at all. standalone RTSP servers and clients which do not rely on HTTP at all.
However, RTSP differs fundamentally from HTTP in that most data However, RTSP differs fundamentally from HTTP in that most data
delivery takes place out-of-band in a different protocol. HTTP is an delivery takes place out-of-band in a different protocol. HTTP is an
asymmetric protocol where the client issues requests and the server asymmetric protocol where the client issues requests and the server
responds. In RTSP, both the media client and media server can issue responds. In RTSP, both the media client and media server can issue
requests. RTSP requests are also not stateless; they may set parame- requests. RTSP requests are also not stateless; they may set parame-
ters and continue to control a media stream long after the request ters and continue to control a media stream long after the request
has been acknowledged. has been acknowledged.
Re-using HTTP functionality has advantages in at least two Re-using HTTP functionality has advantages in at least two
skipping to change at page 1, line 527 skipping to change at page 1, line 563
to Section X.Y of the current HTTP/1.1 specification (RFC 2616 [26]). 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 All the mechanisms specified in this document are described in both
prose and an augmented Backus-Naur form (BNF) similar to that used in 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 differ- [H2.1]. It is described in detail in RFC 2234 [14], with the differ-
ence that this RTSP specification maintains the "#" notation for ence that this RTSP specification maintains the "#" notation for
comma-separated lists from [H2.1]. comma-separated lists from [H2.1].
In this draft, we use indented and smaller-type paragraphs to provide In this draft, we use indented and smaller-type paragraphs to provide
background and motivation. This is intended to give readers who were background and motivation. This is intended to give readers who were
not involved with the formulation of the specification an not involved with the formulation of the specification an understand-
understanding of why things are the way that they are in RTSP. ing of why things are the way that they are in RTSP.
b b
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" and "rtspu" schemes are used to refer to network resources The "rtsp", "rtsps" and "rtspu" schemes are used to refer to network
via the RTSP protocol. This section defines the scheme-specific syn- resources via the RTSP protocol. This section defines the scheme-spe-
tax and semantics for RTSP URLs. | cific syntax and semantics for RTSP URLs.
rtsp_URL = ( "rtsp:" / "rtspu:" / "rtsps" ) || rtsp_URL = ( "rtsp:" / "rtspu:" / "rtsps:" )
"//" host [ ":" port ] [ abs_path ] || "//" host [ ":" port ] [ abs_path ] [ "#" fragment ]
host = As defined by RFC 2732 [30] || host = As defined by RFC 2732 [30]
abs_path = As defined by RFC 2396 [22] || abs_path = As defined by RFC 2396 [22]
port = *DIGIT || port = *DIGIT
Note that fragment and query identifiers do not have a well- Note that fragment and query identifiers do not have a well-
defined meaning at this time, with the interpretation left to defined meaning at this time, with the interpretation left to
the RTSP server. the RTSP server.
The scheme rtsp requires that commands are issued via a reliable pro- The scheme rtsp requires that commands are issued via a reliable pro- |
tocol (within the Internet, TCP), while the scheme rtspu identifies tocol (within the Internet, TCP), while the scheme rtspu identifies |
an unreliable protocol (within the Internet, UDP). The scheme rtsps an unreliable protocol (within the Internet, UDP). The scheme rtsps |
identifies a reliable transport using TLS [27]. identifies a reliable transport using TLS [27]. The rtspu and rtsps |
is not defined in this specification and if for future extensions of |
the protocol.
If the port is empty or not given, port 554 is assumed. The seman- If the port is empty or not given, port 554 is assumed. The seman-
tics are that the identified resource can be controlled by RTSP at tics are that the identified resource can be controlled by RTSP at
the server listening for TCP (scheme "rtsp") connections or UDP 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-URI
for the resource is rtsp_URL. for the resource is rtsp_URL.
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 [16]). 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 lit- of RTSP to use IPv6. This specification is updated to allow for lit-
eral IPv6 addresses in RTSP URLs using the host specification in RFC eral IPv6 addresses in RTSP URLs using the host specification in RFC
2732 [30]. 2732 [30].
A presentation or a stream is identified by a textual media identi- A presentation or a stream is identified by a textual media identi-
fier, using the character set and escape conventions [H3.2] of URLs fier, using the character set and escape conventions [H3.2] of URLs
(RFC 2396 [22]). URLs may refer to a stream or an aggregate of (RFC 2396 [22]). 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 10 can apply to either the whole presentation or an individ- Section 11 can apply to either the whole presentation or an individ-
ual stream within the presentation. Note that some request methods ual stream within the presentation. Note that some request methods
can only be applied to streams, not presentations and vice versa. can only be applied to streams, not presentations and vice 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
identifies the audio stream within the presentation "twister", which can identifies the audio stream within the presentation "twister", which can
be controlled via RTSP requests issued over a TCP connection to port 554 be controlled via RTSP requests issued over a TCP connection to port 554
of host media.example.com of host media.example.com
skipping to change at page 1, line 611 skipping to change at page 1, line 648
The path components of the RTSP URL are opaque to the client and do The path components of the RTSP URL are opaque to the client and do
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 replacing used with non-RTSP media control protocols simply by replacing
the scheme in the URL. the scheme in the URL.
3.3 Session Identifiers 3.3 Session Identifiers
Session identifiers are opaque strings of arbitrary length. Linear Session identifiers are strings of any arbitrary length. A session |
white space must be URL-escaped. A session identifier MUST be chosen identifier MUST be chosen randomly and MUST be at least eight charac- |
randomly and MUST be at least eight octets long to make guessing it ters long to make guessing it more difficult. (See Section 17.)
more difficult. (See Section 17.)
session-id = 8*( ALPHA / DIGIT / safe ) 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 = smpte-type "=" smpte-range-spec
smpte-range-spec = ( smpte-time "-" [ smpte-time ] ) || smpte-range-spec = ( smpte-time "-" [ smpte-time ] )
/ ( "-" smpte-time ) || / ( "-" smpte-time )
smpte-type = "smpte" / "smpte-30-drop" / "smpte-25" || smpte-type = "smpte" / "smpte-30-drop" / "smpte-25"
; other timecodes may be added || ; other timecodes may be added
smpte-time = 1*2DIGIT ":" 1*2DIGIT ":" 1*2DIGIT || smpte-time = 1*2DIGIT ":" 1*2DIGIT ":" 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
skipping to change at page 1, line 698 skipping to change at page 1, line 735
The syntax conforms to ISO 8601. The npt-sec notation is opti- The syntax conforms to ISO 8601. The npt-sec notation is opti-
mized for automatic generation, the ntp-hhmmss notation for mized for automatic generation, the ntp-hhmmss notation for
consumption by human readers. The "now" constant allows 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 neither stored or time-delayed version. This is needed since neither
absolute time nor zero time are appropriate for this case. absolute time nor zero time are appropriate for 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 ||
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 Option Tags 3.7 Feature-tags
Option tags are unique identifiers used to designate new options in Feature-tags are unique identifiers used to designate new features in
RTSP. These tags are used in in Require (Section 12.32), Proxy- RTSP. These tags are used in in Require (Section 13.32), Proxy-
Require (Section 12.27), and Supported (Section 12.38) header fields. Require (Section 13.27), Unsupported (Section 13.41), and Supported
(Section 13.38) header fields.
Syntax: Syntax:
option-tag = token feature-tag = token
The creator of a new RTSP option should either prefix the option with The creator of a new RTSP feature-tag should either prefix the fea-
a reverse domain name (e.g., "com.foo.mynewfeature" is an apt name ture-tag with a reverse domain name (e.g., "com.foo.mynewfeature" is
for a feature whose inventor can be reached at "foo.com"), or regis- an apt name for a feature whose inventor can be reached at
ter the new option with the Internet Assigned Numbers Authority "foo.com"), or register the new feature-tag with the Internet
(IANA), see IANA Section 18. Assigned Numbers Authority (IANA), see IANA Section 18.
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 [18]). Lines are terminated by CRLF, but
receivers should be prepared to also interpret CR and LF by them- receivers should be prepared to also interpret CR and LF by them-
selves as line terminators. selves as line terminators.
Text-based protocols make it easier to add optional parameters 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
skipping to change at page 1, line 747 skipping to change at page 1, line 785
not a concern. Text-based protocols, if done carefully, also not a concern. Text-based protocols, if done carefully, also
allow easy implementation of research prototypes in scripting allow easy implementation of research prototypes in scripting
languages such as Tcl, Visual Basic and Perl. languages such as Tcl, Visual Basic 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 [18])
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.
4.1 Message Types 4.1 Message Types
See [H4.1]. See [H4.1].
skipping to change at page 1, line 780 skipping to change at page 1, line 817
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 terminated (such as the 1xx, 204, and 304 responses) is always terminated
by the first empty line after the header fields, regardless of by the first empty line after the header fields, regardless of
the entity-header fields present in the message. (Note: An the entity-header fields present in the message. (Note: An
empty line consists of only CRLF.) empty line consists of only CRLF.)
2. If a Content-Length header field (section 12.14) is present, 2. If a Content-Length header field (section 13.14) is present,
its value in bytes represents the length of the message-body. its value in bytes represents the length of the message-body.
If this header field is not present, a value of zero is If this header field is not present, a value of zero is
assumed. 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 Con- transfer coding(see [H3.6.1]) and requires the presence of the Con-
tent-Length header field. tent-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 chun- length, even if it is generated dynamically, making the chun-
ked transfer encoding unnecessary. ked 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:
general-header = Cache-Control ; Section 12.9 general-header = Cache-Control ; Section 13.9
/ Connection ; Section 12.10 / Connection ; Section 13.10
/ CSeq ; Section 12.17 / CSeq ; Section 13.17
/ Date ; Section 12.18 / Date ; Section 13.18
/ Timestamp ; Section 12.39 / Timestamp ; Section 13.39
/ Via ; Section 12.44 / 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 of that message, the method to be applied to
the resource, the identifier of the resource, and the protocol ver- the resource, the identifier of the resource, and the protocol ver-
sion in use. sion in use.
Request = Request-Line ; Section 6.1 Request = Request-Line ; Section 6.1
*( general-header ; Section 5 *( general-header ; Section 5
/ request-header ; Section 6.2 / request-header ; Section 6.2
/ entity-header ) ; Section 8.1 / entity-header ) ; Section 8.1
CRLF CRLF
[ message-body ] ; Section 4.3 [ message-body ] ; Section 4.3
6.1 Request Line 6.1 Request Line
Request-Line = Method SP Request-URI SP RTSP-Version CRLF Request-Line = Method SP Request-URI SP RTSP-Version CRLF
Method = "DESCRIBE" ; Section 10.2 Method = "DESCRIBE" ; Section 11.2
/ "ANNOUNCE" ; Section 10.3 / "GET_PARAMETER" ; Section 11.7
/ "GET_PARAMETER" ; Section 10.8 / "OPTIONS" ; Section 11.1
/ "OPTIONS" ; Section 10.1 / "PAUSE" ; Section 11.5
/ "PAUSE" ; Section 10.6 / "PLAY" ; Section 11.4
/ "PLAY" ; Section 10.5 / "PING" ; Section 11.10
/ "PING" ; Section 10.12 / "REDIRECT" ; Section 11.9
/ "RECORD" ; Section 10.11 / "SETUP" ; Section 11.3
/ "REDIRECT" ; Section 10.10 / "SET_PARAMETER" ; Section 11.8
/ "SETUP" ; Section 10.4 / "TEARDOWN" ; Section 11.6
/ "SET_PARAMETER" ; Section 10.9
/ "TEARDOWN" ; Section 10.7
/ extension-method / extension-method
extension-method = token extension-method = token
Request-URI = "*" / absolute_URI Request-URI = "*" / absolute_URI
RTSP-Version = "RTSP" "/" 1*DIGIT "." 1*DIGIT RTSP-Version = "RTSP" "/" 1*DIGIT "." 1*DIGIT
6.2 Request Header Fields 6.2 Request Header Fields
request-header = Accept ; Section 12.1 request-header = Accept ; Section 13.1
/ Accept-Encoding ; Section 12.2 / Accept-Encoding ; Section 13.2
/ Accept-Language ; Section 12.3 / Accept-Language ; Section 13.3
/ Authorization ; Section 12.6 / Authorization ; Section 13.6
/ Bandwidth ; Section 12.7 / Bandwidth ; Section 13.7
/ Blocksize ; Section 12.8 / Blocksize ; Section 13.8
/ From ; Section 12.20 / From ; Section 13.20
/ If-Modified-Since ; Section 12.23 / If-Modified-Since ; Section 13.23
/ Proxy-Require ; Section 12.27 / Proxy-Require ; Section 13.27
/ Range ; Section 12.29 / Range ; Section 13.29
/ Referer ; Section 12.30 / Referer ; Section 13.30
/ Require ; Section 12.32 / Require ; Section 13.32
/ Scale ; Section 12.34 / Scale ; Section 13.34
/ Session ; Section 12.37 / Session ; Section 13.37
/ Speed ; Section 12.35 / Speed ; Section 13.35
/ Supported ; Section 12.38 / Supported ; Section 13.38
/ Transport ; Section 12.40 / Transport ; Section 13.40
/ User-Agent ; Section 12.42 / 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 [26], 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, but HTTP/1.1 requires servers to understand the absolute URL, but
clients are supposed to use the Host request header. This is clients are supposed to use the Host request header. This is
purely needed for backward-compatibility with HTTP/1.0 purely needed for backward-compatibility with HTTP/1.0
servers, a consideration that does not apply to RTSP. servers, a consideration that does not apply to RTSP.
skipping to change at page 1, line 916 skipping to change at page 1, line 951
The first line of a Response message is the Status-Line, consisting The first line of a Response message is the Status-Line, consisting
of the protocol version followed by a numeric status code, and the of the protocol version followed by a numeric status code, and the
textual phrase associated with the status code, with each element textual phrase associated with the status code, with each element
separated by SP characters. No CR or LF is allowed except in the separated by SP characters. No CR or LF is allowed except in the
final CRLF sequence. final CRLF sequence.
Status-Line = RTSP-Version SP Status-Code SP Reason-Phrase CRLF Status-Line = RTSP-Version SP Status-Code SP Reason-Phrase CRLF
7.1.1 Status Code and Reason Phrase 7.1.1 Status Code and Reason Phrase
The Status-Code element is a 3-digit integer result code of the The Status-Code element is a 3-digit integer result code of the
attempt to understand and satisfy the request. These codes are fully attempt to understand and satisfy the request. These codes are fully
defined in Section 11. The Reason-Phrase is intended to give a short defined in Section 12. The Reason-Phrase is intended to give a short
textual description of the Status-Code. The Status-Code is intended textual description of the Status-Code. The Status-Code is intended
for use by automata and the Reason-Phrase is intended for the human 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- user. The client is not required to examine or display the Reason-
Phrase. Phrase.
The first digit of the Status-Code defines the class of response. The The first digit of the Status-Code defines the class of response. The
last two digits do not have any categorization role. There are 5 last two digits do not have any categorization role. There are 5
values for the first digit: values for the first digit:
+ 1xx: Informational - Request received, continuing process + 1xx: Informational - Request received, continuing process
+ 2xx: Success - The action was successfully received, understood, + 2xx: Success - The action was successfully received, understood,
and accepted and accepted
+ 3xx: Redirection - Further action must be taken in order to com- + 3rr: Redirection - Further action must be taken in order to com-
plete the request plete the request
+ 4xx: Client Error - The request contains bad syntax or cannot be + 4xx: Client Error - The request contains bad syntax or cannot be
fulfilled fulfilled
+ 5xx: Server Error - The server failed to fulfill an apparently + 5xx: Server Error - The server failed to fulfill an apparently
valid request valid request
The individual values of the numeric status codes defined for The individual values of the numeric status codes defined for
RTSP/1.0, and an example set of corresponding Reason-Phrase's, are RTSP/1.0, and an example set of corresponding Reason-Phrase's, are
skipping to change at page 1, line 1024 skipping to change at page 1, line 1059
7.1.2 Response Header Fields 7.1.2 Response Header Fields
The response-header fields allow the request recipient to pass addi- The response-header fields allow the request recipient to pass addi-
tional information about the response which cannot be placed in the tional information about the response which cannot be placed in the
Status-Line. These header fields give information about the server Status-Line. These header fields give information about the server
and about further access to the resource identified by the Request- and about further access to the resource identified by the Request-
URI. URI.
response-header = Accept-Ranges ; Section response-header = Accept-Ranges ; Section
12.4 13.4
/ Location ; Section 12.25 / Location ; Section 13.25
/ Proxy-Authenticate ; Section 12.26 / Proxy-Authenticate ; Section 13.26
/ Public ; Section 12.28 / Public ; Section 13.28
/ Range ; Section 12.29 / Range ; Section 13.29
/ Retry-After ; Section 12.31 / Retry-After ; Section 13.31
/ RTP-Info ; Section 12.33 / RTP-Info ; Section 13.33
/ Scale ; Section 12.34 / Scale ; Section 13.34
/ Session ; Section 12.37 / Session ; Section 13.37
/ Server ; Section 12.36 / Server ; Section 13.36
/ Speed ; Section 12.35 / Speed ; Section 13.35
/ Transport ; Section 12.40 / Transport ; Section 13.40
/ Unsupported ; Section 12.41 / Unsupported ; Section 13.41
/ Vary ; Section 12.43 / Vary ; Section 13.43
/ WWW-Authenticate ; Section 12.45 / WWW-Authenticate ; Section 13.45
Response-header field names can be extended reliably only in combina- Response-header field names can be extended reliably only in combina-
tion with a change in the protocol version. However, new or experi- tion with a change in the protocol version. However, new or experi-
mental header fields MAY be given the semantics of response-header mental header fields MAY be given the semantics of response-header
fields if all parties in the communication recognize them to be fields if all parties in the communication recognize them to be
response-header fields. Unrecognized header fields are treated as response-header fields. Unrecognized header fields are treated as
entity-header fields. entity-header fields.
8 Entity
Request and Response messages MAY transfer an entity if not otherwise
restricted by the request method or response status code. An entity
consists of entity-header fields and an entity-body, although some
Code reason Code reason
-------------------------------------------------------- --------------------------------------------------------
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
301 Moved Permanently all 301 Moved Permanently all
skipping to change at page 1, line 1101 skipping to change at page 1, line 1141
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
551 Option not support all 551 Option not support all
Table 1: Status codes and their usage with RTSP methods Table 1: Status codes and their usage with RTSP methods
8 Entity
Request and Response messages MAY transfer an entity if not otherwise
restricted by the request method or response status code. An entity
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 In this section, both sender and recipient refer to either the client
or the server, depending on who sends and who receives the entity. or the server, depending on who sends and who receives the entity.
8.1 Entity Header Fields 8.1 Entity Header Fields
Entity-header fields define optional meta-information about the Entity-header fields define optional meta-information about the
entity-body or, if no body is present, about the resource identified entity-body or, if no body is present, about the resource identified
by the request. by the request.
entity-header = Allow ; Section 12.5 entity-header = Allow ; Section 13.5
/ Content-Base ; Section 12.11 / Content-Base ; Section 13.11
/ Content-Encoding ; Section 12.12 / Content-Encoding ; Section 13.12
/ Content-Language ; Section 12.13 / Content-Language ; Section 13.13
/ Content-Length ; Section 12.14 / Content-Length ; Section 13.14
/ Content-Location ; Section 12.15 / Content-Location ; Section 13.15
/ Content-Type ; Section 12.16 / Content-Type ; Section 13.16
/ Expires ; Section 12.19 / Expires ; Section 13.19
/ Last-Modified ; Section 12.24 / Last-Modified ; Section 13.24
/ extension-header / extension-header
extension-header = message-header extension-header = message-header
The extension-header mechanism allows additional entity-header fields The extension-header mechanism allows additional entity-header fields
to be defined without changing the protocol, but these fields cannot to be defined without changing the protocol, but these fields cannot
be assumed to be recognizable by the recipient. Unrecognized header be assumed to be recognizable by the recipient. Unrecognized header
fields SHOULD be ignored by the recipient and forwarded by proxies. fields SHOULD be ignored by the recipient and forwarded by proxies.
8.2 Entity Body 8.2 Entity Body
See [H7.2] with the addition that a RTSP message with an entity body | See [H7.2] with the addition that a RTSP message with an entity body
MUST include a Content-Type header. MUST include a Content-Type header.
9 Connections 9 Connections
RTSP requests can be transmitted in several different ways: RTSP requests can be transmitted in several different ways:
+ persistent transport connections used for several request- + persistent transport connections used for several request-
response transactions; response transactions;
+ one connection per request/response transaction; + one connection per request/response transaction;
skipping to change at page 1, line 1170 skipping to change at page 1, line 1205
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
Requests are acknowledged by the receiver unless they are sent to a | Requests are acknowledged by the receiver unless they are sent to a
multicast group. If there is no acknowledgement, the sender may | multicast group. If there is no acknowledgement, the sender may
resend the same message after a timeout of one round-trip time (RTT). | 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 | 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 | initial round-trip value of 500 ms. An implementation MAY cache the
last RTT measurement as the initial value for future connections. | last RTT measurement as the initial value for future connections.
If a reliable transport protocol is used to carry RTSP, requests MUST | If a reliable transport protocol is used to carry RTSP, requests MUST
NOT be retransmitted; the RTSP application MUST instead rely on the | NOT 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 the | If both the underlying reliable transport such as TCP and the
RTSP application retransmit requests, it is possible that each | RTSP application retransmit requests, it is possible that each
packet loss results in two retransmissions. The receiver can- | packet loss results in two retransmissions. The receiver can-
not typically take advantage of the application-layer retrans- | not typically take advantage of the application-layer retrans-
mission since the transport stack will not deliver the | mission since the transport stack will not deliver the appli-
application-layer retransmission before the first attempt has | cation-layer retransmission before the first attempt has
reached the receiver. If the packet loss is caused by conges- | reached the receiver. If the packet loss is caused by conges-
tion, multiple retransmissions at different layers will exac- | tion, multiple retransmissions at different layers will exac-
erbate the congestion. | erbate the congestion.
If RTSP is used over a small-RTT LAN, standard procedures for opti- | If RTSP is used over a small-RTT LAN, standard procedures for opti-
mizing initial TCP round trip estimates, such as those used in T/TCP | mizing initial TCP round trip estimates, such as those used in T/TCP
(RFC 1644) [19], can be beneficial. | (RFC 1644) [19], can be beneficial.
The Timestamp header (Section 12.39) is used to avoid the retransmis- | The Timestamp header (Section 13.39) is used to avoid the retransmis-
sion ambiguity problem [20] and obviates the need for Karn's algo- | sion ambiguity problem [20] and obviates the need for Karn's algo-
rithm. | rithm.
Each request carries a sequence number in the CSeq header (Section | Each request carries a sequence number in the CSeq header (Section
12.17), which MUST be incremented by one for each distinct request | 13.17), which MUST be incremented by one for each distinct request
transmitted. If a request is repeated because of lack of acknowledge- | transmitted. If a request is repeated because of lack of acknowledge-
ment, the request MUST carry the original sequence number (i.e., the | ment, the request MUST carry the original sequence number (i.e., the
sequence number is not incremented). | sequence number is not incremented).
Systems implementing RTSP MUST support carrying RTSP over TCP and MAY | Systems implementing RTSP MUST support carrying RTSP over TCP and MAY
support UDP. The default port for the RTSP server is 554 for both UDP | support UDP. The default port for the RTSP server is 554 for both UDP
and TCP. | and TCP.
A number of RTSP packets destined for the same control end point may | A number of RTSP packets destined for the same control end point may
be packed into a single lower-layer PDU or encapsulated into a TCP | be packed into a single lower-layer PDU or encapsulated into a TCP
stream. RTSP data MAY be interleaved with RTP and RTCP packets. | stream. RTSP data MAY be interleaved with RTP and RTCP packets.
Unlike HTTP, an RTSP message MUST contain a Content-Length header | Unlike HTTP, an RTSP message MUST contain a Content-Length header
field whenever that message contains a payload. Otherwise, an RTSP | field whenever that message contains a payload. Otherwise, an RTSP
packet is terminated with an empty line immediately following the | packet is terminated with an empty line immediately following the
last message header. | last message header.
9.3 The usage of connections | 9.3 The usage of connections
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 fur- | exchange per connection, as presented above. This section gives fur- |
ther rules and recommendations on how to handle these connections so | ther rules and recommendations on how to handle these connections so |
maximum interoperability and flexibility can be achieved. | 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, |
including messages to multiple RTSP sessions. However the persistent | including messages to multiple RTSP sessions. However the persistent |
connection MAY also be closed after a few message exchanges, e.g. the | connection MAY also be closed after a few message exchanges, e.g. the |
initial setup and play command in a session. Later when the client | initial setup and play command in a session. Later when the client |
wishes to send a new request, e.g. pause, to the session a new con- | wishes to send a new request, e.g. pause, to the session a new con- |
nection is opened. This connection may either be for a single message | nection is opened. This connection may either be for a single message |
exchange or can be kept open for several messages, i.e. persistent. | exchange or can be kept open for several messages, i.e. persistent. |
A major motivation for allowing non-persistent connections are that |
they ensure fault tolerance. A server and client supporting non-per- |
sistent connection can survive a loss of a TCP connection, e.g. due |
to a NAT timeout. When the it is discovered that the TCP connection |
has been lost one sets up a new one. |
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 close a connection directly | without data traffic. A server MUST NOT initiate a close of a connec- |
after responding to a TEARDOWN request for the whole session. | tion directly after responding to a TEARDOWN request for the whole |
session. |
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 connec- | on the same server, it is RECOMMENDED to use only a single connec- |
tion. | tion. |
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 REC- | achieve interoperability with old servers any client is strongly REC- |
OMMENDED to use persistent connections. To make it practically possi- | OMMENDED to use persistent connections. |
ble for a client to the rules outlined in this chapter a feature tag |
is defined. |
con.non-persistent || A Client is also strongly RECOMMENDED to use persistent connections |
as it allows the server to send request to the client. In cases |
where no connection exist between the server and the client, this may |
cause the server to be forced to drop the RTSP session without noti- |
fying the client why,due to the lack of signalling channel. An exam- |
ple of such a case is when the server desires to send a REDIRECT |
request for a RTSP session to the client. |
If a service requires the use of persistent connection a option tag | If a service requires the use of persistent connection an feature-tag |
is specified for usage in Require and Proxy-Require. | is specified for usage in the Require and Proxy-Require headers. |
con.persistent || con.persistent ||
A server implemented according to this specification MUST respond | A server implemented according to this specification MUST respond |
that it supports the feature tag above. A client MAY send a request | that it supports the "play.basic" feature-tag above. A client MAY |
including the Supported header in a request to determine support of | send a request including the Supported header in a request to deter- |
non-persistent connections. A server supporting non-persistent con- | mine support of non-persistent connections. A server supporting non- |
nections MUST return the "con.non-persistent" feature tag in its | persistent connections will return the "play.basic" feature-tag in |
response. If the client receives the feature tag in the response, it | its response. If the client receives the feature-tag in the response, |
can be certain that the server handles non-persistent connections. | it can be certain that the server handles non-persistent connections.
9.4 Use of Transport Layer Security | 9.4 Use of IPv6
9.5 Use of IPv6 | This specification has been updated so that it supports IPv6. How-
ever this support was not present in RFC 2326 therefore some interop-
erability issues exist. A RFC 2326 implementation can support 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 use fully
qualified domain name and not a IPv6 address. Further the Transport
header must not use the parameters source and destination.
This specification has been updated so that it supports IPv6. How- | Implementations according to this specification MUST understand IPv6
ever this support was not present in RFC 2326 therefore some interop- | addresses in URLs, and headers. By this requirement the feature-tag
erability issues exist. A RFC 2326 implementation can support IPv6 as | "play.basic" can be used to determine that a server or client is
long as no explicit IPv6 addresses are used within RTSP messages. | capable of handling IPv6 within RTSP.
This require that any RTSP URL pointing at a IPv6 host must use fully |
qualified domain name and not a IPv6 address. Further the Transport |
header must not use the parameters source and destination. |
Implementations according to this specification MUST understand IPv6 | 10 Capability Handling
addresses in URLs, and headers. By this requirement the option-tag |
"play.basic" and "record.basic" can be used to determine that a |
server or client is capable of handling IPv6 within RTSP. |
10 Method Definitions This chapter describes the capability handling mechanism available in
RTSP which allows RTSP to be extended. Extensions too this version of
the protocol are basically done in two ways. First, new headers can
be added. Secondly, new methods can be added. The capability handling
mechanism is designed to handle these two cases.
The method token indicates the method to be performed on the resource | When a method is added the involved parties can use the OPTIONS
identified by the Request-URI case-sensitive. New methods may be | method to discover if it is supported. This is done by issuing a
defined in the future. Method names may not start with a $ character | OPTIONS request to the other party. Depending on the URL it will
(decimal 24) and must be a token as defined by the ABNF. Methods are | either apply in regards to a certain media resource, the whole server
summarized in Table 2. | in general, or simply the next hop. The OPTIONS response will contain
a Public which declares all methods supported for the indicated
resource.
It is not necessary to use OPTIONS to discover support of a method,
it is possible to simple try it. If the receiver of the request does
not support the method it will respond with an error code indicating
the the method are either not implemented (501) or does not apply for
the resource (405). The choice between the two discovery methods
depends on the requirements of the service.
To handle functionality additions that are not new methods feature-
tags are defined. Each feature-tag represents a certain block of
functionality. The amount of functionality that a feature-tag repre-
sents can vary significant. A simple feature-tag can simple represent
the functionality a single header gives. Another feature-tag is
"play.basic" which represents the minimal playback implementation
according to the updated specification.
The feature-tags are then used to determine if the client, server or
proxy supports the functionality that is necessary to achieve the
desired service. To determine support of a feature-tag several dif-
ferent headers can be used, each explained below:
Supported: The supported header are used to determine the complete
set of functionality that both client and server has. The
intended usage is to determine before one needs to use a func-
tionality that it is supported. If can be used in any method
however OPTIONS is the most suitable as one at the same time
determines all methods that are implemented. When sending a
request the requestor declares all its capabilities by includ-
ing all supported feature-tags. The results in that the
receiver learns the requestors feature support. The receiver
then includes its set of features in the response.
Require: The Require header can be included in any request where
the end point, i.e. the client or server, is required to
understand the feature to correctly perform the request. This
can for example be a SETUP request where the server must
understand a certain parameter to be able to set up the media
delivery correctly. Ignoring this parameter would not have the
desired effect and is not acceptable. Therefore the end-point
receiving a request containing a Require must negatively
acknowledge any feature that it does not understand and not
perform the request. The response in cases where features are
not understood are 551 (Option Not Supported). Also the fea-
tures that are not understood are given in the Unsupported
header in the response.
Proxy-Require: This method has the same purpose and workings as
Require except that it only applies to proxies and not the end
point. Features that needs to be supported by both proxies and
end-point needs to be included in both the Require and Proxy-
Require header.
Unsupported: This header is used in 551 error response to tell
which feature(s) that was not supported. Such a response is
only the result of the usage of the Require and/or Proxy-
Require header where one or more feature where not supported.
This information allows the requestor to make the best of sit-
uations as it knows which features that was not supported.
11 Method Definitions
The method token indicates the method to be performed on the resource
identified by the Request-URI case-sensitive. New methods may be
defined in the future. Method names may not start with a $ character
(decimal 24) and must be a token as defined by the ABNF. Methods are
summarized in Table 2.
Notes on Table 2: PAUSE is recommended, but not required in that a
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 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
ANNOUNCE C->S, S->C P,S optional optional
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
RECORD C->S P,S optional optional
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 2: 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
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. SHOULD not try this method again for this server.
10.1 OPTIONS 11.1 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 |
try a nonstandard request. It does not influence the session state. |
The Public header MUST be included in responses to indicate which |
methods that are supported by the server. To specify which methods |
that are possible to use for the specified resource, the Allow MAY be |
used. By including in the OPTIONS request a Supported header, the |
requester can determine which options the other part supports. |
The request URI determines which scope the options request has. By | The behavior is equivalent to that described in [H9.2]. An OPTIONS
giving the URI of a certain media the capabilities regarding this | request may be issued at any time, e.g., if the client is about to
media will be responded. By using the "*" URI the request regards the | try a nonstandard request. It does not influence the session state.
server without any media relevance. The Public header MUST be included in responses to indicate which
methods that are supported by the server. To specify which methods
that are possible to use for the specified resource, the Allow MAY be
used. By including in the OPTIONS request a Supported header, the
requester can determine which features the other part supports.
The request URI determines which scope the OPTIONS request has. By
giving the URI of a certain media the capabilities regarding this
media will be responded. By using the "*" URI the request regards the
next hop only, while having a URL with only the host address regards
the server without any media relevance.
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: implicit-play Require:
Proxy-Require: gzipped-messages Proxy-Require: gzipped-messages
Supported: play-basic Supported: play-basic
S->C: RTSP/1.0 200 OK S->C: RTSP/1.0 200 OK
CSeq: 1 CSeq: 1
Public: DESCRIBE, SETUP, TEARDOWN, PLAY, PAUSE Public: DESCRIBE, SETUP, TEARDOWN, PLAY, PAUSE
Supported: play-basic, gzipped-messages, implicit-play Supported: play-basic, implicit-play, gzipped-messages
Server: PhonyServer 1.0 Server: PhonyServer/1.0
Note that the option tags in Require and Proxy-Require are necessar- Note that some of the feature-tags in Require and Proxy-Require are
ily fictional features (one would hope that we would not purposefully necessarily fictional features (one would hope that we would not pur-
overlook a truly useful feature just so that we could have a strong posefully overlook a truly useful feature just so that we could have
example in this section). a strong example in this section).
10.2 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. It may use
the Accept header to specify the description formats that the client the Accept header to specify the description formats that the client
understands. The server responds with a description of the requested understands. The server responds with a description of the requested
resource. The DESCRIBE reply-response pair constitutes the media ini- resource. The DESCRIBE reply-response pair constitutes the media ini-
tialization phase of RTSP. tialization phase of RTSP.
Example: Example:
skipping to change at page 1, line 1423 skipping to change at page 1, line 1541
+ via the command line or standard input (thus working as a browser + via the command line or standard input (thus working as a browser
helper application launched with an SDP file or other media ini- helper application launched with an SDP file or other media ini-
tialization format). tialization 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.
10.3 ANNOUNCE 11.3 SETUP
The ANNOUNCE method serves two purposes:
When sent from client to server, ANNOUNCE posts the description of a
presentation or media object identified by the request URL to a
server. When sent from server to client, ANNOUNCE updates the ses-
sion description in real-time.
If a new media stream is added to a presentation (e.g., during a live
presentation), the whole presentation description should be sent
again, rather than just the additional components, so that components
can be deleted.
Example:
C->S: ANNOUNCE rtsp://server.example.com/fizzle/foo RTSP/1.0
CSeq: 312
Date: 23 Jan 1997 15:35:06 GMT
Session: 47112344
Content-Type: application/sdp
Content-Length: 332
v=0
o=mhandley 2890844526 2890845468 IN IP4 126.16.64.4
s=SDP Seminar
i=A Seminar on the session description protocol
u=http://www.cs.ucl.ac.uk/staff/M.Handley/sdp.03.ps
e=mjh@isi.edu (Mark Handley)
c=IN IP4 224.2.17.12/127
t=2873397496 2873404696
a=recvonly
m=audio 3456 RTP/AVP 0
m=video 2232 RTP/AVP 31
S->C: RTSP/1.0 200 OK
CSeq: 312
Date: 23 Jan 1997 15:35:06 GMT
Server: PhonyServer 1.0
10.4 SETUP
The SETUP request for a URI specifies the transport mechanism to be The SETUP request for a URI specifies the transport mechanism to be
used for the streamed media. A client can issue a SETUP request for a used for the streamed media. A client can issue a SETUP request for a
stream that is already set up or playing in the session to change stream that is already set up or playing in the session to change
transport parameters, which a server MAY allow. If it does not allow transport parameters, which a server MAY allow. If it does not allow
this, it MUST respond with error 455 (Method Not Valid In This this, it MUST respond with error 455 (Method Not Valid In This
State). State).
A server MAY allow a client to do SETUP while in playing state to add | A server MAY allow a client to do SETUP while in playing state to add
additional media streams. If not supported the server shall responde | additional media streams. If not supported the server shall responde
with error 455 (Method Not Allowed In This State). If supported the | with error 455 (Method Not Allowed In This State). If supported the
added media shall then start to play in sync with the already playing | added media shall then start to play in sync with the already playing
media. To be able to sync the media with the already playing streams | media. To be able to sync the media with the already playing streams
the SETUP response MUST include a RTP-Info header with the timestamp | the SETUP response MUST include a RTP-Info header with the timestamp
value, and a Range header with the corresponding normal play time. To | value, and a Range header with the corresponding normal play time. To
indicate support for this optional support the options-tag: | indicate support for this optional feature the feature-tag:
"setup.playing" is defined. "setup.playing" is defined.
For the benefit of any intervening firewalls, a client must indicate For the benefit of any intervening firewalls, a client must indicate
the transport parameters even if it has no influence over these the transport parameters even if it has no influence over these
parameters, for example, where the server advertises a fixed multi- parameters, for example, where the server advertises a fixed multi-
cast address. cast address.
Since SETUP includes all transport initialization information, Since SETUP includes all transport initialization information,
firewalls and other intermediate network devices (which need firewalls and other intermediate network devices (which need
this information) are spared the more arduous task of parsing this information) are spared the more arduous task of parsing
skipping to change at page 1, line 1513 skipping to change at page 1, line 1591
Date: 23 Jan 1997 15:35:06 GMT Date: 23 Jan 1997 15:35:06 GMT
Server: PhonyServer 1.0 Server: PhonyServer 1.0
Session: 47112344 Session: 47112344
Transport: RTP/AVP;unicast; Transport: RTP/AVP;unicast;
client_port=4588-4589;server_port=6256-6257 client_port=4588-4589;server_port=6256-6257
The server generates session identifiers in response to SETUP The server generates session identifiers in response to SETUP
requests. If a SETUP request to a server includes a session identi- requests. If a SETUP request to a server includes a session identi-
fier, the server MUST bundle this setup request into the existing fier, the server MUST bundle this setup request into the existing
session (aggregated session) or return error 459 (Aggregate Operation session (aggregated session) or return error 459 (Aggregate Operation
Not Allowed) (see Section 11.4.11). Not Allowed) (see Section 12.4.11).
To control an aggregated session an aggregated control URI MUST be | To control an aggregated session an aggregated control URI MUST be
used. The aggregated control URI MUST be different from any of the | used. The aggregated control URI MUST be different from any of the
media control URIs included in the aggregate. The aggregated URI | media control URIs included in the aggregate. The aggregated URI
SHOULD be specified by session description, as no general rule exist | SHOULD be specified by session description, as no general rule exist
to derive it from the included media's. | to derive it from the included media's.
A session will exist until it is torn down by a TEARDOWN request or | A session will exist until it is torn down by a TEARDOWN request or
times out. The server MAY remove a session that have had no liveness | times out. The server MAY remove a session that have had no liveness
signs from the client in the specified timeout time. The default | signs from the client in the specified timeout time. The default
timeout time is 60 seconds, the server MAY set this to another value, | timeout time is 60 seconds, the server MAY set this to another value,
by in the SETUP response include a timeout value in the session | by in the SETUP response include a timeout value in the session
header. For further discussion see chapter 12.37. Signs of client | header. For further discussion see chapter 13.37. Signs of client
liveness are: | liveness are:
+ RTCP sender or receiver reports from the client in any of the RTP | + RTCP sender or receiver reports from the client in any of the RTP
sessions part of the RTSP session. | sessions part of the RTSP session.
+ Any RTSP request which includes a Session header with the ses- | + Any RTSP request which includes a Session header with the ses-
sion's ID. | sion's ID.
10.5 PLAY 11.4 PLAY
The PLAY method tells the server to start sending data via the mecha- The PLAY method tells the server to start sending data via the mecha-
nism specified in SETUP. A client MUST NOT issue a PLAY request until nism specified in SETUP. A client MUST NOT issue a PLAY request until
any outstanding SETUP requests have been acknowledged as successful. any outstanding SETUP requests have been acknowledged as successful.
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 URI 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 ses- | want individual control of the media it must use separate RTSP ses-
sions for each media. | sions for each media.
The PLAY request positions the normal play time to the beginning of | The PLAY request positions the normal play time to the beginning of
the range specified by the Range header and delivers stream data | the range specified by the Range header and delivers stream data
until the end of the range is reached. To allow for precise composi- | until the end of the range is reached. To allow for precise composi-
tion multiple ranges MAY be specified. The range values are valid if | tion multiple ranges MAY be specified. The range values are valid if
all given ranges are part of any media. If a given range value points | all given ranges are part of any media. If a given range value points
outside of the media, the response SHALL be the 457 (Invalid Range) | outside of the media, the response SHALL be the 457 (Invalid Range)
error code. | error code.
The below example will first play seconds 10 through 15, then, imme- | The below example will first play seconds 10 through 15, then, imme-
diately following, seconds 20 to 25, and finally seconds 30 through | diately following, seconds 20 to 25, and finally seconds 30 through
the end. | 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 starts playing a A PLAY request without a Range header is legal. It starts playing a
stream from the beginning unless the stream has been paused. If a stream from the beginning unless the stream has been paused. If a
stream has been paused via PAUSE, stream delivery resumes at the stream has been paused via PAUSE, stream delivery resumes at the
pause point. pause point.
The Range header may also contain a time parameter. This parameter | The Range header may also contain a time parameter. This parameter
specifies a time in UTC at which the playback should start. If the | specifies a time in UTC at which the playback should start. If the
message is received after the specified time, playback is started | message is received after the specified time, playback is started
immediately. The time parameter may be used to aid in synchronization | immediately. The time parameter may be used to aid in synchronization
of streams obtained from different sources. Note: The usage of time | of streams obtained from different sources. Note: The usage of time
has two problems. First, at the time requested the RTSP state machine | has two problems. First, at the time requested the RTSP state machine
may not accept the request. The client will not get any notification | may not accept the request. The client will not get any notification
of the failure. Secondly, the server has difficulties to produce the | of the failure. Secondly, the server has difficulties to produce the
synchronization information for the RTP-Info header ahead of the | synchronization information for the RTP-Info header ahead of the
actually play-out. Due to these reasons it is RECOMMENDED that a | actually play-out. Due to these reasons it is RECOMMENDED that a
client not issues more than one timed request and no request without | client not issues more than one timed request and no request without
timing , until it is performed. The server SHALL in responses to | timing , until it is performed. The server SHALL in responses to
timed PLAY request give in the RTP-Info header, the sequence number | timed PLAY request give in the RTP-Info header, the sequence number
of the next RTP packet that will be send for that media, the RTP | of the next RTP packet that will be send for that media, the RTP
timestamp value corresponding to the activation time of the request. | timestamp value corresponding to the activation time of the request.
Unless the session is in paused state and not plays a single media | Unless the session is in paused state and not plays a single media
packet the RTP sequence number will be in error. The RTP timestamp | packet the RTP sequence number will be in error. The RTP timestamp
should be correct unless another timestamp rate has been used in | should be correct unless another timestamp rate has been used in
between the issuing of the request and activation. | between the issuing of the request and activation.
For a on-demand stream, the server MUST reply with the actual range | Server MUST include a "Range" header in any PLAY response. The |
that will be played back. This may differ from the requested range if | response MUST use the same format as the request's range header con- |
alignment of the requested range to valid frame boundaries is | tained. If no Range header was in the request, the NPT time format |
required for the media source. If no range is specified in the | SHOULD be used unless the client showed support for other formats. |
request, the start position SHALL still be returned in the reply. The | For a session with live media streams the Range header MUST also be |
unit of the range in the reply is the same as that in the request. If | given, containing a valid time indication. It is RECOMMENDED that |
the medias part of an aggregate has different lengths the PLAY | either "npt=now-" or a absolute time value (clock) for the corre- |
request and any Range SHALL be performed as long it is valid for the | sponding time is given, i.e. "clock=20030213T143205Z-". The UTC |
longest media. Media will be sent whenever it is available for the | clock format SHOULD only be used if client has shown support for it.
given play-out point. |
After playing the desired range, the presentation is NOT automati- | For a on-demand stream, the server MUST reply with the actual range
cally paused, media deliver simple stops. A PAUSE request MUST be | that will be played back. This may differ from the requested range if
issued before another PLAY request can issued. Note: This is one | alignment of the requested range to valid frame boundaries is
change resulting in a non-operability with RFC 2326 implementations. | required for the media source. If no range is specified in the
A client not issuing a PAUSE request before a new PLAY will be stuck | request, the start position SHALL still be returned in the reply. The
in PLAYING state. A client desiring to play the media from the begin- | unit of the range in the reply is the same as that in the request. If
ning MUST send a PLAY request with a Range header pointing at the | the medias part of an aggregate has different lengths the PLAY
beginning, e.g. npt=0-. | request and any Range SHALL be performed as long it is valid for the
longest media. Media will be sent whenever it is available for the
given play-out point.
After playing the desired range, the presentation is NOT automati-
cally paused, media deliver simply stops. A PAUSE request MUST be
issued before another PLAY request can issued. Note: This is one
change resulting in a non-operability with RFC 2326 implementations.
A client not issuing a PAUSE request before a new PLAY will be stuck
in PLAYING state. A client desiring to play the media from the begin-
ning MUST send a PLAY request with a Range header pointing at the
beginning, e.g. npt=0-.
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. The playback is to start time code 0:10:20 until the end of the clip. The playback is to start
at 15:36 on 23 Jan 1997. Note: The RTP-Info headers has been broken at 15:36 on 23 Jan 1997. Note: The RTP-Info headers has been broken
into several lines to fit the page. 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-;time=19970123T153600Z Range: smpte=0:10:20-;time=19970123T153600Z
skipping to change at page 1, line 1648 skipping to change at page 1, line 1737
CSeq: 835 CSeq: 835
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: clock=19961108T142300Z-19961108T143520Z Range: clock=19961108T142300Z-19961108T143520Z
RTP-Info:url=rtsp://example.com/meeting.en; RTP-Info:url=rtsp://example.com/meeting.en;
seq=53745;rtptime=484589019 seq=53745;rtptime=484589019
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.
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 [21] is removed
and multiple ranges can be used to achieve a similar performance. If | and multiple ranges can be used to achieve a similar performance. If
a server receives a PLAY request while in the PLAY state, the server | a server receives a PLAY request while in the PLAY state, the server
SHALL responde using the error code 455 (Method Not Valid In This | SHALL responde using the error code 455 (Method Not Valid In This
State). This will signal the client that queued play are not sup- | State). This will signal the client that queued play are not sup-
ported. | ported.
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, has also been decapitated. Instead a client can use, | range header, has also been decapitated. Instead a client can use,
PING, SET_PARAMETER or OPTIONS for keep alive. A server receiving a | PING, SET_PARAMETER or OPTIONS for keep alive. A server receiving a
PLAY keep alive SHALL respond with the 455 error code. | PLAY keep alive SHALL respond with the 455 error code.
When playing live media, indicated by the Transport headers mode | When playing live media, indicated by the Accept-Ranges header the |
parameter the session are in a live state. This live state will put | session are in a live state. This live state will put some restric- |
some restrictions on the action available for a client. A PLAY | tions on the action available for a client. A PLAY request without a |
request without a Range header will start media deliver at the cur- | Range header will start media deliver at the current point in the |
rent point in the live presentation, i.e. now. Any seeking in the | live presentation, i.e. now. Any seeking in the media will be impos- |
media will be impossible. The only allowed usage of the Range header | sible. The only allowed usage of the Range header is npt=now-, and |
is npt=now-, and certain clock units. The usage of npt=now- is unnec- | certain clock units. The usage of npt=now- is unnecessary as it has |
essary as it has the exact same meaning as a request without Range | the exact same meaning as a request without Range header. The clock |
header. The clock format can be used to specify start and stop times | format can be used to specify start and stop times for media delivery |
for media delivery in a live session. | in a live session.
10.6 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 aggre- | (halted) temporarily. A PAUSE request MUST be done with the aggre- |
gated control URI for aggregated sessions, resulting in all media | gated control URI for aggregated sessions, resulting in all media |
being halted, or the media URI for non-aggregated sessions. Any | being halted, or the media URI for non-aggregated sessions. Any |
attempt to do muting of a single media with an PAUSE request in an | attempt to do muting of a single media with an PAUSE request in an |
aggregated session SHALL be responded with error 460 (Only Aggregate | aggregated session SHALL be responded with error 460 (Only Aggregate |
Operation Allowed). After resuming playback or recording, synchro- | Operation Allowed). After resuming playback, synchronization of the |
nization of the tracks MUST be maintained. Any server resources are | tracks MUST be maintained. Any server resources are kept, though |
kept, though servers MAY close the session and free resources after | servers MAY close the session and free resources after being paused |
being paused for the duration specified with the timeout parameter of | for the duration specified with the timeout parameter of the Session |
the Session header in the SETUP message. 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 header MUST contain a single value, expressed as | "pause point". The header MUST contain a single value, expressed as
the beginning value an open range. For example, the following clip | the beginning value an open range. For example, the following clip
will be played from 10 seconds through 21 seconds of the clip's nor- | will be played from 10 seconds through 21 seconds of the clip's nor-
mal play time, under the assumption that the PAUSE request reaches | mal play time, under the assumption that the PAUSE request reaches
the server within 11 seconds of the PLAY request. Note that some | the server within 11 seconds of the PLAY request. Note that some
lines has been broken in an non-correct way to fit the page: | lines has been broken in an non-correct way to fit the page:
C->S: PLAY rtsp://example.com/fizzle/foo RTSP/1.0 | C->S: PLAY rtsp://example.com/fizzle/foo RTSP/1.0
CSeq: 834 | CSeq: 834
Session: 12345678 | Session: 12345678
Range: npt=10-30 | Range: npt=10-30
S->C: RTSP/1.0 200 OK |
CSeq: 834 |
Date: 23 Jan 1997 15:35:06 GMT |
Server: PhonyServer 1.0 |
Range: npt=10-30 |
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 | S->C: RTSP/1.0 200 OK
CSeq: 835 | CSeq: 834
Session: 12345678 | Date: 23 Jan 1997 15:35:06 GMT
Range: npt=21- | Server: PhonyServer 1.0
Range: npt=10-30
RTP-Info:url=rtsp://example.com/fizzle/audiotrack;
seq=5712;rtptime=934207921,
url=rtsp://example.com/fizzle/videotrack;
seq=57654;rtptime=2792482193
Session: 12345678
S->C: RTSP/1.0 200 OK | C->S: PAUSE rtsp://example.com/fizzle/foo RTSP/1.0
CSeq: 835 | CSeq: 835
Date: 23 Jan 1997 15:35:09 GMT | Session: 12345678
Server: PhonyServer 1.0 | Range: npt=21-
Range: npt=21- |
Session: 12345678 | S->C: RTSP/1.0 200 OK
CSeq: 835
Date: 23 Jan 1997 15:35:09 GMT
Server: PhonyServer 1.0
Range: npt=21-
Session: 12345678
The pause request becomes effective the first time the server is | The pause request becomes effective the first time the server is |
encountering the time point specified in any of the multiple ranges. | encountering the time point specified in any of the multiple ranges. |
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 or recorded. If the Range header is | the pause point, it is not played. If the Range header is missing, |
missing, stream delivery is interrupted immediately on receipt of the | stream delivery is interrupted immediately on receipt of the message |
message and the pause point is set to the current normal play time. | and the pause point is set to the current normal play time. However, |
However, the pause point in the media stream MUST be maintained. A | the pause point in the media stream MUST be maintained. A subsequent |
subsequent PLAY request without Range header resumes from the pause | PLAY request without Range header resumes from the pause point and |
point and play until media end. | play until media end.
The actual pause point after any PAUSE request SHALL be returned to | The actual pause point after any PAUSE request SHALL be returned to
the client by adding a Range header with what remains unplayed of the | 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 simple included the Range header from the PAUSE
response. | response.
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 sec- | PAUSE request arrives before the server has started playing the sec-
ond, overlapping range. Regardless of when the PAUSE request arrives, | ond, overlapping range. Regardless of when the PAUSE request arrives,
it sets the pause point to 14. | it sets the pause point to 14.
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
the PAUSE request Range header, a PLAY without range would still | the PAUSE request Range header, a PLAY without range would still
resume at that point in time, specified by the pause's range header, | resume at that point in time, specified by the pause's range header,
as it is assumed that the client has discarded data after that point. | as 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.
10.7 TEARDOWN 11.6 TEARDOWN
The TEARDOWN request stops the stream delivery for the given URI, | The TEARDOWN request stops the stream delivery for the given URI,
freeing the resources associated with it. If the URI is the aggre- | freeing the resources associated with it. If the URI is the aggre-
gated control URI for this presentation, any RTSP session identifier | gated control URI for this presentation, any RTSP session identifier
associated with the session is no longer valid. The use of "*" as URI | associated with the session is no longer valid. The use of "*" as URI
in TEARDOWN will also result in that the session is removed indepen- | in TEARDOWN will also result in that the session is removed indepen-
dent of the number of medias that was part of it. If the URI in the | dent of the number of medias that was part of it. If the URI in the
request was for a media within an aggregated session that media is | request was for a media within an aggregated session that media is
removed from the aggregate. However the session and any other media | removed from the aggregate. However the session and any other media
stream yet not torn down remains, and any valid request, e.g. PLAY or | stream yet not torn down remains, and any valid request, e.g. PLAY or
SETUP, can be issued. As an optional feature a server MAY keep the | SETUP, can be issued. As an optional feature a server MAY keep the
session in case the last remaining media is torn down with a TEARDOWN | session in case the last remaining media is torn down with a TEARDOWN
request with an URI equal to the media URI. To Indicate what has been | request with an URI equal to the media URI. To Indicate what has been
performed, a server that after any TEARDOWN request, still has a | performed, a server that after any TEARDOWN request, still has a
valid session MUST in the response return a session header. | valid session MUST in the response return a session header.
A server MAY choose to allow TEARDOWN of individual media while in | A server MAY choose to allow TEARDOWN of individual media while in
PLAY state. When this is not allowed the response SHALL be 455 | PLAY state. When this is not allowed the response SHALL be 455
(Method Not Valid In This State). If a server implements TEARDOWN and | (Method Not Valid In This State). If a server implements TEARDOWN and
SETUP in PLAY state it MUST signal this using the "setup.playing" | SETUP in PLAY state it MUST signal this using the "setup.playing"
option tag. | feature-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
10.8 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 of a
presentation or stream specified in the URI. If the Session header is | presentation or stream specified in the URI. If the Session header is
present in a request, the value of a parameter MUST be retrieved in | present in a request, the value of a parameter MUST be retrieved in
the sessions context. The content of the reply and response is left | the sessions context. The content of the reply and response is left
to the implementation. GET_PARAMETER with no entity body may be used | to the implementation. GET_PARAMETER with no entity body may be used
to test client or server liveness ("ping"). Example: to test client or server liveness ("ping").
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
jitter jitter
skipping to change at page 1, line 1845 skipping to change at page 1, line 1937
Content-Type: text/parameters Content-Type: text/parameters
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 with parameter. This method is intentionally loosely defined with
the intention that the reply content and response content will the intention that the reply content and response content will
be defined after further experimentation. be defined after further experimentation.
10.9 SET_PARAMETER 11.8 SET_PARAMETER
This method requests to set the value of a parameter for a presenta- This method requests to set the value of a parameter for a presenta-
tion or stream specified by the URI. tion or stream specified by the URI.
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).
The response body SHOULD contain only the parameters that has errors. | The response body SHOULD contain only the parameters that has errors.
Otherwise no body SHALL be returned. Otherwise no body SHALL be returned.
Note: transport parameters for the media stream MUST only be set with Note: transport parameters for the media stream MUST only be set with
the SETUP command. the SETUP command.
Restricting setting transport parameters to SETUP is for the Restricting setting transport parameters to SETUP is for the
benefit of firewalls. benefit of firewalls.
The parameters are split in a fine-grained fashion so that The parameters are split in a fine-grained fashion so that
there can be more meaningful error indications. However, it there can be more meaningful error indications. However, it
skipping to change at page 1, line 1896 skipping to change at page 1, line 1988
Content-length: 10 Content-length: 10
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 with parameter. This method is intentionally loosely defined with
the intention that the reply content and response content will the intention that the reply content and response content will
be defined after further experimentation. be defined after further experimentation.
10.10 REDIRECT 11.9 REDIRECT
A redirect request informs the client that it MUST connect to another | A redirect request informs the client that it MUST connect to another |
server location. REDIRECT SHALL only be sent to the client who cur- | server location. The REDIRECT request MAY contain the header Loca- |
rently has a session at the server. The REDIRECT request MAY contain | tion, which indicates that the client should issue requests for that |
the header Location, which indicates that the client should issue | URL. If the Location URL only contains a host address the client |
requests for that URL. If the Location URL only contains a host | shall connect to the given host, while using the path from the URL on |
address the client shall connect to the given host, while using the | the current server. |
path from the URL on the current server. | If a REDIRECT request contains a Session header, it is end-to-end and |
applies only to the given session. If there are proxies in the |
request chain, they SHOULD NOT disconnect the control channel unless |
there are no remaining sessions. |
The redirect request MAY contain the header Range, which indicates | If a REDIRECT request does not contain a Session header, it is next- |
when the redirection takes effect. If the Range contains a time= | hop and applies to the control connection. The Location header SHOULD |
value that is the wall clock time that the redirection MUST at the | only contain a host address. If there are proxies in the request |
latest take place. When the time= parameter is present the range | chain, they SHOULD do all of the following: (1) respond to the REDI- |
value MUST be ignored. However the range entered MUST be syntactical | RECT request, (2) disconnect the control channel from the requestor, |
correct and SHALL point at the beginning of any on-demand content. If | (3) reconnect to the given host address, and (4) pass the request to |
no time parameter is part of the Range header then redirection SHALL | each applicable client (typically those clients with an active ses- |
take place when the media playout from the server reaches the given | sion or unanswered request from the requestor). Note that the proxy |
time. The range value MUST be a single value in the open ended form, | is responsible for accepting the REDIRECT response from its clients |
e.g. npt=59-. | and these responses MUST NOT be passed on to either the requesting or |
the destination server.
If a Session header is included in the REDIRECT request the client | The redirect request MAY contain the header Range, which indicates
MUST redirect the indicated session. If no Session header is included | when the redirection takes effect. If the Range contains a "time="
the client MUST redirect all sessions that it have on the server | value that is the wall clock time that the redirection MUST at the
sending the request. | latest take place. When the "time=" parameter is present the range
value MUST be ignored. However the range entered MUST be syntactical
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
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,
e.g. npt=59-.
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 MUST issue a TEARDOWN request for the current | resource, the client MUST issue a TEARDOWN request for the current
session. A new session must be established with the designated host. | session. A new session must be established with the designated host.
A client SHOULD issue a new DESCRIBE request with the URL given in | A client SHOULD issue a new DESCRIBE request with the URL given in
the Location header, unless the URL only contains a host address. In | the Location header, unless the URL only contains a host address. In
the cases the Location only contains a host address the client MAY | the cases the Location only contains a host address the client MAY
assume that the media on the server it is redirected to is identical. | assume that the media on the server it is redirected to is identical.
Identical media means that all media configuration information from | Identical media means that all media configuration information from
the old session still is valid except for the host address. In the | the old session still is valid except for the host address. In the
case of absolute URLs in the location header the media redirected to | case of absolute URLs in the location header the media redirected to
can be either identical, slightly different or totally different. | can be either identical, slightly different or totally different.
This is the reason why a new DESCRIBE request SHOULD be issued. | This is the reason why a new DESCRIBE request 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://bigserver.com:8001
Range: clock=19960213T143205Z- | Range: clock=19960213T143205Z-
Session: uZ3ci0K+Ld-M | Session: uZ3ci0K+Ld-M
10.11 RECORD 11.10 PING
This method initiates recording a range of media data according to This method is a bi-directional mechanism for server or client live-
the presentation description. The timestamp reflects start and end ness checking. It has no side effects. The issuer of the request MUST
time (UTC). If no time range is given, use the start or end time pro- include a session header with the session ID of the session that is
vided in the presentation description. If the session has already being checked for liveness.
started, commence recording immediately.
The server decides whether to store the recorded data under the Prior to using this method, an OPTIONS method is RECOMMENDED to be
request-URI or another URI. If the server does not use the request- issued in the direction which the PING method would be used. This
URI, the response SHOULD be 201 (Created) and contain an entity which method MUST NOT be used if support is not indicated by the Public
describes the status of the request and refers to the new resource, header. Note: That an 501 (Not Implemented) response means that the
and a Location header. keep-alive timer has not been updated.
A media server supporting recording of live presentations MUST sup- When a proxy is in use, PING with a * indicates a single-hop liveness
port the clock range format; the smpte format does not make sense. check, whereas PING with a URL including an host address indicates an
end-to-end liveness check.
In this example, the media server was previously invited to the con- Example:
ference indicated.
C->S: RECORD rtsp://example.com/meeting/audio.en RTSP/1.0 C->S: PING * RTSP/1.0
CSeq: 954 CSeq: 123
Session: 12345678 Session: 12345678
Conference: 128.16.64.19/32492374
Note: this example needs work, or needs to be removed. More S->C: RTSP/1.0 200 OK
thoughts on how it works together with ANNOUNCE is needed. CSeq: 123
Also notification on out of disk is needed. The use of aggre- Session:12345678
gated and non-aggregated control needs to be clarified.
10.12 PING
This method is a bi-directional mechanism for server or client live- |
ness checking. It has no side effects. The issuer of the request MUST |
include a session header with the session ID of the session that is |
being checked for liveness. |
Prior to using this method, an OPTIONS method is RECOMMENDED to be |
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 |
header. Note: That an 501 (Not Implemented) response means that the |
keep-alive timer has not been updated. |
When a proxy is in use, PING with a * indicates a single-hop liveness |
check, whereas PING with a URL including an host address indicates an |
end-to-end liveness check. |
Example: |
C->S: PING * RTSP/1.0 |
CSeq: 123 |
Session:12345678 |
S->C: RTSP/1.0 200 OK |
CSeq: 123 |
Session:12345678 |
10.13 Embedded (Interleaved) Binary Data 11.11 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 methods and stream data. This interleaving should | to interleave RTSP messages and media stream data. This interleaving
generally be avoided unless necessary since it complicates client and | should generally be avoided unless necessary since it complicates
server operation and imposes additional overhead. Also head of line | client and server operation and imposes additional overhead. Also
blocking may cause problems. Interleaved binary data SHOULD only be | head of line blocking may cause problems. Interleaved binary data
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, fol- sign (24 decimal), followed by a one-byte channel identifier, fol-
lowed by the length of the encapsulated binary data as a binary, two- lowed by the length of the encapsulated binary data as a binary, two-
byte integer in network byte order. The stream data follows immedi- byte integer in network byte order. The stream data follows immedi-
ately afterwards, without a CRLF, but including the upper-layer pro- ately afterwards, without a CRLF, but including the upper-layer
tocol headers. Each $ block contains exactly one upper-layer protocol protocol headers. Each $ block contains exactly one upper-layer pro-
data unit, e.g., one RTP packet. tocol data unit, e.g., one RTP packet.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| "$" = 24 | Channel ID | Length in bytes |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: 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 12.40). interleaved parameter(Section 13.40).
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. As a default, RTCP packets are by the server over the TCP connection. The usage of RTCP messages is
sent on the first available channel higher than the RTP channel. The indicated by including a range containing a second channel in the
client MAY explicitly request RTCP packets on another channel. This interleaved parameter of the Transport header, see section 13.40. If
is done by specifying two channels in the interleaved parameter of RTCP is used, packets SHALL be sent on the first available channel
the Transport header(Section 12.40). higher than the RTP channel. The channels are bi-directional and
therefore RTCP traffic are sent on the second channel in both direc-
tions.
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 con- are interleaved in such a fashion. Also, this provides a con-
venient way to tunnel RTP/RTCP packets through the TCP control venient way to tunnel RTP/RTCP packets through the TCP control
connection when required by the network configuration and connection when required by the network configuration and
transfer them onto UDP when possible. transfer them onto UDP when possible.
C->S: SETUP rtsp://foo.com/bar.file RTSP/1.0 C->S: SETUP rtsp://foo.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=0-1 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://foo.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://foo.com/bar.file;
seq=232433;rtptime=972948234 seq=232433;rtptime=972948234
S->C: $000{2 byte length}{"length" bytes data, w/RTP header} S->C: $000{2 byte length}{"length" bytes data, w/RTP header}
S->C: $000{2 byte length}{"length" bytes data, w/RTP header} S->C: $000{2 byte length}{"length" bytes data, w/RTP header}
S->C: $001{2 byte length}{"length" bytes RTCP packet} S->C: $001{2 byte length}{"length" bytes RTCP packet}
11 Status Code Definitions 12 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 1 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.
11.1 Success 1xx 12.1 Success 1xx
11.1.1 100 Continue 12.1.1 100 Continue
See, [H10.1.1]. See, [H10.1.1].
11.2 Success 2xx 12.2 Success 2xx
11.2.1 250 Low on Storage Space 12.2.1 250 Low on Storage Space
The server returns this warning after receiving a RECORD request that The server returns this warning after receiving a RECORD request that
it may not be able to fulfill completely due to insufficient storage it may not be able to fulfill completely due to insufficient storage
space. If possible, the server should use the Range header to indi- space. If possible, the server should use the Range header to indi-
cate what time period it may still be able to record. Since other cate what time period it may still be able to record. Since other
processes on the server may be consuming storage space simultane- processes on the server may be consuming storage space simultane-
ously, a client should take this only as an estimate. ously, a client should take this only as an estimate.
11.3 Redirection 3xx 12.3 Redirection 3xx
See [H10.3] for definition of status code 300 to 305. However com- | The notation "3rr" indicates response codes from 300 to 399 inclusive
ments are given for some to how they apply to RTSP. Further a couple | which are meant for redirection. The response code 304 is excluded
of new status codes are defined. | from this set, as it is not used for redirection.
Within RTSP, redirection may be used for load balancing or redirect- | See [H10.3] for definition of status code 300 to 305. However com-
ing stream requests to a server topologically closer to the client. | ments are given for some to how they apply to RTSP. Further a couple
Mechanisms to determine topological proximity are beyond the scope of | of new status codes are defined.
this specification. |
11.3.1 300 Multiple Choices | Within RTSP, redirection may be used for load balancing or redirect-
ing stream requests to a server topologically closer to the client.
Mechanisms to determine topological proximity are beyond the scope of
this specification.
11.3.2 301 Moved Permanently | 12.3.1 300 Multiple Choices
The request resource are moved permanently and resides now at the URI | 12.3.2 301 Moved Permanently
given by the location header. The user client SHOULD redirect auto- |
matically to the given URI. |
11.3.3 302 Found | The request resource are moved permanently and resides now at the URI
given by the location header. The user client SHOULD redirect auto-
matically to the given URI.
The requested resource reside temporarily at the URI given by the | 12.3.3 302 Found
Location header. The Location header MUST be included. |
11.3.4 303 See Other | The requested resource reside temporarily at the URI given by the
Location header. The Location header MUST be included. Is intended to
be used for many types of temporary redirects, e.g. load balancing.
It is RECOMMENDED that one set the reason phrase to something more
meaningful than "Found" in these cases.
This status code SHALL NOT be used in RTSP. However as it was allowed | 12.3.4 303 See Other
to use in RFC 2326 it is possible that such response will be |
received. |
11.3.5 304 Not Modified | 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 will be
received.
11.3.6 305 Use Proxy | 12.3.5 304 Not Modified
See [H10.3.6]. | If the client has performed a conditional DESCRIBE or SETUP (see
12.23) and the requested resource has not been modified, the server
SHOULD send a 304 response. This response MUST NOT contain a message-
body.
11.3.7 350 Going Away | The response MUST include the following header fields:
The server the request was directed at will not be available any | + Date
more. This can be for a number of reasons, such as maintenance, or |
power failure. If there is a alternative server available the Loca- |
tion header SHOULD contain a URI to the same resource at that host. |
In case that no server is available the Location header MUST NOT be |
included. |
In the case the client has an established session on the server giv- | + ETag and/or Content-Location, if the header would have been sent
ing the 350 response code, it SHALL immediately do TEARDOWN on that | in a 200 response to the same request.
session. It is RECOMMENDED that the server tries to send REDIRECT |
request if possible instead of waiting for a client request to |
responde to. |
11.3.8 351 Load Balancing | + Expires, Cache-Control, and/or Vary, if the field-value might
differ from that sent in any previous response for the same vari-
ant.
The server the request was issued for is currently uneven loaded and | This response is independent for the DESCRIBE and SETUP requests.
request that further request is directed to another server. The | That is, a 304 response to DESCRIBE does NOT imply that the resource
Location header MUST be included in the response and contain the URI | content is unchanged and a 304 response to SETUP does NOT imply that
of the other server. If the both server has the requested resource in | the resource description is unchanged. The ETag and If-Match headers
the same place only the Server part of the URI MAY be given. In all | may be used to link the DESCRIBE and SETUP in this manner.
other cases an absolute URI MUST be given.
11.4 Client Error 4xx 12.3.6 305 Use Proxy
11.4.1 400 Bad Request See [H10.3.6].
12.4 Client Error 4xx
12.4.1 400 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 modifica- syntax. The client SHOULD NOT repeat the request without modifica-
tions [H10.4.1]. If the request does not have a CSeq header, the tions [H10.4.1]. If the request does not have a CSeq header, the
server MUST NOT include a CSeq in the response. server MUST NOT include a CSeq in the response.
11.4.2 405 Method Not Allowed 12.4.2 405 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 URI. 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.
11.4.3 451 Parameter Not Understood 12.4.3 451 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).
11.4.4 452 reserved 12.4.4 452 reserved
This error code was removed from RFC 2326 [21] and is obsolete. This error code was removed from RFC 2326 [21] and is obsolete.
11.4.5 453 Not Enough Bandwidth 12.4.5 453 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 fail- This may, for example, be the result of a resource reservation fail-
ure. ure.
11.4.6 454 Session Not Found 12.4.6 454 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.
11.4.7 455 Method Not Valid in This State 12.4.7 455 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.
11.4.8 456 Header Field Not Valid for Resource 12.4.8 456 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.
11.4.9 457 Invalid Range 12.4.9 457 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.
11.4.10 458 Parameter Is Read-Only 12.4.10 458 Parameter Is Read-Only
The parameter to be set by SET_PARAMETER can be read but not modi- | The parameter to be set by SET_PARAMETER can be read but not modi-
fied. When returning this error message the sender SHOULD return a | fied. When returning this error message the sender SHOULD return a
entity body containing the offending parameter(s). entity body containing the offending parameter(s).
11.4.11 459 Aggregate Operation Not Allowed 12.4.11 459 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.
11.4.12 460 Only Aggregate Operation Allowed 12.4.12 460 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.
11.4.13 461 Unsupported Transport 12.4.13 461 Unsupported Transport
The Transport field did not contain a supported transport specifica- The Transport field did not contain a supported transport specifica-
tion. tion.
11.4.14 462 Destination Unreachable 12.4.14 462 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 param- the result of a client attempt to place an invalid Destination param-
eter in the Transport field. eter in the Transport field.
11.5 Server Error 5xx 12.5 Server Error 5xx
11.5.1 551 Option not supported
An option given in the Require or the Proxy-Require fields was not
supported. The Unsupported header SHOULD be returned stating the
option for which there is no support.
12 Header Field Definitions
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 syn-
tax, meaning, and usage. Throughout this section, we use [HX.Y] to
refer to Section X.Y of the current HTTP/1.1 specification RFC 2616
[26]. Examples of each header field are given.
Information about header fields in relation to methods and proxy pro-
cessing is summarized in Table 4 and Table 5.
The "where" column describes the request and response types in which 12.5.1 551 Option not supported
the header field can be used. Values in this column are:
R: header field may only appear in requests; An feature-tag given in the Require or the Proxy-Require fields was
not supported. The Unsupported header SHOULD be returned stating the
feature for which there is no support.
r: header field may only appear in responses; 13 Header Field Definitions
2xx, 4xx, etc.: A numerical value or range indicates response codes
with which the header field can be used;
method direction object acronym Body method direction object acronym Body
----------------------------------------------- -----------------------------------------------
DESCRIBE C->S P,S DES r DESCRIBE C->S P,S DES r
ANNOUNCE C->S, S->C P,S ANN 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
RECORD C->S P,S REC
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 3: 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
section lists the full set of header fields along with notes on syn-
tax, meaning, and usage. Throughout this section, we use [HX.Y] to
refer to Section X.Y of the current HTTP/1.1 specification RFC 2616
[26]. Examples of each header field are given.
Information about header fields in relation to methods and proxy pro-
cessing is summarized in Table 4 and Table 5.
The "where" column describes the request and response types in which
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 responses;
2xx, 4xx, etc.: A numerical value or range indicates response codes
with which the header field can be used;
c: header field is copied from the request to the response. c: header field is copied from the request to the response.
An empty entry in the "where" column indicates that the header field An empty entry in the "where" column indicates that the header field
may be present in all requests and responses. may be present in all requests and responses.
The "proxy" column describes the operations a proxy may perform on a The "proxy" column describes the operations a proxy may perform on a
header field: header field:
a: A proxy can add or concatenate the header field if not present. a: A proxy can add or concatenate the header field if not present.
skipping to change at page 1, line 2314 skipping to change at page 1, line 2399
text of the message. text 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 be m*: The header field SHOULD be sent, but clients/servers need to be
prepared to receive messages without that header field. 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 empty. *: The header field is required if the message body is not empty.
See sections 12.14, 12.16 and 4.3 for details. See sections 13.14, 13.16 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 field in "Optional" means that a Client/Server MAY include the header field in
a request or response, and a Client/Server MAY ignore the header a request or response, and a Client/Server MAY ignore the header
field if present in the request or response (The exception to this field if present in the request or response (The exception to this
rule is the Require header field discussed in 12.32). A "mandatory" rule is the Require header field discussed in 13.32). A "mandatory"
header field MUST be present in a request, and MUST be understood by header field MUST be present in a request, and MUST be understood by
the Client/Server receiving the request. A mandatory response header the Client/Server receiving the request. A mandatory response header
field MUST be present in the response, and the header field MUST be field MUST be present in the response, and the header field MUST be
understood by the Client/Server processing the response. "Not appli- understood by the Client/Server processing the response. "Not appli-
cable" means that the header field MUST NOT be present in a request. cable" means that the header field MUST NOT be present in a request.
If one is placed in a request by mistake, it MUST be ignored by the If one is placed in a request by mistake, it MUST be ignored by the
Client/Server receiving the request. Similarly, a header field Client/Server receiving the request. Similarly, a header field
labeled "not applicable" for a response means that the Client/Server labeled "not applicable" for a response means that the Client/Server
MUST NOT place the header field in the response, and the MUST NOT place the header field in the response, and the
Client/Server MUST ignore the header field in the response. 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 URI. If the
URI contains a comma, or semicolon, the URI MUST be enclosed in dou- URI contains a comma, or semicolon, the URI MUST be enclosed in dou-
ble quotas ("). Any URI parameters are contained within these quotas. ble quotas ("). Any URI parameters are contained within these quotas.
If the URI is not enclosed in double quotas, any semicolon- delimited If the URI is not enclosed in double quotas, any semicolon- delimited
parameters are header-parameters, not URI parameters. parameters are header-parameters, not URI parameters.
12.1 Accept | 13.1 Accept
The Accept request-header field can be used to specify certain pre- The Accept request-header field can be used to specify certain pre-
sentation description content types which are acceptable for the sentation description content types which are acceptable for the
response. response.
The "level" parameter for presentation descriptions is prop- The "level" parameter for presentation descriptions is prop-
erly defined as part of the MIME type registration, not here. erly defined as part of the MIME type registration, not here.
See [H14.1] for syntax.
Example of use:
Accept: application/rtsl q=1.0, application/sdp;level=2
13.2 Accept-Encoding
See [H14.3]
13.3 Accept-Language
See [H14.4]. Note that the language specified applies to the presen-
tation description and any reason phrases, not the media content.
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 -
Authorization R o o o o o o Authorization R o o o o o o
skipping to change at page 1, line 2387 skipping to change at page 1, line 2487
Content-Type r * - - - - - Content-Type r * - - - - -
Content-Type 4xx * * * * * * Content-Type 4xx * * * * * *
CSeq Rc m m m m m m CSeq Rc m m m m m m
Date am o o o o o o Date am o o o o o o
Expires r r o - - - - - Expires r r o - - - - -
From R r o o o o o o From R r o o o o o o
Host o o o o o o Host o o o o o o
If-Match R r - - o - - - If-Match R r - - o - - -
If-Modified-Since R r o - o - - - If-Modified-Since R r o - o - - -
Last-Modified r r o - - - - - Last-Modified r r o - - - - -
Location 3xx o - o - - - Location 3rr o o o o o o
Proxy-Authenticate 407 amr m m m m m m Proxy-Authenticate 407 amr m m m m m m
Proxy-Require R ar o o o o o o Proxy-Require R ar o o o o o o
Public r admr - m* - - - - Public r admr - m* - - - -
Public 501 admr m* m* m* m* m* m* Public 501 admr m* m* m* m* m* m*
Range R - - - o o - Range R - - - o o -
Range r - - c m* - - Range r - - c m* - -
Referer R o o o o o o Referer R o o o o o o
Require R o o o o o o Require R o o o o o o
Retry-After 3xx,503 o o o - - - Retry-After 3rr,503 o o o - - -
RTP-Info r - - o m - - RTP-Info r - - o m - -
Scale - - - o - - Scale - - - o - -
Session R - o o m m m Session R - o o m m m
Session r - c m m m o Session r - c m m m o
Server R - o - - - - Server R - o - - - -
Server r o o o o o o Server r o o o o o o
Speed - - - o - - Speed - - - o - -
Supported R o o o o o o Supported R o o o o o o
Supported r c c c c c c Supported r c c c c c c
Timestamp R o o o o o o Timestamp R o o o o o o
skipping to change at page 1, line 2421 skipping to change at page 1, line 2521
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 4: Overview of RTSP header fields related to methods DESCRIBE,
OPTIONS, SETUP, PLAY, PAUSE, and TEARDOWN. OPTIONS, SETUP, PLAY, PAUSE, and TEARDOWN.
See [H14.1] for syntax. 13.4 Accept-Ranges
Example of use:
Accept: application/rtsl q=1.0, application/sdp;level=2
12.2 Accept-Encoding
See [H14.3] The Accept-Ranges response-header field allows the server to indicate
its acceptance of range requests and possible formats for a resource: |
12.3 Accept-Language Accept-Ranges = "Accept-Ranges" ":" acceptable-ranges ||
acceptable-ranges = 1#range-unit / "none" ||
range-unit = NPT / SMPTE / UTC / LIVE / extension-format ||
extension-format = token ||
See [H14.4]. Note that the language specified applies to the presen- This header has the same syntax as [H14.5]. However new range-units
tation description and any reason phrases, not the media content. are defined and byte-ranges SHALL NOT be used. Inclusion of any of
the three time formats indicates acceptance by the server for PLAY
and PAUSE requests with this format. Inclusion of the "LIVE" tag
indicates that the resource has LIVE properties. The headers value is
valid for the resource specified by the URI in the request, this
response corresponds to.
12.4 Accept-Ranges | Header Where Proxy GPR SPR RDR PNG
Header Where Proxy GPR SPR ANN REC RDR PNG -----------------------------------------------------
--------------------------------------------------------- Allow 405 - - - -
Allow 405 - - m m - - Authorization R o o o o
Authorization R o o o o o o Bandwidth R - o - -
Bandwidth R - o - - - - Blocksize R - o - -
Blocksize R - o - - - - Connection o o o -
Connection o o o o o - Content-Base R o o - -
Content-Base R o o o - - - Content-Base r o o - -
Content-Base r o o - - - - Content-Base 4xx o o o -
Content-Base 4xx o o o o o - Content-Encoding R r o o - -
Content-Encoding R r o o o - - - Content-Encoding r r o o - -
Content-Encoding r r o o - - - - Content-Encoding 4xx r o o o -
Content-Encoding 4xx r o o o o o - Content-Language R r o o - -
Content-Language R r o o o - - - Content-Language r r o o - -
Content-Language r r o o - - - - Content-Language 4xx r o o o -
Content-Language 4xx r o o o o o - Content-Length R r * * - -
Content-Length R r * * * - - - Content-Length r r * * - -
Content-Length r r * * - - - - Content-Length 4xx r * * * -
Content-Length 4xx r * * * * * - Content-Location R o o - -
Content-Location R o o o - - - Content-Location r o o - -
Content-Location r o o - - - - Content-Location 4xx o o o -
Content-Location 4xx o o o o o - Content-Type R * * - -
Content-Type R * * * - - - Content-Type r * * - -
Content-Type r * * - - - - Content-Type 4xx * * * -
Content-Type 4xx * * * * * - CSeq Rc m m m m
CSeq Rc m m m m m m Date am o o o o
Date am o o o o o o From R r o o o o
From R r o o o o o o Host o o o o
Host o o o o o o Last-Modified R r - - - -
Last-Modified R r - - o - - - Last-Modified r r o - - -
Last-Modified r r o - - - - - Location 3rr o o o o
Location R - - - - m - Location R - - m -
Proxy-Authenticate 407 amr m m m m m m Proxy-Authenticate 407 amr m m m m
Proxy-Require R ar o o o o o o Proxy-Require R ar o o o o
Public 501 admr m* m* m* m* m* m* Public 501 admr m* m* m* m*
Range R - - - - o - Range R - - o -
Referer R o o o o o - Referer R o o o -
Require R o o o o o o Require R o o o o
Retry-After 3xx,503 o o - - - - Retry-After 3rr,503 o o - -
Scale - - - o - - Scale - - - -
Session R o o m m o m Session R o o o m
Session r c c m m o m Session r c c o m
Server R o o o - o o Server R o o o o
Server r o o o o - o Server r o o - o
Supported R o o o o o o Supported R o o o o
Supported r c c c c c c Supported r c c c c
Timestamp R o o o o o o Timestamp R o o o o
Timestamp c m m m m m m Timestamp c m m m m
Unsupported r c c c c c c Unsupported r c c c c
User-Agent R m* m* m* m* - m* User-Agent R m* m* - m*
User-Agent r - - - - m* - User-Agent r - - m* -
Vary r c c c c - - Vary r c c - -
Via R amr o o o o o o Via R amr o o o o
Via c dr m m m m m m Via c dr m m m m
WWW-Authenticate 401 m m m m m m WWW-Authenticate 401 m m m m
--------------------------------------------------------- -----------------------------------------------------
Header Where Proxy GPR SPR ANN REC RDR PNG Header Where Proxy GPR SPR RDR PNG
Table 5: Overview of RTSP header fields related to methods GET_PARAM- Table 5: Overview of RTSP header fields related to methods GET_PARAM-
ETER, SET_PARAMETER, ANNOUNCE, RECORD, REDIRECT, and PING. ETER, SET_PARAMETER,REDIRECT, and PING.
The Accept-Ranges response-header field allows the server to indicate |
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 / LIVE ||
This header has the same syntax as [H14.5]. However new range-units |
are defined and byte-ranges SHALL NOT be used. Inclusion of any of |
the three time formats indicates acceptance by the server for PLAY |
and PAUSE requests with this format. Inclusion of the "LIVE" tag |
indicates that the resource has LIVE properties. The headers value is |
valid for the resource specified by the URI in the request, this |
response corresponds to. |
A server is RECOMMENDED to use this header in SETUP responses to | A server is RECOMMENDED to use this header in SETUP responses to
indicate to the client which range time formats the media supports. | indicate to the client which range time formats the media supports.
The header SHOULD also be included in "456" responses which is a | The header SHOULD also be included in "456" responses which is a
result of use of unsupported range formats. | result of use of unsupported range formats.
12.5 Allow 13.5 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-URI. 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, RECORD, SET_PARAMETER Allow: SETUP, PLAY, SET_PARAMETER
12.6 Authorization 13.6 Authorization
See [H14.8] See [H14.8]
12.7 Bandwidth 13.7 Bandwidth
The Bandwidth request-header field describes the estimated bandwidth The Bandwidth request-header field describes the estimated bandwidth
available to the client, expressed as a positive integer and measured available to the client, expressed as a positive integer and measured
in bits per second. The bandwidth available to the client may change in bits per second. The bandwidth available to the client may change
during an RTSP session, e.g., due to modem retraining. during an RTSP session, e.g., due to modem retraining.
Bandwidth = "Bandwidth" ":" 1*DIGIT Bandwidth = "Bandwidth" ":" 1*DIGIT
Example: Example:
Bandwidth: 4000 Bandwidth: 4000
12.8 Blocksize 13.8 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. | only returns an error
(400) if the value is syntactically invalid.
Blocksize = "Blocksize" ":" 1*DIGIT Blocksize = "Blocksize" ":" 1*DIGIT
12.9 Cache-Control 13.9 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 appli- Cache directives must be passed through by a proxy or gateway appli-
cation, regardless of their significance to that application, since cation, regardless of their significance to that application, since
the directives may be applicable to all recipients along the the directives may be applicable to all recipients along the
request/response chain. It is not possible to specify a cache-direc- request/response chain. It is not possible to specify a cache-direc-
tive for a specific cache. tive for a specific cache.
skipping to change at page 1, line 2659 skipping to change at page 1, line 2749
specified number of seconds. specified number of seconds.
must-revalidate: When the must-revalidate directive is present in a must-revalidate: When the must-revalidate directive is present in a
SETUP response received by a cache, that cache MUST NOT use SETUP response received by a cache, that cache MUST NOT use
the entry after it becomes stale to respond to a subsequent the entry after it becomes stale to respond to a subsequent
request without first revalidating it with the origin server. request without first revalidating it with the origin server.
That is, the cache must do an end-to-end revalidation every That is, the cache must do an end-to-end revalidation every
time, if, based solely on the origin server's Expires, the time, if, based solely on the origin server's Expires, the
cached response is stale.) cached response is stale.)
proxy-revalidate: The proxy-revalidate directive has the same mean- | proxy-revalidate: The proxy-revalidate directive has the same mean-
ing as the must-revalidate directive, except that it does not | ing as the must-revalidate directive, except that it does not
apply to non-shared user agent caches. It can be used on a | apply to non-shared user agent caches. It can be used on a
response to an authenticated request to permit the user's | response to an authenticated request to permit the user's
cache to store and later return the response without needing | cache to store and later return the response without needing
to revalidate it (since it has already been authenticated once | to revalidate it (since it has already been authenticated once
by that user), while still requiring proxies that service many | by that user), while still requiring proxies that service many
users to revalidate each time (in order to make sure that each | users to revalidate each time (in order to make sure that each
user has been authenticated). Note that such authenticated | user has been authenticated). Note that such authenticated
responses also need the public cache control directive in | responses also need the public cache control directive in
order to allow them to be cached at all. | order to allow them to be cached at all.
max-age: When an intermediate cache is forced, by means of a max- | max-age: When an intermediate cache is forced, by means of a max-
age=0 directive, to revalidate its own cache entry, and the | age=0 directive, to revalidate its own cache entry, and the
client has supplied its own validator in the request, the sup- | client has supplied its own validator in the request, the sup-
plied validator might differ from the validator currently | plied validator might differ from the validator currently
stored with the cache entry. In this case, the cache MAY use | stored with the cache entry. In this case, the cache MAY use
either validator in making its own request without affecting | either validator in making its own request without affecting
semantic transparency. | semantic transparency.
However, the choice of validator might affect performance. The | However, the choice of validator might affect performance. The
best approach is for the intermediate cache to use its own | best approach is for the intermediate cache to use its own
validator when making its request. If the server replies with | validator when making its request. If the server replies with
304 (Not Modified), then the cache can return its now vali- | 304 (Not Modified), then the cache can return its now vali-
dated copy to the client with a 200 (OK) response. If the | dated copy to the client with a 200 (OK) response. If the
server replies with a new entity and cache validator, however, | server replies with a new entity and cache validator, however,
the intermediate cache can compare the returned validator with | the intermediate cache can compare the returned validator with
the one provided in the client's request, using the strong | the one provided in the client's request, using the strong
comparison function. If the client's validator is equal to the | comparison function. If the client's validator is equal to the
origin server's, then the intermediate cache simply returns | origin server's, then the intermediate cache simply returns
304 (Not Modified). Otherwise, it returns the new entity with | 304 (Not Modified). Otherwise, it returns the new entity with
a 200 (OK) response. a 200 (OK) response.
12.10 Connection 13.10 Connection
See [H14.10]. The use of the connection option "close" in RTSP mes- | See [H14.10]. The use of the connection option "close" in RTSP mes-
sages SHOULD be limited to error messages when the server is unable | sages SHOULD be limited to error messages when the server is unable
to recover and therefore see it necessary to close the connection. | to recover and therefore see it necessary to close the connection.
The reason is that the client shall have the choice of continue using | The reason is that the client shall have the choice of continue using
a connection indefinitely as long as it sends valid messages. a connection indefinitely as long as it sends valid messages.
12.11 Content-Base 13.11 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. URI for resolving relative URLs within the entity.
Content-Base = "Content-Base" ":" absoluteURI Content-Base = "Content-Base" ":" absoluteURI
If no Content-Base field is present, the base URI of an entity is If no Content-Base field is present, the base URI 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 URI
is an absolute URI) or the URI used to initiate the request, in that is an absolute URI) or the URI 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 URI 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.
12.12 Content-Encoding 13.12 Content-Encoding
See [H14.11] See [H14.11]
12.13 Content-Language 13.13 Content-Language
See [H14.12] See [H14.12]
12.14 Content-Length 13.14 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].
12.15 Content-Location 13.15 Content-Location
See [H14.14] See [H14.14]
12.16 Content-Type 13.16 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.
12.17 CSeq 13.17 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 num- | sequence number, the corresponding response will have the same num-
ber. Any retransmitted request must contain the same sequence number | ber. Any retransmitted request must contain the same sequence number
as the original (i.e. the sequence number is not incremented for | as the original (i.e. the sequence number is not incremented for
retransmissions of the same request). For each new RTSP request the | retransmissions of the same request). For each new RTSP request the
CSeq value SHALL be incremented by one. The initial sequence number | CSeq value SHALL be incremented by one. The initial sequence number
MAY be any number. Each sequence number series is unique between each | MAY be any number. Each sequence number series is unique between each
requester and responder, i.e. the client has one series for its | requester and responder, i.e. the client has one series for its
request to a server and the server has another when sending request | request to a server and the server has another when sending request
to the client. Each requester and responder is identified with its | to the client. Each requester and responder is identified with its
network address. network address.
CSeq = "Cseq" ":" 1*DIGIT CSeq = "Cseq" ":" 1*DIGIT
12.18 Date 13.18 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.
12.19 Expires 13.19 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 interpre- description or media-stream should be considered stale. The interpre-
tation depends on the method: tation 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.
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 13 for further discussion of the copy of the entity). See section 14 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 Expires = "Expires" ":" HTTP-date
skipping to change at page 1, line 2791 skipping to change at page 1, line 2880
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 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 12.9). indicated otherwise by a Cache-Control header field (Section 13.9).
12.20 From 13.20 From
See [H14.22]. See [H14.22].
12.21 Host 13.21 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.
It should be silently ignored if sent. It should be silently ignored if sent.
12.22 If-Match 13.22 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.
12.23 If-Modified-Since 13.23 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 will be returned without any message-body.
If-Modified-Since = "If-Modified-Since" ":" HTTP-date 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
12.24 Last-Modified 13.24 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 or ANNOUNCE, the header field indicates the last modifica- DESCRIBE, the header field indicates the last modification date and
tion date and time of the description, for SETUP that of the media time of the description, for SETUP that of the media stream.
stream.
12.25 Location 13.25 Location
See [H14.30]. See [H14.30].
12.26 Proxy-Authenticate 13.26 Proxy-Authenticate
See [H14.33]. See [H14.33].
12.27 Proxy-Require 13.27 Proxy-Require
The Proxy-Require request-header field is used to indicate proxy-sen- | The Proxy-Require request-header field is used to indicate proxy-sen-
sitive features that MUST be supported by the proxy. Any Proxy- | sitive 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 Unsup- | negatively acknowledged by the proxy to the client using the Unsup-
ported header. Servers should treat this field identically to the | ported header. Servers should treat this field identically to the
Require field, i.e. the Proxy-Require requirements does also apply to | Require field, i.e. the Proxy-Require requirements does also apply to
the server. | the server.
See Section 12.32 for more details on the mechanics of this message | See Section 13.32 for more details on the mechanics of this message
and a usage example. | and a usage example.
Proxy-Require = "Proxy-Require" ":" 1#option-tag || Proxy-Require = "Proxy-Require" ":" 1#feature-tag
Example of use: | Example of use:
Proxy-Require: con.non-persistent, record.basic | Proxy-Require: play.basic, con.persistent
12.28 Public 13.28 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 meth- recipient of the capabilities of the server regarding unusual meth-
ods. The methods listed may or may not be applicable to the Request- ods. The methods listed may or may not be applicable to the Request-
URI; the Allow header field (section 14.7) MAY be used to indicate URI; the Allow header field (section 14.7) MAY be used to indicate
methods allowed for a particular URI. methods allowed for a particular URI.
Public = "Public" ":" 1#method 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 This header field applies only to the server directly connected to
the client (i.e., the nearest neighbor in a chain of connections). the client (i.e., the nearest neighbor in a chain of connections).
If the response passes through a proxy, the proxy MUST either remove If the response passes through a proxy, the proxy MUST either remove
the Public header field or replace it with one applicable to its own the Public header field or replace it with one applicable to its own
capabilities. capabilities.
12.29 Range 13.29 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 specifi- time. The range can be specified in a number of units. This specifi-
cation defines the smpte (Section 3.4), npt (Section 3.5), and clock cation defines the smpte (Section 3.4), npt (Section 3.5), and clock
(Section 3.6) range units. Within RTSP, byte ranges [H14.35.1] are (Section 3.6) range units. Within RTSP, byte ranges [H14.35.1] are
not meaningful and MUST NOT be used. The header may also contain a not meaningful and MUST NOT be used. The header may also contain a
time parameter in UTC, specifying the time at which the operation is time parameter in UTC, specifying the time at which the operation is
to be made effective. Servers supporting the Range header MUST under- to be made effective. Servers supporting the Range header MUST under-
stand the NPT range format and SHOULD understand the SMPTE range for- stand the NPT range format and SHOULD understand the SMPTE range for-
mat. The Range response header indicates what range of time is actu- mat. The Range response header indicates what range of time is actu-
ally being played or recorded. If the Range header is given in a time ally being played. If the Range header is given in a time format that
format that is not understood, the recipient should return 501 (Not is not understood, the recipient should return 501 (Not Implemented).
Implemented).
Ranges are half-open intervals, including the lower point, but Ranges are half-open intervals, including the lower point, but
excluding the upper point. In other words, a range of a-b starts excluding the upper 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.
skipping to change at page 1, line 2942 skipping to change at page 1, line 3030
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 [26]
byte-range header. It allows clients to select an excerpt from byte-range header. It allows clients to select an excerpt from
the media object, and to play from a given point to the end as the media object, and to play from a given point to the end as
well as from the current location to a given point. The start well as from the current location to a given point. The start
of playback can be scheduled for any time in the future, of playback can be scheduled for any time in the future,
although a server may refuse to keep server resources for although a server may refuse to keep server resources for
extended idle periods. extended idle periods.
12.30 Referer 13.30 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.
12.31 Retry-After 13.31 Retry-After
See [H14.37]. See [H14.37].
12.32 Require 13.32 Require
The Require request-header field is used by clients to query the | The Require request-header field is used by clients or servers to
server about options that it may or may not support. The server MUST | ensure that the other end-point supports features that are required
respond to this header by using the Unsupported header to negatively | in respect to this request. It can also be used to query if the
acknowledge those options which are NOT supported. The response SHALL | other end-point supports certain features, however the use of the
use the error code 551 (Option Not Supported) Supported (Section 13.38) is much more effective in this purpose.
The server MUST respond to this header by using the Unsupported
header to negatively acknowledge those feature-tags which are NOT
supported. The response SHALL use the error code 551 (Option Not Sup-
ported). This header does not apply to proxies, for the same func-
tionality in respect to proxies see, header Proxy-Require (Section
13.27).
This is to make sure that the client-server interaction will This is to make sure that the client-server interaction will
proceed without delay when all options are understood by both proceed without delay when all features are understood by both
sides, and only slow down if options are not understood (as in sides, and only slow down if features are not understood (as
the case above). For a well-matched client-server pair, the in the example below). For a well-matched client-server pair,
interaction proceeds quickly, saving a round-trip often the interaction proceeds quickly, saving a round-trip often
required by negotiation mechanisms. In addition, it also required by negotiation mechanisms. In addition, it also
removes state ambiguity when the client requires features that removes state ambiguity when the client requires features that
the server does not understand. the server does not understand.
Require = "Require" ":" 1#option-tag 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 C->S: SETUP rtsp://server.com/foo/bar/baz.rm RTSP/1.0
CSeq: 303 CSeq: 303
S->C: RTSP/1.0 200 OK S->C: RTSP/1.0 200 OK
CSeq: 303 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 trans- immutable property of "funky-feature" and thus should not be trans-
mitted with every exchange. mitted 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 12.27). in the Proxy-Require field instead (see Section 13.27).
12.33 RTP-Info 13.33 RTP-Info
The RTP-Info response-header field is used to set RTP-specific param- The RTP-Info response-header field is used to set RTP-specific param-
eters in the PLAY response. For streams using RTP as transport proto- eters in the PLAY response. For streams using RTP as transport proto-
col the RTP-Info header SHALL be part of a 200 response to PLAY. col the RTP-Info header SHALL be part of a 200 response to PLAY.
url: Indicates the stream URL which for which the following RTP url: Indicates the stream URL which for which the following RTP
parameters correspond. parameters correspond, this URL MUST be the same used in the
SETUP request for this media stream. Any relative 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
originated after the seek. originated after the seek.
rtptime: Indicates the RTP timestamp corresponding to the time rtptime: Indicates the RTP timestamp corresponding to the time
value in the Range response header. (Note: For aggregate con- value in the Range response header. (Note: For aggregate con-
trol, a particular stream may not actually generate a packet trol, a particular stream may not actually generate a packet
for the Range time value returned or implied. Thus, there is for the Range time value returned or implied. Thus, there is
no guarantee that the packet with the sequence number indi- no guarantee that the packet with the sequence number
cated by seq actually has the timestamp indicated by rtptime.) indicated by seq actually has the timestamp indicated by rtp-
The client uses this value to calculate the mapping of RTP time.) The client uses this value to calculate the mapping of
time to NPT. RTP time to NPT.
A mapping from RTP timestamps to NTP timestamps (wall A mapping from RTP timestamps to NTP timestamps (wall
clock) is available via RTCP. However, this information clock) is available via RTCP. However, this information
is not sufficient to generate a mapping from RTP times- is not sufficient to generate a mapping from RTP times-
tamps to NPT. Furthermore, in order to ensure that this tamps to NPT. Furthermore, in order to ensure that this
information is available at the necessary time (immedi- information is available at the necessary time (immedi-
ately at startup or after a seek), and that it is deliv- ately at startup or after a seek), and that it is deliv-
ered reliably, this mapping is placed in the RTSP control ered reliably, this mapping is placed in the RTSP control
channel. channel.
skipping to change at page 1, line 3064 skipping to change at page 1, line 3160
compatibility with implementations conformant to RFC 2326 [21]. compatibility with implementations conformant to RFC 2326 [21].
absoluteURI and relativeURI are defined in RFC 2396 [22] with RFC absoluteURI and relativeURI are defined in RFC 2396 [22] with RFC
2732 [30] applied. 2732 [30] applied.
Example: Example:
RTP-Info: url=rtsp://foo.com/bar.avi/streamid=0;seq=45102, RTP-Info: url=rtsp://foo.com/bar.avi/streamid=0;seq=45102,
url=rtsp://foo.com/bar.avi/streamid=1;seq=30211 url=rtsp://foo.com/bar.avi/streamid=1;seq=30211
12.34 Scale 13.34 Scale
A scale value of 1 indicates normal play or record at the normal for- A scale value of 1 indicates normal play at the normal forward view-
ward viewing rate. If not 1, the value corresponds to the rate with ing rate. If not 1, the value corresponds to the rate with respect to
respect to normal viewing rate. For example, a ratio of 2 indicates normal viewing rate. For example, a ratio of 2 indicates twice the
twice the normal viewing rate ("fast forward") and a ratio of 0.5 normal viewing rate ("fast forward") and a ratio of 0.5 indicates
indicates half the normal viewing rate. In other words, a ratio of 2 half the normal viewing rate. In other words, a ratio of 2 has normal
has normal play time increase at twice the wallclock rate. For every play time increase at twice the wallclock rate. For every second of
second of elapsed (wallclock) time, 2 seconds of content will be elapsed (wallclock) time, 2 seconds of content will be delivered. A
delivered. A negative value indicates reverse direction. negative value indicates reverse direction.
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 frag- the audio while preserving pitch or, less desirably, deliver frag-
ments of audio. ments 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. If the | MUST contain the actual scale value chosen by the server.
server does not implement the possibility to scale, it will not |
return a Scale header. A server supporting Scale operations for PLAY | If the server does not implement the possibility to scale, it will
or RECORDSHALL indicate this with the use of the "play.scale" or | not return a Scale header. A server supporting Scale operations for
"record.scale" option tags. PLAY SHALL indicate this with the use of the "play.scale" feature-
tags.
Scale = "Scale" ":" [ "-" ] 1*DIGIT [ "." *DIGIT ] Scale = "Scale" ":" [ "-" ] 1*DIGIT [ "." *DIGIT ]
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
12.35 Speed 13.35 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. Implementa- and desire to serve the media stream at the given speed. Implementa-
tion by the server is OPTIONAL. The default is the bit rate of the tion by the server is OPTIONAL. The default is the bit rate of the
stream. 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 lack of a response header is indication of lack of support from | The lack of a response header is indication of lack of support from
the server of this functionality. Support of the speed functionality | the server of this functionality. Support of the speed functionality
are indicated by the "play.speed" option tag. are indicated by the "play.speed" feature-tag.
Speed = "Speed" ":" 1*DIGIT [ "." *DIGIT ] 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 presen- | meant for use in specific circumstances where preview of the presen-
tation at a higher or lower rate is necessary. Implementors should | tation at a higher or lower rate is necessary. Implementors should
keep in mind that bandwidth for the session may be negotiated before- | keep in mind that bandwidth for the session may be negotiated before-
hand (by means other than RTSP), and therefore re-negotiation may be | hand (by means other than RTSP), and therefore re-negotiation may be
necessary. When data is delivered over UDP, it is highly recommended | necessary. When data is delivered over UDP, it is highly recommended
that means such as RTCP be used to track packet loss rates. If the | that means such as RTCP be used to track packet loss rates. If the
data transport is performed over public best-effort networks the | data transport is performed over public best-effort networks the
sender is responsible for performing congestion control of the | sender is responsible for performing congestion control of the
stream. This MAY result in that the communicated speed is impossible | stream. This MAY result in that the communicated speed is impossible
to maintain. to maintain.
12.36 Server 13.36 Server
See [H14.38], however the header syntax is here corrected. | See [H14.38], however the header syntax is here corrected.
Server = "Server" ":" ( product / comment ) *(SP(product / comment)) || Server = "Server" ":" ( product / comment ) *(SP (product / comment))
12.37 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 started by the media server in a SETUP response and con- RTSP session started by the media server in a SETUP response and con-
cluded by TEARDOWN on the presentation URL. The session identifier is cluded by TEARDOWN on the presentation URL. The session identifier is
chosen by the media server (see Section 3.3) and MUST be returned in chosen by the media server (see Section 3.3) and MUST be returned in
the SETUP response. Once a client receives a Session identifier, it the SETUP response. Once a client receives a Session identifier, it
MUST return it for any request related to that session. MUST return it for any request related to that session.
Session = "Session" ":" session-id [ ";" "timeout" "=" delta-seconds ] Session = "Session" ":" session-id [ ";" "timeout" "=" delta-seconds ]
The timeout parameter is only allowed in a response header. The The timeout parameter is only allowed in a response header. The
server uses it to indicate to the client how long the server is pre- server uses it to indicate to the client how long the server is pre-
pared to wait between RTSP commands or other signs of life before pared to wait between RTSP commands or other signs of life before
closing the session due to lack of activity (see Section A). The closing the session due to lack of activity (see Section A). The
timeout is measured in seconds, with a default of 60 seconds (1 timeout is measured in seconds, with a default of 60 seconds (1
minute). minute).
The mechanisms for showing liveness of the client is, any RTSP mes- The mechanisms for showing liveness of the client is, any RTSP mes-
sage with a Session header, or a RTCP message. It is RECOMMENDED that sage with a Session header, or a RTCP message. It is RECOMMENDED that
a client does not wait to the last second of the timeout before try- a client does not wait to the last second of the timeout before try-
skipping to change at page 1, line 3207 skipping to change at page 1, line 3303
OPTIONS: This method does also work. However it causes the server OPTIONS: This method does also work. However it causes the server
to perform unnecessary processing and result in bigger to perform unnecessary processing and result in bigger
responses than necessary for the task. The reason for this is responses than necessary for the task. The reason for this is
that the Public is always included creating overhead. that the Public is always included creating 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. Control messages for more than one transport sessions or connections. Control messages for more than one
RTSP URL may be sent within a single RTSP session. Hence, it is pos- RTSP URL may be sent within a single RTSP session. Hence, it is pos-
sible that clients use the same session for controlling many streams sible that clients use the same session for controlling many streams
constituting a presentation, as long as all the streams come from the constituting a presentation, as long as all the streams come from the
same server. (See example in Section 14). However, multiple "user" same server. (See example in Section 15). However, multiple "user"
sessions for the same URL from the same client MUST use different sessions for the same URL from the same client MUST use different
session identifiers. session identifiers.
The session identifier is needed to distinguish several deliv- The session identifier is needed to distinguish several deliv-
ery requests for the same URL coming from the same client. ery requests for the same URL coming from the same client.
The response 454 (Session Not Found) is returned if the session iden- The response 454 (Session Not Found) is returned if the session iden-
tifier is invalid. tifier is invalid.
12.38 Supported | 13.38 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 option 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: |
optioSupported to=en"Supported" ":" [option-tag *("," option-tag)] || 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 ||
Supported: bar, blech, baz ||
12.39 Timestamp S->C: RTSP/1.0 200 OK |
Supported: bar, blech, baz |
The Timestamp general-header field describes when the client sent the | 13.39 Timestamp
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 | The Timestamp general-header field describes when the client sent the
the exact same value and MAY, if it has accurate information about | request to the server. The value of the timestamp is of significance
this, add a floating point number indicating the number of seconds | only to the client and may use any timescale. The server MUST echo
that has elapsed since it has received the request. The timestamp is | the exact same value and MAY, if it has accurate information about
used by the client to compute the round-trip time to the server so | this, add a floating point number indicating the number of seconds
that it can adjust the timeout value for retransmissions. It also | 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
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 ] Timestamp = "Timestamp" ":" *(DIGIT) [ "." *(DIGIT) ] [ delay ]
delay = *(DIGIT) [ "." *(DIGIT) ] delay = *(DIGIT) [ "." *(DIGIT) ]
12.40 Transport 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 des- | as destination address, compression, multicast time-to-live and des-
tination port for a single stream. It sets those values not already | tination port for a single stream. It sets those values not already
determined by a presentation description. 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 Transport header field MAY also be used to change certain trans- The Transport header field MAY also be used to change certain trans-
port parameters. A server MAY refuse to change parameters of an port parameters. A server MAY refuse to change parameters of an
existing stream. existing stream.
The server MAY return a Transport response-header field in the The server MAY return a Transport response-header field in the
response to indicate the values actually chosen. response to indicate the values actually chosen.
A Transport request header field MAY contain a list of transport | A Transport request header field MAY contain a list of transport
options acceptable to the client, in the form of multiple transport- | options acceptable to the client, in the form of multiple transport-
spec entries. In that case, the server MUST return the single option | spec entries. In that case, the server MUST return the single option
(transport-spec) which was actually chosen. | (transport-spec) which was actually chosen.
A transport-spec transport option may only contain one of any given | A transport-spec transport option may only contain one of any given
parameter within it. Parameters may be given in any order. Addition- | parameter within it. Parameters may be given in any order. Addition-
ally, it may only contain the unicast or multicast transport | ally, it may only contain the unicast or multicast transport parame-
parameter. ter.
The Transport header field is restricted to describing a sin- The Transport header field is restricted to describing a sin-
gle RTP stream. (RTSP can also control multiple streams as a gle media stream. (RTSP can also control multiple streams as a
single entity.) Making it part of RTSP rather than relying on single entity.) Making it part of RTSP rather than relying on
a multitude of session description formats greatly simplifies a multitude of session description formats greatly simplifies
designs of firewalls. 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.
skipping to change at page 1, line 3301 skipping to change at page 1, line 3399
General parameters: General parameters:
unicast / multicast: This parameter is a mutually exclusive indica- unicast / multicast: This parameter is a mutually exclusive indica-
tion of whether unicast or multicast delivery will be tion 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 trans- that are capable of handling both unicast and multicast trans-
mission MUST indicate such capability by including two full mission MUST indicate such capability by including two full
transport-specs with separate parameters for each. transport-specs with separate parameters for each.
destination: The address to which a stream will be sent. The | destination: The address of the stream recipient to which a stream
client may specify the destination address with the destina- | will be sent. The client originating the RTSP request may
tion parameter. To avoid becoming the unwitting perpetrator of | specify the destination address of the stream recipient with
a remote-controlled denial-of-service attack, a server SHOULD | the destination parameter. When the destination field is spec-
authenticate the client and SHOULD log such attempts before | ified, the recipient may be a different party than the origi-
allowing the client to direct a media stream to an address not | nator of the request. To avoid becoming the unwitting perpe-
chosen by the server. This is particularly important if RTSP | trator of a remote-controlled denial-of-service attack, a
commands are issued via UDP, but implementations cannot rely | server SHOULD authenticate the client originating the request
on TCP as reliable means of client identification by itself. | and SHOULD log such attempts before allowing the client to
IPv6 addresses is RECOMMENDED to be given as fully qualified | direct a media stream to a recipient address not chosen by the
domain to make it backwards compatible with RFC 2326 implemen- | server. While, this is particularly important if RTSP commands
tations. | are issued via UDP, implementations cannot rely on TCP as
reliable means of client identification by itself either.
source: If the source address for the stream is different than can | The server SHOULD NOT allow the destination field to be set
be derived from the RTSP endpoint address (the server in play- | unless a mechanism exists in the system to authorize the
back or the client in recording), the source address SHOULD be | request originator to direct streams to the recipient. It is
specified. To maintain backwards compatibility with RFC 2326, | preferred that this authorization be performed by the recipi-
any IPv6 host's address must be given as a fully qualified | ent itself and the credentials passed along to the server.
domain name. However, in certain cases, such as when recipient address is a
multicast group, or when the recipient is unable to communi-
cate with the server in an out-of-band manner, this may not be
possible. In these cases server may chose another method such
as a server-resident authorization list to ensure that the
request originator has the proper credentials to request
stream delivery to the recipient.
IPv6 addresses are RECOMMENDED to be given as fully qualified
domain to make it backwards compatible with RFC 2326
implementations.
source: If the source address for the stream is different than can
be derived from the RTSP endpoint address (the server in play-
back), the source address SHOULD be specified. To maintain
backwards compatibility with RFC 2326, any IPv6 host's address
must be given as a fully qualified domain name.
This information may also be available through SDP. How- This information may also be available through SDP. How-
ever, since this is more a feature of transport than ever, since this is more a feature of transport than
media initialization, the authoritative source for this media initialization, the authoritative source for this
information should be in the SETUP response. 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 starting stream. The layers are sent to consecutive addresses starting
at the destination address. at the destination address.
dest_addresses: A general destination address parameter that can |
contain one or more address and port pair. For each combina- |
tion of Protocol/Profile/Lower Transport the interpretation of |
the address or addresses needs to be defined. The client or |
server SHALL NOT use this parameter unless both client and |
server has shown support. This parameter MUST be supported by |
client and servers that implements this specification. Support |
is indicated by the use of the feature-tag "play.basic". This |
parameter SHALL NOT be used in the same transport specifica- |
tion as any of the parameters "destination", "source", "port", |
"client_port", and "server_port". |
The same security consideration that are given for the "Desti- |
nation" parameter does also applies to this parameter. This |
parameter can be used for redirecting traffic to recipient not |
desiring the media traffic. |
src_addresses: A General source address parameter that can contain |
one or more address and port pair. For each combination of |
Protocol/Profile/Lower Transport the interpretation of the |
address or addresses needs to be defined. The client or server |
SHALL NOT use this parameter unless both client and server has |
shown support. This parameter MUST be supported by client and |
servers that implements this specification. Support is indi- |
cated by the use 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 address or addresses indicated in the src_addresses param- |
eter SHOULD be used both for sending and receiving of the |
media streams data packet. The main reasons are two: First by |
sending 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 for mode: The mode parameter indicates the methods to be supported for
this session. Valid values are PLAY and RECORD. If not pro- this session. Valid values are PLAY and RECORD. If not pro-
vided, the default is PLAY. vided, the default is PLAY. The RECORD value was defined in
RFC 2326 and is deprecated in this specification.
append: If the mode parameter includes RECORD, the append parameter append: The append parameter was used together with RECORD and is
indicates that the media data should append to the existing now deprecated.
resource rather than overwrite it. If appending is requested
and the server does not support this, it MUST refuse the
request rather than overwrite the resource identified by the
URI. The append parameter is ignored if the mode parameter
does not contain RECORD. |
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 being | stream with the control stream in whatever protocol is being
used by the control stream, using the mechanism defined in | used by the control stream, using the mechanism defined in
Section 10.13. The argument provides the channel number to be | Section 11.11. The argument provides the channel number to be
used in the $ statement and MUST be present. This parameter | used in the $ statement and MUST be present. This parameter
MAY be specified as a range, e.g., interleaved=4-5 in cases | MAY be specified as a range, e.g., interleaved=4-5 in cases
where the transport choice for the media stream requires it, | where the transport choice for the media stream requires it,
e.g. for RTP with RTCP. e.g. for RTP with RTCP. The channel number given in the
request are only a guidance from the client to the server on
what channel number(s) to use. The server MAY set any valid
channel number in the response. The declared channel(s) are
bi-directional, so both end-parties MAY send data on the given
channel. One example of such usage is the second channel used
for RTCP, where both server and client sends RTCP packets on
the same channel.
This allows RTP/RTCP to be handled similarly to the way This allows RTP/RTCP to be handled similarly to the way
that it is done with UDP, i.e., one channel for RTP and that it is done with UDP, i.e., one channel for RTP and
the other for RTCP. the other for RTCP.
Multicast-specific: Multicast-specific:
ttl: multicast time-to-live. ttl: multicast time-to-live.
RTP-specific: RTP-specific:
These parameters are MAY only be used if the media transport protocol
is RTP.
port: This parameter provides the RTP/RTCP port pair for a multi- port: This parameter provides the RTP/RTCP port pair for a multi-
cast session. It is specified as a range, e.g., port=3456-3457 cast session. It is should be specified as a range, e.g.,
port=3456-3457
client_port: This parameter provides the unicast RTP/RTCP port pair client_port: This parameter provides the unicast RTP/RTCP port pair
on the client where media data and control information is to on the client where media data and control information is to
be sent. It is specified as a range, e.g., port=3456-3457 be sent. It is specified as a range, e.g., port=3456-3457
server_port: This parameter provides the unicast RTP/RTCP port pair server_port: This parameter provides the unicast RTP/RTCP port pair
on the server where media data and control information is to on the server where media data and control information is to
be sent. It is specified as a range, e.g., port=3456-3457 be sent. It is specified as a range, e.g., port=3456-3457
client_rtcp_port: This parameter allows to specify the client's | ssrc: The ssrc parameter indicates the RTP SSRC [23] value that
RTCP port number individually from the RTP port. This will | should be (request) or will be (response) used by the media
allow the usage of NAT traversal techniques like STUN [31]. | server. This parameter is only valid for unicast transmission.
However as it introduce after RFC 2326 it may result interop- | It identifies the synchronization source to be associated with
erability problems. Before using this parameter the server | the media stream, and is expressed as an eight digit hexideci-
MUST signal support of either the "play.basic" or the | mal value. In cases that a sender will use multiple SSRCs it
"record.basic" option tags. | SHOULD NOT use this parameter.
client_rtcp_port: This parameter allows to specify the server's | client_ssrc: The client_ssrc parameter indicates the RTP SSRC [23]
RTCP port number individually from the RTP port. This will | value that will be used by the client. This parameter is only
allow the usage of NAT traversal techniques like STUN [31]. | valid for unicast transmission. It identifies the synchroniza-
However as it introduce after RFC 2326 it may result interop- | tion source to be associated with the media stream, and is
erability problems. This parameter MUST only be included in a | expressed as an eight digit hexidecimal value. In cases that a
response, when the request's transport header included the | client will use multiple SSRCs it SHOULD NOT use this parame-
"client_rtcp_port" parameter. | ter.
ssrc: The ssrc parameter indicates the RTP SSRC [23] value that | Transport = "Transport" ":" 1#transport-spec ||
should be (request) or will be (response) used by the media | transport-spec = transport-id *parameter ||
server. This parameter is only valid for unicast transmission. | transport-id = transport-protocol "/" profile ["/" lower-transport]||
It identifies the synchronization source to be associated with | ; no LWS is allowed inside transport-id ||
the media stream, and is expressed as an eight digit hexideci- | transport-protocol = "RTP" / token ||
mal value. In cases that a sender will use multiple SSRC it | profile = "AVP" / token ||
SHOULD NOT use this parameter. lower-transport = "TCP" / "UDP" / token ||
parameter = ";" ( "unicast" / "multicast" ) ||
/ ";" "source" "=" host ||
/ ";" "destination" [ "=" host ] ||
/ ";" "interleaved" "=" channel [ "-" channel ]||
/ ";" "append" ||
/ ";" "ttl" "=" ttl ||
/ ";" "layers" "=" 1*DIGIT ||
/ ";" "port" "=" port-spec ||
/ ";" "client_port" "=" port-spec ||
/ ";" "server_port" "=" port-spec ||
/ ";" "ssrc" "=" ssrc ||
/ ";" "client_ssrc" "=" ssrc ||
/ ";" "mode" "=" mode-spec ||
/ ";" "dest_addresses" "=" addr-list ||
/ ";" "src_addresses" "=" addr-list ||
/ ";" trn-parameter-extension ||
port-spec = port [ "-" port ] ||
trn-parameter-extension = par-name "=" trn-par-value ||
par-name = token ||
trn-par-value = *unreserved ||
ttl = 1*3(DIGIT) ||
ssrc = 8*8(HEX) ||
channel = 1*3(DIGIT) ||
mode-spec = <"> 1#mode <"> / mode ||
mode = "PLAY" / "RECORD" / token ||
addr-list = host-port *("/" host-port) ||
host-port = host [":" port] ||
host = see chapter 16 ||
port = see chapter 16 ||
Transport = "Transport" ":" 1#transport-spec The combination of transport protocol, profile and lower transport |
transport-spec = transport-id *parameter needs to be defined. A number of combinations are defined in the |
transport-id = transport-protocol "/" profile ["/" lower-transport] appendix B.
; no LWS is allowed inside transport-id
transport-protocol = "RTP" / token
profile = "AVP" / token
lower-transport = "TCP" / "UDP" / token
parameter = ";" ( "unicast" / "multicast" )
/ ";" "source" "=" address
/ ";" "destination" [ "=" address ]
/ ";" "interleaved" "=" channel [ "-" channel ]
/ ";" "append"
/ ";" "ttl" "=" ttl
/ ";" "layers" "=" 1*DIGIT
/ ";" "port" "=" port [ "-" port ]
/ ";" "client_port" "=" port [ "-" port ]
/ ";" "server_port" "=" port [ "-" port ]
/ ";" "client_rtcp_port" "=" port
/ ";" "server_rtcp_port" "=" port
/ ";" "ssrc" "=" ssrc
/ ";" "mode" "=" mode-spec
ttl = 1*3(DIGIT)
port = 1*5(DIGIT)
ssrc = 8*8(HEX)
channel = 1*3(DIGIT)
address = host ;As defined in RFC 2732 [30]
mode-spec = <"> 1#mode <"> / mode
mode = "PLAY" / "RECORD" / token
Below is a usage example, showing a client advertising the capability Below is a usage example, showing a client advertising the capability
to handle multicast or unicast, preferring multicast. Since this is a to handle multicast or unicast, preferring multicast. Since this is a
unicast-only stream, the server responds with the proper transport unicast-only stream, the server responds with the proper transport
parameters for unicast. parameters for unicast.
C->S: SETUP rtsp://example.com/foo/bar/baz.rm RTSP/1.0 C->S: SETUP rtsp://example.com/foo/bar/baz.rm RTSP/1.0
CSeq: 302 CSeq: 302
Transport: RTP/AVP;multicast;mode="PLAY", Transport: RTP/AVP;multicast;mode="PLAY",
RTP/AVP;unicast;client_port=3456-3457;mode="PLAY" RTP/AVP;unicast;client_port=3456-3457;mode="PLAY"
S->C: RTSP/1.0 200 OK S->C: RTSP/1.0 200 OK
CSeq: 302 CSeq: 302
Date: 23 Jan 1997 15:35:06 GMT Date: 23 Jan 1997 15:35:06 GMT
Session: 47112344 Session: 47112344
Transport: RTP/AVP;unicast;client_port=3456-3457; Transport: RTP/AVP;unicast;client_port=3456-3457;
server_port=6256-6257;mode="PLAY" server_port=6256-6257;mode="PLAY"
12.41 Unsupported 13.41 Unsupported
The Unsupported response-header field lists the features not sup- The Unsupported response-header field lists the features not sup-
ported by the server. In the case where the feature was specified via ported by the server. In the case where the feature was specified via
the Proxy-Require field (Section 12.27), if there is a proxy on the the Proxy-Require field (Section 13.27), if there is a proxy on the
path between the client and the server, the proxy MUST send a path between the client and the server, the proxy MUST send a
response message with a status code of 551 (Option Not Supported). response message with a status code of 551 (Option Not Supported).
The request SHALL NOT be forwarded. The request SHALL NOT be forwarded.
See Section 12.32 for a usage example. See Section 13.32 for a usage example.
Unsupported = "Unsupported" ":" 1#option-tag Unsupported = "Unsupported" ":" feature-tag *("," feature-tag)
12.42 User-Agent 13.42 User-Agent
See [H14.43] for explanation, however the syntax is clarified due to | See [H14.43] for explanation, however the syntax is clarified due to
an error in RFC 2616. A Client SHOULD include this header in all RTSP | an error in RFC 2616. A Client SHOULD include this header in all RTSP
messages it sends. | messages it sends.
User-Agent = "User-Agent" ":" ( product / comment ) 0*(SP || User-Agent = "User-Agent" ":" ( product / comment ) 0*(SP
(product / comment) || (product / comment)
12.43 Vary 13.43 Vary
See [H14.44] See [H14.44]
12.44 Via 13.44 Via
See [H14.45]. See [H14.45].
12.45 WWW-Authenticate 13.45 WWW-Authenticate
See [H14.47]. See [H14.47].
13 Caching 14 Caching
In HTTP, response-request pairs are cached. RTSP differs signifi- In HTTP, response-request pairs are cached. RTSP differs signifi- |
cantly in that respect. Responses are not cacheable, with the excep- cantly in that respect. Responses are not cacheable, with the excep- |
tion of the presentation description returned by DESCRIBE or included tion of the presentation description returned by DESCRIBE. (Since the |
with ANNOUNCE. (Since the responses for anything but DESCRIBE and responses for anything but DESCRIBE and GET_PARAMETER do not return |
GET_PARAMETER do not return any data, caching is not really an issue any data, caching is not really an issue for these requests.) How- |
for these requests.) However, it is desirable for the continuous ever, it is desirable for the continuous media data, typically deliv- |
media data, typically delivered out-of-band with respect to RTSP, to ered out-of-band with respect to RTSP, to be cached, as well as the |
be cached, as well as the session description. session description.
On receiving a SETUP or PLAY request, a proxy ascertains whether it On receiving a SETUP or PLAY request, a proxy ascertains whether it
has an up-to-date copy of the continuous media content and its has an up-to-date copy of the continuous media content and its
description. It can determine whether the copy is up-to-date by issu- description. It can determine whether the copy is up-to-date by issu-
ing a SETUP or DESCRIBE request, respectively, and comparing the ing a SETUP or DESCRIBE request, respectively, and comparing the
Last-Modified header with that of the cached copy. If the copy is not Last-Modified header with that of the cached copy. If the copy is not
up-to-date, it modifies the SETUP transport parameters as appropriate up-to-date, it modifies the SETUP transport parameters as appropriate
and forwards the request to the origin server. Subsequent control and forwards the request to the origin server. Subsequent control
commands such as PLAY or PAUSE then pass the proxy unmodified. The commands such as PLAY or PAUSE then pass the proxy unmodified. The
proxy delivers the continuous media data to the client, while possi- proxy delivers the continuous media data to the client, while possi-
bly making a local copy for later reuse. The exact behavior allowed bly making a local copy for later reuse. The exact behavior allowed
to the cache is given by the cache-response directives described in to the cache is given by the cache-response directives described in
Section 12.9. A cache MUST answer any DESCRIBE requests if it is cur- Section 13.9. A cache MUST answer any DESCRIBE requests if it is cur-
rently serving the stream to the requestor, as it is possible that rently serving the stream to the requestor, as it is possible that
low-level details of the stream description may have changed on the low-level details of the stream description may have changed on the
origin-server. origin-server.
Note that an RTSP cache, unlike the HTTP cache, is of the "cut- Note that an RTSP cache, unlike the HTTP cache, is of the "cut-
through" variety. Rather than retrieving the whole resource from the through" variety. Rather than retrieving the whole resource from the
origin server, the cache simply copies the streaming data as it origin server, the cache simply copies the streaming data as it
passes by on its way to the client. Thus, it does not introduce addi- passes by on its way to the client. Thus, it does not introduce addi-
tional latency. tional latency.
skipping to change at page 1, line 3520 skipping to change at page 1, line 3684
cache has to store the content type, content language, and so on for cache has to store the content type, content language, and so on for
the objects it caches, a media cache has to store the presentation the objects it caches, a media cache has to store the presentation
description. Typically, a cache eliminates all transport-references description. Typically, a cache eliminates all transport-references
(that is, multicast information) from the presentation description, (that is, multicast information) from the presentation description,
since these are independent of the data delivery from the cache to since these are independent of the data delivery from the cache to
the client. Information on the encodings remains the same. If the the client. Information on the encodings remains the same. If the
cache is able to translate the cached media data, it would create a cache is able to translate the cached media data, it would create a
new presentation description with all the encoding possibilities it new presentation description with all the encoding possibilities it
can offer. can offer.
14 Examples 15 Examples
The following examples refer to stream description formats that are The following examples refer to stream description formats that are
not standards, such as RTSL. The following examples are not to be not standards, such as RTSL. The following examples are not to be
used as a reference for those formats. used as a reference for those formats.
14.1 Media on Demand (Unicast) 15.1 Media on Demand (Unicast)
Client C requests a movie from media servers A (audio.example.com ) Client C requests a movie from media servers A (audio.example.com )
and V (video.example.com ). The media description is stored on a web and V (video.example.com ). The media description is stored on a web
server W. The media description contains descriptions of the presen- server W. The media description contains descriptions of the presen-
tation and all its streams, including the codecs that are available, tation and all its streams, including the codecs that are available,
dynamic RTP payload types, the protocol stack, and content informa- dynamic RTP payload types, the protocol stack, and content informa-
tion such as language or copyright restrictions. It may also give an tion such as language or copyright restrictions. It may also give an
indication about the timeline of the movie. indication about the timeline of the movie.
In this example, the client is only interested in the last part of In this example, the client is only interested in the last part of
the movie. the movie.
C->W: GET /twister.sdp HTTP/1.1 C->W: GET /twister.sdp HTTP/1.1
Host: www.example.com Host: www.example.com
Accept: application/sdp Accept: application/sdp
W->C: HTTP/1.0 200 OK W->C: HTTP/1.0 200 OK
Date: 23 Jan 1997 15:35:06 GMT
Content-Type: application/sdp Content-Type: application/sdp
v=0 v=0
o=- 2890844526 2890842807 IN IP4 192.16.24.202 o=- 2890844526 2890842807 IN IP4 192.16.24.202
s=RTSP Session s=RTSP Session
e=adm@example.com
m=audio 0 RTP/AVP 0 m=audio 0 RTP/AVP 0
a=control:rtsp://audio.example.com/twister/audio.en a=control:rtsp://audio.example.com/twister/audio.en
m=video 0 RTP/AVP 31 m=video 0 RTP/AVP 31
a=control:rtsp://video.example.com/twister/video a=control:rtsp://video.example.com/twister/video
C->A: SETUP rtsp://audio.example.com/twister/audio.en RTSP/1.0 C->A: SETUP rtsp://audio.example.com/twister/audio.en RTSP/1.0
CSeq: 1 CSeq: 1
User-Agent: PhonyClient/1.2
Transport: RTP/AVP/UDP;unicast;client_port=3056-3057 Transport: RTP/AVP/UDP;unicast;client_port=3056-3057
A->C: RTSP/1.0 200 OK A->C: RTSP/1.0 200 OK
CSeq: 1 CSeq: 1
Session: 12345678 Session: 12345678
Transport: RTP/AVP/UDP;unicast;client_port=3056-3057; Transport: RTP/AVP/UDP;unicast;client_port=3056-3057;
server_port=5000-5001 server_port=5000-5001
C->V: SETUP rtsp://video.example.com/twister/video RTSP/1.0 C->V: SETUP rtsp://video.example.com/twister/video RTSP/1.0
CSeq: 1 CSeq: 1
User-Agent: PhonyClient/1.2
Transport: RTP/AVP/UDP;unicast;client_port=3058-3059 Transport: RTP/AVP/UDP;unicast;client_port=3058-3059
V->C: RTSP/1.0 200 OK V->C: RTSP/1.0 200 OK
CSeq: 1 CSeq: 1
Session: 23456789 Session: 23456789
Transport: RTP/AVP/UDP;unicast;client_port=3058-3059; Transport: RTP/AVP/UDP;unicast;client_port=3058-3059;
server_port=5002-5003 server_port=5002-5003
C->V: PLAY rtsp://video.example.com/twister/video RTSP/1.0 C->V: PLAY rtsp://video.example.com/twister/video RTSP/1.0
CSeq: 2 CSeq: 2
User-Agent: PhonyClient/1.2
Session: 23456789 Session: 23456789
Range: smpte=0:10:00- Range: smpte=0:10:00-
V->C: RTSP/1.0 200 OK V->C: RTSP/1.0 200 OK
CSeq: 2 CSeq: 2
Session: 23456789 Session: 23456789
Range: smpte=0:10:00-0:20:00 Range: smpte=0:10:00-0:20:00
RTP-Info: url=rtsp://video.example.com/twister/video; RTP-Info: url=rtsp://video.example.com/twister/video;
seq=12312232;rtptime=78712811 seq=12312232;rtptime=78712811
C->A: PLAY rtsp://audio.example.com/twister/audio.en RTSP/1.0 C->A: PLAY rtsp://audio.example.com/twister/audio.en RTSP/1.0
CSeq: 2 CSeq: 2
User-Agent: PhonyClient/1.2
Session: 12345678 Session: 12345678
Range: smpte=0:10:00- Range: smpte=0:10:00-
A->C: RTSP/1.0 200 OK A->C: RTSP/1.0 200 OK
CSeq: 2 CSeq: 2
User-Agent: PhonyClient/1.2
Session: 12345678 Session: 12345678
Range: smpte=0:10:00-0:20:00 Range: smpte=0:10:00-0:20:00
RTP-Info: url=rtsp://audio.example.com/twister/audio.en; RTP-Info: url=rtsp://audio.example.com/twister/audio.en;
seq=876655;rtptime=1032181 seq=876655;rtptime=1032181
C->A: TEARDOWN rtsp://audio.example.com/twister/audio.en RTSP/1.0 C->A: TEARDOWN rtsp://audio.example.com/twister/audio.en RTSP/1.0
CSeq: 3 CSeq: 3
User-Agent: PhonyClient/1.2
Session: 12345678 Session: 12345678
A->C: RTSP/1.0 200 OK A->C: RTSP/1.0 200 OK
CSeq: 3 CSeq: 3
C->V: TEARDOWN rtsp://video.example.com/twister/video RTSP/1.0 C->V: TEARDOWN rtsp://video.example.com/twister/video RTSP/1.0
CSeq: 3 CSeq: 3
User-Agent: PhonyClient/1.2
Session: 23456789 Session: 23456789
V->C: RTSP/1.0 200 OK V->C: RTSP/1.0 200 OK
CSeq: 3 CSeq: 3
Even though the audio and video track are on two different servers, Even though the audio and video track are on two different servers,
and may start at slightly different times and may drift with respect and may start at slightly different times and may drift with respect
to each other, the client can synchronize the two using standard RTP to each other, the client can synchronize the two using standard RTP
methods, in particular the time scale contained in the RTCP sender methods, in particular the time scale contained in the RTCP sender
reports. reports.
14.2 Streaming of a Container file 15.2 Streaming of a Container file
For purposes of this example, a container file is a storage entity in For purposes of this example, a container file is a storage entity in
which multiple continuous media types pertaining to the same end-user which multiple continuous media types pertaining to the same end-user
presentation are present. In effect, the container file represents an presentation are present. In effect, the container file represents an
RTSP presentation, with each of its components being RTSP streams. RTSP presentation, with each of its components being RTSP streams.
Container files are a widely used means to store such presentations. Container files are a widely used means to store such presentations.
While the components are transported as independent streams, it is While the components are transported as independent streams, it is
desirable to maintain a common context for those streams at the desirable to maintain a common context for those streams at the
server end. server end.
This enables the server to keep a single storage handle open This enables the server to keep a single storage handle open
easily. It also allows treating all the streams equally in easily. It also allows treating all the streams equally in
case of any prioritization of streams by the server. case of any prioritization of streams by the server.
It is also possible that the presentation author may wish to prevent It is also possible that the presentation author may wish to prevent
skipping to change at page 1, line 3646 skipping to change at page 1, line 3821
trol all the streams via a single control message using an aggregate trol all the streams via a single control message using an aggregate
URL. URL.
The following is an example of using a single RTSP session to control The following is an example of using a single RTSP session to control
multiple streams. It also illustrates the use of aggregate URLs. multiple streams. It also illustrates the use of aggregate URLs.
Client C requests a presentation from media server M. The movie is Client C requests a presentation from media server M. The movie is
stored in a container file. The client has obtained an RTSP URL to stored in a container file. The client has obtained an RTSP URL to
the container file. the container file.
C->M: DESCRIBE rtsp://foo/twister RTSP/1.0 C->M: DESCRIBE rtsp://example.com/twister RTSP/1.0
CSeq: 1 CSeq: 1
M->C: RTSP/1.0 200 OK M->C: RTSP/1.0 200 OK
CSeq: 1 CSeq: 1
Date: 23 Jan 1997 15:35:06 GMT
Content-Type: application/sdp Content-Type: application/sdp
Content-Length: 164 Content-Length: 164
v=0 v=0
o=- 2890844256 2890842807 IN IP4 172.16.2.93 o=- 2890844256 2890842807 IN IP4 172.16.2.93
s=RTSP Session s=RTSP Session
i=An Example of RTSP Session Usage i=An Example of RTSP Session Usage
a=control:rtsp://foo/twister e=adm@example.com
a=control:rtsp://example.com/twister
t=0 0 t=0 0
m=audio 0 RTP/AVP 0 m=audio 0 RTP/AVP 0
a=control:rtsp://foo/twister/audio a=control:rtsp://example.com/twister/audio
m=video 0 RTP/AVP 26 m=video 0 RTP/AVP 26
a=control:rtsp://foo/twister/video a=control:rtsp://example.com/twister/video
C->M: SETUP rtsp://foo/twister/audio RTSP/1.0 C->M: SETUP rtsp://example.com/twister/audio RTSP/1.0
CSeq: 2 CSeq: 2
Transport: RTP/AVP;unicast;client_port=8000-8001 Transport: RTP/AVP;unicast;client_port=8000-8001
M->C: RTSP/1.0 200 OK M->C: RTSP/1.0 200 OK
CSeq: 2 CSeq: 2
Transport: RTP/AVP;unicast;client_port=8000-8001; Transport: RTP/AVP;unicast;client_port=8000-8001;
server_port=9000-9001 server_port=9000-9001
Session: 12345678 Session: 12345678
C->M: SETUP rtsp://foo/twister/video RTSP/1.0 C->M: SETUP rtsp://example.com/twister/video RTSP/1.0
CSeq: 3 CSeq: 3
Transport: RTP/AVP;unicast;client_port=8002-8003 Transport: RTP/AVP;unicast;client_port=8002-8003
Session: 12345678 Session: 12345678
M->C: RTSP/1.0 200 OK M->C: RTSP/1.0 200 OK
CSeq: 3 CSeq: 3
Transport: RTP/AVP;unicast;client_port=8002-8003; Transport: RTP/AVP;unicast;client_port=8002-8003;
server_port=9004-9005 server_port=9004-9005
Session: 12345678 Session: 12345678
C->M: PLAY rtsp://foo/twister RTSP/1.0
C->M: PLAY rtsp://example.com/twister RTSP/1.0
CSeq: 4 CSeq: 4
Range: npt=0- Range: npt=0-
Session: 12345678 Session: 12345678
M->C: RTSP/1.0 200 OK M->C: RTSP/1.0 200 OK
CSeq: 4 CSeq: 4
Session: 12345678 Session: 12345678
RTP-Info: url=rtsp://foo/twister/video; Range: npt=0-
seq=9810092;rtptime=3450012 RTP-Info: url=rtsp://example.com/twister/video;
seq=12345;rtptime=3450012,
url=rtsp://example.com/twister/audio;
seq=54321;rtptime=2876889
C->M: PAUSE rtsp://foo/twister/video RTSP/1.0 C->M: PAUSE rtsp://example.com/twister/video RTSP/1.0
CSeq: 5 CSeq: 5
Session: 12345678 Session: 12345678
M->C: RTSP/1.0 460 Only aggregate operation allowed M->C: RTSP/1.0 460 Only aggregate operation allowed
CSeq: 5 CSeq: 5
C->M: PAUSE rtsp://foo/twister RTSP/1.0 C->M: PAUSE rtsp://example.com/twister RTSP/1.0
CSeq: 6 CSeq: 6
Session: 12345678 Session: 12345678
M->C: RTSP/1.0 200 OK M->C: RTSP/1.0 200 OK
CSeq: 6 CSeq: 6
Session: 12345678 Session: 12345678
C->M: SETUP rtsp://example.com/twister RTSP/1.0
C->M: SETUP rtsp://foo/twister RTSP/1.0
CSeq: 7 CSeq: 7
Transport: RTP/AVP;unicast;client_port=10000 Transport: RTP/AVP;unicast;client_port=10000
Session: 12345678
M->C: RTSP/1.0 459 Aggregate operation not allowed M->C: RTSP/1.0 459 Aggregate operation not allowed
CSeq: 7 CSeq: 7
In the first instance of failure, the client tries to pause one In the first instance of failure, the client tries to pause one
stream (in this case video) of the presentation. This is disallowed stream (in this case video) of the presentation. This is not allowed
for that presentation by the server. In the second instance, the as this session is set up for aggregated control. In the second
aggregate URL may not be used for SETUP and one control message is instance, the aggregate URL may not be used for SETUP and one control
required per stream to set up transport parameters. message is required per stream to set up transport parameters.
This keeps the syntax of the Transport header simple and This keeps the syntax of the Transport header simple and
allows easy parsing of transport information by firewalls. allows easy parsing of transport information by firewalls.
14.3 Single Stream Container Files 15.3 Single Stream Container Files
Some RTSP servers may treat all files as though they are "container Some RTSP servers may treat all files as though they are "container
files", yet other servers may not support such a concept. Because of files", yet other servers may not support such a concept. Because of
this, clients SHOULD use the rules set forth in the session descrip- this, clients SHOULD use the rules set forth in the session descrip-
tion for request URLs, rather than assuming that a consistent URL may tion for request URLs, rather than assuming that a consistent URL may
always be used throughout. Here's an example of how a multi-stream always be used throughout. Here's an example of how a multi-stream
server might expect a single-stream file to be served: server might expect a single-stream file to be served:
C->S DESCRIBE rtsp://foo.com/test.wav RTSP/1.0 C->S DESCRIBE rtsp://foo.com/test.wav RTSP/1.0
Accept: application/x-rtsp-mh, application/sdp Accept: application/x-rtsp-mh, application/sdp
CSeq: 1 CSeq: 1
skipping to change at page 1, line 3771 skipping to change at page 1, line 3952
CSeq: 2 CSeq: 2
Session: 2034820394 Session: 2034820394
C->S PLAY rtsp://foo.com/test.wav RTSP/1.0 C->S PLAY rtsp://foo.com/test.wav RTSP/1.0
CSeq: 3 CSeq: 3
Session: 2034820394 Session: 2034820394
S->C RTSP/1.0 200 OK S->C RTSP/1.0 200 OK
CSeq: 3 CSeq: 3
Session: 2034820394 Session: 2034820394
Range: npt=0-600
RTP-Info: url=rtsp://foo.com/test.wav/streamid=0; RTP-Info: url=rtsp://foo.com/test.wav/streamid=0;
seq=981888;rtptime=3781123 seq=981888;rtptime=3781123
Note the different URL in the SETUP command, and then the switch back Note the different URL in the SETUP command, and then the switch back
to the aggregate URL in the PLAY command. This makes complete sense to the aggregate URL in the PLAY command. This makes complete sense
when there are multiple streams with aggregate control, but is less when there are multiple streams with aggregate control, but is less
than intuitive in the special case where the number of streams is than intuitive in the special case where the number of streams is
one. one.
In this special case, it is recommended that servers be forgiving of In this special case, it is recommended that servers be forgiving of
implementations that send: implementations that send:
C->S PLAY rtsp://foo.com/test.wav/streamid=0 RTSP/1.0 C->S PLAY rtsp://foo.com/test.wav/streamid=0 RTSP/1.0
skipping to change at page 1, line 3800 skipping to change at page 1, line 3982
One would also hope that server implementations are also forgiving of One would also hope that server implementations are also forgiving of
the following: the following:
C->S SETUP rtsp://foo.com/test.wav RTSP/1.0 C->S SETUP rtsp://foo.com/test.wav RTSP/1.0
Transport: rtp/avp/udp;client_port=6970-6971;mode="PLAY" Transport: rtp/avp/udp;client_port=6970-6971;mode="PLAY"
CSeq: 2 CSeq: 2
Since there is only a single stream in this file, it's not ambiguous Since there is only a single stream in this file, it's not ambiguous
what this means. what this means.
14.4 Live Media Presentation Using Multicast 15.4 Live Media Presentation Using Multicast
The media server M chooses the multicast address and port. Here, we The media server M chooses the multicast address and port. Here, we
assume that the web server only contains a pointer to the full assume that the web server only contains a pointer to the full
description, while the media server M maintains the full description. description, while the media server M maintains the full description.
C->W: GET /concert.sdp HTTP/1.1 C->W: GET /concert.sdp HTTP/1.1
Host: www.example.com Host: www.example.com
W->C: HTTP/1.1 200 OK W->C: HTTP/1.1 200 OK
Content-Type: application/x-rtsl Content-Type: application/x-rtsl
skipping to change at page 1, line 3847 skipping to change at page 1, line 4029
port=3456-3457;ttl=16 port=3456-3457;ttl=16
Session: 0456804596 Session: 0456804596
C->M: PLAY rtsp://live.example.com/concert/audio RTSP/1.0 C->M: PLAY rtsp://live.example.com/concert/audio RTSP/1.0
CSeq: 3 CSeq: 3
Session: 0456804596 Session: 0456804596
M->C: RTSP/1.0 200 OK M->C: RTSP/1.0 200 OK
CSeq: 3 CSeq: 3
Session: 0456804596 Session: 0456804596
Range:npt=now-
14.5 Recording
The conference participant client C asks the media server M to record
the audio and video portions of a meeting. The client uses the
ANNOUNCE method to provide meta-information about the recorded ses-
sion to the server.
C->M: ANNOUNCE rtsp://server.example.com/meeting RTSP/1.0
CSeq: 90
Content-Type: application/sdp
Content-Length: 121
v=0
o=camera1 3080117314 3080118787 IN IP4 195.27.192.36
s=IETF Meeting, Munich - 1
i=The thirty-ninth IETF meeting will be held in Munich, Germany
u=http://www.ietf.org/meetings/Munich.html
e=IETF Channel 1 <ietf39-mbone@uni-koeln.de>
p=IETF Channel 1 +49-172-2312 451
c=IN IP4 224.0.1.11/127
t=3080271600 3080703600
a=tool:sdr v2.4a6
a=type:test
m=audio 21010 RTP/AVP 5
c=IN IP4 224.0.1.11/127
a=ptime:40
m=video 61010 RTP/AVP 31
c=IN IP4 224.0.1.12/127
M->C: RTSP/1.0 200 OK
CSeq: 90
C->M: SETUP rtsp://server.example.com/meeting/audiotrack RTSP/1.0
CSeq: 91
Transport: RTP/AVP;multicast;destination=224.0.1.11;
port=21010-21011;mode=record;ttl=127
M->C: RTSP/1.0 200 OK
CSeq: 91
Session: 50887676
Transport: RTP/AVP;multicast;destination=224.0.1.11;
port=21010-21011;mode=record;ttl=127
C->M: SETUP rtsp://server.example.com/meeting/videotrack RTSP/1.0
CSeq: 92
Session: 50887676
Transport: RTP/AVP;multicast;destination=224.0.1.12;
port=61010-61011;mode=record;ttl=127
M->C: RTSP/1.0 200 OK
CSeq: 92
Transport: RTP/AVP;multicast;destination=224.0.1.12;
port=61010-61011;mode=record;ttl=127
C->M: RECORD rtsp://server.example.com/meeting RTSP/1.0
CSeq: 93
Session: 50887676
Range: clock=19961110T1925-19961110T2015
M->C: RTSP/1.0 200 OK
CSeq: 93
15 RTSP and NATs
15.1 Introduction
Today there is Network Address Translators (NAT) [32] everywhere and
a protocol must make sure that it can work over them in some fashion.
The problem with RTSP is that it carries information about network
addresses and ports inside it self. When the media streams who's
addresses referred in RTSP are changed to protocol stops working.
15.2 STUN
To make STUN work together with RTP/RTCP it will be needed to have
the possibility to signal the RTCP ports independent of the RTP port
for a stream. To accommodate this two new Transport header parameters
are defined, server_rtcp_port and client_rtcp_port.
15.3 Application Level Gateways
15.4 TCP Tunneling
16 Syntax 16 Syntax
The RTSP syntax is described in an augmented Backus-Naur form (BNF) The RTSP syntax is described in an augmented Backus-Naur form (BNF)
as defined in RFC 2234 [14]. Also the "#" rule from RFC 2616 [26] is as defined in RFC 2234 [14]. Also the "#" rule from RFC 2616 [26] is
also defined and used in this syntax description. also defined and used in this syntax description.
16.1 Base Syntax 16.1 Base Syntax
OCTET = <any 8-bit sequence of data> OCTET = <any 8-bit sequence of data>
skipping to change at page 1, line 3982 skipping to change at page 1, line 4082
extra = "!" / "*" / "'" / "(" / ")" / "," extra = "!" / "*" / "'" / "(" / ")" / ","
hex = DIGIT / "A" / "B" / "C" / "D" / "E" / "F" / hex = DIGIT / "A" / "B" / "C" / "D" / "E" / "F" /
"a" / "b" / "c" / "d" / "e" / "f" "a" / "b" / "c" / "d" / "e" / "f"
escape = "%" hex hex escape = "%" hex hex
reserved = ";" / "/" / "?" / ":" / "@" / "&" / "=" reserved = ";" / "/" / "?" / ":" / "@" / "&" / "="
unreserved = alpha / digit / safe / extra unreserved = alpha / digit / safe / extra
xchar = unreserved / reserved / escape xchar = unreserved / reserved / escape
16.2 RTSP Protocol Definition 16.2 RTSP Protocol Definition
16.2.1 Message Syntax
generRTSP-message= st=rtRequest / Response ; RTSP/1.0 messages generRTSP-message= st=rtRequest / Response ; RTSP/1.0 messages
*(message-header CRLF) *(message-header CRLF)
CRLF CRLF
[ message-body ] [ message-body ]
start-line = Request-Line / Status-Line start-line = Request-Line / Status-Line
Request g=nerRequest-Line ; Sec;iSection 6.1 Request g=nerRequest-Line ; Sec;iSection 6.1
/ request-header ; Section 6.2 / request-header ; Section 6.2
/ entity-header ) ; Section 8.1 / entity-header ) ; Section 8.1
CRLF CRLF
[ message-body ] ; Section 4.3 [ message-body ] ; Section 4.3
Response = Status-Line ; Section 7.1 Response = Status-Line ; Section 7.1
*( general-header ; Section 5 *( general-header ; Section 5
/ response-header ; Section 7.1.2 / response-header ; Section 7.1.2
/ entity-header ) ; Section 8.1 / entity-header ) ; Section 8.1
CRLF CRLF
skipping to change at page 1, line 4002 skipping to change at page 1, line 4105
Response = Status-Line ; Section 7.1 Response = Status-Line ; Section 7.1
*( general-header ; Section 5 *( general-header ; Section 5
/ response-header ; Section 7.1.2 / response-header ; Section 7.1.2
/ entity-header ) ; Section 8.1 / entity-header ) ; Section 8.1
CRLF CRLF
[ message-body ] ; Section 4.3 [ message-body ] ; Section 4.3
Request-Line = Method SP Request-URI SP RTSP-Version CRLF Request-Line = Method SP Request-URI SP RTSP-Version CRLF
Status-Line = RTSP-Version SP Status-Code SP Reason-Phrase CRLF Status-Line = RTSP-Version SP Status-Code SP Reason-Phrase CRLF
Method = "DESCRIBE" ; Section 10.2 Method = "DESCRIBE" ; Section 11.2
/ "ANNOUNCE" ; Section 10.3 / "GET_PARAMETER" ; Section 11.7
/ "GET_PARAMETER" ; Section 10.8 / "OPTIONS" ; Section 11.1
/ "OPTIONS" ; Section 10.1 / "PAUSE" ; Section 11.5
/ "PAUSE" ; Section 10.6 / "PLAY" ; Section 11.4
/ "PLAY" ; Section 10.5 / "PING" ; Section 11.10
/ "PING" ; Section 10.12 / "REDIRECT" ; Section 11.9
/ "RECORD" ; Section 10.11 / "SETUP" ; Section 11.3
/ "REDIRECT" ; Section 10.10 / "SET_PARAMETER" ; Section 11.8
/ "SETUP" ; Section 10.4 / "TEARDOWN" ; Section 11.6
/ "SET_PARAMETER" ; Section 10.9
/ "TEARDOWN" ; Section 10.7
/ extension-method / extension-method
extension-method = token extension-method = token
Request-URI = "*" / absolute_URI Request-URI = "*" / absolute_URI
RTSP-Version = "RTSP" "/" 1*DIGIT "." 1*DIGIT RTSP-Version = "RTSP" "/" 1*DIGIT "." 1*DIGIT
Status-Code = "100" ; Continue Status-Code = "100" ; Continue
/ "200" ; OK / "200" ; OK
/ "201" ; Created / "201" ; Created
/ "250" ; Low on Storage Space / "250" ; Low on Storage Space
skipping to change at page 1, line 4068 skipping to change at page 1, line 4169
/ "501" ; Not Implemented / "501" ; Not Implemented
/ "502" ; Bad Gateway / "502" ; Bad Gateway
/ "503" ; Service Unavailable / "503" ; Service Unavailable
/ "504" ; Gateway Time-out / "504" ; Gateway Time-out
/ "505" ; RTSP Version not supported / "505" ; RTSP Version not supported
/ "551" ; Option not supported / "551" ; Option not supported
/ extension-code / extension-code
extension-code = 3DIGIT extension-code = 3DIGIT
Reason-Phrase = *<TEXT, excluding CR, LF> Reason-Phrase = *<TEXT, excluding CR, LF>
general-header = Cache-Control ; Section 12.9
/ Connection ; Section 12.10
/ CSeq ; Section 12.17
/ Date ; Section 12.18
/ Timestamp ; Section 12.39
/ Via ; Section 12.44
request-header = Accept ; Section 12.1
/ Accept-Encoding ; Section 12.2
/ Accept-Language ; Section 12.3
/ Authorization ; Section 12.6
/ Bandwidth ; Section 12.7
/ Blocksize ; Section 12.8
/ From ; Section 12.20
/ If-Modified-Since ; Section 12.23
/ Proxy-Require ; Section 12.27
/ Range ; Section 12.29
/ Referer ; Section 12.30
/ Require ; Section 12.32
/ Scale ; Section 12.34
/ Session ; Section 12.37
/ Speed ; Section 12.35
/ Supported ; Section 12.38
/ Transport ; Section 12.40
/ User-Agent ; Section 12.42
response-header = Accept-Ranges ; Section 12.4 general-header = Cache-Control ; Section 13.9
/ Location ; Section 12.25 / Connection ; Section 13.10
/ Proxy-Authenticate ; Section 12.26 / CSeq ; Section 13.17
/ Public ; Section 12.28 / Date ; Section 13.18
/ Range ; Section 12.29 / Timestamp ; Section 13.39
/ Retry-After ; Section 12.31 / Via ; Section 13.44
/ RTP-Info ; Section 12.33 request-header = Accept ; Section 13.1
/ Scale ; Section 12.34 / Accept-Encoding ; Section 13.2
/ Session ; Section 12.37 / Accept-Language ; Section 13.3
/ Server ; Section 12.36 / Authorization ; Section 13.6
/ Speed ; Section 12.35 / Bandwidth ; Section 13.7
/ Transport ; Section 12.40 / Blocksize ; Section 13.8
/ Unsupported ; Section 12.41 / From ; Section 13.20
/ Vary ; Section 12.43 / If-Modified-Since ; Section 13.23
/ WWW-Authenticate ; Section 12.45 / 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
response-header = Accept-Ranges ; Section 13.4
/ Location ; Section 13.25
/ Proxy-Authenticate ; Section 13.26
/ Public ; Section 13.28
/ Range ; Section 13.29
/ Retry-After ; Section 13.31
/ RTP-Info ; Section 13.33
/ Scale ; Section 13.34
/ Session ; Section 13.37
/ Server ; Section 13.36
/ Speed ; Section 13.35
/ Transport ; Section 13.40
/ Unsupported ; Section 13.41
/ Vary ; Section 13.43
/ WWW-Authenticate ; Section 13.45
rtsp_URL = ( "rtsp:" / "rtspu:" / "rtsps" ) rtsp_URL = ( "rtsp:" / "rtspu:" / "rtsps" )
"//" host [ ":" port ] [ abs_path ] "//" host [ ":" port ] [ abs_path ] [ "#" fragment ]
host = As defined by RFC 2732 [30] host = As defined by RFC 2732 [30]
abs_path = As defined by RFC 2396 [22] abs_path = As defined by RFC 2396 [22]
port = *DIGIT port = *DIGIT
smpte-range = smpte-type "=" smpte-range-spec smpte-range = smpte-type "=" smpte-range-spec
smpte-range-spec = ( smpte-time "-" [ smpte-time ] ) / ( "-" smpte-time ) smpte-range-spec = ( smpte-time "-" [ smpte-time ] ) / ( "-" smpte-time )
smpte-type = "smpte" / "smpte-30-drop" / "smpte-25" smpte-type = "smpte" / "smpte-30-drop" / "smpte-25"
; other timecodes may be added ; other timecodes may be added
smpte-time = 1*2DIGIT ":" 1*2DIGIT ":" 1*2DIGIT smpte-time = 1*2DIGIT ":" 1*2DIGIT ":" 1*2DIGIT
[ ":" 1*2DIGIT [ "." 1*2DIGIT ] ] [ ":" 1*2DIGIT [ "." 1*2DIGIT ] ]
npt-range = ["npt" "="] npt-range-spec npt-range = ["npt" "="] npt-range-spec
; implementations SHOULD use npt= prefix, but SHOULD ; implementations SHOULD use npt= prefix, but SHOULD
; be prepared to interoperate with RFC 2326 ; be prepared to interoperate with RFC 2326
; implementations which don't use it ; implementations which don't use it
npt-range-spec = ( npt-time "-" [ npt-time ] ) / ( "-" npt-time ) npt-range-spec = ( npt-time "-" [ npt-time ] ) / ( "-" npt-time )
npt-time = "now" / npt-sec / npt-hhmmss npt-time = "now" / npt-sec / npt-hhmmss
npt-sec = 1*DIGIT [ "." *DIGIT ] npt-sec = 1*DIGIT [ "." *DIGIT ]
npt-hhmmss = npt-hh ":" npt-mm ":" npt-ss [ "." *DIGIT ] npt-hhmmss = npt-hh ":" npt-mm ":" npt-ss [ "." *DIGIT ]
npt-hh = 1*DIGIT ; any positive number npt-hh = 1*DIGIT ; any positive number
npt-mm = 1*2DIGIT ; 0-59 npt-mm = 1*2DIGIT ; 0-59
skipping to change at page 1, line 4139 skipping to change at page 1, line 4240
npt-hh = 1*DIGIT ; any positive number npt-hh = 1*DIGIT ; any positive number
npt-mm = 1*2DIGIT ; 0-59 npt-mm = 1*2DIGIT ; 0-59
npt-ss = 1*2DIGIT ; 0-59 npt-ss = 1*2DIGIT ; 0-59
utc-range = "clock" "=" utc-range-spec utc-range = "clock" "=" utc-range-spec
utc-range-spec = ( utc-time "-" [ utc-time ] ) / ( "-" utc-time ) utc-range-spec = ( utc-time "-" [ utc-time ] ) / ( "-" utc-time )
utc-time = utc-date "T" utc-time "Z" utc-time = utc-date "T" utc-time "Z"
utc-date = 8DIGIT ; < YYYYMMDD > utc-date = 8DIGIT ; < YYYYMMDD >
utc-time = 6DIGIT [ "." fraction ]; < HHMMSS.fraction > utc-time = 6DIGIT [ "." fraction ]; < HHMMSS.fraction >
fraction = 1*DIGIT fraction = 1*DIGIT
option-tag = token feature-tag = token
16.2.2 Header Syntax
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 ]
/ ";" "append"
/ ";" "ttl" "=" ttl
/ ";" "layers" "=" 1*DIGIT
/ ";" "port" "=" port-spec
/ ";" "client_port" "=" port-spec
/ ";" "server_port" "=" port-spec
/ ";" "ssrc" "=" ssrc
/ ";" "client_ssrc" "=" ssrc
/ ";" "mode" "=" mode-spec
/ ";" "dest_addresses" "=" addr-list
/ ";" "src_addresses" "=" addr-list
/ ";" trn-parameter-extension
port-spec = port [ "-" port ]
trn-parameter-extension = par-name "=" trn-par-value
par-name = token
trn-par-value = *unreserved
ttl = 1*3(DIGIT)
ssrc = 8*8(HEX)
channel = 1*3(DIGIT)
mode-spec = <"> 1#mode <"> / mode
mode = "PLAY" / "RECORD" / token
addr-list = host-port *("/" host-port)
host-port = host [":" port]
host = see chapter 16
port = see chapter 16
17 Security Considerations 17 Security Considerations
Because of the similarity in syntax and usage between RTSP servers Because of the similarity in syntax and usage between RTSP servers
and HTTP servers, the security considerations outlined in [H15] and HTTP servers, the security considerations outlined in [H15]
apply. Specifically, please note the following: apply. Specifically, please note the following:
Authentication Mechanisms: RTSP and HTTP share common authentica- Authentication Mechanisms: RTSP and HTTP share common authentica-
tion schemes, and thus should follow the same prescriptions tion schemes, and thus should follow the same prescriptions
with regards to authentication . See chapter 15.1 of [2] for with regards to authentication . See chapter 15.1 of [2] for
skipping to change at page 1, line 4219 skipping to change at page 1, line 4359
The attacker may initiate traffic flows to one or more IP The attacker may initiate traffic flows to one or more IP
addresses by specifying them as the destination in SETUP addresses by specifying them as the destination in SETUP
requests. While the attacker's IP address may be known in this requests. While the attacker's IP address may be known in this
case, this is not always useful in prevention of more attacks case, this is not always useful in prevention of more attacks
or ascertaining the attackers identity. Thus, an RTSP server or ascertaining the attackers identity. Thus, an RTSP server
SHOULD only allow client-specified destinations for RTSP-ini- SHOULD only allow client-specified destinations for RTSP-ini-
tiated traffic flows if the server has verified the client's tiated traffic flows if the server has verified the client's
identity, either against a database of known users using RTSP identity, either against a database of known users using RTSP
authentication mechanisms (preferably digest authentication or authentication mechanisms (preferably digest authentication or
stronger), or other secure means. | stronger), or other secure means.
Session hijacking: Since there is no or little relation between a | Session hijacking: Since there is no or little relation between a
transport layer connection and an RTSP session, it is possible | transport layer connection and an RTSP session, it is possible
for a malicious client to issue requests with random session | for a malicious client to issue requests with random session
identifiers which would affect unsuspecting clients. The | identifiers which would affect unsuspecting clients. The
server SHOULD use a large, random and non-sequential session | server SHOULD use a large, random and non-sequential session
identifier to minimize the possibility of this kind of attack. identifier to minimize the possibility of this kind of attack.
Authentication: Servers SHOULD implement both basic and digest [6] Authentication: Servers SHOULD implement both basic and digest [6]
authentication. In environments requiring tighter security for authentication. In environments requiring tighter security for
the control messages, transport layer mechanisms such as TLS the control messages, transport layer mechanisms such as TLS
(RFC 2246 [27]) SHOULD be used. (RFC 2246 [27]) SHOULD be used.
Stream issues: RTSP only provides for stream control. Stream deliv- Stream issues: RTSP only provides for stream control. Stream deliv-
ery issues are not covered in this section, nor in the rest of ery issues are not covered in this section, nor in the rest of
this draft. RTSP implementations will most likely rely on this draft. RTSP implementations will most likely rely on
skipping to change at page 1, line 4249 skipping to change at page 1, line 4389
Persistently suspicious behavior: RTSP servers SHOULD return error Persistently suspicious behavior: RTSP servers SHOULD return error
code 403 (Forbidden) upon receiving a single instance of code 403 (Forbidden) upon receiving a single instance of
behavior which is deemed a security risk. RTSP servers SHOULD behavior which is deemed a security risk. RTSP servers SHOULD
also be aware of attempts to probe the server for weaknesses also be aware of attempts to probe the server for weaknesses
and entry points and MAY arbitrarily disconnect and ignore and entry points and MAY arbitrarily disconnect and ignore
further requests clients which are deemed to be in violation further requests clients which are deemed to be in violation
of local security policy. of local security policy.
18 IANA Considerations 18 IANA Considerations
This section set up a number of registers for RTSP that should be |
maintained by IANA. For each registry there is a description on what |
it shall contain, what specification is needed when adding a entry |
with IANA, and finally the entries that this document needs to regis- |
ter. See also the section 1.6 "Extending RTSP". |
The sections describing how to register an item uses some of the |
requirements level described in RFC 2434 [29], namely " First Come, |
First Served", "Specification Required", and "Standards Action". |
A registration request to IANA MUST contain the following informa- | This section set up a number of registers for RTSP that should be
tion: | maintained by IANA. For each registry there is a description on what
it shall contain, what specification is needed when adding a entry
+ A name of the item to register according to the rules specified | with IANA, and finally the entries that this document needs to regis-
by the intended registry. | ter. See also the section 1.6 "Extending RTSP".
+ Indication of who has change control over the option (for exam- |
ple, IETF, ISO, ITU-T, other international standardization bod- |
ies, a consortium or a particular company or group of companies); |
+ A reference to a further description, if available, for example |
(in order of preference) an RFC, a published standard, a pub- |
lished paper, a patent filing, a technical report, documented |
source code or a computer manual; |
+ For proprietary options, contact information (postal and email | The sections describing how to register an item uses some of the
address); | requirements level described in RFC 2434 [29], namely " First Come,
First Served", "Specification Required", and "Standards Action".
18.1 Option-tags | A registration request to IANA MUST contain the following informa-
tion:
18.1.1 Description | + A name of the item to register according to the rules specified
by the intended registry.
When a client and server try to determine what part and functionality | + Indication of who has change control over the feature (for exam-
of the RTSP specification and any future extensions that its counter | ple, IETF, ISO, ITU-T, other international standardization bod-
part implements there is need for a namespace. This registry con- | ies, a consortium or a particular company or group of companies);
tains named entries representing certain functionality. | + A reference to a further description, if available, for example
(in order of preference) an RFC, a published standard, a pub-
lished paper, a patent filing, a technical report, documented
source code or a computer manual;
The usage of option-tags is explained in section 3.7 and 10.1. | + For proprietary features, contact information (postal and email
address);
18.1.2 Registering New Option Tags with IANA | 18.1 Feature-tags
The registering of option tags is done on a first come, first served | 18.1.1 Description
basis. |
The name of the option MUST follow these rules: The name may be of | When a client and server try to determine what part and functionality
any length, but SHOULD be no more than twenty characters long. The | of the RTSP specification and any future extensions that its counter
name MUST not contain any spaces, or control characters. Any propri- | part implements there is need for a namespace. This registry con-
etary option SHALL have as the first part of the name a vendor tag, | tains named entries representing certain functionality.
which identifies the organization. |
18.1.3 Registered entries | The usage of feature-tags is explained in section 10 and 11.1.
The following options tags are in this specification defined and | 18.1.2 Registering New Feature-tags with IANA
hereby registered. The change control belongs to the Authors and the |
IETF MMUSIC WG. |
play.basic: The minimal implementation for playback operations | The registering of feature-tags is done on a first come, first served
according to section D. | basis.
play.scale: Support of scale operations for media playback. | The name of the feature MUST follow these rules: The name may be of
any length, but SHOULD be no more than twenty characters long. The
name MUST not contain any spaces, or control characters. Any propri-
etary feature SHALL have as the first part of the name a vendor tag,
which identifies the organization.
play.speed: Support of the speed functionality for playback. | 18.1.3 Registered entries
record.basic: The minimal implementation for record operations | The following feature-tags are in this specification defined and
according to section D. | hereby registered. The change control belongs to the Authors and the
IETF MMUSIC WG.
record.setup: The use of setup and teardown in record state. | play.basic: The minimal implementation for playback operations
according to section D.
record.scale: Support of scale operations for media recording. | play.scale: Support of scale operations for media playback.
setup.playing: The use of teardown and setup in play state. | play.speed: Support of the speed functionality for playback.
con.non-persistent: Support and use of non-persistent connections, | setup.playing: The use of SETUP and TEARDOWN in play state.
see chapter 9.3. |
con.persistent: Support and use of persistent connections, see | con.persistent: Support and use of persistent connections, see
chapter 9.3. | chapter 9.3.
18.2 RTSP Methods | 18.2 RTSP Methods
18.2.1 Description | 18.2.1 Description
What a method is, is described in section 10. Extending the protocol | What a method is, is described in section 11. Extending the protocol
with new methods allow for totally new functionality. | with new methods allow for totally new functionality.
18.2.2 Registering New Methods with IANA | 18.2.2 Registering New Methods with IANA
A new method MUST be registered through an IETF standard track docu- | A new method MUST be registered through an IETF standard track docu-
ment. The reason is that new methods may radically change the proto- | ment. The reason is that new methods may radically change the proto-
cols behavior and purpose. | cols behavior and purpose.
A specification for a new RTSP method MUST consist of the following | A specification for a new RTSP method MUST consist of the following
items: | items:
+ A method name which follows the BNF rules for methods. | + A method name which follows the BNF rules for methods.
+ A clear specification on what action and response a request with |
the method will result in. Which directions the method is used, |
C->S or S->C or both. How the use of headers, if any, modifies |
the behavior and effect of the method. |
+ A list or table specifying which of the registered headers that | + A clear specification on what action and response a request with
are allowed to use with the method in request or/and response. | the method will result in. Which directions the method is used,
C->S or S->C or both. How the use of headers, if any, modifies
the behavior and effect of the method.
+ Describe how the method relates to network proxies. | + A list or table specifying which of the registered headers that
are allowed to use with the method in request or/and response.
18.2.3 Registered Entries | + Describe how the method relates to network proxies.
This specification, RFCXXXX, registers 12 methods: DESCRIBE, | 18.2.3 Registered Entries
ANNOUNCE, GET_PARAMETER, OPTIONS, PAUSE, PING, PLAY, RECORD, REDI- |
RECT, SETUP, SET_PARAMETER, and TEARDOWN. |
18.3 RTSP Status Codes | This specification, RFCXXXX, registers 10 methods: DESCRIBE,
GET_PARAMETER, OPTIONS, PAUSE, PING, PLAY, REDIRECT, SETUP,
SET_PARAMETER, and TEARDOWN.
18.3.1 Description | 18.3 RTSP Status Codes
A status code is the three digit numbers used to convey information | 18.3.1 Description
in RTSP response messages, see 7. The number space is limited and |
care should be taken not to fill the space. |
18.3.2 Registering New Status Codes with IANA | A status code is the three digit numbers used to convey information
in RTSP response messages, see 7. The number space is limited and
care should be taken not to fill the space.
A new status code can only be registered by an IETF standards track | 18.3.2 Registering New Status Codes with IANA
document. A specification for a new status code MUST specify the fol- |
lowing: |
+ The requested number. | A new status code can only be registered by an IETF standards track
document. A specification for a new status code MUST specify the fol-
lowing:
+ A description what the status code means and the expected behav- | + The requested number.
ior of the sender and receiver of the code. |
18.3.3 Registered Entries | + A description what the status code means and the expected behav-
ior of the sender and receiver of the code.
RFCXXX, registers the numbered status code defined in the BNF entry | 18.3.3 Registered Entries
"Status-Code" except "extension-code" in section 7.1.1. |
18.4 RTSP Headers | RFCXXX, registers the numbered status code defined in the BNF entry
"Status-Code" except "extension-code" in section 7.1.1.
18.4.1 Description | 18.4 RTSP Headers
By specifying new headers a method(s) can be enhanced in many differ- | 18.4.1 Description
ent ways. An unknown header will be ignored by the receiving entity. |
If the new header is vital for a certain functionality, a option tag |
for the functionality can be created and demanded to be used by the |
counter-part with the inclusion of a Require header carrying the |
option tag. |
18.4.2 Registering New Headers with IANA | By specifying new headers a method(s) can be enhanced in many differ-
ent ways. An unknown header will be ignored by the receiving entity.
If the new header is vital for a certain functionality, a feature-tag
for the functionality can be created and demanded to be used by the
counter-part with the inclusion of a Require header carrying the fea-
ture-tag.
A public available specification is required to register a header. | 18.4.2 Registering New Headers with IANA
The specification SHOULD be a standards document, preferable an IETF |
RFC. |
The specification MUST contain the following information: | A public available specification is required to register a header.
The specification SHOULD be a standards document, preferable an IETF
RFC.
+ The name of the header. | The specification MUST contain the following information:
+ A BNF specification of the header syntax. | + The name of the header.
+ A list or table specifying when the header may be used, encom- | + A BNF specification of the header syntax.
passing all methods, their request or response, the direction |
(C->S or S->C). |
+ How the header shall be handled by proxies. | + A list or table specifying when the header may be used, encom-
passing all methods, their request or response, the direction
(C->S or S->C).
+ A description of the purpose of the header. | + How the header shall be handled by proxies.
18.4.3 Registered entries | + A description of the purpose of the header.
All headers specified in section 12 in RFCXXXX are to be registered. | 18.4.3 Registered entries
18.5 Parameters | All headers specified in section 13 in RFCXXXX are to be registered.
18.5.1 Description | Furthermore the following RTSP headers defined in other specifica-
tions are registered:
A Parameter allow the counterpart to set something with the owner of | + x-wap-profile defined in [35].
the parameter. Both the client and the server can have parameters. |
18.5.2 Registering New Parameters with IANA | + x-wap-profile-diff defined in [35].
Any Parameter is registered on a first come, first served basis. The | + x-wap-profile-warning defined in [35].
following rules apply for parameters: |
+ The parameter name is a BNF token. The name SHOULD not be more | + x-predecbufsize defined in [35].
than 20 characters long. Any proprietary parameter should start |
the name with a vendor tag, as clearly as possible identifying |
the company or person. |
+ Any non proprietary parameter MUST in the form of BNF specify | + x-initpredecbufperiod defined in [35].
what value types that are associated with the parameter. |
18.5.3 Registered entries | + x-initpostdecbufperiod defined in [35].
For the moment no known parameters are defined in RFC XXXX. | Note: The use of "X-" is NOT RECOMMENDED but the above headers in
the register list was defined prior to the clarification.
18.6 MIME type registration | 18.5 Transport Header registries
One new MIME type is registered, text/parameters. To be defined. | The transport header contains a number of parameters which have pos-
sibilities for future extensions. Therefore registries for these must
be defined.
18.7 Transport Header registries | 18.5.1 Transport Protocols
The transport header contains a number of parameters which have pos- | A registry for the parameter transport-protocol shall be defined with