draft-ietf-mmusic-rfc2326bis-01.txt   draft-ietf-mmusic-rfc2326bis-02.txt 
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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-01.txt draft-ietf-mmusic-rfc2326bis-02.txt
June 06, 2002 November 01, 2002
Expires: December, 2002 Expires: April, 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
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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 Purpose 1.1 The Update of the Specification |
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- |
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 goal is to progress RTSP to draft standard. If that is possible |
without first publishing it as a proposed standard is not yet deter- |
mined, as it depends on the changes necessary to make the protocol |
work. |
See the list of changes in chapter F to see what has been addressed. |
The currently open issues are listed in chapter E |
There is currently a list of reported bugs available at "http://rtsp- |
spec.sourceforge.net". This list should be taken into account when |
reading this specification. A lot of these bugs are addressed but not |
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 |
MMUSIC WG's mailing list mmusic@ietf.org and the authors. |
Take special notice of the following: |
+ The example section 14 has not yet been revised as the changes |
to protocol has not been completed. |
+ The BNF chapter 16 has neither been compiled completely. |
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 10.13). 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 notion of an RTSP connection; instead, a server maintains There is no necessity for a notion of an RTSP connection; instead, a
a session labeled by an identifier. An RTSP session is in no way tied server maintains a session labeled by an identifier. An RTSP session
to a transport-level connection such as a TCP connection. During an is in normally not tied to a transport-level connection such as a TCP
RTSP session, an RTSP client may open and close many reliable trans- connection. During an RTSP session, an RTSP client may open and close
port connections to the server to issue RTSP requests. Alternatively, many reliable transport connections to the server to issue RTSP
it may use a connectionless transport protocol such as UDP. requests. Alternatively, it may use a connectionless transport proto-
col such as UDP.
The streams controlled by RTSP may use RTP [1], but the operation of The streams controlled by RTSP may use RTP [1], but the operation of
RTSP does not depend on the transport mechanism used to carry contin- RTSP does not depend on the transport mechanism used to carry contin-
uous media. uous media.
The protocol is intentionally similar in syntax and operation to The protocol is intentionally similar in syntax and operation to
HTTP/1.1 [26] so that extension mechanisms to HTTP can in most cases HTTP/1.1 [26] so that extension mechanisms to HTTP can in most cases
also be added to RTSP. However, RTSP differs in a number of important also be added to RTSP. However, RTSP differs in a number of important
aspects from HTTP: aspects from HTTP:
+ RTSP introduces a number of new methods and has a different pro- + RTSP introduces a number of new methods and has a different pro-
tocol identifier. tocol identifier.
+ An RTSP server needs to maintain state by default in almost all + An RTSP server needs to maintain state by default in almost all
cases, as opposed to the stateless nature of HTTP. cases, as opposed to the stateless nature of HTTP.
+ Both an RTSP server and client can issue requests. + Both an RTSP server and client can issue requests.
+ Data is carried out-of-band by a different protocol. (There is an + Data is usually carried out-of-band by a different protocol.
exception to this.) Session descriptions is one possible exception.
+ RTSP is defined to use ISO 10646 (UTF-8) rather than ISO 8859-1, + RTSP is defined to use ISO 10646 (UTF-8) rather than ISO 8859-1,
consistent with current HTML internationalization efforts [3]. consistent with current HTML internationalization efforts [3].
+ The Request-URI always contains the absolute URI. Because of + The Request-URI always contains the absolute URI. Because of
backward compatibility with a historical blunder, HTTP/1.1 [26] backward compatibility with a historical blunder, HTTP/1.1 [26]
carries only the absolute path in the request and puts the host carries only the absolute path in the request and puts the host
name in a separate header field. name in a separate header field.
This makes "virtual hosting" easier, where a single host This makes "virtual hosting" easier, where a single host
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tributed teaching applications. Several parties in the confer- tributed teaching applications. Several parties in the confer-
ence may 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].
1.2 Requirements 1.3 Requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [4]. document are to be interpreted as described in RFC 2119 [4].
1.3 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. |
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 continuous media data from the media Client: The client requests media service from the media server. |
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
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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,
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 or recording services
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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 15 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
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 media record or 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-
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tation. The presentation description may take several differ- tation. The presentation description may take several differ-
ent formats, including but not limited to the session descrip- ent formats, including but not limited to the session descrip-
tion format SDP. tion format SDP.
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 complete RTSP "transaction", e.g., the viewing of a RTSP session: A state established on a RTSP server by a client with |
movie. A session typically consists of a client setting up a an SETUP request. The RTSP session exist until it either time- |
transport mechanism for the continuous media stream (SETUP), outs or is explicitly removed by a TEARDOWN request. The ses- |
starting the stream with PLAY or RECORD, and closing the sion contains state about which media resources that can be |
stream with TEARDOWN. played or recorded, 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.
1.4 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.
Easy to parse: RTSP can be parsed by standard HTTP or MIME parsers. Easy to parse: RTSP can be parsed by standard HTTP or MIME parsers.
Secure: RTSP re-uses web security mechanisms, either at the trans- Secure: RTSP re-uses web security mechanisms, either at the trans-
port level (TLS, RFC 2246 [27]) or within the protocol itself. port level (TLS, RFC 2246 [27]) or within the protocol itself.
All HTTP authentication mechanisms such as basic (RFC 2616 All HTTP authentication mechanisms such as basic (RFC 2616
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Proxy and firewall friendly: The protocol should be readily handled Proxy and firewall friendly: The protocol should be readily handled
by both application and transport-layer (SOCKS [11]) fire- by both application and transport-layer (SOCKS [11]) fire-
walls. A firewall may need to understand the SETUP method to walls. A firewall may need to understand the SETUP method to
open a "hole" for the UDP media stream. open a "hole" for the UDP media stream.
HTTP-friendly: Where sensible, RTSP reuses HTTP concepts, so that HTTP-friendly: Where sensible, RTSP reuses HTTP concepts, so that
the existing infrastructure can be reused. This infrastructure the existing infrastructure can be reused. This infrastructure
includes PICS (Platform for Internet Content Selection includes PICS (Platform for Internet Content Selection
[12,13]) for associating labels with content. However, RTSP [12,13]) for associating labels with content. However, RTSP
does not just add methods to HTTP since the controlling does not just add methods to HTTP since the controlling con-
continuous media requires server state in most cases. tinuous media requires server state in most cases.
Appropriate server control: If a client can start a stream, it must Appropriate server control: If a client can start a stream, it must
be able to stop a stream. Servers should not start streaming be able to stop a stream. Servers should not start streaming
to clients in such a way that clients cannot stop the stream. to clients in such a way that clients cannot stop the stream.
Transport negotiation: The client can negotiate the transport Transport negotiation: The client can negotiate the transport
method prior to actually needing to process a continuous media method prior to actually needing to process a continuous media
stream. stream.
Capability negotiation: If basic features are disabled, there must Capability negotiation: If basic features are disabled, there must
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An earlier requirement in RTSP was multi-client capability. An earlier requirement in RTSP was multi-client capability.
However, it was determined that a better approach was to make However, it was determined that a better approach was to make
sure that the protocol is easily extensible to the multi- sure that the protocol is easily extensible to the multi-
client scenario. Stream identifiers can be used by several client scenario. Stream identifiers can be used by several
control streams, so that "passing the remote" would be possi- control streams, so that "passing the remote" would be possi-
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.
1.5 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- + A server may only be capable of playback thus has no need to sup-
port the RECORD request. 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.
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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.
1.6 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.
For the purposes of this specification, a presentation description is For the purposes of this specification, a presentation description is
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Multicast, server chooses address: The media server picks the mul- Multicast, server chooses address: The media server picks the mul-
ticast address and port. This is the typical case for a live ticast address and port. This is the typical case for a live
or near-media-on-demand transmission. or near-media-on-demand transmission.
Multicast, client chooses address: If the server is to participate Multicast, client chooses address: If the server is to participate
in an existing multicast conference, the multicast address, in an existing multicast conference, the multicast address,
port and encryption key are given by the conference descrip- port and encryption key are given by the conference descrip-
tion, established by means outside the scope of this specifi- tion, established by means outside the scope of this specifi-
cation. cation.
1.7 RTSP States 1.8 RTSP States
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 Section 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, RECORD, PAUSE, and TEAR-
DOWN. DOWN.
SETUP: Causes the server to allocate resources for a stream and SETUP: Causes the server to allocate resources for a stream and
start an RTSP session. create an RTSP session.
PLAY and RECORD: Starts data transmission on a stream allocated via PLAY and RECORD: 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 12.37) 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 10.4).
1.8 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 stan-
dalone RTSP servers and clients which do not rely on HTTP at all. dalone RTSP servers and clients which do not rely on HTTP at all.
However, RTSP differs fundamentally from HTTP in that data delivery However, RTSP differs fundamentally from HTTP in that most data
takes place out-of-band in a different protocol. HTTP is an asymmet- delivery takes place out-of-band in a different protocol. HTTP is an
ric 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
areas, namely security and proxies. The requirements are very areas, namely security and proxies. The requirements are very
similar, so having the ability to adopt HTTP work on caches, similar, so having the ability to adopt HTTP work on caches,
proxies and authentication is valuable. proxies and authentication is valuable.
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2 Notational Conventions 2 Notational Conventions
Since many of the definitions and syntax are identical to HTTP/1.1, Since many of the definitions and syntax are identical to HTTP/1.1,
this specification only points to the section where they are defined this specification only points to the section where they are defined
rather than copying it. For brevity, [HX.Y] is to be taken to refer rather than copying it. For brevity, [HX.Y] is to be taken to refer
to Section X.Y of the current HTTP/1.1 specification (RFC 2616 [26]). 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 "1#" notation for ence that this RTSP specification maintains the "#" notation for
comma-separated lists. 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 understand- not involved with the formulation of the specification an
ing of why things are the way that they are in RTSP. understanding of why things are the way that they are in RTSP.
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. 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" and "rtspu" schemes are used to refer to network resources
via the RTSP protocol. This section defines the scheme-specific syn- via the RTSP protocol. This section defines the scheme-specific syn-
tax and semantics for RTSP URLs. tax and semantics for RTSP URLs. |
rtsp_URL = ( "rtsp:" | "rtspu:" )
"//" host [ ":" port ] [ abs_path ]
host = <A legal Internet host domain name of IP address
(in dotted decimal form), as defined by Section 2.1
of RFC 1123 [15]>
port = *DIGIT
abs_path is defined in [H3.2.1]. rtsp_URL = ( "rtsp:" / "rtspu:" / "rtsps" ) ||
"//" host [ ":" port ] [ abs_path ] ||
host = As defined by RFC 2732 [30] ||
abs_path = As defined by RFC 2396 [22] ||
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). an unreliable protocol (within the Internet, UDP). The scheme rtsps
identifies a reliable transport using TLS [27].
If the port is empty or not given, port 554 is assumed. The semantics If the port is empty or not given, port 554 is assumed. The seman-
are that the identified resource can be controlled by RTSP at the tics are that the identified resource can be controlled by RTSP at
server listening for TCP (scheme "rtsp") connections or UDP (scheme the server listening for TCP (scheme "rtsp") connections or UDP
"rtspu") packets on that port of host, and the Request-URI for the (scheme "rtspu") packets on that port of host, and the Request-URI
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]). (see RFC 1924 [16]). Note: Using qualified domain names in any URL is
one requirement for making it possible for RFC 2326 implementations
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
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 1738 [17]). 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 10 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
skipping to change at page 1, line 571 skipping to change at page 1, line 614
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 opaque strings of arbitrary length. Linear
white space must be URL-escaped. A session identifier MUST be chosen white space must be URL-escaped. A session identifier MUST be chosen
randomly and MUST be at least eight octets long to make guessing it randomly and MUST be at least eight octets long to make guessing it
more difficult. (See Section 16.) 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-time ) smpte-range-spec = ( smpte-time "-" [ smpte-time ] ) ||
smpte-type = "smpte" | "smpte-30-drop" | "smpte-25" / ( "-" smpte-time ) ||
; other timecodes may be added smpte-type = "smpte" / "smpte-30-drop" / "smpte-25" ||
smpte-time = 1*2DIGIT ":" 1*2DIGIT ":" 1*2DIGIT ; other timecodes may be added ||
[ ":" 1*2DIGIT ] [ "." 1*2DIGIT ] smpte-time = 1*2DIGIT ":" 1*2DIGIT ":" 1*2DIGIT ||
[ ":" 1*2DIGIT [ "." 1*2DIGIT ] ] ||
Examples: Examples:
smpte=10:12:33:20- smpte=10:12:33:20-
smpte=10:07:33- smpte=10:07:33-
smpte=10:07:00-10:07:33:05.01 smpte=10:07:00-10:07:33:05.01
smpte-25=10:07:00-10:07:33:05.01 smpte-25=10:07:00-10:07:33:05.01
3.5 Normal Play Time 3.5 Normal Play Time
Normal play time (NPT) indicates the stream absolute position rela- Normal play time (NPT) indicates the stream absolute position rela-
tive to the beginning of the presentation. The timestamp consists of tive to the beginning of the presentation, not to be confused with
a decimal fraction. The part left of the decimal may be expressed in the Network Time Protocol (NTP). The timestamp consists of a decimal
either seconds or hours, minutes, and seconds. The part right of the fraction. The part left of the decimal may be expressed in either
decimal point measures fractions of a second. seconds or hours, minutes, and seconds. The part right of the decimal
point measures fractions of a second.
The beginning of a presentation corresponds to 0.0 seconds. Negative The beginning of a presentation corresponds to 0.0 seconds. Negative
values are not defined. The special constant now is defined as the values are not defined. The special constant now is defined as the
current instant of a live event. It may be used only for live events. current instant of a live event. It MAY only be used for live events,
and SHALL NOT be used for on-demand content.
NPT is defined as in DSM-CC: "Intuitively, NPT is the clock the NPT is defined as in DSM-CC: "Intuitively, NPT is the clock the
viewer associates with a program. It is often digitally displayed on viewer associates with a program. It is often digitally displayed on
a VCR. NPT advances normally when in normal play mode (scale = 1), a VCR. NPT advances normally when in normal play mode (scale = 1),
advances at a faster rate when in fast scan forward (high positive advances at a faster rate when in fast scan forward (high positive
scale ratio), decrements when in scan reverse (high negative scale scale ratio), decrements when in scan reverse (high negative scale
ratio) and is fixed in pause mode. NPT is (logically) equivalent to ratio) and is fixed in pause mode. NPT is (logically) equivalent to
SMPTE time codes." [5] SMPTE time codes." [5]
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
npt-ss = 1*2DIGIT ; 0-59 npt-ss = 1*2DIGIT ; 0-59
Examples: Examples:
npt=123.45-125 npt=123.45-125
npt=12:05:35.3- npt=12:05:35.3-
skipping to change at page 1, line 652 skipping to change at page 1, line 698
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 = ["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 ||
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 Option Tags
Option tags are unique identifiers used to designate new options in Option tags are unique identifiers used to designate new options in
RTSP. These tags are used in in Require (Section 12.32) and Proxy- RTSP. These tags are used in in Require (Section 12.32), Proxy-
Require (Section 12.27) header fields. Require (Section 12.27), and Supported (Section 12.38) header fields.
Syntax: Syntax:
option-tag = token option-tag = token
The creator of a new RTSP option should either prefix the option with The creator of a new RTSP option should either prefix the option with
a reverse domain name (e.g., "com.foo.mynewfeature" is an apt name a reverse domain name (e.g., "com.foo.mynewfeature" is an apt name
for a feature whose inventor can be reached at "foo.com"), or regis- for a feature whose inventor can be reached at "foo.com"), or regis-
ter the new option with the Internet Assigned Numbers Authority ter the new option with the Internet Assigned Numbers Authority
(IANA). (IANA), see IANA Section 18.
3.7.1 Registering New Option Tags with IANA
When registering a new RTSP option, the following information should
be provided:
+ Name and description of option. The name may be of any length,
but SHOULD be no more than twenty characters long. The name MUST
not contain any spaces, control characters or periods.
+ 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 paper, a patent fil-
ing, a technical report, documented source code or a computer
manual;
+ For proprietary options, contact information (postal and email
address);
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 723 skipping to change at page 1, line 748
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. that is 8-bit clean. RTSP messages are vulnerable to bit errors and |
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].
4.2 Message Headers 4.2 Message Headers
See [H4.2] See [H4.2].
4.3 Message Body 4.3 Message Body
See [H4.3] See [H4.3]
4.4 Message Length 4.4 Message Length
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):
skipping to change at page 1, line 771 skipping to change at page 1, line 797
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: and Warning headers are not defined. RTSP further defines the CSeq,
and Timestamp:
general-header = Cache-Control ; Section 12.9 general-header = Cache-Control ; Section 12.9
| Connection ; Section 12.10 / Connection ; Section 12.10
| CSeq ; Section 12.17 / CSeq ; Section 12.17
| Date ; Section 12.18 / Date ; Section 12.18
| Via ; Section 12.44 / Timestamp ; Section 12.39
/ Via ; Section 12.44
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 10.2
| "ANNOUNCE" ; Section 10.3 / "ANNOUNCE" ; Section 10.3
| "GET_PARAMETER" ; Section 10.8 / "GET_PARAMETER" ; Section 10.8
| "OPTIONS" ; Section 10.1 / "OPTIONS" ; Section 10.1
| "PAUSE" ; Section 10.6 / "PAUSE" ; Section 10.6
| "PLAY" ; Section 10.5 / "PLAY" ; Section 10.5
| "RECORD" ; Section 10.11 / "PING" ; Section 10.12
| "REDIRECT" ; Section 10.10 / "RECORD" ; Section 10.11
| "SETUP" ; Section 10.4 / "REDIRECT" ; Section 10.10
| "SET_PARAMETER" ; Section 10.9 / "SETUP" ; Section 10.4
| "TEARDOWN" ; Section 10.7 / "SET_PARAMETER" ; Section 10.9
| extension-method / "TEARDOWN" ; Section 10.7
/ 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 12.1
| Accept-Encoding ; Section 12.2 / Accept-Encoding ; Section 12.2
| Accept-Language ; Section 12.3 / Accept-Language ; Section 12.3
| Authorization ; Section 12.6 / Authorization ; Section 12.6
| Bandwidth ; Section 12.7 / Bandwidth ; Section 12.7
| Blocksize ; Section 12.8 / Blocksize ; Section 12.8
| From ; Section 12.20 / From ; Section 12.20
| If-Modified-Since ; Section 12.23 / If-Modified-Since ; Section 12.23
| Proxy-Require ; Section 12.27 / Proxy-Require ; Section 12.27
| Range ; Section 12.29 / Range ; Section 12.29
| Referer ; Section 12.30 / Referer ; Section 12.30
| Require ; Section 12.32 / Require ; Section 12.32
| Scale ; Section 12.34 / Scale ; Section 12.34
| Session ; Section 12.37 / Session ; Section 12.37
| Speed ; Section 12.35 / Speed ; Section 12.35
| Transport ; Section 12.40 / Supported ; Section 12.38
| User-Agent ; Section 12.42 / Transport ; Section 12.40
/ User-Agent ; Section 12.42
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.
The asterisk "*" in the Request-URI means that the request does not The asterisk "*" in the Request-URI means that the request does not
apply to a particular resource, but to the server itself, and is only apply to a particular resource, but to the server or proxy itself,
allowed when the method used does not necessarily apply to a and is only allowed when the method used does not necessarily apply
resource. One example would be: to a resource.
One example would be:
OPTIONS * RTSP/1.0 OPTIONS * RTSP/1.0
Which will determine the capabilities of the server or the proxy that
first receives the request. If one needs to address the server explic-
itly one needs to put in a absolute URL with the servers address.
OPTIONS rtsp://example.com RTSP/1.0
7 Response 7 Response
[H6] applies except that HTTP-Version is replaced by RTSP-Version. [H6] applies except that HTTP-Version is replaced by RTSP-Version.
Also, RTSP defines additional status codes and does not define some Also, RTSP defines additional status codes and does not define some
HTTP codes. The valid response codes and the methods they can be used HTTP codes. The valid response codes and the methods they can be used
with are defined in Table 1. with are defined in Table 1.
After receiving and interpreting a request message, the recipient After receiving and interpreting a request message, the recipient
responds with an RTSP response message. responds with an RTSP response message.
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
7.1 Status-Line 7.1 Status-Line
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.
skipping to change at page 1, line 914 skipping to change at page 1, line 952
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
presented below. The reason phrases listed here are only recommended presented below. The reason phrases listed here are only recommended
-- they may be replaced by local equivalents without affecting the -- they may be replaced by local equivalents without affecting the
protocol. Note that RTSP adopts most HTTP/1.1 [26] status codes and protocol. Note that RTSP adopts most HTTP/1.1 [26] status codes and
adds RTSP-specific status codes starting at x50 to avoid conflicts adds RTSP-specific status codes starting at x50 to avoid conflicts
with newly defined HTTP status codes. with newly defined HTTP status codes.
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
| "300" ; Multiple Choices / "300" ; Multiple Choices
| "301" ; Moved Permanently / "301" ; Moved Permanently
| "302" ; Moved Temporarily / "302" ; Moved Temporarily
| "303" ; See Other / "303" ; See Other
| "304" ; Not Modified / "304" ; Not Modified
| "305" ; Use Proxy / "305" ; Use Proxy
| "400" ; Bad Request / "350" ; Going Away
| "401" ; Unauthorized / "351" ; Load Balancing
| "402" ; Payment Required / "400" ; Bad Request
| "403" ; Forbidden / "401" ; Unauthorized
| "404" ; Not Found / "402" ; Payment Required
| "405" ; Method Not Allowed / "403" ; Forbidden
| "406" ; Not Acceptable / "404" ; Not Found
| "407" ; Proxy Authentication Required / "405" ; Method Not Allowed
| "408" ; Request Time-out / "406" ; Not Acceptable
| "410" ; Gone / "407" ; Proxy Authentication Required
| "411" ; Length Required / "408" ; Request Time-out
| "412" ; Precondition Failed / "410" ; Gone
| "413" ; Request Entity Too Large / "411" ; Length Required
| "414" ; Request-URI Too Large / "412" ; Precondition Failed
| "415" ; Unsupported Media Type / "413" ; Request Entity Too Large
| "451" ; Parameter Not Understood / "414" ; Request-URI Too Large
| "452" ; reserved / "415" ; Unsupported Media Type
| "453" ; Not Enough Bandwidth / "451" ; Parameter Not Understood
| "454" ; Session Not Found / "452" ; reserved
| "455" ; Method Not Valid in This State / "453" ; Not Enough Bandwidth
| "456" ; Header Field Not Valid for Resource / "454" ; Session Not Found
| "457" ; Invalid Range / "455" ; Method Not Valid in This State
| "458" ; Parameter Is Read-Only / "456" ; Header Field Not Valid for Resource
| "459" ; Aggregate operation not allowed / "457" ; Invalid Range
| "460" ; Only aggregate operation allowed / "458" ; Parameter Is Read-Only
| "461" ; Unsupported transport / "459" ; Aggregate operation not allowed
| "462" ; Destination unreachable / "460" ; Only aggregate operation allowed
| "500" ; Internal Server Error / "461" ; Unsupported transport
| "501" ; Not Implemented / "462" ; Destination unreachable
| "502" ; Bad Gateway / "500" ; Internal Server Error
| "503" ; Service Unavailable / "501" ; Not Implemented
| "504" ; Gateway Time-out / "502" ; Bad Gateway
| "505" ; RTSP Version not supported / "503" ; Service Unavailable
| "551" ; Option not supported / "504" ; Gateway Time-out
| extension-code / "505" ; RTSP Version not supported
/ "551" ; Option not supported
/ extension-code
extension-code = 3DIGIT extension-code = 3DIGIT
Reason-Phrase = *<TEXT, excluding CR, LF> Reason-Phrase = *<TEXT, excluding CR, LF>
RTSP status codes are extensible. RTSP applications are not required RTSP status codes are extensible. RTSP applications are not required
to understand the meaning of all registered status codes, though such to understand the meaning of all registered status codes, though such
understanding is obviously desirable. However, applications MUST understanding is obviously desirable. However, applications MUST
understand the class of any status code, as indicated by the first understand the class of any status code, as indicated by the first
digit, and treat any unrecognized response as being equivalent to the digit, and treat any unrecognized response as being equivalent to the
x00 status code of that class, with the exception that an unrecog- x00 status code of that class, with the exception that an unrecog-
nized response MUST NOT be cached. For example, if an unrecognized nized response MUST NOT be cached. For example, if an unrecognized
status code of 431 is received by the client, it can safely assume status code of 431 is received by the client, it can safely assume
that there was something wrong with its request and treat the that there was something wrong with its request and treat the
response as if it had received a 400 status code. In such cases, user response as if it had received a 400 status code. In such cases, user
skipping to change at page 1, line 983 skipping to change at page 1, line 1023
information which will explain the unusual status. information which will explain the unusual status.
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 = Location ; Section 12.25 response-header = Accept-Ranges ; Section
| Proxy-Authenticate ; Section 12.26 12.4
| Public ; Section 12.28 / Location ; Section 12.25
| Range ; Section 12.29 / Proxy-Authenticate ; Section 12.26
| Retry-After ; Section 12.31 / Public ; Section 12.28
| RTP-Info ; Section 12.33 / Range ; Section 12.29
| Scale ; Section 12.34 / Retry-After ; Section 12.31
| Session ; Section 12.37 / RTP-Info ; Section 12.33
| Server ; Section 12.36 / Scale ; Section 12.34
| Speed ; Section 12.35 / Session ; Section 12.37
| Transport ; Section 12.40 / Server ; Section 12.36
| Unsupported ; Section 12.41 / Speed ; Section 12.35
| Vary ; Section 12.43 / Transport ; Section 12.40
| WWW-Authenticate ; Section 12.45 / Unsupported ; Section 12.41
/ Vary ; Section 12.43
/ WWW-Authenticate ; Section 12.45
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.
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
302 Moved Temporarily all 302 Found all
303 See Other all 303 See Other all
305 Use Proxy all 305 Use Proxy all
350 Going Away all
351 Load Balancing all
-------------------------------------------------------- --------------------------------------------------------
400 Bad Request all 400 Bad Request all
401 Unauthorized all 401 Unauthorized all
402 Payment Required all 402 Payment Required all
403 Forbidden all 403 Forbidden all
404 Not Found all 404 Not Found all
405 Method Not Allowed all 405 Method Not Allowed all
406 Not Acceptable all 406 Not Acceptable all
407 Proxy Authentication Required all 407 Proxy Authentication Required all
408 Request Timeout all 408 Request Timeout all
410 Gone all 410 Gone all
411 Length Required all 411 Length Required all
412 Precondition Failed DESCRIBE, SETUP 412 Precondition Failed DESCRIBE, SETUP
413 Request Entity Too Large all 413 Request Entity Too Large all
414 Request-URI Too Long all 414 Request-URI Too Long all
415 Unsupported Media Type all 415 Unsupported Media Type all
451 Parameter Not Understood SETUP 451 Parameter Not Understood SET_PARAMETER
452 reserved n/a 452 reserved n/a
453 Not Enough Bandwidth SETUP 453 Not Enough Bandwidth SETUP
454 Session Not Found all 454 Session Not Found all
455 Method Not Valid In This State all 455 Method Not Valid In This State all
456 Header Field Not Valid all 456 Header Field Not Valid all
457 Invalid Range PLAY 457 Invalid Range PLAY, PAUSE
458 Parameter Is Read-Only SET_PARAMETER 458 Parameter Is Read-Only SET_PARAMETER
459 Aggregate Operation Not Allowed all 459 Aggregate Operation Not Allowed all
460 Only Aggregate Operation Allowed all 460 Only Aggregate Operation Allowed all
461 Unsupported Transport all 461 Unsupported Transport all
462 Destination Unreachable all 462 Destination Unreachable all
-------------------------------------------------------- --------------------------------------------------------
500 Internal Server Error all 500 Internal Server Error all
501 Not Implemented all 501 Not Implemented all
502 Bad Gateway all 502 Bad Gateway all
503 Service Unavailable all 503 Service Unavailable all
504 Gateway Timeout all 504 Gateway Timeout all
505 RTSP Version Not Supported all 505 RTSP Version Not Supported all
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
entity-header fields.
8 Entity 8 Entity
Request and Response messages MAY transfer an entity if not otherwise Request and Response messages MAY transfer an entity if not otherwise
restricted by the request method or response status code. An entity restricted by the request method or response status code. An entity
consists of entity-header fields and an entity-body, although some consists of entity-header fields and an entity-body, although some
responses will only include the entity-headers. responses will only include the entity-headers.
In this section, both sender and recipient refer to either the client 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 metainformation 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 12.5
| Content-Base ; Section 12.11 / Content-Base ; Section 12.11
| Content-Encoding ; Section 12.12 / Content-Encoding ; Section 12.12
| Content-Language ; Section 12.13 / Content-Language ; Section 12.13
| Content-Length ; Section 12.14 / Content-Length ; Section 12.14
| Content-Location ; Section 12.15 / Content-Location ; Section 12.15
| Content-Type ; Section 12.16 / Content-Type ; Section 12.16
| Expires ; Section 12.19 / Expires ; Section 12.19
| Last-Modified ; Section 12.24 / Last-Modified ; Section 12.24
| 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] See [H7.2] with the addition that a RTSP message with an entity body |
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;
+ connectionless mode. + connectionless mode.
The type of transport connection is defined by the RTSP URI (Section The type of transport connection is defined by the RTSP URI (Section
3.2). For the scheme "rtsp", a persistent connection is assumed, 3.2). For the scheme "rtsp", a connection is assumed, while the
while the scheme "rtspu" calls for RTSP requests to be sent without scheme "rtspu" calls for RTSP requests to be sent without setting up
setting up a connection. a connection.
Unlike HTTP, RTSP allows the media server to send requests to the Unlike HTTP, RTSP allows the media server to send requests to the
media client. However, this is only supported for persistent connec- media client. However, this is only supported for persistent connec-
tions, as the media server otherwise has no reliable way of reaching tions, as the media server otherwise has no reliable way of reaching
the client. Also, this is the only way that requests from media the client. Also, this is the only way that requests from media
server to client are likely to traverse firewalls. server to client are likely to traverse firewalls.
9.1 Pipelining 9.1 Pipelining
A client that supports persistent connections or connectionless mode A client that supports persistent connections or connectionless mode
MAY "pipeline" its requests (i.e., send multiple requests without MAY "pipeline" its requests (i.e., send multiple requests without
waiting for each response). A server MUST send its responses to those waiting for each response). A server MUST send its responses to those
requests in the same order that the requests were received. requests in the same order that the requests were received.
9.2 Reliability and Acknowledgements 9.2 Reliability and Acknowledgements
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 |
application-layer retransmission before the first attempt has application-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 12.39) 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 is incremented by one for each distinct request trans- 12.17), which MUST be incremented by one for each distinct request |
mitted. If a request is repeated because of lack of acknowledgement, transmitted. If a request is repeated because of lack of acknowledge- |
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 |
TCP can be used for both persistent connections and for one message |
exchange per connection, as presented above. This section gives fur- |
ther rules and recommendations on how to handle these connections so |
maximum interoperability and flexibility can be achieved. |
A server SHALL handle both persistent connections and one |
request/response transaction per connection. A persistent connection |
MAY be used for all transactions between the server and client, |
including messages to multiple RTSP sessions. However the persistent |
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 |
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 |
exchange or can be kept open for several messages, i.e. persistent. |
The client MAY close the connection at any time when no outstanding |
request/response transactions exist. The server SHOULD NOT close the |
connection unless at least one RTSP session timeout period has passed |
without data traffic. A server MUST NOT close a connection directly |
after responding to a TEARDOWN request for the whole session. |
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 |
on the same server, it is RECOMMENDED to use only a single connec- |
tion. |
Older services which was implemented according to RFC 2326 sometimes |
requires the client to use persistent connection. The client closing |
the connection may result in that the server removes the session. To |
achieve interoperability with old servers any client is strongly REC- |
OMMENDED to use persistent connections. To make it practically possi- |
ble for a client to the rules outlined in this chapter a feature tag |
is defined. |
con.non-persistent ||
If a service requires the use of persistent connection a option tag |
is specified for usage in Require and Proxy-Require. |
con.persistent ||
A server implemented according to this specification MUST respond |
that it supports the feature tag above. A client MAY send a request |
including the Supported header in a request to determine support of |
non-persistent connections. A server supporting non-persistent con- |
nections MUST return the "con.non-persistent" feature tag in its |
response. If the client receives the feature tag in the response, it |
can be certain that the server handles non-persistent connections. |
9.4 Use of Transport Layer Security |
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. |
Implementations according to this specification MUST understand IPv6 |
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 10 Method Definitions
The method token indicates the method to be performed on the resource The method token indicates the method to be performed on the resource |
identified by the Request-URI case-sensitive. New methods may be identified by the Request-URI case-sensitive. New methods may be |
defined in the future. Method names may not start with a $ character defined in the future. Method names may not start with a $ character |
(decimal 24) and must be a token. Methods are summarized in Table 2. (decimal 24) and must be a token as defined by the ABNF. Methods are |
summarized in Table 2. |
method direction object Server req. Client req.
----------------------------------------------------------------
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
OPTIONS C->S, S->C P,S R=Req, Sd=Opt Sd=Req, R=Opt
PAUSE C->S P,S recommended recommended
PING C->S, S->C P,S recommended optional
PLAY C->S P,S required required
RECORD C->S P,S optional optional
REDIRECT S->C P,S optional optional
SETUP C->S S required required
SET_PARAMETER C->S, S->C P,S optional optional
TEARDOWN C->S P,S required required
Table 2: Overview of RTSP methods, their direction, and what objects
(P: presentation, S: stream) they operate on. Legend: R=Responde to,
Sd=Send, Opt: Optional, Req: Required, Rec: Recommended
Notes on Table 2: PAUSE is recommended, but not required in that a Notes on Table 2: PAUSE is recommended, but not required in that a
fully functional server can be built that does not support this fully functional server can be built that does not support this
method, for example, for live feeds. If a server does not support a method, for example, for live feeds. If a server does not support a
particular method, it MUST return 501 (Not Implemented) and a client particular method, it MUST return 501 (Not Implemented) and a client
SHOULD not try this method again for this server. SHOULD not try this method again for this server.
10.1 OPTIONS 10.1 OPTIONS
method direction object requirement 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 |
DESCRIBE C->S P,S recommended try a nonstandard request. It does not influence the session state. |
ANNOUNCE C->S, S->C P,S optional The Public header MUST be included in responses to indicate which |
GET_PARAMETER C->S, S->C P,S optional methods that are supported by the server. To specify which methods |
OPTIONS C->S, S->C P,S required (S->C: optional) that are possible to use for the specified resource, the Allow MAY be |
PAUSE C->S P,S recommended used. By including in the OPTIONS request a Supported header, the |
PING C->S, S->C P,S optional requester can determine which options the other part supports. |
PLAY C->S P,S required
RECORD C->S P,S optional
REDIRECT S->C P,S optional
SETUP C->S S required
SET_PARAMETER C->S, S->C P,S optional
TEARDOWN C->S P,S required
Table 2: Overview of RTSP methods, their direction, and what objects
(P: presentation, S: stream) they operate on
The behavior is equivalent to that described in [H9.2]. An OPTIONS The request URI determines which scope the options request has. By |
request may be issued at any time, e.g., if the client is about to giving the URI of a certain media the capabilities regarding this |
try a nonstandard request. It does not influence server state. media will be responded. By using the "*" URI the request 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
Require: implicit-play Require: implicit-play
Proxy-Require: gzipped-messages Proxy-Require: gzipped-messages
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
Server: PhonyServer 1.0
Note that these are necessarily fictional features (one would hope Note that the option tags in Require and Proxy-Require are necessar-
that we would not purposefully overlook a truly useful feature just ily fictional features (one would hope that we would not purposefully
so that we could have a strong example in this section). overlook a truly useful feature just so that we could have a strong
example in this section).
10.2 DESCRIBE 10.2 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:
C->S: DESCRIBE rtsp://server.example.com/fizzle/foo RTSP/1.0 C->S: DESCRIBE rtsp://server.example.com/fizzle/foo RTSP/1.0
CSeq: 312 CSeq: 312
User-Agent: PhonyClient 1.2
Accept: application/sdp, application/rtsl, application/mheg Accept: application/sdp, application/rtsl, application/mheg
S->C: RTSP/1.0 200 OK S->C: RTSP/1.0 200 OK
CSeq: 312 CSeq: 312
Date: 23 Jan 1997 15:35:06 GMT Date: 23 Jan 1997 15:35:06 GMT
Server: PhonyServer 1.0
Content-Type: application/sdp Content-Type: application/sdp
Content-Length: 376 Content-Length: 376
v=0 v=0
o=mhandley 2890844526 2890842807 IN IP4 126.16.64.4 o=mhandley 2890844526 2890842807 IN IP4 126.16.64.4
s=SDP Seminar s=SDP Seminar
i=A Seminar on the session description protocol i=A Seminar on the session description protocol
u=http://www.cs.ucl.ac.uk/staff/M.Handley/sdp.03.ps u=http://www.cs.ucl.ac.uk/staff/M.Handley/sdp.03.ps
e=mjh@isi.edu (Mark Handley) e=mjh@isi.edu (Mark Handley)
c=IN IP4 224.2.17.12/127 c=IN IP4 224.2.17.12/127
t=2873397496 2873404696 t=2873397496 2873404696
a=recvonly a=recvonly
m=audio 3456 RTP/AVP 0 m=audio 3456 RTP/AVP 0
m=video 2232 RTP/AVP 31 m=video 2232 RTP/AVP 31
m=whiteboard 32416 UDP WB m=application 32416 UDP WB
a=orient:portrait a=orient:portrait
The DESCRIBE response MUST contain all media initialization informa- The DESCRIBE response MUST contain all media initialization informa-
tion for the resource(s) that it describes. If a media client obtains tion for the resource(s) that it describes. If a media client obtains
a presentation description from a source other than DESCRIBE and that a presentation description from a source other than DESCRIBE and that
description contains a complete set of media initialization parame- description contains a complete set of media initialization parame-
ters, the client SHOULD use those parameters and not then request a ters, the client SHOULD use those parameters and not then request a
description for the same media via RTSP. description for the same media via RTSP.
Additionally, servers SHOULD NOT use the DESCRIBE response as a means Additionally, servers SHOULD NOT use the DESCRIBE response as a means
skipping to change at page 1, line 1329 skipping to change at page 1, line 1460
u=http://www.cs.ucl.ac.uk/staff/M.Handley/sdp.03.ps u=http://www.cs.ucl.ac.uk/staff/M.Handley/sdp.03.ps
e=mjh@isi.edu (Mark Handley) e=mjh@isi.edu (Mark Handley)
c=IN IP4 224.2.17.12/127 c=IN IP4 224.2.17.12/127
t=2873397496 2873404696 t=2873397496 2873404696
a=recvonly a=recvonly
m=audio 3456 RTP/AVP 0 m=audio 3456 RTP/AVP 0
m=video 2232 RTP/AVP 31 m=video 2232 RTP/AVP 31
S->C: RTSP/1.0 200 OK S->C: RTSP/1.0 200 OK
CSeq: 312 CSeq: 312
Date: 23 Jan 1997 15:35:06 GMT
Server: PhonyServer 1.0
10.4 SETUP 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 playing to change transport parameters, which stream that is already set up or playing in the session to change
a server MAY allow. If it does not allow this, it MUST respond with transport parameters, which a server MAY allow. If it does not allow
error 455 (Method Not Valid In This State). For the benefit of any this, it MUST respond with error 455 (Method Not Valid In This
intervening firewalls, a client must indicate the transport parame- State).
ters even if it has no influence over these parameters, for example,
where the server advertises a fixed multicast address. 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 |
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 |
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 |
value, and a Range header with the corresponding normal play time. To |
indicate support for this optional support the options-tag: |
"setup.playing" is defined.
For the benefit of any intervening firewalls, a client must indicate
the transport parameters even if it has no influence over these
parameters, for example, where the server advertises a fixed multi-
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
the DESCRIBE response, which has been reserved for media ini- the DESCRIBE response, which has been reserved for media ini-
tialization. tialization.
The Transport header specifies the transport parameters acceptable to The Transport header specifies the transport parameters acceptable to
the client for data transmission; the response will contain the the client for data transmission; the response will contain the
transport parameters selected by the server. transport parameters selected by the server.
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;unicast;client_port=4588-4589 Transport: RTP/AVP;unicast;client_port=4588-4589
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
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 or return error 459 (Aggregate Operation Not Allowed) (see session (aggregated session) or return error 459 (Aggregate Operation
Section 11.4.10). Not Allowed) (see Section 11.4.11).
To control an aggregated session an aggregated control URI MUST be |
used. The aggregated control URI MUST be different from any of the |
media control URIs included in the aggregate. The aggregated URI |
SHOULD be specified by session description, as no general rule exist |
to derive it from the included media's. |
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 |
signs from the client in the specified timeout time. The default |
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 |
header. For further discussion see chapter 12.37. Signs of client |
liveness are: |
+ RTCP sender or receiver reports from the client in any of the RTP |
sessions part of the RTSP session. |
+ Any RTSP request which includes a Session header with the ses- |
sion's ID. |
10.5 PLAY 10.5 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.
The PLAY request positions the normal play time to the beginning of In an aggregated session the PLAY request MUST contain an aggregated |
the range specified and delivers stream data until the end of the control URL. A server SHALL responde with error 460 (Only Aggregate |
range is reached. PLAY requests may be pipelined (queued); a server Operation Allowed) if the client PLAY request URI is for one of the |
MUST queue PLAY requests to be executed in order. That is, a PLAY media. The media in an aggregate SHALL be played in sync. If a client |
request arriving while a previous PLAY request is still active is want individual control of the media it must use separate RTSP ses- |
delayed until the first has been completed. sions for each media. |
This allows precise editing. For example, regardless of how
closely spaced the two PLAY requests in the example below
arrive, the server will first play seconds 10 through 15,
then, immediately following, seconds 20 to 25, and finally
seconds 30 through the end.
C->S: PLAY rtsp://audio.example.com/audio RTSP/1.0 The PLAY request positions the normal play time to the beginning of |
CSeq: 835 the range specified by the Range header and delivers stream data |
Session: 12345678 until the end of the range is reached. To allow for precise composi- |
Range: npt=10-15 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 |
outside of the media, the response SHALL be the 457 (Invalid Range) |
error code. |
C->S: PLAY rtsp://audio.example.com/audio RTSP/1.0 The below example will first play seconds 10 through 15, then, imme- |
CSeq: 836 diately following, seconds 20 to 25, and finally seconds 30 through |
Session: 12345678 the end. |
Range: npt=20-25
C->S: PLAY rtsp://audio.example.com/audio RTSP/1.0 C->S: PLAY rtsp://audio.example.com/audio RTSP/1.0 |
CSeq: 837 CSeq: 835 |
Session: 12345678 Session: 12345678 |
Range: 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. of streams obtained from different sources. Note: The usage of time |
has two problems. First, at the time requested the RTSP state machine |
may not accept the request. The client will not get any notification |
of the failure. Secondly, the server has difficulties to produce the |
synchronization information for the RTP-Info header ahead of the |
actually play-out. Due to these reasons it is RECOMMENDED that a |
client not issues more than one timed request and no request without |
timing , until it is performed. The server SHALL in responses to |
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 |
timestamp value corresponding to the activation time of the request. |
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 |
should be correct unless another timestamp rate has been used in |
between the issuing of the request and activation. |
For a on-demand stream, the server replies with the actual range that For a on-demand stream, the server MUST reply with the actual range |
will be played back. This may differ from the requested range if that will be played back. This may differ from the requested range if |
alignment of the requested range to valid frame boundaries is alignment of the requested range to valid frame boundaries is |
required for the media source. If no range is specified in the required for the media source. If no range is specified in the |
request, the current position is returned in the reply. The unit of request, the start position SHALL still be returned in the reply. The |
the range in the reply is the same as that in the request. unit of the range in the reply is the same as that in the request. If |
the medias part of an aggregate has different lengths the PLAY |
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 automatically After playing the desired range, the presentation is NOT automati- |
paused, as if a PAUSE request had been issued. cally paused, media deliver simple 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. at 15:36 on 23 Jan 1997. Note: The RTP-Info headers has been broken
into several lines to fit the page.
C->S: PLAY rtsp://audio.example.com/twister.en RTSP/1.0 C->S: PLAY rtsp://audio.example.com/twister.en RTSP/1.0
CSeq: 833 CSeq: 833
Session: 12345678 Session: 12345678
Range: smpte=0:10:20-;time=19970123T153600Z Range: smpte=0:10:20-;time=19970123T153600Z
S->C: RTSP/1.0 200 OK S->C: RTSP/1.0 200 OK
CSeq: 833 CSeq: 833
Date: 23 Jan 1997 15:35:06 GMT Date: 23 Jan 1997 15:35:06 GMT
Server: PhonyServer 1.0
Range: smpte=0:10:22-;time=19970123T153600Z Range: smpte=0:10:22-;time=19970123T153600Z
RTP-Info:url=rtsp://audio.example.com/twister.en;seq=14783;rtptime=2345962545 RTP-Info:url=rtsp://example.com/twister.en;
seq=14783;rtptime=2345962545
For playing back a recording of a live presentation, it may be desir- For playing back a recording of a live presentation, it may be desir-
able to use clock units: able to use clock units:
C->S: PLAY rtsp://audio.example.com/meeting.en RTSP/1.0 C->S: PLAY rtsp://audio.example.com/meeting.en RTSP/1.0
CSeq: 835 CSeq: 835
Session: 12345678 Session: 12345678
Range: clock=19961108T142300Z-19961108T143520Z Range: clock=19961108T142300Z-19961108T143520Z
S->C: RTSP/1.0 200 OK S->C: RTSP/1.0 200 OK
CSeq: 835 CSeq: 835
Date: 23 Jan 1997 15:35:06 GMT Date: 23 Jan 1997 15:35:06 GMT
Server:PhonyServer 1.0
Range: clock=19961108T142300Z-19961108T143520Z Range: clock=19961108T142300Z-19961108T143520Z
RTP-Info:url=rtsp://audio.example.com/meeting.en;seq=53745;rtptime=484589019 RTP-Info:url=rtsp://example.com/meeting.en;
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. Range header. If the pause point is located later than the given end |
value, a 457 (Invalid Range) response SHALL be given. |
The queued play functionality described in RFC 2326 [21] is removed |
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 |
SHALL responde using the error code 455 (Method Not Valid In This |
State). This will signal the client that queued play are not sup- |
ported. |
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, |
PING, SET_PARAMETER or OPTIONS for keep alive. A server receiving a |
PLAY keep alive SHALL respond with the 455 error code. |
When playing live media, indicated by the Transport headers mode |
parameter the session are in a live state. This live state will put |
some restrictions on the action available for a client. A PLAY |
request without a Range header will start media deliver at the cur- |
rent point in the live presentation, i.e. now. Any seeking in the |
media will be impossible. The only allowed usage of the Range header |
is npt=now-, and certain clock units. The usage of npt=now- is unnec- |
essary as it has the exact same meaning as a request without Range |
header. The clock format can be used to specify start and stop times |
for media delivery in a live session. |
10.6 PAUSE 10.6 PAUSE
The PAUSE request causes the stream delivery to be interrupted The PAUSE request causes the stream delivery to be interrupted |
(halted) temporarily. If the request URL names a stream, only play- (halted) temporarily. A PAUSE request MUST be done with the aggre- |
back and recording of that stream is halted. For example, for audio, gated control URI for aggregated sessions, resulting in all media |
this is equivalent to muting. If the request URL names a presentation being halted, or the media URI for non-aggregated sessions. Any |
or group of streams, delivery of all currently active streams within attempt to do muting of a single media with an PAUSE request in an |
the presentation or group is halted. After resuming playback or aggregated session SHALL be responded with error 460 (Only Aggregate |
recording, synchronization of the tracks MUST be maintained. Any Operation Allowed). After resuming playback or recording, synchro- |
server resources are kept, though servers MAY close the session and nization of the tracks MUST be maintained. Any server resources are |
free resources after being paused for the duration specified with the kept, though servers MAY close the session and free resources after |
timeout parameter of the Session header in the SETUP message. being paused for the duration specified with the timeout parameter of |
the Session header in the SETUP message.
Example: Example:
C->S: PAUSE rtsp://example.com/fizzle/foo RTSP/1.0 C->S: PAUSE rtsp://example.com/fizzle/foo RTSP/1.0
CSeq: 834 CSeq: 834
Session: 12345678 Session: 12345678
S->C: RTSP/1.0 200 OK S->C: RTSP/1.0 200 OK
CSeq: 834 CSeq: 834
Date: 23 Jan 1997 15:35:06 GMT Date: 23 Jan 1997 15:35:06 GMT
Range: npt=45.76
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: | mal play time, under the assumption that the PAUSE request reaches |
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: |
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 | 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 |
Server: PhonyServer 1.0 |
Range: npt=10-30 | Range: npt=10-30 |
RTP-Info:url=rtsp://example.com/fizzle/foo/audiotrack;seq=5712;rtptime=934207921,| RTP-Info:url=rtsp://example.com/fizzle/audiotrack; |
url=rtsp://example.com/fizzle/foo/videotrack;seq=57654;rtptime=2792482193| 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 | C->S: PAUSE rtsp://example.com/fizzle/foo RTSP/1.0 |
CSeq: 835 | CSeq: 835 |
Session: 12345678 | Session: 12345678 |
Range: npt=21- | Range: npt=21- |
S->C: RTSP/1.0 200 OK | S->C: RTSP/1.0 200 OK |
CSeq: 835 | CSeq: 835 |
Date: 23 Jan 1997 15:35:09 GMT | Date: 23 Jan 1997 15:35:09 GMT |
Server: PhonyServer 1.0 |
Range: npt=21- | Range: npt=21- |
Session: 12345678 |
The normal play time for the stream is set to the pause point. The The pause request becomes effective the first time the server is |
pause request becomes effective the first time the server is encoun- encountering the time point specified in any of the multiple ranges. |
tering the time point specified in any of the currently pending PLAY If the Range header specifies a time outside any range from the PLAY |
requests. If the Range header specifies a time outside any currently request, the error 457 (Invalid Range) SHALL be returned. If a media |
pending PLAY requests, the error 457 (Invalid Range) is returned. If unit (such as an audio or video frame) starts presentation at exactly |
a media unit (such as an audio or video frame) starts presentation at the pause point, it is not played or recorded. If the Range header is |
exactly the pause point, it is not played or recorded. If the Range missing, stream delivery is interrupted immediately on receipt of the |
header is missing, stream delivery is interrupted immediately on message and the pause point is set to the current normal play time. |
receipt of the message and the pause point is set to the current nor- However, the pause point in the media stream MUST be maintained. A |
mal play time. subsequent PLAY request without Range header resumes from the pause |
point and play until media end. |
A PAUSE request discards all queued PLAY requests. However, the pause The actual pause point after any PAUSE request SHALL be returned to |
point in the media stream MUST be maintained. A subsequent PLAY the client by adding a Range header with what remains unplayed of the |
request without Range header resumes from the pause point. PLAY request's ranges, i.e. including all the remaining ranges part |
of multiple range specification. If one desires to resume playing a |
ranged request, one simple included the Range header from the PAUSE |
response. |
For example, if the server has play requests for ranges 10 to 15 and For example, if the server have a play request for ranges 10 to 15 |
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 stops after completing the first request is for NPT 16, the server returns a 457 error message. To |
play request and discards the second play request. prevent that the second range is played and the server stops after |
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 PLAY request effectively being ignored, assum- range, with the second range effectively being ignored, assuming the |
ing the PAUSE request arrives before the server has started playing PAUSE request arrives before the server has started playing the sec- |
the second, overlapping range. Regardless of when the PAUSE request ond, overlapping range. Regardless of when the PAUSE request arrives, |
arrives, it sets the NPT 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 |
Range header, a PLAY would still resume at that point in time, as it the PAUSE request Range header, a PLAY without range would still |
is assumed that the client has discarded data after that point. This resume at that point in time, specified by the pause's range header, |
ensures continuous pause/play cycling without gaps. as it is assumed that the client has discarded data after that point. |
This ensures continuous pause/play cycling without gaps.
10.7 TEARDOWN 10.7 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 presenta- freeing the resources associated with it. If the URI is the aggre- |
tion URI for this presentation, any RTSP session identifier associ- gated control URI for this presentation, any RTSP session identifier |
ated with the session is no longer valid. Unless all transport param- associated with the session is no longer valid. The use of "*" as URI |
eters are defined by the session description, a SETUP request has to in TEARDOWN will also result in that the session is removed indepen- |
be issued before the session can be played again. 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 |
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 |
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 |
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 |
valid session MUST in the response return a session header. |
A server that after processing the TEARDOWN still has a valid session A server MAY choose to allow TEARDOWN of individual media while in |
MUST in the response return a session header. PLAY state. When this is not allowed the response SHALL be 455 |
(Method Not Valid In This State). If a server implements TEARDOWN and |
SETUP in PLAY state it MUST signal this using the "setup.playing" |
option 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
10.8 GET_PARAMETER 10.8 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. The content of the reply presentation or stream specified in the URI. If the Session header is |
and response is left to the implementation. GET_PARAMETER with no present in a request, the value of a parameter MUST be retrieved in |
entity body may be used to test client or server liveness ("ping"). the sessions context. The content of the reply and response is left |
to the implementation. GET_PARAMETER with no entity body may be used |
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 1606 skipping to change at page 1, line 1850
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 10.9 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 SHOULD only contain a single parameter to allow the client A request is RECOMMENDED to only contain a single parameter to allow |
to determine why a particular request failed. If the request contains the client to determine why a particular request failed. If the |
several parameters, the server MUST only act on the request if all of request contains several parameters, the server MUST only act on the |
the parameters can be set successfully. A server MUST allow a parame- request if all of the parameters can be set successfully. A server |
ter to be set repeatedly to the same value, but it MAY disallow MUST allow a parameter to be set repeatedly to the same value, but it |
changing parameter values. MAY disallow changing parameter values. If the receiver of the |
request does not understand or can locate a parameter error 451 |
(Parameter Not Understood) SHALL be used. In the case a parameter is |
not allowed to change the error code 458 (Parameter Is Read-Only). |
The response body SHOULD contain only the parameters that has errors. |
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
may make sense to allow the setting of several parameters if may make sense to allow the setting of several parameters if
skipping to change at page 1, line 1649 skipping to change at page 1, line 1898
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 10.10 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. It contains the mandatory header Location, which server location. REDIRECT SHALL only be sent to the client who cur- |
indicates that the client should issue requests for that URL. It may rently has a session at the server. The REDIRECT request MAY contain |
contain the parameter Range, which indicates when the redirection the header Location, which indicates that the client should issue |
takes effect. If the client wants to continue to send or receive requests for that URL. If the Location URL only contains a host |
media for this URI, the client MUST issue a TEARDOWN request for the address the client shall connect to the given host, while using the |
current session and a SETUP for the new session at the designated path from the URL on the current server. |
host.
This example request redirects traffic for this URI to the new server The redirect request MAY contain the header Range, which indicates |
at the given play time: when the redirection takes effect. If the Range contains a time= |
value that is the wall clock time that the redirection MUST at the |
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-. |
S->C: REDIRECT rtsp://example.com/fizzle/foo RTSP/1.0 If a Session header is included in the REDIRECT request the client |
CSeq: 732 MUST redirect the indicated session. If no Session header is included |
Location: rtsp://bigserver.com:8001 the client MUST redirect all sessions that it have on the server |
Range: clock=19960213T143205Z- sending the request. |
If the client wants to continue to send or receive media for this |
resource, the client MUST issue a TEARDOWN request for the current |
session. A new session must be established with the designated host. |
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 cases the Location only contains a host address the client MAY |
assume that the media on the server it is redirected to is identical. |
Identical media means that all media configuration information from |
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 |
can be either identical, slightly different or totally different. |
This is the reason why a new DESCRIBE request SHOULD be issued. |
This example request redirects traffic for this session to the new |
server at the given absolute time: |
S->C: REDIRECT rtsp://example.com/fizzle/foo RTSP/1.0 |
CSeq: 732 |
Location: rtsp://bigserver.com:8001 |
Range: clock=19960213T143205Z- |
Session: uZ3ci0K+Ld-M |
10.11 RECORD 10.11 RECORD
This method initiates recording a range of media data according to This method initiates recording a range of media data according to
the presentation description. The timestamp reflects start and end the presentation description. The timestamp reflects start and end
time (UTC). If no time range is given, use the start or end time pro- time (UTC). If no time range is given, use the start or end time pro-
vided in the presentation description. If the session has already vided in the presentation description. If the session has already
started, commence recording immediately. started, commence recording immediately.
The server decides whether to store the recorded data under the The server decides whether to store the recorded data under the
skipping to change at page 1, line 1691 skipping to change at page 1, line 1969
port the clock range format; the smpte format does not make sense. port the clock range format; the smpte format does not make sense.
In this example, the media server was previously invited to the con- In this example, the media server was previously invited to the con-
ference indicated. ference indicated.
C->S: RECORD rtsp://example.com/meeting/audio.en RTSP/1.0 C->S: RECORD rtsp://example.com/meeting/audio.en RTSP/1.0
CSeq: 954 CSeq: 954
Session: 12345678 Session: 12345678
Conference: 128.16.64.19/32492374 Conference: 128.16.64.19/32492374
Note: this example needs work, or needs to be removed. Note: this example needs work, or needs to be removed. More
thoughts on how it works together with ANNOUNCE is needed.
Also notification on out of disk is needed. The use of aggre-
gated and non-aggregated control needs to be clarified.
10.12 PING | 10.12 PING
This method is a bi-directional mechanism for server or client live- | This method is a bi-directional mechanism for server or client live- |
ness checking. It has no side effects. | 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 |
Prior to using this method, an OPTIONS method MUST be issued in the | being checked for liveness. |
direction which the PING method would be used. This method MUST NOT | Prior to using this method, an OPTIONS method is RECOMMENDED to be |
be used if support is not indicated by the Public header. | 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 | When a proxy is in use, PING with a * indicates a single-hop liveness |
check, whereas PING with a URL indicates an end-to-end liveness | check, whereas PING with a URL including an host address indicates an |
check. | end-to-end liveness check. |
Example: | Example: |
C->S: PING * RTSP/1.0 | C->S: PING * RTSP/1.0 |
CSeq: 123 | CSeq: 123 |
Session:12345678 |
S->C: RTSP/1.0 200 OK | S->C: RTSP/1.0 200 OK |
CSeq: 123 | CSeq: 123 |
Session:12345678 |
10.13 Embedded (Interleaved) Binary Data 10.13 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 methods and stream data. This interleaving should |
generally be avoided unless necessary since it complicates client and generally be avoided unless necessary since it complicates client and |
server operation and imposes additional overhead. Interleaved binary server operation and imposes additional overhead. Also head of line |
data SHOULD only be used if RTSP is carried over TCP. blocking may cause problems. Interleaved binary data 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 pro-
tocol headers. Each $ block contains exactly one upper-layer protocol tocol headers. Each $ block contains exactly one upper-layer protocol
data unit, e.g., one RTP packet. data unit, e.g., one RTP packet.
The channel identifier is defined in the Transport header with the The channel identifier is defined in the Transport header with the
skipping to change at page 1, line 1748 skipping to change at page 1, line 2035
the Transport header(Section 12.40). the Transport header(Section 12.40).
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;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;interleaved=0-1 Transport: RTP/AVP/TCP;unicast;interleaved=0-1
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
skipping to change at page 1, line 1775 skipping to change at page 1, line 2062
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 11 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. listing of which status codes may be returned by which requests. All
error messages, 4xx and 5xx MAY return a body containing further
information about the error.
11.1 Success 2xx 11.1 Success 1xx
11.1.1 250 Low on Storage Space 11.1.1 100 Continue
See, [H10.1.1].
11.2 Success 2xx
11.2.1 250 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.
11.2 Redirection 3xx 11.3 Redirection 3xx
See [H10.3]. See [H10.3] for definition of status code 300 to 305. However com- |
ments are given for some to how they apply to RTSP. Further a couple |
of new status codes are defined. |
Within RTSP, redirection may be used for load balancing or redirect- Within RTSP, redirection may be used for load balancing or redirect- |
ing stream requests to a server topologically closer to the client. ing stream requests to a server topologically closer to the client. |
Mechanisms to determine topological proximity are beyond the scope of Mechanisms to determine topological proximity are beyond the scope of |
this specification. this specification. |
11.3 Client Error 4xx 11.3.1 300 Multiple Choices |
11.4 400 Bad Request 11.3.2 301 Moved Permanently |
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. |
11.3.3 302 Found |
The requested resource reside temporarily at the URI given by the |
Location header. The Location header MUST be included. |
11.3.4 303 See Other |
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. |
11.3.5 304 Not Modified |
11.3.6 305 Use Proxy |
See [H10.3.6]. |
11.3.7 350 Going Away |
The server the request was directed at will not be available any |
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- |
ing the 350 response code, it SHALL immediately do TEARDOWN on that |
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 |
The server the request was issued for is currently uneven loaded and |
request that further request is directed to another server. The |
Location header MUST be included in the response and contain the URI |
of the other server. If the both server has the requested resource in |
the same place only the Server part of the URI MAY be given. In all |
other cases an absolute URI MUST be given.
11.4 Client Error 4xx
11.4.1 400 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.
11.4.1 405 Method Not Allowed 11.4.2 405 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.
11.4.2 451 Parameter Not Understood 11.4.3 451 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. contained in the request.When returning this error message the sender |
SHOULD return a entity body containing the offending parameter(s).
11.4.3 452 reserved 11.4.4 452 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.
11.4.4 453 Not Enough Bandwidth 11.4.5 453 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.
11.4.5 454 Session Not Found 11.4.6 454 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.
11.4.6 455 Method Not Valid in This State 11.4.7 455 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.
11.4.7 456 Header Field Not Valid for Resource 11.4.8 456 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. 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 |
Accept-Ranges header SHOULD be returned to inform the client of which |
format(s) that are allowed.
11.4.8 457 Invalid Range 11.4.9 457 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.
11.4.9 458 Parameter Is Read-Only 11.4.10 458 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. fied. When returning this error message the sender SHOULD return a |
entity body containing the offending parameter(s).
11.4.10 459 Aggregate Operation Not Allowed 11.4.11 459 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
stream URL. media URL.
11.4.11 460 Only Aggregate Operation Allowed 11.4.12 460 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 (presentation) URL. The method may be applied it is not an aggregate control (presentation) URL. The method may be |
on the presentation URL. applied on the aggregate control URL.
11.4.12 461 Unsupported Transport 11.4.13 461 Unsupported Transport
The Transport field did not contain a supported transport specifica- The Transport field did not contain a supported transport specifica-
tion. tion.
11.4.13 462 Destination Unreachable 11.4.14 462 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 11.5 Server Error 5xx
11.5.1 551 Option not supported 11.5.1 551 Option not supported
An option given in the Require or the Proxy-Require fields was not An option given in the Require or the Proxy-Require fields was not
supported. The Unsupported header should be returned stating the supported. The Unsupported header SHOULD be returned stating the
option for which there is no support. option for which there is no support.
12 Header Field Definitions 12 Header Field Definitions
The general syntax for header fields is covered in Section 4.2 This | The general syntax for header fields is covered in Section 4.2 This |
section lists the full set of header fields along with notes on | section lists the full set of header fields along with notes on syn-
method direction object requirement acronym Body 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
DESCRIBE C->S P,S recommended DES r [26]. Examples of each header field are given.
ANNOUNCE C->S, S->C P,S optional ANN R
GET_PARAMETER C->S, S->C P,S optional GPR R,r
OPTIONS C->S P,S required OPT
S->C optional
PAUSE C->S P,S recommended PSE
PING C->S, S->C P,S optional PNG
PLAY C->S P,S required PLY
RECORD C->S P,S optional REC
REDIRECT S->C P,S optional RDR
SETUP C->S S required STP
SET_PARAMETER C->S, S->C P,S optional SPR R,r?
TEARDOWN C->S P,S required TRD
Table 3: Overview of RTSP methods, their direction, and what objects
(P: presentation, S: stream) they operate on. Body notes if a method
is allowed to carry body and in which direction, R = Request,
r=response. Note: There has been some usage of the body to convey
more information in error messages for responses containing error
codes. Some error messages seem to mandate such usage.
syntax, meaning, and usage. Throughout this section, we use [HX.Y] | Information about header fields in relation to methods and proxy pro-
to refer to Section X.Y of the current HTTP/1.1 specification RFC | cessing is summarized in Table 4 and Table 5.
2616 [26]. Examples of each header field are given. |
Information about header fields in relation to methods and proxy pro- | The "where" column describes the request and response types in which
cessing is summarized in Table 4. | the header field can be used. Values in this column are:
The "where" column describes the request and response types in which | R: header field may only appear in requests;
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;
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;
method direction object acronym Body
-----------------------------------------------
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
OPTIONS C->S P,S OPT
S->C
PAUSE C->S P,S PSE
PING C->S, S->C P,S PNG
PLAY C->S P,S PLY
RECORD C->S P,S REC
REDIRECT S->C P,S RDR
SETUP C->S S STP
SET_PARAMETER C->S, S->C P,S SPR R,r
TEARDOWN C->S P,S TRD
2xx, 4xx, etc.: A numerical value or range indicates response codes | Table 3: Overview of RTSP methods, their direction, and what objects
with which the header field can be used; | (P: presentation, S: stream) they operate on. Body notes if a method
c: header field is copied from the request to the response. | 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
have a body
An empty entry in the "where" column indicates that the header field | c: header field is copied from the request to the response.
may be present in all requests and responses. |
The "proxy" column describes the operations a proxy may perform on a | An empty entry in the "where" column indicates that the header field
header field: | may be present in all requests and responses.
a: A proxy can add or concatenate the header field if not present. | The "proxy" column describes the operations a proxy may perform on a
header field:
m: A proxy can modify an existing header field value. | a: A proxy can add or concatenate the header field if not present.
d: A proxy can delete a header field value. | m: A proxy can modify an existing header field value.
r: A proxy must be able to read the header field, and thus this | d: A proxy can delete a header field value.
header field cannot be encrypted. |
The rest of the columns relate to the presence of a header field in a | r: A proxy must be able to read the header field, and thus this
method. The method names are abbreviated according to table 3: | header field cannot be encrypted.
c: Conditional; requirements on the header field depend on the con- | The rest of the columns relate to the presence of a header field in a
text of the message. | method. The method names when abbreviated, are according to table 3:
m: The header field is mandatory. | c: Conditional; requirements on the header field depend on the con-
text of the message.
m*: The header field SHOULD be sent, but clients/servers need to be | m: The header field is mandatory.
prepared to receive messages without that header field. |
o: The header field is optional. | m*: The header field SHOULD be sent, but clients/servers need to be
prepared to receive messages without that header field.
t: The header field SHOULD be sent, but clients/servers need to be | o: The header field is optional.
prepared to receive messages without that header field. If a |
stream-based protocol (such as TCP) is used as a transport, |
then the header field MUST be sent. |
*: 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 12.14, 12.16 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 12.32). 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 | understood by the Client/Server processing the response. "Not appli-
applicable" means that the header field MUST NOT be present in a | cable" means that the header field MUST NOT be present in a request.
request. If one is placed in a request by mistake, it MUST be ignored | If one is placed in a request by mistake, it MUST be ignored by the
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 12.1 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.
Header Where Proxy DES OPT SETUP PLAY PAUSE TRD
--------------------------------------------------------------
Accept R o - - - - -
Accept-Encoding R r o - - - - -
Accept-Language R r o - - - - -
Accept-Ranges r r - - o - - -
Accept-Ranges 456 r - - - o o -
Allow r - o - - - -
Allow 405 - - - m m -
Authorization R o o o o o o
Bandwidth R o o o o - -
Blocksize R o - o o - -
Cache-Control r - - o - - -
Connection o o o o o o
Content-Base r o - - - - -
Content-Base 4xx o o o o o o
Content-Encoding R r - - - - - -
Content-Encoding r r o - - - - -
Content-Encoding 4xx r o o o o o o
Content-Language R r - - - - - -
Content-Language r r o - - - - -
Content-Language 4xx r o o o o o o
Content-Length r r * - - - - -
Content-Length 4xx r * * * * * *
Content-Location r o - - - - -
Content-Location 4xx o o o o o o
Content-Type r * - - - - -
Content-Type 4xx * * * * * *
CSeq Rc m m m m m m
Date am o o o o o o
Expires r r o - - - - -
From R r o o o o o o
Host o o o o o o
If-Match R r - - o - - -
If-Modified-Since R r o - o - - -
Last-Modified r r o - - - - -
Location 3xx o - o - - -
Proxy-Authenticate 407 amr m m m m m m
Proxy-Require R ar o o o o o o
Public r admr - m* - - - -
Public 501 admr m* m* m* m* m* m*
Range R - - - o o -
Range r - - c m* - -
Referer R o o o o o o
Require R o o o o o o
Retry-After 3xx,503 o o o - - -
RTP-Info r - - o m - -
Scale - - - o - -
Session R - o o m m m
Session r - c m m m o
Server R - o - - - -
Server r o o o o o o
Speed - - - o - -
Supported R o o o o o o
Supported r c c c c c c
Timestamp R o o o o o o
Timestamp c m m m m m m
Transport - - m - - -
Unsupported r c c c c c c
User-Agent R m* m* m* m* m* m*
Vary r c c c c c c
Via R amr o o o o o o
Via c dr m m m m m m
WWW-Authenticate 401 m m m m m m
--------------------------------------------------------------
Header Where Proxy DES OPT SETUP PLAY PAUSE TRD
Table 4: Overview of RTSP header fields related to methods DESCRIBE,
OPTIONS, SETUP, PLAY, PAUSE, and TEARDOWN.
See [H14.1] for syntax. See [H14.1] for syntax.
Example of use: Example of use:
Accept: application/rtsl, application/sdp;level=2 Accept: application/rtsl q=1.0, application/sdp;level=2
12.2 Accept-Encoding 12.2 Accept-Encoding
See [H14.3] See [H14.3]
12.3 Accept-Language 12.3 Accept-Language
See [H14.4]. Note that the language specified applies to the presen- See [H14.4]. Note that the language specified applies to the presen-
tation description and any reason phrases, not the media content. tation description and any reason phrases, not the media content.
12.4 Accept-Ranges | 12.4 Accept-Ranges |
Header Where Proxy DES OPT GPR SPR ANN STP PLY REC PSE TRD RDR PNG Header Where Proxy GPR SPR ANN REC RDR PNG
--------------------------------------------------------------------------------- ---------------------------------------------------------
Accept R o - - - - - - - - - - - Allow 405 - - m m - -
Accept-Encoding R r o - - - - - - - - - - - Authorization R o o o o o o
Accept-Language R r o - - - - - - - - - - - Bandwidth R - o - - - -
Accept-Ranges r - - - - - - o - - - - - Blocksize R - o - - - -
Allow 405 - - - - m - m m m - - - Connection o o o o o -
Authorization R o o o o o o o o o o o o Content-Base R o o o - - -
Bandwidth R o - - o - o o - - - - - Content-Base r o o - - - -
Blocksize R o - - o - o o - - - - - Content-Base 4xx o o o o o -
Cache-Control r - - - - - o - - - - - - Content-Encoding R r o o o - - -
Connection o o o o o o o o o o o - Content-Encoding r r o o - - - -
Content-Base R - - o o o - - - - - - - Content-Encoding 4xx r o o o o o -
Content-Base r o - o o - - - - - - - - Content-Language R r o o o - - -
Content-Base 4xx o o o o o o o o o o o - Content-Language r r o o - - - -
Content-Encoding R r - - o o o - - - - - - - Content-Language 4xx r o o o o o -
Content-Encoding r r o - o o - - - - - - - - Content-Length R r * * * - - -
Content-Encoding 4xx r o o o o o o o o o o o - Content-Length r r * * - - - -
Content-Language R r - - o o o - - - - - - - Content-Length 4xx r * * * * * -
Content-Language r r o - o o - - - - - - - - Content-Location R o o o - - -
Content-Language 4xx r o o o o o o o o o o o - Content-Location r o o - - - -
Content-Length R r - - * * * - - - - - - - Content-Location 4xx o o o o o -
Content-Length r r * - * * - - - - - - - - Content-Type R * * * - - -
Content-Length 4xx r * * * * * * * * * * * - Content-Type r * * - - - -
Content-Location R - - o o o - - - - - - - Content-Type 4xx * * * * * -
Content-Location r o - o o - - - - - - - - CSeq Rc m m m m m m
Content-Location 4xx o o o o o o o o o o o - Date am o o o o o o
Content-Type R - - * * * - - - - - - - From R r o o o o o o
Content-Type r * - * * - - - - - - - - Host o o o o o o
Content-Type 4xx * * * * * * * * * * * - Last-Modified R r - - o - - -
CSeq Rc m m m m m m m m m m m m Last-Modified r r o - - - - -
Date am o o o o o o o o o o o o Location R - - - - m -
Expires r r o - - - - - - - - - - - Proxy-Authenticate 407 amr m m m m m m
From R r o o o o o o o o o o o o Proxy-Require R ar o o o o o o
Host o o o o o o o o o o o o Public 501 admr m* m* m* m* m* m*
If-Match R r - - - - - o - - - - - - Range R - - - - o -
If-Modified-Since R r o - - - - o - - - - - - Referer R o o o o o -
Last-Modified R r - - - - o - - - - - - - Require R o o o o o o
Last-Modified r r o - o - - - - - - - - - Retry-After 3xx,503 o o - - - -
Location R - - - - - - - - - - m - Scale - - - o - -
Location 3xx m - - - - m - - - - - - Session R o o m m o m
Proxy-Authenticate 407 amr m m m m m m m m m m m m Session r c c m m o m
Proxy-Require R ar o o o o o o o o o o o o Server R o o o - o o
Public r admr - m* - - - - - - - - - - Server r o o o o - o
Public 501 admr m* m* m* m* m* m* m* m* m* m* m* m* Supported R o o o o o o
Range R - - - - - - o - o - o - Supported r c c c c c c
Range r - - - - - - m* - - - - - Timestamp R o o o o o o
Referer R o o o o o o o o o o o - Timestamp c m m m m m m
Require R o o o o o o o o o o o o Unsupported r c c c c c c
Retry-After 3xx,503 o o o o - o - - - - - - User-Agent R m* m* m* m* - m*
RTP-Info r - - - - - - m - - - - - User-Agent r - - - - m* -
Scale - - - - - - o o - - - - Vary r c c c c - -
Session R - o o o m o m m m m m m Via R amr o o o o o o
Session r - c c c m m m m m o m m Via c dr m m m m m m
Server R - o o o o - - - - - o o WWW-Authenticate 401 m m m m m m
Server r o o o o o o o o o o - o ---------------------------------------------------------
Speed - - - - - - o - - - - - Header Where Proxy GPR SPR ANN REC RDR PNG
Supported R o o o o o o o o o o o o
Supported r c c c c c c c c c c c c
Timestamp R o o o o o o o o o o o o
Timestamp c m m m m m m m m m m m m
Transport - - - - - m - - - - - -
Unsupported r c c c c c c c c c c c c
User-Agent R m* m* m* m* m* m* m* m* m* m* - -
User-Agent r - - - - - - - - - - m* -
Vary r c c c c c c c c c c - -
Via R amr o o o o o o o o o o o o
Via c dr m m m m m m m m m m m m
WWW-Authenticate 401 m m m m m m m m m m m m
---------------------------------------------------------------------------------
Header Where Proxy DES OPT GPR SPR ANN STP PLY REC PSE TRD RDR PNG
Table 4: Overview of RTSP header fields Table 5: Overview of RTSP header fields related to methods GET_PARAM-
ETER, SET_PARAMETER, ANNOUNCE, RECORD, 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 |
indicate to the client which range time formats the media supports. |
The header SHOULD also be included in "456" responses which is a |
result of use of unsupported range formats. |
12.5 Allow 12.5 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. Allowed) response. See [H14.7] for syntax definition.
Example of use: Example of use:
Allow: SETUP, PLAY, RECORD, SET_PARAMETER Allow: SETUP, PLAY, RECORD, SET_PARAMETER
12.6 Authorization 12.6 Authorization
See [H14.8] See [H14.8]
12.7 Bandwidth 12.7 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
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12.8 Blocksize 12.8 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 (416) 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 12.9 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 2158 skipping to change at page 1, line 2581
tive for a specific cache. tive for a specific cache.
Cache-Control should only be specified in a SETUP request and its Cache-Control should only be specified in a SETUP request and its
response. Note: Cache-Control does not govern the caching of response. Note: Cache-Control does not govern the caching of
responses as for HTTP, but rather of the stream identified by the responses as for HTTP, but rather of the stream identified by the
SETUP request. Responses to RTSP requests are not cacheable, except SETUP request. Responses to RTSP requests are not cacheable, except
for responses to DESCRIBE. for responses to DESCRIBE.
Cache-Control = "Cache-Control" ":" 1#cache-directive Cache-Control = "Cache-Control" ":" 1#cache-directive
cache-directive = cache-request-directive cache-directive = cache-request-directive
| cache-response-directive / cache-response-directive
cache-request-directive = "no-cache" cache-request-directive = "no-cache"
| "max-stale" / "max-stale" ["=" delta-seconds]
| "min-fresh" / "min-fresh" "=" delta-seconds
| "only-if-cached" / "only-if-cached"
| cache-extension / cache-extension
cache-response-directive = "public" cache-response-directive = "public"
| "private" / "private"
| "no-cache" / "no-cache"
| "no-transform" / "no-transform"
| "must-revalidate" / "must-revalidate"
| "proxy-revalidate" / "proxy-revalidate"
| "max-age" "=" delta-seconds / "max-age" "=" delta-seconds
| cache-extension / cache-extension
cache-extension = token [ "=" ( token | quoted-string ) ] cache-extension = token [ "=" ( token / quoted-string ) ]
delta-seconds = 1*DIGIT
no-cache: Indicates that the media stream MUST NOT be cached any- no-cache: Indicates that the media stream MUST NOT be cached any-
where. This allows an origin server to prevent caching even by where. This allows an origin server to prevent caching even by
caches that have been configured to return stale responses to caches that have been configured to return stale responses to
client requests. client requests.
public: Indicates that the media stream is cacheable by any cache. public: Indicates that the media stream is cacheable by any cache.
private: Indicates that the media stream is intended for a single private: Indicates that the media stream is intended for a single
user and MUST NOT be cached by a shared cache. A private (non- user and MUST NOT be cached by a shared cache. A private (non-
skipping to change at page 1, line 2235 skipping to change at page 1, line 2659
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- |
ing as the must-revalidate directive, except that it does not |
apply to non-shared user agent caches. It can be used on a |
response to an authenticated request to permit the user's |
cache to store and later return the response without needing |
to revalidate it (since it has already been authenticated once |
by that user), while still requiring proxies that service many |
users to revalidate each time (in order to make sure that each |
user has been authenticated). Note that such authenticated |
responses also need the public cache control directive in |
order to allow them to be cached at all. |
max-age: When an intermediate cache is forced, by means of a max- |
age=0 directive, to revalidate its own cache entry, and the |
client has supplied its own validator in the request, the sup- |
plied validator might differ from the validator currently |
stored with the cache entry. In this case, the cache MAY use |
either validator in making its own request without affecting |
semantic transparency. |
However, the choice of validator might affect performance. The |
best approach is for the intermediate cache to use its own |
validator when making its request. If the server replies with |
304 (Not Modified), then the cache can return its now vali- |
dated copy to the client with a 200 (OK) response. If the |
server replies with a new entity and cache validator, however, |
the intermediate cache can compare the returned validator with |
the one provided in the client's request, using the strong |
comparison function. If the client's validator is equal to the |
origin server's, then the intermediate cache simply returns |
304 (Not Modified). Otherwise, it returns the new entity with |
a 200 (OK) response.
12.10 Connection 12.10 Connection
See [H14.10] 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 |
to recover and therefore see it necessary to close the connection. |
The reason is that the client shall have the choice of continue using |
a connection indefinitely as long as it sends valid messages.
12.11 Content-Base 12.11 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. This header field URI for resolving relative URLs within the entity.
is described as Base in RFC 1808, which is expected to be revised.
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 12.12 Content-Encoding
skipping to change at page 1, line 2282 skipping to change at page 1, line 2742
See [H14.14] See [H14.14]
12.16 Content-Type 12.16 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 12.17 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). retransmissions of the same request). For each new RTSP request the |
CSeq value SHALL be incremented by one. The initial sequence number |
MAY be any number. Each sequence number series is unique between each |
requester and responder, i.e. the client has one series for its |
request to a server and the server has another when sending request |
to the client. Each requester and responder is identified with its |
network address.
CSeq = "Cseq" ":" 1*DIGIT CSeq = "Cseq" ":" 1*DIGIT
12.18 Date 12.18 Date
See [H14.18]. 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 in all other RTSP messages.
12.19 Expires 12.19 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.
skipping to change at page 1, line 2323 skipping to change at page 1, line 2791
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 12.9).
12.20 From 12.20 From
See [H14.22]. See [H14.22].
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12.25 Location 12.25 Location
See [H14.30]. See [H14.30].
12.26 Proxy-Authenticate 12.26 Proxy-Authenticate
See [H14.33]. See [H14.33].
12.27 Proxy-Require 12.27 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 if not supported. negatively acknowledged by the proxy to the client using the Unsup- |
Servers should treat this field identically to the Require field. ported header. Servers should treat this field identically to the |
Require field, i.e. the Proxy-Require requirements does also apply to |
the server. |
See Section 12.32 for more details on the mechanics of this message See Section 12.32 for more details on the mechanics of this message |
and a usage example. and a usage example. |
Proxy-Require = "Proxy-Require" ":" 1#option-tag ||
Example of use: |
Proxy-Require: con.non-persistent, record.basic |
12.28 Public 12.28 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, MGET, MHEAD, GET, HEAD 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 12.29 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
skipping to change at page 1, line 2455 skipping to change at page 1, line 2928
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.
Range = "Range" ":" 1#ranges-specifier [ ";" "time" "=" utc-time ] Range = "Range" ":" 1#ranges-specifier [ ";" "time" "=" utc-time ]
ranges-specifier = npt-range | utc-range | smpte-range ranges-specifier = npt-range / utc-range / smpte-range
Example: Example:
Range: clock=19960213T143205Z-;time=19970123T143720Z Range: clock=19960213T143205Z-;time=19970123T143720Z
The notation is similar to that used for the HTTP/1.1 [26] The notation is similar to that used for the HTTP/1.1 [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,
skipping to change at page 1, line 2480 skipping to change at page 1, line 2953
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 12.31 Retry-After
See [H14.37]. See [H14.37].
12.32 Require 12.32 Require
The Require request-header field is used by clients to query the The Require request-header field is used by clients to query the |
server about options that it may or may not support. The server MUST server about options that it may or may not support. The server MUST |
respond to this header by using the Unsupported header to negatively respond to this header by using the Unsupported header to negatively |
acknowledge those options which are NOT supported. acknowledge those options which are NOT supported. The response SHALL |
use the error code 551 (Option Not Supported)
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 options are understood by both
sides, and only slow down if options are not understood (as in sides, and only slow down if options are not understood (as in
the case above). For a well-matched client-server pair, the the case above). For a well-matched client-server pair, the
interaction proceeds quickly, saving a round-trip often 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.
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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 12.27).
12.33 RTP-Info 12.33 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. 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.
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.
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.
skipping to change at page 1, line 2565 skipping to change at page 1, line 3041
In order to compensate for drift for long, uninterrupted pre- In order to compensate for drift for long, uninterrupted pre-
sentations, RTSP clients should additionally map NPT to NTP, sentations, RTSP clients should additionally map NPT to NTP,
using initial RTCP sender reports to do the mapping, and later using initial RTCP sender reports to do the mapping, and later
reports to check drift against the mapping. reports to check drift against the mapping.
Syntax: Syntax:
RTP-Info = "RTP-Info" ":" 1#rtsp-info-spec RTP-Info = "RTP-Info" ":" 1#rtsp-info-spec
rtsp-info-spec = stream-url 1*parameter rtsp-info-spec = stream-url 1*parameter
stream-url = quoted-url | unquoted-url stream-url = quoted-url / unquoted-url
unquoted-url = "url" "=" safe-url unquoted-url = "url" "=" safe-url
| ";" "mode" = <"> 1#Method <"> / ";" "mode" = <"> 1#Method <">
quoted-url = "url" "=" <"> needquote-url <"> quoted-url = "url" "=" <"> needquote-url <">
safe-url = url safe-url = url
needquote-url = url needquote-url = url //That contains ; or ,
url = ( absoluteURI | relativeURI ) url = ( absoluteURI / relativeURI )
parameter = ";" "seq" "=" 1*DIGIT parameter = ";" "seq" "=" 1*DIGIT
| ";" "rtptime" "=" 1*DIGIT / ";" "rtptime" "=" 1*DIGIT
Additional constraint: safe-url MUST NOT contain the semicolon (";") Additional constraint: safe-url MUST NOT contain the semicolon (";")
or comma (",") characters. The quoted-url form SHOULD only be used or comma (",") characters. The quoted-url form SHOULD only be used
when a URL does not meet the safe-url constraint, in order to ensure when a URL does not meet the safe-url constraint, in order to ensure
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]. absoluteURI and relativeURI are defined in RFC 2396 [22] with RFC
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 12.34 Scale
A scale value of 1 indicates normal play or record at the normal for- A scale value of 1 indicates normal play or record at the normal for-
ward viewing rate. If not 1, the value corresponds to the rate with ward viewing rate. If not 1, the value corresponds to the rate with
skipping to change at page 1, line 2607 skipping to change at page 1, line 3084
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. MUST contain the actual scale value chosen by the server. If the |
server does not implement the possibility to scale, it will not |
If the request contains a Range parameter, the new scale value will return a Scale header. A server supporting Scale operations for PLAY |
take effect at that time. or RECORDSHALL indicate this with the use of the "play.scale" or |
"record.scale" option 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 12.35 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. If the request contains a Range parameter, speed of zero is invalid. All speeds may not be possible to support. |
the new speed value will take effect at that time. 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 server of this functionality. Support of the speed functionality |
are indicated by the "play.speed" option 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. that means such as RTCP be used to track packet loss rates. If the |
data transport is performed over public best-effort networks the |
sender is responsible for performing congestion control of the |
stream. This MAY result in that the communicated speed is impossible |
to maintain.
12.36 Server 12.36 Server
See [H14.38] See [H14.38], however the header syntax is here corrected. |
Server = "Server" ":" ( product / comment ) *(SP(product / comment)) ||
12.37 Session 12.37 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 before closing the session due to pared to wait between RTSP commands or other signs of life before
lack of activity (see Section A). The timeout is measured in seconds, closing the session due to lack of activity (see Section A). The
with a default of 60 seconds (1 minute). timeout is measured in seconds, with a default of 60 seconds (1
minute).
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
a client does not wait to the last second of the timeout before try-
ing to send a liveness message. Even for RTSP messages using reliable
protocols, such as TCP, the message may take some time to arrive
safely at the receiver. To show liveness between RTSP request with
other effects, the following mechanisms can be used, in descending
order of preference:
RTCP: Is used to report transport statistics and SHALL also work as
keep alive. The server can determine the client by used net-
work address and port together with the fact that the client
is reporting on the servers SSRC(s). A downside of using RTCP
is that it gives lower statistical guarantees to reach the
server. However that probability is so little that it can be
ignored in most cases. For example, a session with 60 seconds
timeout and enough bitrate assigned to the RTCP messages, so
the client sends a message on average every 5 seconds. That
session have for a network with 5 % packet loss the probabil-
ity to not get a liveness sign over to the server in the time-
out interval is 2.4*E-16. In sessions with shorter timeout
times, or much higher packet loss, or small RTCP bandwidths
SHOULD use any of the mechanisms below.
PING: The use of the PING method is the best of the RTSP based
methods. It has no other effects than updating the timeout
timer. In that way it will be a minimal message, that also
does not cause any extra processing for the server. The down-
side is that it may not be implemented. A client SHOULD use a
OPTIONS request to verify support of the PING at the server.
It is possible to detect support by sending a PING to the
server. If a 200 (OK) message is received the server supports
it. In case a 501 (Not Implemented) is received it does not
support PING and there is no meaning in continue trying. Also
the reception of a error message will also mean that the live-
ness timer is not updated.
SET_PARAMETER: When using SET_PARAMETER for keep alive, no body
SHOULD be included. This method is basically as good as PING,
however the implementation support of the method is today lim-
ited. The same considerations as for PING apply regarding
checking of support in server and proxies.
OPTIONS: This method does also work. However it causes the server
to perform unnecessary processing and result in bigger
responses than necessary for the task. The reason for this is
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 14). 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 | 12.38 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 cooresponding 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 option 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. |
Example: | Example: |
C->S OPTIONS rtsp://example.com/ RTSP/1.0 || optioSupported to=en"Supported" ":" [option-tag *("," option-tag)] ||
C->S: OPTIONS rtsp://example.com/ RTSP/1.0 ||
Supported: foo, bar, blech || Supported: foo, bar, blech ||
S->C: RTSP/1.0 200 OK ||
SuppoS->C:RTSP/1.0e200 OKz || Supported: bar, blech, baz ||
12.39 Timestamp 12.39 Timestamp
The Timestamp general-header field describes when the client sent the The Timestamp general-header field describes when the client sent the |
request to the server. The value of the timestamp is of significance request to the server. The value of the timestamp is of significance |
only to the client and may use any timescale. The server MUST echo only to the client and may use any timescale. The server MUST echo |
the exact same value and MAY, if it has accurate information about the exact same value and MAY, if it has accurate information about |
this, add a floating point number indicating the number of seconds this, add a floating point number indicating the number of seconds |
that has elapsed since it has received the request. The timestamp is that has elapsed since it has received the request. The timestamp is |
used by the client to compute the round-trip time to the server so used by the client to compute the round-trip time to the server so |
that it can adjust the timeout value for retransmissions. that it can adjust the timeout value for retransmissions. It also |
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 12.40 Transport
The Transport request-header field indicates which transport protocol The Transport request- and response- header field indicates which |
is to be used and configures its parameters such as destination transport protocol is to be used and configures its parameters such |
address, compression, multicast time-to-live and destination port for as destination address, compression, multicast time-to-live and des- |
a single stream. It sets those values not already determined by a tination port for a single stream. It sets those values not already |
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 a 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 parame- | ally, it may only contain the unicast or multicast transport |
ter. parameter.
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 RTP 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.
Below are the configuration parameters associated with transport: Below are the configuration parameters associated with transport:
General parameters: General parameters:
unicast | multicast: This parameter is a mutually exclusive 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 to which a stream will be sent. The |
client may specify the destination address with the destina- | client may specify the destination address with the destina- |
tion parameter. To avoid becoming the unwitting perpetrator of | tion parameter. To avoid becoming the unwitting perpetrator of |
a remote-controlled denial-of-service attack, a server SHOULD | a remote-controlled denial-of-service attack, a server SHOULD |
authenticate the client and SHOULD log such attempts before | authenticate the client and SHOULD log such attempts before |
allowing the client to direct a media stream to an address not | allowing the client to direct a media stream to an address not |
chosen by the server. This is particularly important if RTSP | chosen by the server. This is particularly important if RTSP |
commands are issued via UDP, but implementations cannot rely | commands are issued via UDP, but implementations cannot rely |
on TCP as reliable means of client identification by itself. on TCP as reliable means of client identification by itself. |
IPv6 addresses is RECOMMENDED to be given as fully qualified |
domain to make it backwards compatible with RFC 2326 implemen- |
tations. |
source: If the source address for the stream is different than can source: If the source address for the stream is different than can |
be derived from the RTSP endpoint address (the server in play- be derived from the RTSP endpoint address (the server in play- |
back or the client in recording), the source address MAY be back or the client in recording), the source address SHOULD be |
specified. 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.
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.
append: If the mode parameter includes RECORD, the append parameter append: If the mode parameter includes RECORD, the append parameter
indicates that the media data should append to the existing indicates that the media data should append to the existing
resource rather than overwrite it. If appending is requested resource rather than overwrite it. If appending is requested
and the server does not support this, it MUST refuse the and the server does not support this, it MUST refuse the
request rather than overwrite the resource identified by the request rather than overwrite the resource identified by the
URI. The append parameter is ignored if the mode parameter URI. The append parameter is ignored if the mode parameter
does not contain RECORD. 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 10.13. The argument provides the channel number to be |
used in the $ statement. This parameter may be specified as a used in the $ statement and MUST be present. This parameter |
range, e.g., interleaved=4-5 in cases where the transport MAY be specified as a range, e.g., interleaved=4-5 in cases |
choice for the media stream requires it. where the transport choice for the media stream requires it, |
e.g. for RTP with RTCP.
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:
skipping to change at page 1, line 2826 skipping to change at page 1, line 3371
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 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
ssrc: The ssrc parameter indicates the RTP SSRC [23] value that client_rtcp_port: This parameter allows to specify the client's |
should be (request) or will be (response) used by the media RTCP port number individually from the RTP port. This will |
server. This parameter is only valid for unicast transmission. allow the usage of NAT traversal techniques like STUN [31]. |
It identifies the synchronization source to be associated with However as it introduce after RFC 2326 it may result interop- |
the media stream, and is expressed as an eight digit hexideci- erability problems. Before using this parameter the server |
mal value. MUST signal support of either the "play.basic" or the |
"record.basic" option tags. |
client_rtcp_port: This parameter allows to specify the server's |
RTCP port number individually from the RTP port. This will |
allow the usage of NAT traversal techniques like STUN [31]. |
However as it introduce after RFC 2326 it may result interop- |
erability problems. This parameter MUST only be included in a |
response, when the request's transport header included the |
"client_rtcp_port" parameter. |
ssrc: The ssrc parameter indicates the RTP SSRC [23] value that |
should be (request) or will be (response) used by the media |
server. This parameter is only valid for unicast transmission. |
It identifies the synchronization source to be associated with |
the media stream, and is expressed as an eight digit hexideci- |
mal value. In cases that a sender will use multiple SSRC it |
SHOULD NOT use this parameter.
Transport = "Transport" ":" 1#transport-spec Transport = "Transport" ":" 1#transport-spec
transport-spec = transport-id *parameter transport-spec = transport-id *parameter
transport-id = transport-protocol "/" profile ["/" lower-transport] transport-id = transport-protocol "/" profile ["/" lower-transport]
; no LWS is allowed inside transport-id ; no LWS is allowed inside transport-id
transport-protocol = "RTP" | token transport-protocol = "RTP" / token
profile = "AVP" | token profile = "AVP" / token
lower-transport = "TCP" | "UDP" | token lower-transport = "TCP" / "UDP" / token
parameter = ";" ( "unicast" | "multicast" ) parameter = ";" ( "unicast" / "multicast" )
| ";" "source" [ "=" address ] / ";" "source" "=" address
| ";" "destination" [ "=" address ] / ";" "destination" [ "=" address ]
| ";" "interleaved" "=" channel [ "-" channel ] / ";" "interleaved" "=" channel [ "-" channel ]
| ";" "append" / ";" "append"
| ";" "ttl" "=" ttl / ";" "ttl" "=" ttl
| ";" "layers" "=" 1*DIGIT / ";" "layers" "=" 1*DIGIT
| ";" "port" "=" port [ "-" port ] / ";" "port" "=" port [ "-" port ]
| ";" "client_port" "=" port [ "-" port ] / ";" "client_port" "=" port [ "-" port ]
| ";" "server_port" "=" port [ "-" port ] / ";" "server_port" "=" port [ "-" port ]
| ";" "source" "=" address / ";" "client_rtcp_port" "=" port
| ";" "ssrc" "=" ssrc / ";" "server_rtcp_port" "=" port
| ";" "mode" "=" mode-spec / ";" "ssrc" "=" ssrc
/ ";" "mode" "=" mode-spec
ttl = 1*3(DIGIT) ttl = 1*3(DIGIT)
port = 1*5(DIGIT) port = 1*5(DIGIT)
ssrc = 8*8(HEX) ssrc = 8*8(HEX)
channel = 1*3(DIGIT) channel = 1*3(DIGIT)
address = host address = host ;As defined in RFC 2732 [30]
mode-spec = <"> 1#mode <"> | mode mode-spec = <"> 1#mode <"> / mode
mode = "PLAY" | "RECORD" | token 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"
skipping to change at page 1, line 2882 skipping to change at page 1, line 3445
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 12.41 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 12.32), if there is a proxy on the the Proxy-Require field (Section 12.27), if there is a proxy on the
path between the client and the server, the proxy MUST insert 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.
See Section 12.32 for a usage example. See Section 12.32 for a usage example.
Unsupported = "Unsupported" ":" 1#option-tag Unsupported = "Unsupported" ":" 1#option-tag
12.42 User-Agent 12.42 User-Agent
See [H14.43] 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 |
messages it sends. |
User-Agent = "User-Agent" ":" ( product / comment ) 0*(SP ||
(product / comment) ||
12.43 Vary 12.43 Vary
See [H14.44] See [H14.44]
12.44 Via 12.44 Via
See [H14.45]. See [H14.45].
12.45 WWW-Authenticate 12.45 WWW-Authenticate
skipping to change at page 1, line 3343 skipping to change at page 1, line 3910
port=61010-61011;mode=record;ttl=127 port=61010-61011;mode=record;ttl=127
C->M: RECORD rtsp://server.example.com/meeting RTSP/1.0 C->M: RECORD rtsp://server.example.com/meeting RTSP/1.0
CSeq: 93 CSeq: 93
Session: 50887676 Session: 50887676
Range: clock=19961110T1925-19961110T2015 Range: clock=19961110T1925-19961110T2015
M->C: RTSP/1.0 200 OK M->C: RTSP/1.0 200 OK
CSeq: 93 CSeq: 93
15 Syntax 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
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 used in RFC 2068 [2]. as defined in RFC 2234 [14]. Also the "#" rule from RFC 2616 [26] is
also defined and used in this syntax description.
15.1 Base Syntax 16.1 Base Syntax
OCTET = <any 8-bit sequence of data> OCTET = <any 8-bit sequence of data>
CHAR = <any US-ASCII character (octets 0 - 127)> CHAR = <any US-ASCII character (octets 0 - 127)>
UPALPHA = <any US-ASCII uppercase letter "A".."Z"> UPALPHA = <any US-ASCII uppercase letter "A".."Z">
LOALPHA = <any US-ASCII lowercase letter "a".."z"> LOALPHA = <any US-ASCII lowercase letter "a".."z">
ALPHA = UPALPHA | LOALPHA ALPHA = UPALPHA / LOALPHA
DIGIT = <any US-ASCII digit "0".."9"> DIGIT = <any US-ASCII digit "0".."9">
CTL = <any US-ASCII control character CTL = <any US-ASCII control character
(octets 0 - 31) and DEL (127)> (octets 0 - 31) and DEL (127)>
CR = <US-ASCII CR, carriage return (13)> CR = <US-ASCII CR, carriage return (13)>
LF = <US-ASCII LF, linefeed (10)> LF = <US-ASCII LF, linefeed (10)>
SP = <US-ASCII SP, space (32)> SP = <US-ASCII SP, space (32)>
HT = <US-ASCII HT, horizontal-tab (9)> HT = <US-ASCII HT, horizontal-tab (9)>
<"> = <US-ASCII double-quote mark (34)> <"> = <US-ASCII double-quote mark (34)>
BACKSLASH = <US-ASCII backslash (92)> BACKSLASH = <US-ASCII backslash (92)>
CRLF = CR LF CRLF = CR LF
LWS = [CRLF] 1*( SP | HT ) LWS = [CRLF] 1*( SP / HT )
TEXT = <any OCTET except CTLs> TEXT = <any OCTET except CTLs>
tspecials = "(" | ")" | "<" | ">" | "@" tspecials = "(" / ")" / "<" / ">" / "@"
| "," | ";" | ":" | BACKSLASH | <"> / "," / ";" / ":" / BACKSLASH / <">
| "/" | "[" | "]" | "?" | "=" / "/" / "[" / "]" / "?" / "="
| "{" | "}" | SP | HT / "{" / "}" / SP / HT
token = 1*<any CHAR except CTLs or tspecials> token = 1*<any CHAR except CTLs or tspecials>
quoted-string = ( <"> *(qdtext) <"> ) quoted-string = ( <"> *(qdtext) <"> )
qdtext = <any TEXT except <">> qdtext = <any TEXT except <">>
quoted-pair = BACKSLASH CHAR quoted-pair = BACKSLASH CHAR
message-header = field-name ":" [ field-value ] CRLF message-header = field-name ":" [ field-value ] CRLF
field-name = token field-name = token
field-value = *( field-content | LWS ) field-value = *( field-content / LWS )
field-content = <the OCTETs making up the field-value and field-content = <the OCTETs making up the field-value and
consisting consisting
of either *TEXT or combinations of token, tspecials, of either *TEXT or combinations of token, tspecials,
and quoted-string> and quoted-string>
safe = "$" | "-" | "_" | "." | "+" safe = "$" / "-" / "_" / "." / "+"
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 Security Considerations 16.2 RTSP Protocol Definition
generRTSP-message= st=rtRequest / Response ; RTSP/1.0 messages
*(message-header CRLF)
CRLF
[ message-body ]
start-line = Request-Line / Status-Line
Request g=nerRequest-Line ; Sec;iSection 6.1
/ request-header ; Section 6.2
/ entity-header ) ; Section 8.1
CRLF
[ message-body ] ; Section 4.3
Response = Status-Line ; Section 7.1
*( general-header ; Section 5
/ response-header ; Section 7.1.2
/ entity-header ) ; Section 8.1
CRLF
[ message-body ] ; Section 4.3
Request-Line = Method SP Request-URI SP RTSP-Version CRLF
Status-Line = RTSP-Version SP Status-Code SP Reason-Phrase CRLF
Method = "DESCRIBE" ; Section 10.2
/ "ANNOUNCE" ; Section 10.3
/ "GET_PARAMETER" ; Section 10.8
/ "OPTIONS" ; Section 10.1
/ "PAUSE" ; Section 10.6
/ "PLAY" ; Section 10.5
/ "PING" ; Section 10.12
/ "RECORD" ; Section 10.11
/ "REDIRECT" ; Section 10.10
/ "SETUP" ; Section 10.4
/ "SET_PARAMETER" ; Section 10.9
/ "TEARDOWN" ; Section 10.7
/ extension-method
extension-method = token
Request-URI = "*" / absolute_URI
RTSP-Version = "RTSP" "/" 1*DIGIT "." 1*DIGIT
Status-Code = "100" ; Continue
/ "200" ; OK
/ "201" ; Created
/ "250" ; Low on Storage Space
/ "300" ; Multiple Choices
/ "301" ; Moved Permanently
/ "302" ; Moved Temporarily
/ "303" ; See Other
/ "304" ; Not Modified
/ "305" ; Use Proxy
/ "400" ; Bad Request
/ "401" ; Unauthorized
/ "402" ; Payment Required
/ "403" ; Forbidden
/ "404" ; Not Found
/ "405" ; Method Not Allowed
/ "406" ; Not Acceptable
/ "407" ; Proxy Authentication Required
/ "408" ; Request Time-out
/ "410" ; Gone
/ "411" ; Length Required
/ "412" ; Precondition Failed
/ "413" ; Request Entity Too Large
/ "414" ; Request-URI Too Large
/ "415" ; Unsupported Media Type
/ "451" ; Parameter Not Understood
/ "452" ; reserved
/ "453" ; Not Enough Bandwidth
/ "454" ; Session Not Found
/ "455" ; Method Not Valid in This State
/ "456" ; Header Field Not Valid for Resource
/ "457" ; Invalid Range
/ "458" ; Parameter Is Read-Only
/ "459" ; Aggregate operation not allowed
/ "460" ; Only aggregate operation allowed
/ "461" ; Unsupported transport
/ "462" ; Destination unreachable
/ "500" ; Internal Server Error
/ "501" ; Not Implemented
/ "502" ; Bad Gateway
/ "503" ; Service Unavailable
/ "504" ; Gateway Time-out
/ "505" ; RTSP Version not supported
/ "551" ; Option not supported
/ extension-code
extension-code = 3DIGIT
Reason-Phrase = *<TEXT, excluding CR, LF>
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
/ Location ; Section 12.25
/ Proxy-Authenticate ; Section 12.26
/ Public ; Section 12.28
/ Range ; Section 12.29
/ Retry-After ; Section 12.31
/ RTP-Info ; Section 12.33
/ Scale ; Section 12.34
/ Session ; Section 12.37
/ Server ; Section 12.36
/ Speed ; Section 12.35
/ Transport ; Section 12.40
/ Unsupported ; Section 12.41
/ Vary ; Section 12.43
/ WWW-Authenticate ; Section 12.45
rtsp_URL = ( "rtsp:" / "rtspu:" / "rtsps" )
"//" host [ ":" port ] [ abs_path ]
host = As defined by RFC 2732 [30]
abs_path = As defined by RFC 2396 [22]
port = *DIGIT
smpte-range = smpte-type "=" smpte-range-spec
smpte-range-spec = ( smpte-time "-" [ smpte-time ] ) / ( "-" smpte-time )
smpte-type = "smpte" / "smpte-30-drop" / "smpte-25"
; other timecodes may be added
smpte-time = 1*2DIGIT ":" 1*2DIGIT ":" 1*2DIGIT
[ ":" 1*2DIGIT [ "." 1*2DIGIT ] ]
npt-range = ["npt" "="] npt-range-spec
; implementations SHOULD use npt= prefix, but SHOULD
; be prepared to interoperate with RFC 2326
; implementations which don't use it
npt-range-spec = ( npt-time "-" [ npt-time ] ) / ( "-" npt-time )
npt-time = "now" / npt-sec / npt-hhmmss
npt-sec = 1*DIGIT [ "." *DIGIT ]
npt-hhmmss = npt-hh ":" npt-mm ":" npt-ss [ "." *DIGIT ]
npt-hh = 1*DIGIT ; any positive number
npt-mm = 1*2DIGIT ; 0-59
npt-ss = 1*2DIGIT ; 0-59
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
option-tag = token
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
client authentication issues, and chapter 15.2 of [2] for client authentication issues, and chapter 15.2 of [2] for
issues regarding support for multiple authentication mecha- issues regarding support for multiple authentication mecha-
nisms. nisms. Also see [H15.6].
Abuse of Server Log Information: RTSP and HTTP servers will presum- Abuse of Server Log Information: RTSP and HTTP servers will presum-
ably have similar logging mechanisms, and thus should be ably have similar logging mechanisms, and thus should be
equally guarded in protecting the contents of those logs, thus equally guarded in protecting the contents of those logs, thus
protecting the privacy of the users of the servers. See protecting the privacy of the users of the servers. See
[H15.1.1] for HTTP server recommendations regarding server [H15.1.1] for HTTP server recommendations regarding server
logs. logs.
Transfer of Sensitive Information: There is no reason to believe Transfer of Sensitive Information: There is no reason to believe
that information transferred via RTSP may be any less sensi- that information transferred via RTSP may be any less sensi-
skipping to change at page 1, line 3469 skipping to change at page 1, line 4219
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 relation between a transport Session hijacking: Since there is no or little relation between a |
layer connection and an RTSP session, it is possible for a transport layer connection and an RTSP session, it is possible |
malicious client to issue requests with random session identi- for a malicious client to issue requests with random session |
fiers which would affect unsuspecting clients. The server identifiers which would affect unsuspecting clients. The |
SHOULD use a large, random and non-sequential session identi- server SHOULD use a large, random and non-sequential session |
fier 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
other protocols such as RTP, IP multicast, RSVP and IGMP, and other protocols such as RTP, IP multicast, RSVP and IGMP, and
skipping to change at page 1, line 3498 skipping to change at page 1, line 4248
other applicable specifications. other applicable specifications.
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.
17 IANA Considerations 18 IANA Considerations
This section set up a number of registers for RTSP that should be 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 maintained by IANA. For each registry there is a description on what |
it shall contain, what specification is needed when adding a entry it shall contain, what specification is needed when adding a entry |
with IANA, and finally the entries that this document needs to regis- with IANA, and finally the entries that this document needs to regis- |
ter. See also the section 1.5 "Extending RTSP". ter. See also the section 1.6 "Extending RTSP". |
The sections describing how to register an item uses some of the The sections describing how to register an item uses some of the |
requirements level described in RFC 2434 [29], namely " First Come, requirements level described in RFC 2434 [29], namely " First Come, |
First Served", "Specification Required", and "Standards Action". First Served", "Specification Required", and "Standards Action". |
A registration request to IANA MUST contain the following informa- A registration request to IANA MUST contain the following informa- |
tion: tion: |
+ A name of the item to register according to the rules specified + A name of the item to register according to the rules specified |
by the intended registry. by the intended registry. |
+ Indication of who has change control over the option (for exam- + Indication of who has change control over the option (for exam- |
ple, IETF, ISO, ITU-T, other international standardization bod- ple, IETF, ISO, ITU-T, other international standardization bod- |
ies, a consortium or a particular company or group of companies); ies, a consortium or a particular company or group of companies); |
+ A reference to a further description, if available, for example + A reference to a further description, if available, for example |
(in order of preference) an RFC, a published paper, a patent fil- (in order of preference) an RFC, a published standard, a pub- |
ing, a technical report, documented source code or a computer lished paper, a patent filing, a technical report, documented |
manual; source code or a computer manual; |
+ For proprietary options, contact information (postal and email + For proprietary options, contact information (postal and email |
address); address); |
17.1 Option-tags 18.1 Option-tags |
17.1.1 Description 18.1.1 Description |
When a client and server try to determine what part and functionality When a client and server try to determine what part and functionality |
of the RTSP specification and any future extensions that its counter of the RTSP specification and any future extensions that its counter |
part implements there is need for a namespace. This registry con- part implements there is need for a namespace. This registry con- |
tains named entries representing certain functionality. tains named entries representing certain functionality. |
The usage of option-tags is explained in section 3.7 and 10.1. The usage of option-tags is explained in section 3.7 and 10.1. |
17.1.2 Registering New Option Tags with IANA 18.1.2 Registering New Option Tags with IANA |
The registering of option tags is done on a first come, first served The registering of option tags is done on a first come, first served |
basis. basis. |
The name of the option MUST follow these rules: The name may be of The name of the option MUST follow these rules: The name may be of |
any length, but SHOULD be no more than twenty characters long. The any length, but SHOULD be no more than twenty characters long. The |
name MUST not contain any spaces, control characters or periods. Any name MUST not contain any spaces, or control characters. Any propri- |
proprietary option SHOULD have as the first part of the name a vendor etary option SHALL have as the first part of the name a vendor tag, |
tag, which identifies the company/person. which identifies the organization. |
17.1.3 Registered entries 18.1.3 Registered entries |
The following options tags are in this specification defined and The following options tags are in this specification defined and |
hereby registered. The change control belongs to the Authors and the hereby registered. The change control belongs to the Authors and the |
IETF MMUSIC WG. IETF MMUSIC WG. |
play-basic: The minimal implementation for playback operations play.basic: The minimal implementation for playback operations |
according to section D. according to section D. |
record-basic: The minimal implementation for record operations play.scale: Support of scale operations for media playback. |
according to section D.
play-setup: The use of teardown and setup in play state. play.speed: Support of the speed functionality for playback. |
record-setup: The use of setup and teardown in record state. record.basic: The minimal implementation for record operations |
according to section D. |
17.2 RTSP Methods record.setup: The use of setup and teardown in record state. |
17.2.1 Description record.scale: Support of scale operations for media recording. |
What a method is, is described in section 10. Extending the protocol setup.playing: The use of teardown and setup in play state. |
with new methods allow for totally new functionality.
17.2.2 Registering New Methods with IANA con.non-persistent: Support and use of non-persistent connections, |
see chapter 9.3. |
A new method can only be registered through an IETF standards action. con.persistent: Support and use of persistent connections, see |
The reason is that new methods may radically change the protocols chapter 9.3. |
behavior and purpose.
A specification for a new RTSP method MUST consist of the following 18.2 RTSP Methods |
items:
+ A method name which follows the BNF rules for methods. 18.2.1 Description |
+ A clear specification on what action and response a request with What a method is, is described in section 10. Extending the protocol |
the method will result in. Which directions the method is used, with new methods allow for totally new functionality. |
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 18.2.2 Registering New Methods with IANA |
are allowed to use with the method in request or/and response.
+ Describe how the method relates to network proxies. A new method MUST be registered through an IETF standard track docu- |
ment. The reason is that new methods may radically change the proto- |
cols behavior and purpose. |
17.2.3 Registered entries A specification for a new RTSP method MUST consist of the following |
This specification, RFCXXXX, registers 12 methods: DESCRIBE, items: |
ANNOUNCE, GET_PARAMETER, OPTIONS, PAUSE, PING, PLAY, RECORD, REDI-
RECT, SETUP, SET_PARAMETER, and TEARDOWN.
17.3 RTSP Headers + 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. |
17.3.1 Description + A list or table specifying which of the registered headers that |
are allowed to use with the method in request or/and response. |
By specifying new headers a method(s) can be enhanced in many differ- + Describe how the method relates to network proxies. |
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.
Unregistered headers SHALL have a name starting with "X-" to signal 18.2.3 Registered Entries |
that it is a experimental header.
17.3.2 Registering New Headers with IANA This specification, RFCXXXX, registers 12 methods: DESCRIBE, |
ANNOUNCE, GET_PARAMETER, OPTIONS, PAUSE, PING, PLAY, RECORD, REDI- |
RECT, SETUP, SET_PARAMETER, and TEARDOWN. |
A specification is required to register a header. 18.3 RTSP Status Codes |
The specification MUST contain the following information: 18.3.1 Description |
+ The header name following the BNF definition. 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 BNF specification of how information (if any) is carried in the 18.3.2 Registering New Status Codes with IANA |
header.
+ A list or table specifying when the header may be used, encom- A new status code can only be registered by an IETF standards track |
passing all methods, their request or response, the direction document. A specification for a new status code MUST specify the fol- |
(C->S or S->C). lowing: |
+ How the header shall be handled by proxies. + The requested number. |
+ A description of the purpose of the header. + A description what the status code means and the expected behav- |
ior of the sender and receiver of the code. |
17.3.3 Registered entries 18.3.3 Registered Entries |
All headers specified in section 12 in RFC XXXX are to be registered. RFCXXX, registers the numbered status code defined in the BNF entry |
"Status-Code" except "extension-code" in section 7.1.1. |
17.4 Parameters 18.4 RTSP Headers |
17.4.1 Description 18.4.1 Description |
A Parameter allow the counterpart to set something with the owner of By specifying new headers a method(s) can be enhanced in many differ- |
the parameter. Both the client and the server can have parameters. 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. |
17.4.2 Registering New Parameters with IANA 18.4.2 Registering New Headers with IANA |
Any Parameter is registered on a first come, first served basis. The A public available specification is required to register a header. |
following rules apply for parameters: The specification SHOULD be a standards document, preferable an IETF |
RFC. |
+ The parameter name is a BNF token. The name SHOULD not be more The specification MUST contain the following information: |
than 20 characters long. Any proprietary parameter should start
the name with a vendor tag, as clearly as possible identify the
company or person.
+ Any non proprietary parameter MUST in the form of BNF specify + The name of the header. |
what value types that are associated with the parameter.
17.4.3 Registered entries + A BNF specification of the header syntax. |
For the moment no known parameters are defined in RFC XXXX. + 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). |
+ How the header shall be handled by proxies. |
+ A description of the purpose of the header. |
18.4.3 Registered entries |
All headers specified in section 12 in RFCXXXX are to be registered. |
18.5 Parameters |
18.5.1 Description |
A Parameter allow the counterpart to set something with the owner of |
the parameter. Both the client and the server can have parameters. |
18.5.2 Registering New Parameters with IANA |
Any Parameter is registered on a first come, first served basis. The |
following rules apply for parameters: |
+ The parameter name is a BNF token. The name SHOULD not be more |
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 |
what value types that are associated with the parameter. |
18.5.3 Registered entries |
For the moment no known parameters are defined in RFC XXXX. |
18.6 MIME type registration |
One new MIME type is registered, text/parameters. To be defined. |
18.7 Transport Header registries |
The transport header contains a number of parameters which have pos- |
sibilities for future extensions. Therefore registries for these must |
be defined. |
18.7.1 Transport Protocols |
A registry for the parameter transport-protocol shall be defined with |
the following rules: |
+ Registering requires public available standards specification. |
+ A contact person or organization with address and email. |
+ A value definition that are following the BNF token definition. |
+ A describing text that explains how the registered value are used |
in RTSP. |
This specification register 1 value: |
+ Use of the RTP [23] protocol for media transport. The usage is |
explained in RFC XXXX, appendix B. |
18.7.2 Profile |
A registry for the parameter profile shall be defined with the fol- |
lowing rules: |
+ Registering requires public available standards specification. |
+ A contact person or organization with address and email. |
+ A value definition that are following the BNF token definition. |
+ A definition of which Transport protocol(s) that this profile is |
valid for. |
+ A describing text that explains how the registered value are used |
in RTSP. |
+ The "RTP profile for audio and video conferences with minimal |
control" [1] MUST only be used when the transport headers trans- |
port-protocol is "RTP". |
18.7.3 Lower Transport |
A registry for the parameter lower-transport shall be defined with |
the following rules: |
+ Registering requires public available standards specification. |
+ A contact person or organization with address and email. |
+ A value definition that are following the BNF token definition. |
+ A describing text that explains how the registered value are used |
in RTSP. |
+ Indicates the use of the "User datagram protocol" [7] for media |
transport. |
+ Indicates the use Transmission control protocol [9] for media |
transport. |
18.7.4 Transport modes |
A registry for the transport parameter mode shall be defined with the |
following rules: |
+ Registering requires a IETF standard tracks document. |
+ A contact person or organization with address and email. |
+ A value definition that are following the BNF token definition. |
+ A describing text that explains how the registered value are used |
in RTSP. |
+ See RFC XXXX. |
+ See RFC XXXX. |
18.8 Cache Directive Extensions |
There exist a number of cache directives which can be sent in the |
Cache-Control header. A registry for this cache directives shall be |
defined with the following rules: |
+ Registering requires a IETF standard tracks document. |
+ A registration shall name a contact person. |
+ Name of the directive and a definition of the value, if any. |
+ A describing text that explains how the cache directive is used |
for RTSP controlled media streams. |
A RTSP Protocol State Machine A RTSP Protocol State Machine
The RTSP session state machine describe the behavior of the protocol The RTSP session state machine describe the behavior of the protocol |
from RTSP session initialization through RTSP session termination. from RTSP session initialization through RTSP session termination. |
State machine is defined on a per session basis which is uniquely State machine is defined on a per session basis which is uniquely |
identified by the RTSP session identifier. The session may contain identified by the RTSP session identifier. The session may contain |
zero or more media streams depending on state. If a single media zero or more media streams depending on state. If a single media |
stream is part of the session it is in non-aggregated control. If two stream is part of the session it is in non-aggregated control. If two |
or more is part of the session it is in aggregated control. or more is part of the session it is in aggregated control. |
This state machine is one possible representation that helps explain This state machine is one possible representation that helps explain |
how the protocol works and when different requests are allowed. We how the protocol works and when different requests are allowed. We |
find it a reasonable representation but does not mandate it, and find it a reasonable representation but does not mandate it, and |
other representations can be created. other representations can be created. |
A.1 States A.1 States |
The state machine contains five states, described below. For each The state machine contains five states, described below. For each |
state there exist a table which shows which requests and events that state there exist a table which shows which requests and events that |
is allowed and if they will result in a state change. is allowed and if they will result in a state change. |
Init: Initial state no session exist. Init: Initial state no session exist. |
Ready-nm: Ready state without any medias. Ready-nm: Ready state without any medias. |
Ready: Session is ready to start playing or recording. Ready: Session is ready to start playing or recording. |
Play: Session is playing, i.e. sending media stream data in the Play: Session is playing, i.e. sending media stream data in the |
direction S->C. direction S->C. |
Record: Session is recording, i.e. sending media stream data in the Record: Session is recording, i.e. sending media stream data in the |
direction C->S. direction C->S. |
A.2 State variables A.2 State variables |
This representation of the state machine needs more than its state to This representation of the state machine needs more than its state to |
work. A small number of variables are also needed and is explained work. A small number of variables are also needed and is explained |
below. below. |
NRM: The number of media streams part of this session. NRM: The number of media streams part of this session. |
RP: Resume point, the point in the presentation time line at which RP: Resume point, the point in the presentation time line at which |
a request to continue will resume from. A time format for a request to continue will resume from. A time format for the |
variable is not mandated. variable is not mandated. |
A.3 Abbreviations A.3 Abbreviations |
To make the state tables more compact a number of abbreviations are To make the state tables more compact a number of abbreviations are |
used, which are explained below. used, which are explained below. |
PP: Pause Point, the point in the presentation time line at which IFI: IF Implemented. |
the presentation was paused.
Prs: Presentation, the complete multimedia presentation. md: Media |
IFI: IF Implemented. PP: Pause Point, the point in the presentation time line at which |
the presentation was paused. |
RedP: Redirect Point, the point in the presentation time line at Prs: Presentation, the complete multimedia presentation. |
which a REDIRECT was specified to occur.
SES: Session. RedP: Redirect Point, the point in the presentation time line at |
which a REDIRECT was specified to occur. |
A.4 State Tables SES: Session. |
This section contains a table for each state. The table contains all A.4 State Tables |
the requests and events that this state is allowed to act on. The
events which is method names are, unless noted, requests with the
given method in the direction client to server (C->S). In some cases
there exist one or more requisite. The response column tells what
type of response actions should be performed. Possible actions that
is requested for an event includes: response codes, e.g. 200, headers
that MUST be included in the response, setting of state variables, or
setting of other session related parameters. The new state column
tells which state the state machine shall change to.
The response to valid request meeting the requisites is normally a This section contains a table for each state. The table contains all |
2xx (SUCCESS) unless other noted in the response column. The excep- the requests and events that this state is allowed to act on. The |
tions shall be given a response according to the response column. If events which is method names are, unless noted, requests with the |
the request does not meet the requisite, is erroneous or some other given method in the direction client to server (C->S). In some cases |
type of error occur the appropriate response code MUST be sent. If there exist one or more requisite. The response column tells what |
the response code is a 4xx the session state is unchanged. A response type of response actions should be performed. Possible actions that |
code of 3xx will result in that the session is ended and its state is is requested for an event includes: response codes, e.g. 200, headers |
changed to Init. However there exist restrictions to when a 3xx that MUST be included in the response, setting of state variables, or |
response may be used. A 5xx response SHALL not result in any change setting of other session related parameters. The new state column |
of the session state, except if the error is not possible to recover tells which state the state machine shall change to. |
from. A unrecoverable error SHOULD result in ending of the session.
The server will timeout the session after the period of time speci- The response to valid request meeting the requisites is normally a |
fied in the SETUP response, if no activity from the client is 2xx (SUCCESS) unless other noted in the response column. The excep- |
detected. Therefore there exist a timeout event for all states tions shall be given a response according to the response column. If |
except Init. the request does not meet the requisite, is erroneous or some other |
type of error occur the appropriate response code MUST be sent. If |
the response code is a 4xx the session state is unchanged. A response |
code of 3xx will result in that the session is ended and its state is |
changed to Init. However there exist restrictions to when a 3xx |
response may be used. A 5xx response SHALL not result in any change |
of the session state, except if the error is not possible to recover |
from. A unrecoverable error SHALL result the ending of the session. |
As it in the general case can't be determined if it was a unrecover- |
able error or not the client will be required to test. In the case |
that the next request after a 5xx is responded with 454 (Session Not |
Found) the client SHALL assume that the session has been ended. |
In the case that NRM=1 the presentation URL is equal to the media The server will timeout the session after the period of time speci- |
URL. For NRM>1 the presentation URL MUST be other than any of the fied in the SETUP response, if no activity from the client is |
medias that are part of the session. This applies to all states. detected. Therefore there exist a timeout event for all states |
except Init. |
In the case that NRM=1 the presentation URL is equal to the media |
URL. For NRM>1 the presentation URL MUST be other than any of the |
medias that are part of the session. This applies to all states. |
Event Prerequisite Response Event Prerequisite Response
----------------------------------------------------------------- -----------------------------------------------------------------
DESCRIBE Needs REDIRECT 3xx Redirect DESCRIBE Needs REDIRECT 3xx Redirect
DESCRIBE 200, Session description DESCRIBE 200, Session description
OPTIONS Session ID 200, Reset session timeout timer OPTIONS Session ID 200, Reset session timeout timer
OPTIONS 200 OPTIONS 200
SET_PARAMETER Valid parameter 200, change value of parameter SET_PARAMETER Valid parameter 200, change value of parameter
GET_PARAMETER Valid parameter 200, return value of parameter GET_PARAMETER Valid parameter 200, return value of parameter
ANNOUNCE C->S, IFI record. ANNOUNCE C->S, IFI RECORD.
ANNOUNCE S->C, Update SES descr. ANNOUNCE S->C, Update Session description.
Table 5: None state-machine changing events
The methods in Table 5 do not have any effect on the state machine or Table 6: None state-machine changing events
the state variables. However some methods do change other session
related parameters, for example SET_PARAMETER which will set the
parameter(s) specified in its body.
The initial state of the state machine, see Table 6 can only be left The methods in Table 6 do not have any effect on the state machine or |
by processing a correct SETUP request. As seen in the table the two the state variables. However some methods do change other session |
state variables are also set by a correct request. This table also related parameters, for example SET_PARAMETER which will set the |
shows that a correct SETUP can in some cases be redirected to another parameter(s) specified in its body. |
URL and/or server by a 3xx response.
The initial state of the state machine, see Table 7 can only be left |
by processing a correct SETUP request. As seen in the table the two |
Action Requisite New State Response Action Requisite New State Response
------------------------------------------------- -------------------------------------------------
SETUP Ready NRM=1, RP=0.0 SETUP Ready NRM=1, RP=0.0
SETUP Needs Redirect Init 3xx Redirect SETUP Needs Redirect Init 3xx Redirect
Table 6: State: Init Table 7: State: Init
state variables are also set by a correct request. This table also |
shows that a correct SETUP can in some cases be redirected to another |
URL and/or server by a 3xx response. |
Action Requisite New State Response Action Requisite New State Response
-------------------------------------------------------------- ----------------------------------------------------------
SETUP Ready NRM=1,RP=0.0 SETUP Ready NRM=1,RP=0.0
SETUP Needs Redirect Init 3xx SETUP Needs Redirect Init 3xx
TEARDOWN URL=* Init No session hdr. TEARDOWN URL=* Init No session hdr.
Timeout Init Timeout Init
S->C:REDIRECT Range hdr Play Set RedP S->C:REDIRECT Range hdr Ready-nm Set RedP
S->C:REDIRECT no range hdr Init Stop Media Playout S->C:REDIRECT no range hdr Init
RedP reached Init RedP reached Init
Table 7: State: Ready-nm Table 8: State: Ready-nm
The Ready-nm state has no media streams and therefore can't play or
record. This state exist so that all session related parameters and
resources can be kept while changing media stream(s). As seen in
Table 7 the operations are limited to setting up a new media or tear-
ing down the session. The established session can also be redirected
with the REDIRECT method.
In the Ready state, see Table 8, some of the actions are depending on
the number of media streams in the session, i.e. aggregated or non-
aggregated control. A setup request in the ready state can either add
one more media stream to the session or if the media stream (same
URL) already is part of the session change the transport parameters.
TEARDOWN is depending on both the request URI and the number of media
stream within the session. If the request URI is either * or the pre-
sentations URI the whole session is torn down. If a media URL is used
in the TEARDOWN request the session will remain and a session header
MUST be returned in the response. The number of media streams remain-
ing after tearing down a media stream determines the new state.
The Play state table, see Table 9, is the largest. The table contains The optional Ready-nm state has no media streams and therefore can't |
an number of request that has presentation URL as a prerequisite on play or record. This state exist so that all session related parame- |
the request URL, this is due to the exclusion of non-aggregated ters and resources can be kept while changing media stream(s). As |
stream control in sessions with more than one media stream. seen in Table 8 the operations are limited to setting up a new media |
or tearing down the session. The established session can also be |
redirected with the REDIRECT method. |
In the Ready state, see Table 9, some of the actions are depending on |
the number of media streams (NRM) in the session, i.e. aggregated or |
non-aggregated control. A setup request in the ready state can either |
add one more media stream to the session or if the media stream (same |
URL) already is part of the session change the transport parameters. |
TEARDOWN is depending on both the request URI and the number of media |
stream within the session. If the request URI is either * or the pre- |
sentations URI the whole session is torn down. If a media URL is used |
in the TEARDOWN request and more than one media exist in the session, |
the session will remain and a session header MUST be returned in the |
response. If only a single media stream remains in the session when |
performing a TEARDOWN with a media URL , it is optional to keep the |
Action Requisite New State Response Action Requisite New State Response
--------------------------------------------------------------------- ---------------------------------------------------------------------
SETUP New URL Ready NRM+=1 SETUP New URL Ready NRM+=1
SETUP Setten up URL Ready Change transport param. SETUP Setten up URL Ready Change transport param.
TEARDOWN URL=* Init No session hdr TEARDOWN URL=* Init No session hdr
TEARDOWN Prs URL,NRM>1 Init No session hdr TEARDOWN Prs URL,NRM>1 Init No session hdr
TEARDOWN md URL,NRM=1 Ready-nm Session hdr, NRM=0 TEARDOWN md URL,NRM=1IFI Ready-nm Session hdr, NRM=0
TEARDOWN md URL,NRM=1 Init No Session hdr, NRM=0
TEARDOWN md URL,NRM>1 Ready Session hdr, NRM-=1 TEARDOWN md URL,NRM>1 Ready Session hdr, NRM-=1
PLAY Prs URL, No range Play Play from RP PLAY Prs URL, No range Play Play from RP
PLAY Prs URL, Range Play according to range PLAY Prs URL, Range Play according to range
RECORD Record RECORD Prs URL Record
S->C:REDIRECT Range hdr Ready Set RedP S->C:REDIRECT Range hdr Ready Set RedP
S->C:REDIRECT no range hdr Init S->C:REDIRECT no range hdr Init
Timeout Init Timeout Init
RedP reached Init RedP reached Init
Table 8: State: Ready Table 9: State: Ready
session. If the session still exist after the request a Session MUST |
be returned in the response. The number of media streams remaining |
after tearing down a media stream determines the new state. |
The Play state table, see Table 10, is the largest. The table con- |
tains an number of request that has presentation URL as a prerequi- |
site on the request URL, this is due to the exclusion of non-aggre- |
gated stream control in sessions with more than one media stream. |
To avoid inconsistencies between the client and server, automatic |
state transitions are avoided. This can be seen at for example "End |
of media" event when all media has finished playing, the session |
still remain in Play state. An explicit PAUSE request must be sent to |
change the state to Ready. It may appear that there exist two auto- |
matic transitions in "RedP reached" and "PP reached", however they |
are requested and acknowledge before they take place. The time at |
which the transition will happen is known by looking at the range |
header. If the client sends request close in time to these transi- |
tions it must be prepared for getting error message as the state may |
or may not have changed. |
SETUP and TEARDOWN requests with media URLs in aggregated sessions |
may not be handled by the server as it is optional functionality. Use |
the service discovery mechanism with OPTIONS to find out in before- |
hand if the server implements it. If the functionality is not imple- |
mented but still tried by the client a "501 Not Implemented" response |
Action Requisite New State Response Action Requisite New State Response
------------------------------------------------------------------------ ------------------------------------------------------------------------
PAUSE PrsURL,No range Ready Set RP to present point PAUSE PrsURL,No range Ready Set RP to present point
PAUSE PrsURL,Range>now Play Set RP & PP to given point PAUSE PrsURL,Range>now Play Set RP & PP to given point
PAUSE PrsURL,Range<=now Ready Set RP to present pos. PAUSE PrsURL,Range<=now Ready Set RP to Range Hdr.
PP reached Ready RP = PP PP reached Ready RP = PP
End of media All media Play No action, RP = Invalid End of media All media Play No action, RP = Invalid
End of media >=1 Media plays Play No action End of media >=1 Media plays Play No action
End of range Play Set RP = End of range End of range Play Set RP = End of range
SETUP New URL,IFI Play NRM+=1, 200, RTP-Info SETUP New URL,IFI Play NRM+=1, 200, *A
SETUP New URL Play 501 SETUP New URL Play 455
SETUP Setuped URL Play Change transport param. SETUP Setuped URL Play 455
SETUP Setuped URL, IFI Play Change transport param.
TEARDOWN URL=* Init No session hdr TEARDOWN URL=* Init No session hdr
TEARDOWN Prs URL,NRM>1 Init No session hdr TEARDOWN Prs URL,NRM>1 Init No session hdr
TEARDOWN md URL,NRM=1,IFI Ready-nm Session hdr TEARDOWN md URL,NRM=1,IFI Ready-nm Session hdr
TEARDOWN md URL,NRM>1,IFI Play Session hdr TEARDOWN md URL,NRM>1,IFI Play Session hdr
TEARDOWN md URL Play 501 TEARDOWN md URL Play 455
S->C:REDIRECT Range hdr Play Set RedP S->C:REDIRECT Range hdr Play Set RedP
S->C:REDIRECT no range hdr Init Stop Media Playout S->C:REDIRECT no range hdr Init Stop Media Playout
RedP reached Init Stop Media playout RedP reached Init Stop Media playout
Timeout Init Timeout Init Stop Media playout
Table 9: State: Play Table 10: State: Play, *A: RTP-Info and Range header
To avoid inconsistencies between the client and server, automatic SHALL be received. |
state transitions are avoided. This can be seen at for example "End
of media" event when all media has finished playing, the session
still remain in Play state. An explicit PAUSE request must be sent to
change the state to Ready. It may appear that there exist two auto-
matic transitions in "RedP reached" and "PP reached", however they
are requested and acknowledge before they take place. The time at
which the transition will happen is known by looking at the range
header. If the client sends request close in time to these transi-
tions it must be prepared for getting error message as the state may
or may not have changed.
SETUP and TEARDOWN requests with media URLs in aggregated sessions The Record state Table 11 has only one event which is unique for this |
may not be handled by the server as it is optional functionality. Use table, namely the "out-of-disc" event. This event will happen if the |
the service discovery mechanism with OPTIONS to find out in before- recording server runs out of disc space. The state machine will |
hand if the server implements it. If the functionality is not imple- remain in the Record state but the server will not be able to perform |
mented but still tried by the client a "501 Not Implemented" response the actions related to the state. |
SHALL be received.
Something is needed to signal the client the fact that the |
server run out of disc space and not was capable of recording |
the data sent by the client. |
B Interaction with RTP
RTSP allows media clients to control selected, non-contiguous sec-
tions of media presentations, rendering those streams with an RTP
media layer[23]. The media layer rendering the RTP stream should not
be affected by jumps in NPT. Thus, both RTP sequence numbers and RTP
Action Requisite New State Response Action Requisite New State Response
------------------------------------------------------------ ------------------------------------------------------------
PAUSE Ready PAUSE No range hdr Ready
PAUSE range hdr > now Record Set PP
PAUSE range hdr <= now Ready Set PP
Out-of-disc Record Stop recording Out-of-disc Record Stop recording
TEARDOWN URL=* Init No session hdr TEARDOWN URL=* Init No session hdr
TEARDOWN Prs URL,NRM>1 Init No session hdr TEARDOWN Prs URL,NRM>1 Init No session hdr
TEARDOWN md URL,NRM=1,IFI Ready-nm Session hdr TEARDOWN md URL,NRM=1,IFI Ready-nm Session hdr
TEARDOWN md URL,NRM>1,IFI Record Session hdr TEARDOWN md URL,NRM>1,IFI Record Session hdr
TEARDOWN md URL Record 501 TEARDOWN md URL Record 501
S->C:REDIRECT Range hdr Record Set RedP S->C:REDIRECT Range hdr Record Set RedP
S->C:REDIRECT w/o range hdr Init Stop Recording S->C:REDIRECT w/o range hdr Init Stop Recording
RedP reached Init Stop Recording RedP reached Init Stop Recording
PP reached Ready Stop Recording
Timeout Init Timeout Init
Table 10: State: Record Table 11: State: Record
The Record state Table 10 has only one event which is unique for this
table, namely the "out-of-disc" event. This event will happen if the
recording server runs out of disc space. The state machine will
remain in the Record state but the server will not be able to perform
the actions related to the state.
Something is needed to signal the client the fact that the
server run out of disc space and not was capable of recording
the data sent by the client.
B Interaction with RTP
RTSP allows media clients to control selected, non-contiguous sec-
tions of media presentations, rendering those streams with an RTP
media layer[23]. The media layer rendering the RTP stream should not
be affected by jumps in NPT. Thus, both RTP sequence numbers and RTP
timestamps MUST be continuous and monotonic across jumps of NPT. timestamps MUST be continuous and monotonic across jumps of NPT.
As an example, assume a clock frequency of 8000 Hz, a packetization As an example, assume a clock frequency of 8000 Hz, a packetization
interval of 100 ms and an initial sequence number and timestamp of interval of 100 ms and an initial sequence number and timestamp of
zero. First we play NPT 10 through 15, then skip ahead and play NPT zero. First we play NPT 10 through 15, then skip ahead and play NPT
18 through 20. The first segment is presented as RTP packets with 18 through 20. The first segment is presented as RTP packets with
sequence numbers 0 through 49 and timestamp 0 through 39,200. The sequence numbers 0 through 49 and timestamp 0 through 39,200. The
second segment consists of RTP packets with sequence number 50 second segment consists of RTP packets with sequence number 50
through 69, with timestamps 40,000 through 55,200. through 69, with timestamps 40,000 through 55,200.
skipping to change at page 1, line 3984 skipping to change at page 1, line 4885
SDP (RFC 2327 [24]): SDP (RFC 2327 [24]):
C.1.1 Control URL C.1.1 Control URL
The "a=control:" attribute is used to convey the control URL. This The "a=control:" attribute is used to convey the control URL. This
attribute is used both for the session and media descriptions. If attribute is used both for the session and media descriptions. If
used for individual media, it indicates the URL to be used for con- used for individual media, it indicates the URL to be used for con-
trolling that particular media stream. If found at the session level, trolling that particular media stream. If found at the session level,
the attribute indicates the URL for aggregate control. the attribute indicates the URL for aggregate control.
control-attribute = "a=" "control" ":" url
Example: Example:
a=control:rtsp://example.com/foo a=control:rtsp://example.com/foo
This attribute may contain either relative and absolute URLs, follow- This attribute may contain either relative and absolute URLs, follow-
ing the rules and conventions set out in RFC 1808 [25]. Implementa- ing the rules and conventions set out in RFC 2396 [22]. Implementa-
tions should look for a base URL in the following order: tions should look for a base URL in the following order:
1. the RTSP Content-Base field; 1. the RTSP Content-Base field;
2. the RTSP Content-Location field; 2. the RTSP Content-Location field;
3. the RTSP request URL. 3. the RTSP request URL.
If this attribute contains only an asterisk (*), then the URL is If this attribute contains only an asterisk (*), then the URL is
treated as if it were an empty embedded URL, and thus inherits the treated as if it were an empty embedded URL, and thus inherits the
entire base URL. entire base URL.
For SDP retrieved from a container file, there are certain things to |
consider. Lets say that the container file has the following URL: |
"rtsp://example.com/container.mp4". A media level relative URL needs |
to contain the file name container.mp4 in the beginning to be |
resolved correctly relative to the before given URL. An alternative |
if one does not desire to enter the container files name is to ensure |
that the base URL for the SDP document becomes: "rtsp://exam- |
ple.com/container.mp4/", i.e. an extra trailing slash. When using |
the URL resolution rules in RFC 2396 that will resolve correctly. |
However as a warning if the session level control URL is a * that |
control URL will be equal to "rtsp://example.com/container.mp4/" and |
include the slash. |
C.1.2 Media Streams C.1.2 Media Streams
The "m=" field is used to enumerate the streams. It is expected that The "m=" field is used to enumerate the streams. It is expected that
all the specified streams will be rendered with appropriate synchro- all the specified streams will be rendered with appropriate synchro-
nization. If the session is unicast, the port number serves as a rec- nization. If the session is unicast, the port number serves as a rec-
ommendation from the server to the client; the client still has to ommendation from the server to the client; the client still has to
include it in its SETUP request and may ignore this recommendation. include it in its SETUP request and may ignore this recommendation.
If the server has no preference, it SHOULD set the port number value If the server has no preference, it SHOULD set the port number value
to zero. to zero.
skipping to change at page 1, line 4023 skipping to change at page 1, line 4939
m=audio 0 RTP/AVP 31 m=audio 0 RTP/AVP 31
C.1.3 Payload Type(s) C.1.3 Payload Type(s)
The payload type(s) are specified in the "m=" field. In case the pay- The payload type(s) are specified in the "m=" field. In case the pay-
load type is a static payload type from RFC 1890 [1], no other infor- load type is a static payload type from RFC 1890 [1], no other infor-
mation is required. In case it is a dynamic payload type, the media mation is required. In case it is a dynamic payload type, the media
attribute "rtpmap" is used to specify what the media is. The "encod- attribute "rtpmap" is used to specify what the media is. The "encod-
ing name" within the "rtpmap" attribute may be one of those specified ing name" within the "rtpmap" attribute may be one of those specified
in RFC 1890 (Sections 5 and 6), or an experimental encoding with a in RFC 1890 (Sections 5 and 6), or an MIME type registered with IANA,
"X-" prefix as specified in SDP (RFC 2327 [24]). Codec-specific or an experimental encoding with a "X-" prefix as specified in SDP
parameters are not specified in this field, but rather in the "fmtp" (RFC 2327 [24]). Codec-specific parameters are not specified in this
attribute described below. Implementors seeking to register new field, but rather in the "fmtp" attribute described below. Implemen-
encodings should follow the procedure in RFC 1890 [1]. If the media tors seeking to register new encodings should follow the procedure in