GENWiki

Premier IT Outsourcing and Support Services within the UK

User Tools

Site Tools


rfc:rfc3555

Network Working Group S. Casner Request for Comments: 3555 Packet Design Category: Standards Track P. Hoschka

                                                         W3C/INRIA/MIT
                                                             July 2003
           MIME Type Registration of RTP Payload Formats

Status of this Memo

 This document specifies an Internet standards track protocol for the
 Internet community, and requests discussion and suggestions for
 improvements.  Please refer to the current edition of the "Internet
 Official Protocol Standards" (STD 1) for the standardization state
 and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

 Copyright (C) The Internet Society (2003).  All Rights Reserved.

Abstract

 This document defines the procedure to register RTP Payload Formats
 as audio, video or other MIME subtype names.  This is useful in a
 text-based format or control protocol to identify the type of an RTP
 transmission.  This document also registers all the RTP payload
 formats defined in the RTP Profile for Audio and Video Conferences as
 MIME subtypes.  Some of these may also be used for transfer modes
 other than RTP.

Table of Contents

 1. Introduction ..................................................  2
    1.1. IANA Considerations ......................................  2
    1.2. Terminology ..............................................  3
 2. Procedure For Registering MIME Types for RTP Payload Types ....  3
 3. Mapping to SDP Parameters .....................................  5
 4. Registrations for "Audio/Video Profile" .......................  6
    4.1. Audio Type Registrations .................................  6
    4.2. Video Type Registrations ................................. 30
 5. Security Considerations ....................................... 42
 6. Normative References .......................................... 43
 7. Authors' Addresses ............................................ 44
 8. Full Copyright Statement ...................................... 45

Casner & Hoschka Standards Track [Page 1] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

1. Introduction

 The MIME registration procedure described in RFC 2048 [1] was
 originally designed for transport of multimedia information via
 asynchronous Internet mail, but the MIME namespace now provides
 identification for other transport modes as well.  This document
 defines the procedure to register MIME subtype names for use with the
 Real-time Transport Protocol (RTP), RFC 3550 [2], to identify RTP
 payload formats.
 This document also registers all the RTP payload formats defined in
 the RTP Profile for Audio and Video Conferences, RFC 3551 [3], as
 MIME subtypes under the "audio" and "video" MIME types.

1.1. IANA Considerations

 This document registers the following MIME subtypes:
    audio/DVI4
    audio/G722
    audio/G723
    audio/G726-16
    audio/G726-24
    audio/G726-32
    audio/G726-40
    audio/G728
    audio/G729
    audio/G729D
    audio/G729E
    audio/GSM
    audio/GSM-EFR
    audio/L8
    audio/L16
    audio/LPC
    audio/MPA
    audio/PCMA
    audio/PCMU
    audio/QCELP
    audio/RED
    audio/VDVI
    video/BT656
    video/CelB
    video/JPEG
    video/H261
    video/H263
    video/H263-1998
    video/H263-2000
    video/MPV

Casner & Hoschka Standards Track [Page 2] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

    video/MP2T
    video/MP1S
    video/MP2P
    video/BMPEG
    video/nv
 MIME subtype audio/L16 has already been registered via RFC 2586 for
 transports other than RTP.  That registration is incorporated here
 and augmented with additional information for RTP transport.

1.2. Terminology

 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
 document are to be interpreted as described in RFC 2119 [4] and
 indicate requirement levels for implementations compliant with this
 specification.

2. Procedure For Registering MIME Types for RTP Payload Types

 Registering an RTP payload type as a MIME type follows the same
 procedures as described in RFC 2048 and uses the registration
 template shown in Section 2.8 of RFC 2048.  Some additional
 parameters are required to specify how a particular payload format is
 transported over RTP:
    Published specification
       A description of the encoding and a specification of the
       payload format must be provided, usually by reference to an RTP
       payload format specification RFC.  That RFC may be separate, or
       the MIME subtype registration may be incorporated into the
       payload format specification RFC.  The payload format
       specification MUST include the RTP timestamp clock rate (or
       multiple rates for audio encodings with multiple sampling
       rates).
       A reference to a further description of the data compression
       format itself should be provided, if available.
    Required parameters
       If the payload format does not have a fixed RTP timestamp clock
       rate, then a "rate" parameter is required to specify the RTP
       timestamp clock rate.  A particular payload format may have
       additional required parameters.

Casner & Hoschka Standards Track [Page 3] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

    Optional parameters
       Most audio payload formats can have an optional "channels"
       parameter to specify the number of audio channels included in
       the transmission.  Any payload format, but most likely audio
       formats, may also include the optional parameters "ptime", to
       specify the recommended length of time in milliseconds
       represented by the media in a packet, and/or "maxptime" to
       specify the maximum amount of media which can be encapsulated
       in each packet, expressed as time in milliseconds.  The "ptime"
       and "maxptime" parameters are defined in the Session
       Description Protocol (SDP) [5].
       A particular payload format may have additional optional
       parameters.
    Encoding considerations
       The fact that the type can be transferred via RTP MUST be
       noted.
 Depending on whether the type has already been registered for
 transfer with a non-RTP protocol (e.g. MIME mail or http) or not,
 several different cases can occur:
    a) Not yet registered as a MIME type
       A new registration should be constructed using the MIME
       registration template.  The registration may specify transfer
       via other means in addition to RTP if that is feasible and
       desired.  The encoding considerations must specify how the type
       is transferred via RTP.
       Optional parameters may be defined as needed, and it must be
       clearly stated whether to which mode(s) of transfer the
       parameters apply.
    b) MIME type exists for a non-RTP protocol
       The encoding considerations of the existing type should be
       changed to indicate that the type can also be transferred via
       RTP.
       RTP-specific parameters may be added, and it must be clearly
       stated that these are only to be used when the media type is
       transmitted via RTP transport.

Casner & Hoschka Standards Track [Page 4] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

    c) Update an existing MIME type for RTP to be used for a non-RTP
       protocol
       The encoding considerations of the existing type should be
       changed to indicate that the type can also be transferred via a
       non-RTP protocol (e.g. SMTP, HTTP).
       Non-RTP-specific parameters can be added, and it must be
       clearly stated that these are only to be used when the media
       type is transmitted via a non-RTP transport.

3. Mapping to SDP Parameters

 The representation of a MIME media type is specified in the syntax of
 the Content-Type header field in RFC 2045 [6] as follows:
    type "/" subtype  *(";" parameter)
 Parameters may be required for a particular type or subtype or they
 may be optional.  For media types which represent RTP payload
 formats, the parameters "rate", "channels", "ptime", and "maxptime"
 have general definitions (given above) that may apply across types
 and subtypes.  The format for a parameter is specified in RFC 2045 as
    attribute "=" value
 where attribute is the parameter name and the permissible values are
 specified for each parameter.  The value may need to be a quoted
 string if it contains any of the special characters listed in RFC
 2045.
 The information carried in the media type string has a specific
 mapping to fields in the Session Description Protocol (SDP) [5],
 which is commonly used to describe RTP sessions.  The mapping is as
 follows:
    o  The MIME type (e.g., audio) goes in SDP "m=" as the media name.
    o  The MIME subtype (payload format) goes in SDP "a=rtpmap" as the
       encoding name.
    o  The general (possibly optional) parameters "rate" and
       "channels" also go in "a=rtpmap" as clock rate and encoding
       parameters, respectively.
    o  The general (and optional) parameters "ptime" and "maxptime" go
       in the SDP "a=ptime" and "a=maxptime" attributes, respectively.

Casner & Hoschka Standards Track [Page 5] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

    o  Any payload-format-specific parameters go in the SDP "a=fmtp"
       attribute.  The set of allowed parameters is defined by the RFC
       that specifies the payload format and MUST NOT be extended by
       the MIME subtype registration without a corresponding revision
       of the payload format specification.  The format and syntax of
       these parameters may also be defined by the payload format
       specification, but it is suggested that the parameters be
       copied directly from the MIME media type string as a semicolon
       separated list of parameter=value pairs.  For payload formats
       that specify some other syntax for the fmtp parameters, the
       registration of that payload format as a MIME subtype must
       specify what the parameters are in MIME format and how to map
       them to the SDP "a=fmtp" attribute.  See Section 4.1.21 for an
       example.
 An example mapping is as follows:
    audio/L16; rate=48000; channels=2; ptime=5; emphasis=50-15
    m=audio 49170 RTP/AVP 97
    a=rtpmap:97 L16/48000/2
    a=fmtp:97 emphasis=50-15
    a=ptime:5
 Note that the payload format (encoding) names defined in the RTP
 Profile are commonly shown in upper case.  MIME subtypes are commonly
 shown in lower case.  These names are case-insensitive in both
 places.  Similarly, parameter names are case-insensitive both in MIME
 types and in the default mapping to the SDP a=fmtp attribute.

4. Registrations for "Audio/Video Profile"

 In the following sections, all RTP payload formats described in the
 RTP Profile for Audio and Video Conferences, RFC 3551 [3], are
 registered as MIME subtypes.

4.1. Audio Type Registrations

 The following sections register all of the RTP audio payload types
 defined in RFC 3551 as MIME types.
 For most audio payload formats, the RTP timestamp clock rate is equal
 to the sampling rate.  Some payload formats operate only at one fixed
 sampling rate, while others are adjustable.

Casner & Hoschka Standards Track [Page 6] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.1.1. Registration of MIME media type audio/DVI4

 MIME media type name: audio
 MIME subtype name: DVI4
 Required parameters: rate
      The RTP timestamp clock rate, which is equal to the sampling
      rate.  The typical rate is 8000, but other rates may be
      specified.
 Optional parameters: ptime, maxptime
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 3551
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 7] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.1.2. Registration of MIME media type audio/G722

 MIME media type name: audio
 MIME subtype name: G722
 Required parameters: None
 Optional parameters: ptime, maxptime
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 3551
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 8] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.1.3. Registration of MIME media type audio/G723

 MIME media type name: audio
 MIME subtype name: G723
 Required parameters: None
 Optional parameters:
      ptime, maxptime
      bitrate: the data rate in kb/s used or preferred for the audio
      bit stream, with permissible values 5.3 or 6.3.  If
      unspecified, the bitrate may change from frame to frame as
      indicated inband.
      annexa: indicates that Annex A, voice activity detection, is
      used or preferred.  Permissible values are "yes" and "no"
      (without the quotes); "yes" is implied if this parameter is
      omitted.
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 3551
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 9] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.1.4. Registration of MIME media type audio/G726-16

 MIME media type name: audio
 MIME subtype name: G726-16
 Required parameters: None
 Optional parameters: ptime, maxptime
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 3551
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 10] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.1.5. Registration of MIME media type audio/G726-24

 MIME media type name: audio
 MIME subtype name: G726-24
 Required parameters: None
 Optional parameters: ptime, maxptime
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 3551
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 11] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.1.6. Registration of MIME media type audio/G726-32

 MIME media type name: audio
 MIME subtype name: G726-32
 Required parameters: None
 Optional parameters: ptime, maxptime
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 3551
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 12] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.1.7. Registration of MIME media type audio/G726-40

 MIME media type name: audio
 MIME subtype name: G726-40
 Required parameters: None
 Optional parameters: ptime, maxptime
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 3551
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 13] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.1.8. Registration of MIME media type audio/G728

 MIME media type name: audio
 MIME subtype name: G728
 Required parameters: None
 Optional parameters: ptime, maxptime
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 3551
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 14] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.1.9. Registration of MIME media type audio/G729

 MIME media type name: audio
 MIME subtype name: G729
 Required parameters: None
 Optional parameters:
      ptime, maxptime
      annexb: indicates that Annex B, voice activity detection, is
      used or preferred.  Permissible values are "yes" and "no"
      (without the quotes); "yes" is implied if this parameter is
      omitted.
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 3551
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 15] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.1.10. Registration of MIME media type audio/G729D

 MIME media type name: audio
 MIME subtype name: G729D
 Required parameters: None
 Optional parameters:
      ptime, maxptime
      annexb: indicates that Annex B, voice activity detection, is
      used or preferred.  Permissible values are "yes" and "no"
      (without the quotes); "yes" is implied if this parameter is
      omitted.
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 3551
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 16] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.1.11. Registration of MIME media type audio/G729E

 MIME media type name: audio
 MIME subtype name: G729E
 Required parameters: None
 Optional parameters:
      ptime, maxptime
      annexb: indicates that Annex B, voice activity detection, is
      used or preferred.  Permissible values are "yes" and "no"
      (without the quotes); "yes" is implied if this parameter is
      omitted.
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 3551
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 17] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.1.12. Registration of MIME media type audio/GSM

 MIME media type name: audio
 MIME subtype name: GSM
 Required parameters: None
 Optional parameters: ptime, maxptime
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 3551
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 18] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.1.13. Registration of MIME media type audio/GSM-EFR

 MIME media type name: audio
 MIME subtype name: GSM-EFR
 Required parameters: None
 Optional parameters: ptime, maxptime
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 3551
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 19] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.1.14. Registration of MIME media type audio/L8

 MIME media type name: audio
 MIME subtype name: L8
 Required parameters: rate, the RTP timestamp clock rate
 Optional parameters: channels, ptime, maxptime
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 3551
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 20] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.1.15. Registration of MIME media type audio/L16

 MIME subtype audio/L16 has already been registered via RFC 2586 for
 transports other than RTP.  That registration is incorporated here
 and augmented with additional information for RTP transport.
 MIME media type name: audio
 MIME subtype name: L16
 Required parameters
      rate: number of samples per second -- For non-RTP transport,
      the permissible values for rate are 8000, 11025, 16000, 22050,
      24000, 32000, 44100, and 48000 samples per second.  For RTP
      transport, other values are permissible but the aforementioned
      values are RECOMMENDED.  For RTP, the rate parameter indicates
      the RTP timestamp clock rate, which is equal to the sample
      rate.
 Optional parameters
      channels: how many audio streams are interleaved -- defaults
      to 1; stereo would be 2, etc.  Interleaving takes place
      between individual two-byte samples.
      emphasis: analog preemphasis applied to the signal before
      quantization.  The only emphasis value defined here is
      emphasis=50-15 to indicate the 50/15 microsecond preemphasis
      used with Compact Disks.  This parameter MUST be omitted if no
      analog preemphasis was applied.
      channel-order: specifies the sample interleaving order for
      multiple-channel audio streams (see [7] Section 7).
      Permissible values are DV.LRLsRs, DV.LRCS, DV.LRCWo,
      DV.LRLsRsC, DV.LRLsRsCS, DV.LmixRmixTWoQ1Q2,
      DV.LRCWoLsRsLmixRmix, DV.LRCWoLs1Rs1Ls2Rs2, DV.LRCWoLsRsLcRc.
      For interoperation with DV video systems, only a subset of
      these channel combinations is specified for use with 20-bit
      linear encoding in the DV video specification [4]; those are
      DV.LRLsRs, DV.LRCS, DV.LmixRmixTWoQ1Q2.  This parameter MUST
      be omitted when the AIFF-C channel order convention (see RFC
      3551) is in use.
      For RTP, ptime: RECOMMENDED duration of each packet in
      milliseconds.
      For RTP, maxptime: maximum duration of each packet in
      milliseconds.

Casner & Hoschka Standards Track [Page 21] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

 Encoding considerations
      Audio data is binary data, and must be encoded for non-binary
      transport; the Base64 encoding is suitable for Email.  Note
      that audio data does not compress easily using lossless
      compression.
      This type is also defined for transfer via RTP [RFC 3550].
 Security considerations
      Audio data is believed to offer no security risks.
      See Section 5 of RFC 3555.
 Interoperability considerations
      This type is compatible with the encoding used in the WAV
      (Microsoft Windows RIFF) and Apple AIFF union types, and with
      the public domain "sox" and "rateconv" programs.
 Published specification
      RFC 2586 for non-RTP transports, RFC 3551 for RTP
 Applications which use this media
      The public domain "sox" and "rateconv" programs accept this
      type.
      1. Magic number(s) : None
      2. File extension(s) : WAV L16
      3. Macintosh file type code : AIFF
 Person to contact for further information
      1. Name : James Salsman
      2. E-mail : jps-L16@bovik.org
 Intended usage
      Common
      It is expected that many audio and speech applications will
      use this type.  Already the most popular platforms provide
      this type with the rate=11025 parameter referred to as "radio
      quality speech."
 Author/Change controller
      James Salsman for non-RTP transports.
      Stephen Casner for RTP transport.

Casner & Hoschka Standards Track [Page 22] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.1.16. Registration of MIME media type audio/LPC

 MIME media type name: audio
 MIME subtype name: LPC
 Required parameters: None
 Optional parameters: ptime, maxptime
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 3551
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 23] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.1.17. Registration of MIME media type audio/MPA

 MIME media type name: audio
 MIME subtype name: MPA (MPEG audio)
 Required parameters: None
 Optional parameters:
      layer: which layer of MPEG audio encoding; permissible values
      are 1, 2, 3.
      samplerate: the rate at which audio is sampled.  MPEG-1 audio
      supports sampling rates of 32, 44.1, and 48 kHz; MPEG-2
      supports sampling rates of 16, 22.05 and 24 kHz.  This parameter
      is separate from the RTP timestamp clock rate which is always
      90000 Hz for MPA.
      mode: permissible values are "stereo", "joint_stereo",
      "single_channel", "dual_channel".  The "channels" parameter
      does not apply to MPA.  It is undefined to put a number of
      channels in the SDP rtpmap attribute for MPA.
      bitrate: the data rate for the audio bit stream.
      ptime: RECOMMENDED duration of each packet in milliseconds.
      maxptime: maximum duration of each packet in milliseconds.
      Parameters which are omitted are left to the encoder to choose
      based on the session bandwidth, configuration information, or
      other constraints.  The selected layer as well as the sampling
      rate and mode are indicated in the payload so receivers can
      process the data without these parameters being specified
      externally.
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 3551
 Applications which use this media type:
      Audio and video streaming and conferencing tools.

Casner & Hoschka Standards Track [Page 24] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

4.1.18. Registration of MIME media type audio/PCMA

 MIME media type name: audio
 MIME subtype name: PCMA
 Required parameters: rate
      The RTP timestamp clock rate, which is equal to the sampling
      rate.  The typical rate is 8000, but other rates may be
      specified.
 Optional parameters: channels, ptime, maxptime
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 3551
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 25] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.1.19. Registration of MIME media type audio/PCMU

 MIME media type name: audio
 MIME subtype name: PCMU
 Required parameters: rate
      The RTP timestamp clock rate, which is equal to the sampling
      rate.  The typical rate is 8000, but other rates may be
      specified.
 Optional parameters: channels, ptime, maxptime
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 3551
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 26] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.1.20. Registration of MIME media type audio/QCELP

 MIME media type name: audio
 MIME subtype name: QCELP
 Required parameters: None
 Optional parameters: ptime, maxptime
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 2658
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 27] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.1.21. Registration of MIME media type audio/RED

 MIME media type name: audio
 MIME subtype name: RED
 Required parameters:
      pt: a comma-separated list of RTP payload types.  Because
      comma is a special character, the list must be a quoted-string
      (enclosed in double quotes).  For static payload types, each
      list element is simply the type number.  For dynamic payload
      types, each list element is a mapping of the dynamic payload
      type number to an embedded MIME content-type specification for
      the payload format corresponding to the dynamic payload type.
      The format of the mapping is:
         dynamic-payload-type "=" content-type
      If the content-type string includes a comma, then the
      content-type string MUST be a quoted-string.  If the content-
      type string does not include a comma, it MAY still be quoted.
      Since it is part of the list which must itself be a quoted-
      string, that means the quotation marks MUST be quoted with
      backslash quoting as specified in RFC 2045.  If the content-
      type string itself contains a quoted-string, then the
      requirement for backslash quoting is recursively applied.  To
      specify the audio/RED payload format in SDP, the pt parameter
      is mapped to an a=fmtp attribute by eliminating the parameter
      name (pt) and changing the commas to slashes.  For example,
      'pt="0,5"' maps to 'a=fmtp:99 0/5'.  A more complicated
      example, with a dynamic payload type, is:
         pt = "0, 103 = \"audio/G729D;annexb=yes\" "
         m=audio 49170 RTP/AVP 99 0 103
         a=rtpmap:99 RED/8000
         a=fmtp:99 0/103
         a=rtpmap:103 G729D/8000
         a=fmtp:103 annexb=yes
 Optional parameters: ptime, maxptime
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none

Casner & Hoschka Standards Track [Page 28] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

 Published specification: RFC 2198
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

4.1.22. Registration of MIME media type audio/VDVI

 MIME media type name: audio
 MIME subtype name: VDVI
 Required parameters: None
 Optional parameters: ptime, maxptime
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 3551
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 29] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.2. Video Type Registrations

 For all of the video payload formats registered here, the RTP
 timestamp clock rate is always 90000 Hz, so the "rate" parameter is
 not applicable.  Likewise, the "channel" parameter is not used with
 video, and while "ptime" and "maxptime" could be used with video,
 they typically are not.

4.2.1. Registration of MIME media type video/BT656

 MIME media type name: video
 MIME subtype name: BT656
 Required parameters: None
 Optional parameters: None
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 2431
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 30] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.2.2. Registration of MIME media type video/CelB

 MIME media type name: video
 MIME subtype name: CelB
 Required parameters: None
 Optional parameters: None
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 2029
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 31] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.2.3. Registration of MIME media type video/JPEG

 MIME media type name: video
 MIME subtype name: JPEG
 Required parameters: None
 Optional parameters: None
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 2435
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 32] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.2.4. Registration of MIME media type video/H261

 MIME media type name: video
 MIME subtype name: H261
 Required parameters: None
 Optional parameters: None
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 2032
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 33] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.2.5. Registration of MIME media type video/H263

 MIME media type name: video
 MIME subtype name: H263
 Required parameters: None
 Optional parameters: None
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 2190
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 34] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.2.6. Registration of MIME media type video/H263-1998

 MIME media type name: video
 MIME subtype name: H263-1998
 Required parameters: None
 Optional parameters: None
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 2429
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 35] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.2.7. Registration of MIME media type video/H263-2000

 MIME media type name: video
 MIME subtype name: H263-2000
 Required parameters: None
 Optional parameters:
      profile: H.263 profile number, in the range 0 through 10,
      specifying the supported H.263 annexes/subparts.
      level: Level of bitstream operation, in the range 0 through
      100, specifying the level of computational complexity of the
      decoding process.
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 2429
      The specific values for the profile and level parameters and
      their meaning are defined in Annex X of ITU-T Recommendation
      H.263, "Video coding for low bit rate communication".  Note
      that the RTP payload format for H263-2000 is the same as for
      H263-1998, but additional annexes/subparts are specified along
      with the profiles and levels.
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 36] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.2.8. Registration of MIME media type video/MPV

 MIME media type name: video
 MIME subtype name: MPV
      MPEG-1 or -2 Elementary Streams
 Required parameters: None
 Optional parameters:
      type: the type of MPEG video, from the set "mpeg1",
      "mpeg2-halfd1", or "mpeg2-fulld1".  The default is "mpeg1".
      The mapping to a=fmtp is identity.
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 2250
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 37] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.2.9. Registration of MIME media type video/MP2T

 MIME media type name: video
 MIME subtype name: MP2T
      MPEG-2 Transport Streams
 Required parameters: None
 Optional parameters: None
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 2250
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 38] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.2.10. Registration of MIME media type video/MP1S

 MIME media type name: video
 MIME subtype name: MP1S
      MPEG-1 Systems Streams
 Required parameters: None
 Optional parameters: None
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 2250
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 39] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.2.11. Registration of MIME media type video/MP2P

 MIME media type name: video
 MIME subtype name: MP2P
      MPEG-2 Program Streams
 Required parameters: None
 Optional parameters: None
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 2250
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 40] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.2.12. Registration of MIME media type video/BMPEG

 MIME media type name: video
 MIME subtype name: BMPEG
 Required parameters: None
 Optional parameters: None
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 2343
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

Casner & Hoschka Standards Track [Page 41] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

4.2.13. Registration of MIME media type video/nv

 MIME media type name: video
 MIME subtype name: nv
 Required parameters: None
 Optional parameters: None
 Encoding considerations:
      This type is only defined for transfer via RTP [RFC 3550].
 Security considerations: See Section 5 of RFC 3555
 Interoperability considerations: none
 Published specification: RFC 3551
 Applications which use this media type:
      Audio and video streaming and conferencing tools.
 Additional information: none
 Person & email address to contact for further information:
      Stephen Casner <casner@acm.org>
 Intended usage: COMMON
 Author/Change controller:
      Stephen Casner

5. Security Considerations

 The MIME subtype registration procedure specified in this memo does
 not impose any security considerations on its own.  This memo also
 contains several MIME type registrations.  The registrations
 themselves do not impose security risks, but some may state security
 considerations specific to the particular registration.
 Several audio and video encodings are perfect for hiding data using
 steganography.
 The RTP specification, RFC 3550, provides security considerations for
 the transport of audio and video data over RTP, including the use of
 encryption where confidentiality is required.

Casner & Hoschka Standards Track [Page 42] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

6. Normative References

 [1] Freed, N., Klensin, J. and J. Postel, "Multipurpose Internet Mail
     Extensions (MIME) Part Four: Registration Procedures", BCP 13,
     RFC 2048, November 1996.
 [2] Schulzrinne, H., Casner, S., Frederick, R. and V. Jacobson, "RTP:
     A Transport Protocol for Real-Time Applications", RFC 3550, July
     2003.
 [3] Schulzrinne, H. and S. Casner, "RTP Profile for Audio and Video
     Conferences with Minimal Control", RFC 3551, July 2003.
 [4] Bradner, S., "Key words for use in RFCs to Indicate Requirement
     Levels", BCP 14, RFC 2119, March 1997.
 [5] Handley, M. and V. Jacobson, "SDP: Session Description Protocol",
     RFC 2327, April 1998.
 [6] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
     Extensions (MIME) Part One: Format of Internet Message Bodies",
     RFC 2045, November 1996.
 [7] Kobayashi, K., Ogawa, A., Casner, S. and C. Bormann, "RTP Payload
     Format for 12-bit DAT Audio and 20- and 24-bit Linear Sampled
     Audio", RFC 3190, January 2002.

Casner & Hoschka Standards Track [Page 43] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

7. Authors' Addresses

 Stephen L. Casner
 Packet Design
 3400 Hillview Avenue, Building 3
 Palo Alto, CA 94304
 United States
 Phone: +1 650 739-1843
 EMail: casner@acm.org
 Philipp Hoschka
 INRIA
 Route des Lucioles 2004
 06904, Sophia-Antipolis Cedex
 BP 93, France
 Phone: (+33) 4 92 38 79 84
 Fax:   (+33) 4 92 38 77 65
 EMail: ph@w3.org
 W3C
 http://www.w3.org/people/hoschka

Casner & Hoschka Standards Track [Page 44] RFC 3555 MIME Type Registration of RTP Payload Formats July 2003

8. Full Copyright Statement

 Copyright (C) The Internet Society (2003).  All Rights Reserved.
 This document and translations of it may be copied and furnished to
 others, and derivative works that comment on or otherwise explain it
 or assist in its implementation may be prepared, copied, published
 and distributed, in whole or in part, without restriction of any
 kind, provided that the above copyright notice and this paragraph are
 included on all such copies and derivative works.  However, this
 document itself may not be modified in any way, such as by removing
 the copyright notice or references to the Internet Society or other
 Internet organizations, except as needed for the purpose of
 developing Internet standards in which case the procedures for
 copyrights defined in the Internet Standards process must be
 followed, or as required to translate it into languages other than
 English.
 The limited permissions granted above are perpetual and will not be
 revoked by the Internet Society or its successors or assigns.
 This document and the information contained herein is provided on an
 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

 Funding for the RFC Editor function is currently provided by the
 Internet Society.

Casner & Hoschka Standards Track [Page 45]

/data/webs/external/dokuwiki/data/pages/rfc/rfc3555.txt · Last modified: 2003/07/14 19:12 by 127.0.0.1

Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki