Audio/Video Transport (avt)

In addition to this official charter maintained by the IETF Secretariat, there is additional information about this working group on the Web at:

RTP FAQ Page

Last Modified: 2006-08-22

Additional information is available at tools.ietf.org/wg/avt

Chair(s):

Colin Perkins <csp@csperkins.org>

Tom Taylor <taylor@nortel.com>

Roni Even <roni.even@polycom.co.il>

Real-time Applications and Infrastructure Area Director(s):

Jon Peterson <jon.peterson@neustar.biz>

Cullen Jennings <fluffy@cisco.com>

Real-time Applications and Infrastructure Area Advisor:

Cullen Jennings <fluffy@cisco.com>

Mailing Lists:

General Discussion: avt@ietf.org
To Subscribe: https://www1.ietf.org/mailman//listinfo/avt
Archive: http://www.ietf.org/mail-archive/web/avt/index.html

Description of Working Group:

The Audio/Video Transport Working Group was formed to specify a
protocol for real-time transmission of audio and video over unicast
and multicast UDP/IP. This is the Real-time Transport Protocol, RTP,
together with its associated profiles and payload formats. The current
aims of the working group are:

- to review and revise existing payload formats to advance those which
are useful to Draft Standard, and to declare others as
Historic. Milestones will be established as a champion for each
payload format is identified.

- to develop payload formats for new media codecs, and to document
best-current practices in payload format design. The group continues
to be precluded from work on codecs themselves because of overlap with
the other standards bodies, and because the IETF does not have the
ability to effectively review new codecs. An exception was made for
the freeware iLBC codec on a highly experimental basis, but acceptance
of new codec work is unexpected and subject to rechartering.

- to complete the forward error correction work to update RFC 2733 in
the form of the ULP payload format

- to extend RTP to work with Source-Specific Multicast sessions with
unicast feedback

- to provide a framing mechanism for RTP over TCP and TLS

- in collaboration with the MPLS and ROHC WGs, to develop a solution
for
header compression of RTP across MPLS networks that avoid
decompression and compression at each MPLS node.

- to develop a new RTP profile for the combination of the SRTP profile
and the Extended RTP Profile for RTCP-based Feedback (RTP/SAVPF)

- to maintain and enhance the SRTP Profile, with review and input from
the Security Area

- to develop a new RTP profile for usage of TFRC (RFC 3448) with RTP
over UDP to allow application developers to gain experience with TCP
friendly congestion control.

- to develop a MIB for RTCP XR (RFC 3611).

- to update the RTP MIB, including aligning it with RFC 3550.

- to clarify how RTP is used for media in conferencing with centralized
nodes performing relay, translation or mixing of media.

- to develop the mechanisms needed for efficient control of media and
its encoding process in RTP based conferencing, both over multicast
and transport containing relays, translators and mixers. An example of
such a mechanism is a method to request a full intra coded frame of
video. This would be used to allow joining participants to receive
video immediately after joining instead of waiting for the next intra
coded frame. It also allows mixers to perform switching between media
sources without the need to re-encode the media.

- to develop a solution for carrying media meta data, specifically
SMPTE timestamps, to enhance the media stream. Such transport may be
done in either RTP or RTCP depending on which is most suitable. The WG
may consider if a generalized mechanism should be developed to enable
future types of meta data to be easier to include.

- to develop two new metric blocks for the RTCP XR (RFC 3611) framework
to provide information on the media quality experienced by the
receiver of RTP flows. One metrics block is for high resolution
measurements of audio and speech quality. A second one for providing
information on the quality of video. The timescale to complete this
second block and the included metrics are highly dependable on the
development of standardized subjective metrics for video quality. The
WG will consider what metrics that are available and if they should be
included or not. The metrics blocks shall not duplicate signaling
information anyway necessary for the establishment of the session.

The longer term goals of the working group are to advance the SRTP
Profile, the Extended RTP Profile for RTCP-based Feedback, the
Compressed RTP framework, and the RTP MIB to Draft Standard.

The group has no plans to develop new RTP profiles beyond those listed
above, but will consider rechartering to produce profile level
extensions if appropriate.

Goals and Milestones:

Done		Review DCCP including prototypes and API; feedback to DCCP WG
Done		Initial draft requirements for ECRTP over MPLS; discuss with MPLS WG
Done		Submit iLBC payload format for Proposed Standard
Done		Submit iLBC codec specification for Experimental
Done		Advance RTP specification and A/V profile to Full Standard
Done		Submit RTP/SAVPF profile for Proposed Standard
Done		Finished investigation of advanced FEC codes for RTP, update plan
Done		Submit ULP Payload Format for Proposed Standard
Aug 2006		Submit SMTPE Timestamping of Media for Proposed Standard
Sep 2006		Submit RTCP/SSM draft for Proposed Standard
Nov 2006		Submit update of RTP MIB for Proposed or Draft Standard
Nov 2006		Submit RTCP XR MIB for Proposed Standard
Nov 2006		Submit
Nov 2006		Submit RTP Profile for TFRC for Proposed Standard
Nov 2006		Submit RTCP XR High Resolution Audio Metrics for Proposed Standard
Nov 2006		Submit Codec Control Messages for Proposed Standard
Mar 2007		Submit SRTP for Draft Standard
Mar 2007		Submit RTCP XR Video Metrics block for Proposed Standard
Sep 2007		Submit RTP/AVPF for Draft Standard

Internet-Drafts:

RTP Payload Format for Generic Forward Error Correction (99256 bytes)
RTCP Extensions for Single-Source Multicast Sessions with Unicast Feedback (152206 bytes)
RTP Payload Format for JPEG 2000 Video Streams (59751 bytes)
RTP Payload for DTMF Digits, Telephony Tones and Telephony Signals (124512 bytes)
Extended Secure RTP Profile for RTCP-based Feedback (RTP/SAVPF) (38176 bytes)
RTP Payload Format for ITU-T Rec. H.263 Video (66105 bytes)
RTP Profile for TCP Friendly Rate Control (27445 bytes)
RTP Payload Format for ATRAC Family (59785 bytes)
RTP Payload Format for H.263 using RFC2190 to Historic status (9844 bytes)
RTP Control Protocol Extended Reports (RTCP XR) VoIP Metrics Management Information Base (80227 bytes)
RTP Payload Format and File Storage Format for the Adaptive Multi-Rate (AMR) and Adaptive Multi-Rate Wideband (AMR-WB) Audio Codecs (140759 bytes)
Definition of Events For Modem, FAX, and Text Telephony Signals (119259 bytes)
Media Type Registration of RTP Payload Formats (25119 bytes)
Protocol Extensions for Header Compression over MPLS (75940 bytes)
A general mechanism for RTP Header Extensions (27688 bytes)
Associating Time-codes with RTP streams (25722 bytes)
RTP Payload Format for ITU-T Recommendation G.722.1 (22473 bytes)
Enhancements to RTP Payload Formats for EVRC Family Codecs (43032 bytes)
Real-time Transport Protocol (RTP) MIB Version 2 (65253 bytes)
Media Type Registration of Payload Formats in the RTP Profile for Audio and Video Conferences (47877 bytes)
How to Write an RTP Payload Format (101953 bytes)
Transmission Time offsets in RTP streams (16932 bytes)
The use of AES-192 and AES-256 in Secure RTP (28538 bytes)
RTP Topologies (37242 bytes)
Codec Control Messages in the RTP Audio-Visual Profile with Feedback (AVPF) (113517 bytes)
Multiplexing RTP Data and Control Packets on a Single Port (31545 bytes)
RTCP XR - IP Video Metrics Report Blocks (38847 bytes)

Request For Comments:

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