Audio/Video Transport (avt)

Last modified: 2011-03-18

Additional information is available at the RTP FAQ Page

Chairs

Real-Time Applications and Infrastructure Area Directors

Real-Time Applications and Infrastructure Area Advisor

Mailing Lists:

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

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, along with its
associated profiles and payload formats.

RTP itself has been shepherded to Full Standard. Its associated
profiles, extensions, and payload formats are currently at various
levels of stardards maturity. This working group's current work
centers in four areas:

1) Maintenance of the core RTP/RTCP protocols and the AVP, SAVP, AVPF,
and SAVPF profiles

2) Specification and maintenance of payload formats for use with RTP

3) Specification of metric blocks for use with the RTCP Extended Report
(XR) framework

4) Extensions to the core protocols to facilitate joining,
synchronizing, control, and monitoring of RTP multimedia
sessions

In these areas, the group is chartered to focus on the following
tasks. Work supporting those areas, but not reflected in these
tasks must not be accepted by the working group without an explicit
re-chartering. In particular, new items supporting the fourth area
are expected to be reviewed in DISPATCH before being considered new
charter items for this group.

1) Maintenance of the core RTP/SRTP/RTCP protocols
and the AVP, SAVP, AVPF, and SAVPF profiles
- maintain and enhance the SRTP Profile, with review and input
from the Security Area
- specify how to use Explicit Congestion Notification (ECN)
with RTP/RTCP
- continue to investigate the export of summarized RTP/RTCP
information for operations and monitoring purposes

2) Specification and maintenance of payload formats for use with RTP
- provide guidelines for payload format design
- develop payload formats for new media codecs
- review and revise existing payload formats to advance those
which are useful to Draft Standard or Standard, and to
declare others as Historic.

3) Specification of metric blocks for use with the
RTCP Extended Report (XR) framework
- provide a mechanism allowing identification data for
a set of related metric reports to be carried separately
and identified in those reports by reference
- provide report blocks for delay, delay variation, and discard
- provide report blocks for burst/gap discard and loss
- provide report blocks supporting rapid synchronization
of multiple RTP streams
- provide report blocks for jitter buffer metrics
- provide report blocks for loss concealment metrics

4) Extensions to the core protocols to facilitate joining,
synchronizing, control, and monitoring of RTP multimedia
sessions
- develop tools to support rapid acquisition of multimedia streams
- specify necessary extensions to support rapid synchronization of
multiple RTP streams

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 Submit ULP Payload Format for Proposed Standard
Done Finished investigation of advanced FEC codes for RTP, update plan
Done Submit SMTPE Timestamping of Media for Proposed Standard
Done Submit Codec Control Messages for Proposed Standard
Done Submit Multiplexing of RTCP and RTP on the same port for Proposed Standard
Done Submit RTCP/SSM draft for Proposed Standard
Done Submit draft on Enhancing RTP header extensions for proposed standard
Done Submit RTP Payload Format for ITU-T Recommendation G.711.1 for Proposed Standard
Done Submit RTP payload format for mU-law EMbedded Codec for Low-delay IP communication (UEMCLIP) speech codec for Proposed Standard
Done Submit Transmission Time offsets in RTP streams for Proposed Standard
Done Submit RTP Payload Format for Adaptive TRansform Acoustic Coding (ATRAC) Family for Proposed Standard
Done Submit RTP Payload Format for JPEG 2000 Video Streams for Proposed Standard
Done Submit Payload Format for JPEG 2000 Video: Extensions for Scalability and Main Header Recovery for Proposed Standard
Done Submit RTP Payload Format for the Speex Codec for Proposed Standard
Done Submit G.729.1 RTP Payload Format update: DTX support for Proposed Standard
Done Submit RTP Payload Format for ITU-T Recommendation G.722.1 for Proposed Standard
Done Submit draft on Mechanisms to keep NAT bindings for RTP flows alive for BCP
Done Submit The SEED Cipher Algorithm and Its Use with the Secure Real-time Transport Protocol (SRTP) for Proposed Standard
Done Submit RTP Payload Format for Elementary Streams with MPEG Surround multi-channel audio for Proposed Standard
Done Submit Support for reduced size RTCP, opportunities and consequences
Done Submit RTP Payload Format for SPIRIT IP-MR Speech Codec Software for Proposed Standard
Done Submit Post-Repair Loss RLE Report Block Type for RTCP XR for Proposed Standard
Done Submit RTP Payload Format for H.264 Video for Proposed Standard
Done Submit RTP Payload Format for G.719 audio for Proposed Standard
Done Submit draft explaining why SRTP need not be mandatory for media transport, for Informational
Done Policy for Registering SRTP Transforms for Proposed Standard
Done RTP Payload Format for GSM-HR for Proposed Standard
Done Submit RTP Payload Format for H.264 RCDO Video for Proposed Standard
Done Submit Unicast-Based Rapid Acquisition of Multicast RTP Sessions for Proposed Standard
Done Submit Rapid Synchronization of RTP Flows for Proposed Standard
Done Submit Forward-shifted RTP Redundancy Payload Support for Proposed Standard
Done Submit RTP Payload Format for SVC Video for Proposed Standard
Done Submit Guidelines for Extending the RTP Control Protocol (RTCP) for Informational
Done Submit Guideline for Choosing RTCP CNAME as proposed standard
Done Submit RTCP port for multicast sessions as proposed standard
Done Submit use of AES-192 and AES-256 in Secure RTP for Proposed Standard

Internet-Drafts

Request for Comments