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 investigate and if suitable develop a framework for advanced
  FEC codes and their usage for RTP, possibly with alignment to
  the RMT WG's FEC building block.

- 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 as 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
  the full intra request. Used to allow joining participants to receive video
  with good quality from the start. It also allows mixers to perform switching
  between media sources without the need to encode the media once more.

- 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
Nov 2005   Submit ULP Payload Format for Proposed Standard
Done	   Finished investigation of advanced FEC codes for RTP, update plan
Dec 2005   Submit any extensions for RTP HC on MPLS networks for Proposed Standard
Mar 2006   Submit SRTP for Draft Standard
Aug 2006   Submit SMTPE Timestamping of Media for Proposed Standard
Sep 2006   Submit RTCP/SSM draft for Proposed Standard
Mar
Nov 2006   Submit SRTP "use of AES-192 and AES-256 in SRTP" for Proposed standard
Nov 2006   Submit update of RTP MIB for Proposed or Draft Standard
Mar
Nov 2006   Submit RTCP XR MIB for Proposed Standard
Nov 2006   Submit RTP Profile for TFRC for Proposed Standard
Aug
Nov 2006   Submit update of RTP MIB RTCP XR High Resolution Audio Metrics for Proposed or Draft Standard
Aug
Nov 2006   Submit Codec Control Messages for Proposed Standard
Mar 2007   Submit SRTP for Draft Standard
Mar 2007   Submit RTCP XR MIB Video Metrics block for Proposed Standard
Sep 2006 2007   Submit RTP/AVPF for Draft Standard