Audio/Video Transport (avt)
---------------------------

 Charter
 Last Modified: 2008-04-23

 Current Status: Active Working Group

 Chair(s):
     Colin Perkins  <csp@csperkins.org>
     Roni Even  <roni.even@polycom.co.il>
     Tom Taylor  <tom.taylor@rogers.com>

 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
centralised 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 signalling information anyway necessary for the
establishment of the session.
          
- to specify how the RFC 3550 requirement on RTCP senders to always
send compound packets can be relaxed to allow for non-compound
packets. The specification need to define under which criteria
non-compound RTCP packets may be sent while maintaining the
functionality that motivated the usage of compound RTCP packets
and keep the bandwidth within specified limits.
          
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 

   Feb 2007       Submit Codec Control Messages for Proposed Standard 

   Done         Submit SMTPE Timestamping of Media for Proposed Standard 

   Mar 2007       Submit SRTP for Draft Standard 

   Mar 2007       Submit RTCP XR Video Metrics block for Proposed Standard 

   Done         Submit Multiplexing of RTCP and RTP on the same port for 
                Proposed Standard 

   Apr 2007       Submit RTCP/SSM draft for Proposed Standard 

   Jul 2007       Submit update of RTP MIB for Proposed or Draft Standard 

   Done         Submit draft on Enhancing RTP header extensions for proposed 
                standard 

   Aug 2007       Submit RTCP XR MIB for Proposed Standard 

   Aug 2007       Submit RTCP XR High Resolution Audio Metrics for Proposed 
                Standard 

   Sep 2007       Submit RTP/AVPF for Draft Standard 

   Dec 2007       Submit in band keying mechanism for SRTP draft for Proposed 
                Standard 

   Feb 2008       Submit draft on Mechanisms to keep NAT bindings for RTP flows 
                alive for BCP 

   Sep 2008       Submit Non-Compound usage specification for PS 


 Internet-Drafts:

Posted Revised         I-D Title   <Filename>
------ ------- --------------------------------------------
Feb 2002 Jan 2008   <draft-ietf-avt-rtcpssm-17.txt>
                RTCP Extensions for Single-Source Multicast Sessions with 
                Unicast Feedback 

May 2002 Apr 2008   <draft-ietf-avt-rtp-jpeg2000-19.txt>
                RTP Payload Format for JPEG 2000 Video Streams 

Aug 2004 Apr 2008   <draft-ietf-avt-rtp-atrac-family-16.txt>
                RTP Payload Format for Adaptive TRansform Acoustic Coding 
                (ATRAC) Family 

Feb 2005 Apr 2008   <draft-ietf-avt-rtp-jpeg2000-beam-10.txt>
                Payload Format for JPEG 2000 Video: Extensions for Scalability 
                and Main Header Recovery 

Aug 2005 Jun 2008   <draft-ietf-avt-smpte-rtp-13.txt>
                Associating Time-codes with RTP streams 

Aug 2005 Mar 2008   <draft-ietf-avt-rtp-hdrext-15.txt>
                A general mechanism for RTP Header Extensions 

Aug 2005 May 2008   <draft-ietf-avt-rfc3047-bis-06.txt>
                RTP Payload Format for ITU-T Recommendation G.722.1 

Oct 2005 Feb 2008   <draft-ietf-avt-rtp-speex-05.txt>
                RTP Payload Format for the Speex Codec 

Feb 2006 Feb 2008   <draft-ietf-avt-rtp-vorbis-09.txt>
                RTP Payload Format for Vorbis Encoded Audio 

May 2006 Feb 2008   <draft-ietf-avt-rtp-howto-03.txt>
                How to Write an RTP Payload Format 

Aug 2006 Mar 2008   <draft-ietf-avt-rtp-toffset-07.txt>
                Transmission Time offsets in RTP streams 

Oct 2006 Aug 2007   <draft-ietf-avt-rtp-and-rtcp-mux-07.txt>
                Multiplexing RTP Data and Control Packets on a Single Port 

Dec 2006 Jun 2008   <draft-ietf-avt-rtp-svc-11.txt>
                RTP Payload Format for SVC Video 

Jan 2007 Feb 2008   <draft-ietf-avt-rfc4695-bis-03.txt>
                RTP Payload Format for MIDI 

Feb 2007 Feb 2008   <draft-ietf-avt-rtcphr-03.txt>
                RTCP HR - High Resolution VoIP Metrics Report Blocks 

May 2007 Mar 2008   <draft-ietf-avt-rfc3189bis-01.txt>
                RTP Payload Format for DV (IEC 61834) Video 

May 2007 Feb 2008   <draft-ietf-avt-rtp-uemclip-04.txt>
                RTP payload format for mU-law EMbedded Codec for Low-delay IP 
                communication (UEMCLIP) speech codec 

Jun 2007 Apr 2008   <draft-ietf-avt-app-rtp-keepalive-03.txt>
                Application Mechanism for maintaining alive the Network Address 
                Translator (NAT) mappings associated to RTP flows. 

Jul 2007 Jan 2008   <draft-ietf-avt-rtp-h264-params-01.txt>
                Parameters for Static Macroblocks and Aspect Ratio in the RTP 
                Payload Format for H.264 Video 

Jul 2007 Feb 2008   <draft-ietf-avt-dtls-srtp-02.txt>
                Datagram Transport Layer Security (DTLS) Extension to Establish 
                Keys for Secure Real-time Transport Protocol (SRTP) 

Sep 2007 Mar 2008   <draft-ietf-avt-forward-shifted-red-01.txt>
                Forward-shifted RTP Redundancy Payload Support 

Oct 2007 May 2008   <draft-ietf-avt-seed-srtp-02.txt>
                The SEED Cipher Algorithm and Its Use with the Secure Real-time 
                Transport Protocol (SRTP) 

Nov 2007 May 2008   <draft-ietf-avt-rtcp-non-compound-05.txt>
                Support for reduced size RTCP, opportunities and consequences 

Dec 2007 May 2008   <draft-ietf-avt-rtp-h264-rcdo-01.txt>
                RTP Payload Format for H.264 RCDO Video 

Feb 2008 May 2008   <draft-ietf-avt-rfc4749-dtx-update-01.txt>
                G.729.1 RTP Payload Format update: DTX support 

Apr 2008 Apr 2008   <draft-ietf-avt-rtp-g711wb-03.txt>
                RTP Payload Format for ITU-T Recommendation G.711.1 

Apr 2008 Apr 2008   <draft-ietf-avt-rtp-ipmr-00.txt>
                RTP Payload Format for SPIRIT IP-MR Speech Codec Software 

 Request For Comments:

  RFC   Stat Published     Title
------- -- ----------- ------------------------------------
RFC1889 PS   Jan 1996    RTP: A Transport Protocol for Real-Time Applications 

RFC1890 PS   Jan 1996    RTP Profile for Audio and Video Conferences with Minimal 
                       Control 

RFC2029 PS   Oct 1996    RTP Payload Format of Sun's CellB Video Encoding 

RFC2038 PS   Oct 1996    RTP Payload Format for MPEG1/MPEG2 Video 

RFC2032 PS   Oct 1996    RTP payload format for H.261 video streams 

RFC2035 PS   Oct 1996    RTP Payload Format for JPEG-compressed Video 

RFC2190 PS   Sep 1997    RTP Payload Format for H.263 Video Streams 

RFC2198 PS   Sep 1997    RTP Payload for Redundant Audio Data 

RFC2250 PS   Jan 1998    RTP Payload Format for MPEG1/MPEG2 Video 

RFC2343 E    May 1998    RTP Payload Format for Bundled MPEG 

RFC2354 I    Jun 1998    Options for Repair of Streaming Media 

RFC2429 PS   Oct 1998    RTP Payload Format for the 1998 Version of ITU-T Rec. 
                       H.263 Video (H.263+) 

RFC2431 PS   Oct 1998    RTP Payload Format for BT.656 Video Encoding 

RFC2435 PS   Oct 1998    RTP Payload Format for JPEG-compressed Video 

RFC2508 PS   Feb 1999    Compressing IP/UDP/RTP Headers for Low-Speed Serial 
                       Links 

RFC2733 PS   Dec 1999    An RTP Payload Format for Generic Forward Error 
                       Correction 

RFC2736BCP  Dec 1999    Guidelines for Writers of RTP Payload Format 
                       Specifications 

RFC2762 E    Feb 2000    Sampling of the Group Membership in RTP 

RFC2793 PS   Jun 2000    RTP Payload for Text Conversation 

RFC2833 PS   Jun 2000    RTP Payload for DTMF Digits, Telephony Tones and 
                       Telephony Signals 

RFC2862 PS   Jul 2000    RTP Payload Format for Real-Time Pointers 

RFC2959 PS   Oct 2000    Real-Time Transport Protocol Management Information Base 

RFC3009 PS   Dec 2000    Registration of parityfec MIME types 

RFC3016 PS   Dec 2000    RTP payload format for MPEG-4 Audio/Visual streams 

RFC3047 PS   Feb 2001    RTP Payload Format for ITU-T Recommendation G.722.1 

RFC3119 PS   Jun 2001    A More Loss-Tolerant RTP Payload Format for MP3 Audio 

RFC3158 I    Aug 2001    RTP Testing Strategies 

RFC3190 PS   Jan 2002    RTP Payload Format for 12-bit DAT, 20- and 24-bit Linear 
                       Sampled Audio 

RFC3189 PS   Jan 2002    RTP Payload Format for DV Format Video 

RFC3267 PS   Jul 2002    RTP payload format and file storage format for the 
                       Adoptive Multi-Rate (AMR) and Adaptive Multi-Rate 
                       Wideband (AMR-WB) audio codecs 

RFC3389 PS   Oct 2002    RTP Payload for Comfort Noise 

RFC3497 PS   Mar 2003    RTP Payload Format for Society of Motion Picture and 
                       Television Engineers (SMPTE) 292M Video 

RFC3558 PS   Jul 2003    RTP Payload Format for Enhanced Variable Rate Codecs 
                       (EVRC) and Selectable Mode Vocoders SMV 

RFC3557 PS   Jul 2003    RTP Payload Format for European Telecommunications 
                       Standards Institute (ETSI) European Standard ES 201 108 
                       Distributed Speech Recognition Encoding 

RFC3556 PS   Jul 2003    Session Description Protocol (SDP) Bandwidth Modifiers 
                       for RTP Control Protocol (RTCP) Bandwidth 

RFC3555 PS   Jul 2003    MIME Type Registration of RTP Payload Formats 

RFC3551 DS   Jul 2003    RTP Profile for Audio and Video Conferences with Minimal 
                       Control 

RFC3550 DS   Jul 2003    RTP: A Transport Protocol for Real-Time Applications 

RFC3545 PS   Jul 2003    Enhanced Compressed RTP (CRTP) for links with High 
                       Delay,Packet Loss and Reordering 

RFC3611Standard  Nov 2003    RTP Control Protocol Extended Reports (RTCP XR) 

RFC3640Standard  Dec 2003    RTP Payload Format for Transport of MPEG-4 Elementary 
                       Streams 

RFC3711Standard  Mar 2004    The Secure Real-time Transport Protocol 

RFC3952 E    Dec 2004    RTP Payload Format for iLBC Speech 

RFC3951 E    Dec 2004    Internet Low Bit Rate Codec 

RFC3984Standard  Feb 2005    RTP payload Format for H.264 Video 

RFC4040Standard  Apr 2005    RTP payload format for a 64 kbit/s transparent call 

RFC4060Standard  May 2005    RTP Payload Formats for European Telecommunications 
                       Standardsv Institute (ETSI) European Standard ES 202 
                       050, ES 202 211, and ES 202 212 Distributed Speech 
                       Recognition Encoding 

RFC4103Standard  Jun 2005    RTP Payload for Text Conversation 

RFC4102Standard  Jun 2005    Registration of the text/red MIME Sub-Type 

RFC4175Standard  Sep 2005    RTP Payload Format for Uncompressed Video 

RFC4184Standard  Oct 2005    RTP Payload Format for AC-3 Audio 

RFC4247 I    Nov 2005    Requirements for Header Compression over MPLS 

RFC4170BCP  Nov 2005    Tunneling Multiplexed Compressed RTP (TCRTP) 

RFC4298Standard  Dec 2005    RTP Payload Format for BroadVoice Speech Codecs 

RFC4348Standard  Jan 2006    Real-Time Transport Protocol (RTP) Payload Format for 
                       the Variable-Rate Multimode Wideband (VMR-WB) Audio 
                       Codec 

RFC4351 H    Jan 2006    Real-Time Transport Protocol (RTP) Payload for Text 
                       Conversation Interleaved in an Audio Stream 

RFC4352Standard  Jan 2006    RTP Payload Format for the Extended Adaptive Multi-Rate 
                       Wideband (AMR-WB+) Audio Codec 

RFC4396Standard  Feb 2006    RTP Payload Format for 3rd Generation Partnership 
                       Project (3GPP) Timed Text 

RFC4425 PS   Feb 2006    RTP Payload Format for Video Codec 1 (VC-1) 

RFC4421Standard  Feb 2006    RTP Payload Format for Uncompressed Video: Additional 
                       Colour Sampling Modes 

RFC4424 PS   Feb 2006    Real-Time Transport Protocol (RTP) Payload Format for 
                       the Variable-Rate Multimode Wideband (VMR-WB) Extension 
                       Audio Codec 

RFC4573 PS   Jul 2006    MIME Type Registration for RTP Payload Format for H.224 

RFC4585 PS   Jul 2006    Extended RTP Profile for Real-time Transport Control 
                       Protocol (RTCP)-Based Feedback (RTP/AVPF) 

RFC4571 PS   Jul 2006    Framing Real-time Transport Protocol (RTP) and RTP 
                       Control Protocol (RTCP) Packets over Connection-Oriented 
                       Transport 

RFC4588 PS   Jul 2006    RTP Retransmission Payload Format 

RFC4598 PS   Jul 2006    Real-time Transport Protocol (RTP) Payload Format for 
                       Enhanced AC-3 (E-AC-3) Audio 

RFC4587 PS   Aug 2006    RTP Payload Format for H.261 Video Streams 

RFC4749 PS   Oct 2006    RTP Payload Format for the G.729.1 Audio Codec 

RFC4696 I    Nov 2006    An Implementation Guide for RTP MIDI 

RFC4695 PS   Nov 2006    RTP Payload Format for MIDI 

RFC4733 PS   Dec 2006    RTP Payload for DTMF Digits, Telephony Tones and 
                       Telephony Signals 

RFC4734 PS   Dec 2006    Definition of Events For Modem, FAX, and Text Telephony 
                       Signals 

RFC4788 PS   Jan 2007    Enhancements to RTP Payload Formats for EVRC Family 
                       Codecs 

RFC4629 PS   Jan 2007    RTP Payload Format for ITU-T Rec. H.263 Video 

RFC4628 I    Feb 2007    RTP Payload Format for H.263 using RFC2190 to Historic 
                       status 

RFC4856 PS   Feb 2007    Media Type Registration of Payload Formats in the RTP 
                       Profile for Audio and Video Conferences 

RFC4855 PS   Feb 2007    Media Type Registration of RTP Payload Formats 

RFC4867 PS   Apr 2007    RTP Payload Format and File Storage Format for the 
                       Adaptive Multi-Rate (AMR) and Adaptive Multi-Rate 
                       Wideband (AMR-WB) Audio Codecs 

RFC4901 PS   Jun 2007    Protocol Extensions for Header Compression over MPLS 

RFC5109 PS   Dec 2007    RTP Payload Format for Generic Forward Error Correction 

RFC5117 I    Jan 2008    RTP Topologies 

RFC5219 PS   Feb 2008    A More Loss-Tolerant RTP Payload Format for MP3 Audio 

RFC5104 PS   Feb 2008    Codec Control Messages in the RTP Audio-Visual Profile 
                       with Feedback (AVPF) 

RFC5124 PS   Feb 2008    Extended Secure RTP Profile for RTCP-based Feedback 
                       (RTP/SAVPF) 

RFC5188 PS   Feb 2008    RTP payload format for Enhanced Variable Rate Wideband 
                       Codec (EVRC-WB) and media subtype updates for EVRC-B 
                       codec 

RFC5244 PS   Jun 2008    Definition of Events For Channel-Oriented Telephony 
                       Signalling