Audio/Video Transport (avt) --------------------------- Charter Current status: active working group Chair(s): Stephen Casner Transport Area Director(s) Allison Mankin Mailing lists: General Discussion:rem-conf@es.net To Subscribe: rem-conf-request@es.net Archive: nic.es.net:pub/mailing-lists/mail-archive/rem-conf Description of Working Group: The Audio/Video Transport Working Group was formed to specify experimental protocols for real-time transmission of audio and video over UDP and IP multicast. The focus of this group is near-term and its purpose is to integrate and coordinate the current AV transport efforts of existing research activities. No standards-track protocols are expected to be produced because UDP transmission of audio and video is only sufficient for small-scale experiments over fast portions of the Internet. However, the transport protocols produced by this working group should be useful on a larger scale in the future in conjunction with additional protocols to access network-level resource management mechanisms. Those mechanisms, research efforts now, will provide low-delay service and guard against unfair consumption of bandwidth by audio/video traffic. Similarly, initial experiments can work without any connection establishment procedure so long as a priori agreements on port numbers and coding types have been made. To go beyond that, we will need to address simple control protocols as well. Since IP multicast traffic may be received by anyone, the control protocols must handle authentication and key exchange so that the audio/video data can be encrypted. More sophisticated connection management is also the subject of current research. It is expected that standards-track protocols integrating transport, resource management, and connection management will be the result of later working group efforts. The AVT Working Group may design independent protocols specific to each medium, or a common, lightweight, real-time transport protocol may be extracted. Sequencing of packets and synchronization among streams are important functions, so one issue is the form of timestamps and/or sequence numbers to be used. The working group will not focus on compression or coding algorithms which are domain of higher layers. Internet-Drafts: Posted Revised I-D Title ------ ------- ------------------------------------------ Oct 92 Oct 93 Issues in Designing a Transport Protocol for Audio and Video Conferences and other Multiparticipant Real-Time Applications Dec 92 Oct 93 RTP: A Transport Protocol for Real-Time Applications Dec 92 Sep 93 Media Encodings Dec 92 Oct 93 Sample Profile for the Use of RTP for Audio and Video Conferences with Minimal Control Mar 93 Dec 93 Packetization of H.261 video streams