Multi-stream Media Conferencing Bo Burman Ericsson AB draft-westerlund-clue-multistream-conference-00 IPR Disclosure • For referred drafts – http://datatracker.ietf.org/ipr/1637/ – http://datatracker.ietf.org/ipr/1638/ – http://datatracker.ietf.org/ipr/1639/ – http://datatracker.ietf.org/ipr/1640/ – http://datatracker.ietf.org/ipr/1641/ – http://datatracker.ietf.org/ipr/1644/ IETF 83 - CLUE - March 2012 draft-westerlund-clue-multistream-conference 2 Purpose • The draft defines a framework and requirements for allowing endpoints with different capabilities to participate in a conference, with each endpoint being able to use as high-quality media as possible IETF 83 - CLUE - March 2012 draft-westerlund-clue-multistream-conference 3 Overview • A set of selected use cases – Each focusing on an end-point “quality category” – Tries to avoid transcoding • Proposed methods to support the above – RTP usage – Signaling extensions IETF 83 - CLUE - March 2012 draft-westerlund-clue-multistream-conference 4 Assumptions • End-points of different “quality categories” are present in the same conference • It is desirable to use as high quality media as possible to every end-point • A more capable, higher quality, end-point can always receive a lower quality stream encoded with the same codec IETF 83 - CLUE - March 2012 draft-westerlund-clue-multistream-conference 5 Low Quality Sender Low RTP Mixer Low IETF 83 - CLUE - March 2012 Med draft-westerlund-clue-multistream-conference High 6 Medium Quality Sender Med RTP Mixer Low IETF 83 - CLUE - March 2012 Med draft-westerlund-clue-multistream-conference High 7 Medium Quality Sender Med RTP Mixer Transcoding Low IETF 83 - CLUE - March 2012 T Med draft-westerlund-clue-multistream-conference High 8 draft-westerlund-avtcore-rtp-simulcast Medium Quality Sender Med Simulcast RTP Mixer Low IETF 83 - CLUE - March 2012 Med draft-westerlund-clue-multistream-conference High 9 Medium Quality Sender Med Scalable coding RTP Mixer Low IETF 83 - CLUE - March 2012 Med draft-westerlund-clue-multistream-conference High 10 High Quality Sender • Similar to above • Left as an exercise for the reader IETF 83 - CLUE - March 2012 draft-westerlund-clue-multistream-conference 11 draft-westerlund-avtcore-max-ssrc-00 Multiple Channel Sender How many simultaneous channels could and should be sent? Multiple High max-send-ssrc=4 max-recv-ssrc=“many” RTP Mixer max-send-ssrc=“many” An answerer’s max-send-ssrc ≤ offerer’s max-recv-ssrc max-recv-ssrc=1 max-recv-ssrc=1 Low IETF 83 - CLUE - March 2012 Med max-recv-ssrc=1 max-recv-ssrc=2 High draft-westerlund-clue-multistream-conference Dual High 12 draft-westerlund-avtcore-max-ssrc-00 Multi-quality Local Composition Assuming RTP Mixer has a choice of qualities available RTP Mixer *: max-send-ssrc=“many” High: max-recv-ssrc=1 Med: max-recv-ssrc=1 Low: max-recv-ssrc=3 Med Low Low Low High IETF 83 - CLUE - March 2012 draft-westerlund-clue-multistream-conference 13 Mixer Stream Roles and SSRC Active speaker Last active speaker Quiet SSRC B SSRC C Quiet SSRC A SSRC E RTP Mixer Active speaker Quiet SSRC M3 (A) SSRC M4 (C) SSRC M5 (E) Mixer SSRC has a SSRC M1 (B) “role” and the source that currently holds SSRC M2 (D) that “role” is identified by CSRC IETF 83 - CLUE - March 2012 SSRC D Last Quiet Quiet Quiet Mixer SSRC need not change often and should be feasible to tie to a certain decoder resource draft-westerlund-clue-multistream-conference 14 Mixer Stream Roles and SSRC Last active speaker Quiet Quiet SSRC B SSRC C Active speaker SSRC A SSRC E RTP Mixer Active speaker Quiet SSRC M3 (D) SSRC M4 (C) SSRC M5 (E) Mixer SSRC has a SSRC M1 (A) “role” and the source that currently holds SSRC M2 (B) that “role” is identified by CSRC IETF 83 - CLUE - March 2012 SSRC D Last Quiet Quiet Quiet Mixer SSRC need not change often and should be feasible to tie to a certain decoder resource draft-westerlund-clue-multistream-conference 15 Mixer Stream Roles and SSRC Last active speaker Quiet Quiet SSRC B SSRC C Active speaker SSRC A SSRC E RTP Mixer Mixer SSRC has a SSRC M1 (A) “role” and the source that currently holds that “role” is identified by CSRC Active speaker IETF 83 - CLUE - March 2012 SSRC D Quiet SSRC M2 (B, D, C, E) Last Quiet Quiet Quiet Some Mixer SSRC may be “composed” by the Mixer and contain multiple CSRC draft-westerlund-clue-multistream-conference 16 draft-westerlund-dispatch-stream-selection-00 Receiver Stream Selection Last active speaker Quiet Quiet SSRC B SSRC C Active speaker SSRC A Quiet SSRC M3 (D) SSRC M4 (C) SSRC M5 (E) Receiving end-point SSRC M1 (A) wants to tie a certain source SSRC to a SSRC M2 (B) certain Mixer SSRC (and thus role) “Give me D in M1” IETF 83 - CLUE - March 2012 SSRC E RTP Mixer Active speaker SSRC D Last Quiet Quiet Quiet draft-westerlund-clue-multistream-conference 17 draft-westerlund-dispatch-stream-selection-00 Receiver Stream Selection Last active speaker Quiet Quiet SSRC B SSRC C Active speaker SSRC A SSRC E RTP Mixer “Ack” Receiving end-point wants to tie a certain source SSRC to a certain Mixer SSRC (and thus overrides content of that “role”) Quiet SSRC M3 (A) SSRC M4 (C) SSRC M5 (E) SSRC M1 (D) SSRC M2 (B) Last Active Quiet Quiet Quiet IETF 83 - CLUE - March 2012 SSRC D What to do with replaced “roles” is subject to Mixer implementation and policy; for further consideration draft-westerlund-clue-multistream-conference 18 draft-westerlund-avtext-rtp-stream-pause-00 Avoid Unused Streams Last active speaker Quiet SSRC B “Pause C” Active speaker Quiet SSRC A SSRC C SSRC D SSRC E RTP Mixer Quiet “Pause E” Mixer notices that C SSRC M1 (A) and E streams are currently not received SSRC M2 (B) by anyone and decides to pause them Active speaker IETF 83 - CLUE - March 2012 SSRC M3 (D) Last Quiet draft-westerlund-clue-multistream-conference 19 draft-westerlund-avtext-rtp-stream-pause-00 Avoid Unused Streams Last active speaker Quiet SSRC B “Ack C” Active speaker Quiet SSRC A SSRC C SSRC D SSRC E RTP Mixer Quiet “Ack E” C and E streams are paused and the pauses are ack’ed SSRC M1 (A) SSRC M3 (D) SSRC M2 (B) Active speaker IETF 83 - CLUE - March 2012 Last Quiet Paused streams must be possible to resume very quickly if they are wanted again draft-westerlund-clue-multistream-conference 20 Expected Outcome • CLUE is asked to take the presented use cases and proposed solutions into account in its work and when progressing the WG drafts IETF 83 - CLUE - March 2012 draft-westerlund-clue-multistream-conference 21
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