Multi-stream Media Conferencing

Multi-stream Media Conferencing

Bo BurmanEricsson AB

draft-westerlund-clue-multistream-conference-00

IETF 83 - CLUE - March 2012 draft-westerlund-clue-multistream-conference 2

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/

http://datatracker.ietf.org/ipr/1641/


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


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


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


Low Quality Sender

Low

Med High

RTPMixer

Low


Medium Quality Sender

RTPMixer

Med

Med HighLow



RTPMixer

Med

TTranscoding

Med HighLow



RTPMixer

Med

Simulcast

draft-westerlund-avtcore-rtp-simulcast

Med HighLow



RTPMixer

Med

Scalable coding

Med HighLow


High Quality Sender

• Similar to above

• Left as an exercise for the reader


Multiple Channel Sender

Low Med High Dual High

RTPMixer

Multiple HighHow manysimultaneouschannelscould andshould besent? max-recv-ssrc=“many”

max-send-ssrc=4

max-send-ssrc=“many”

max-recv-ssrc=2max-recv-ssrc=1max-recv-ssrc=1max-recv-ssrc=1

An answerer’s max-send-ssrc ≤ offerer’s max-recv-ssrc

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Multi-quality Local Composition

RTPMixer

AssumingRTP Mixerhas a choiceof qualitiesavailable

*: max-send-ssrc=“many”

High: max-recv-ssrc=1Med: max-recv-ssrc=1Low: max-recv-ssrc=3

HighLow

Med Low

Low

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Mixer Stream Roles and SSRC

RTPMixer

Mixer SSRC has a“role” and the sourcethat currently holdsthat “role” is identifiedby CSRC

Activespeaker

Quiet

Last Quiet

Quiet

Activespeaker

Lastactive

speaker

Quiet Quiet

Quiet

SSRC A

SSRC M1 (B)

SSRC C SSRC D

SSRC E

SSRC B

SSRC M2 (D)

SSRC M3 (A)SSRC M4 (C)SSRC M5 (E)

Mixer SSRC need not changeoften and should be feasibleto tie to a certain decoderresource



RTPMixer


Activespeaker

Quiet

Last Quiet

Quiet

Activespeaker

Lastactive

speakerQuiet

Quiet

Quiet

SSRC A

SSRC M1 (A)

SSRC C SSRC D

SSRC E

SSRC B

SSRC M2 (B)

SSRC M3 (D)SSRC M4 (C)SSRC M5 (E)

Mixer SSRC need not changeoften and should be feasibleto tie to a certain decoderresource



RTPMixer


Activespeaker

Quiet

Last Quiet

Quiet

Activespeaker

Lastactive

speakerQuiet

Quiet

Quiet

SSRC A

SSRC M1 (A)

SSRC C SSRC D

SSRC E

SSRC B

SSRC M2 (B, D, C, E)

Some Mixer SSRC maybe “composed” by theMixer and containmultiple CSRC


Receiver Stream Selection

RTPMixer

Receiving end-pointwants to tie a certainsource SSRC to acertain Mixer SSRC(and thus role)

Activespeaker

Quiet

Last Quiet

Quiet

Activespeaker

Lastactive

speakerQuiet

Quiet

Quiet

SSRC A

SSRC M1 (A)

SSRC C SSRC D

SSRC E

SSRC B

SSRC M2 (B)

SSRC M3 (D)SSRC M4 (C)SSRC M5 (E)

“Give me D in M1”

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Receiver Stream Selection

RTPMixer

Receiving end-pointwants to tie a certainsource SSRC to acertain Mixer SSRC(and thus overridescontent of that “role”)

QuietQuiet

Last Active

Quiet

Activespeaker

Lastactive

speakerQuiet

Quiet

Quiet

SSRC A

SSRC M1 (D)

SSRC C SSRC D

SSRC E

SSRC B

SSRC M2 (B)

SSRC M3 (A)SSRC M4 (C)SSRC M5 (E)

“Ack”

Quiet

What to do with replaced“roles” is subject to Mixerimplementation and policy;for further consideration

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Avoid Unused Streams

RTPMixer

Mixer notices that Cand E streams arecurrently not receivedby anyone and decidesto pause them

Activespeaker

LastQuiet

Activespeaker

Lastactive

speakerQuiet

Quiet

Quiet

SSRC A

SSRC M1 (A)

SSRC C SSRC D

SSRC E

SSRC B

SSRC M2 (B)

SSRC M3 (D)

draft-westerlund-avtext-rtp-stream-pause-00

“Pause C”

“Pause E”


Avoid Unused Streams

RTPMixer

C and E streams arepaused and thepauses are ack’ed

Activespeaker

LastQuiet

Activespeaker

Lastactive

speakerQuiet

Quiet

Quiet

SSRC A

SSRC M1 (A)

SSRC C SSRC D

SSRC E

SSRC B

SSRC M2 (B)

SSRC M3 (D)

Paused streams must bepossible to resume veryquickly if they are wantedagain

“Ack C”

“Ack E”

draft-westerlund-avtext-rtp-stream-pause-00


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

Multi-stream Media Conferencing

Documents

Transcript of Multi-stream Media Conferencing