Re: [webrtc-pc] Regarding "a=msid"

The decision on TPAC was to "Stop saying anything about track.id mapping".

>From what I can find, we mention track IDs in these places:

- addTrack: _"... and add the MSID of the track added ..."_, this should probably say "of the streams added" instead since that is the only thing signaled with MSID.
- replaceTrack: _"To avoid track identifiers changing on the remote receiving end when a track is replaced, the sender MUST retain the original track identifier and stream associations and use these in subsequent negotiations."_
- NOTE under 5. RTP Media API: "... whether the IDs end up matching depends on the relative ordering of calls to addTrack, addTransceiver and setRemoteDescription, and which side generates the offer ..." and so on (it says more).
- setRemoteDescription: _"Create an RTCRtpReceiver, receiver, from the media description."_ where in create an RTCRtpReceiver: _"If an id string, id, was given as input to this algorithm, initialize track.id to id. (Otherwise the value generated when track was created will be used.)"_

JSEP has been updated not to signal track IDs, which means "from media description" would not involve a track ID. But what if you're communicating with an endpoint that does signal the track ID? We'll have to either say "use that track ID if it is not already in-use" if we want to avoid duplicate IDs, or remove the track ID from the creation steps such that it is always random no matter what was signaled.

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Received on Thursday, 8 November 2018 09:33:37 UTC