* Handle multiple codecs in renegotiation
update pion to v3.1.9 for answer same order of codec as publisher.
register enable codecs in subscriber peerconnectin created.
add codec parameter to buffer.bind
buffer should use the codec of TrackRemote as it's codec mime.
sent h264blankframe when DownTrack closing
- Update ion-sfu to v1.20.14
- Enable `abs-send-time` for video tracks
Reference: ion-sfu PR - https://github.com/livekit/ion-sfu/pull/12
Testing:
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- Look at SDP offer in subscriber PC and ensure that abs-send-time is negotiated.
- Ensure that downstream packets have `abs-send-time` extension for video packets.
TODO:
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- Not yet setting this for audio tracks. Eventually we want to move
to TWCC. This is just a step along the way.
* protobuf updates to support new protocol
* use dedicated publish & subscribe peerconnections
* update client to work with dedicated PCs
* fix Go client negotiation, reduced length of UUID
