rtp: new rtpbin2 element
See individual commits.
Includes:
- RTP/AVP profile
- RTP/AVPF profile
- PLI/FIR handling
- Reduced size RTCP
- Jitterbuffer
- CNAME synchronisation
TODO:
-
Handle SSRC/PT mapping better and also externally.
Some changes from the existing rtpbin:
- Multiple RTP sessions RTCP handling use the same thread/s and thus less threads overall in multi-session use cases.
- Cleaner RTCP scheduling code
- CNAME synchronsation happens in a single place instead of being split between jitterbuffer and rtpbin
- send and receive halves have been split in order to facilitate SFU/MCU/etc use cases without wormhole elements.
Edited by Matthew Waters