[webrtc-pc] Specify how codecs should be prioritized.

henbos has just created a new issue for https://github.com/w3c/webrtc-pc:

== Specify how codecs should be prioritized. ==
[RFC 3264](https://www.ietf.org/rfc/rfc3264.txt) sections 5.1 and 6.1 says offer/answer contains codecs that we are willing to send/recv/sendrecv, depending on direction.
It says the answer MAY change the order of the codec list depending on priority, but that it is RECOMMENDED not to change the order if it does not have a preference, such that the original priority is preserved.

Implicit about this, I think, is that we'll pick the first codec that both offerer and answerer supports.
The offerer has a say of priority by proposing the list of codecs, and the answerer has a say of priority by being able to modify the order in the answer. The order is based on setCodecPreferences().

This is my understanding based on current spec status:
- If offerer used setCodecPreferences() but the answerer didn't, the offerer's priority will be respected.
- If the answerer used setCodecPreferences(), the offerer's priority will override any priority that the offerer may have asked for.

Is this what is intended?

Please view or discuss this issue at https://github.com/w3c/webrtc-pc/issues/2009 using your GitHub account

Received on Friday, 19 October 2018 14:03:50 UTC