[webrtc-pc] [[ReceiveCodecs]] is only set on answer. How to achieve early media? (#2369)

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

== [[ReceiveCodecs]] is only set on answer. How to achieve early media? ==
In order to support early media, we have to be prepared to receive streams with the proposed codecs even if we have not yet set the answer. This is not true for sending, which can wait until answer, but for receiving, I think decoders would be configured at setLocalDescription(offer).

Shouldn't this be reflected in [[ReceiveCodecs]]? getParameters() is said to return a value for codecs even if [[SendEncodings]] has not been set by a remote description (#2313).

Please view or discuss this issue at https://github.com/w3c/webrtc-pc/issues/2369 using your GitHub account