Chrome <-> Firefox renegotiation issues due to audio codecs

[nathanoehlman]

In the following situation:

1. Chrome + Firefox have an active peer connection (no streams)
2. Chrome adds a stream, causes a renegotiation, succeeds
3. Firefox adds a stream, causes a renegotiation, fails at the point of setting the local description answer on Chrome with the message Failed to set local answer sdp: Session error code: ERROR_CONTENT. Session error description: Failed to set local audio description recv parameters..

According to https://bugs.chromium.org/p/webrtc/issues/detail?id=5450, this is a problem in Chrome due to Chrome using the incorrect payload type of 100 instead of 120 for VP8.

[silviapfeiffer]

Onto more sdp munging...

[nathanoehlman]

Unfortunately I tried the SDP munging listed in that bug report, however, when Chrome creates the first offer, and then Firefox the second, it doesn't work :(

[silviapfeiffer]

Could we always replace 120 with 100 on Chrome's SDP? Does Chrome identify that correctly also?

[nathanoehlman]

That was one of the initial things I tried, unfortunately it didn't work either.