Failed to execute 'setRemoteDescription' on 'RTCPeerConnection' in Chromium

Question

I am unable to call rtcConnection.setRemoteDescription() for this SDP offer in Chrome and Edge. It works well in Firefox. In Firefox the WebRTC communication is established and works, not in Chrome after the failure. The SDP is for audio stream only. I am sending this from Gstreamer pipeline and receiving in browser. Therefore I could possibly make changes change on both ends, but not sure that the problem is. Opus should be supported SDP: v=0\r\no=- 3161453914730518631 0 IN IP4 0.0.0.0\r\ns=-\r\nt=0 0\r\na=ice-options:trickle\r\nm=audio 9 UDP/TLS/RTP/SAVPF 97\r\nc=IN IP4 0.0.0.0\r\na=setup:actpass\r\na=ice-ufrag:n27/J2qABz9HDHxkf9RkwhgjBOTiPDfL\r\na=ice-pwd:76MaG+dD4chsG/ulzhPtPdrnzr7ykCK+\r\na=rtcp-mux\r\na=rtcp-rsize\r\na=sendonly\r\na=rtpmap:97 OPUS/48000\r\na=rtcp-fb:97 transport-cc\r\na=extmap:5 http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01\r\na=mid:audio0\r\na=fingerprint:sha-256 A3:DA:A3:F4:04:4E:20:57:A3:7D:C2:BB:7B:4C:39:D3:77:FE:7A:32:DA:84:C5:39:8D:4A:61:1D:28:BD:A8:D9\r\na=rtcp-mux-only\r\n

Have tried to remove the extmap:5 and it did not help either. I we need it for CC anyway. I have tried to change the bitrate number in OPUS to lower number, but does not change either. The exact same SDP woks well in Firefox so this is not completelly wrong

Answer 1

opus is defined with a channel count of 2 always: https://www.rfc-editor.org/rfc/rfc7587#section-7

Replacing

a=rtpmap:97 OPUS/48000

with

a=rtpmap:97 OPUS/48000/2

should do the trick.