recvonly answer, how to change that?
I know, this has already been an issue for some others two years ago. The answer was all the time "gst rejects the offer because port 0 in m line" or so.
I'm now seemingly having the same problem, but I don't know how to solve this. The offerer is Chrome 92 on macOS.
I can see the 0 port in the audio m line:
m=audio 9 UDP/TLS/RTP/SAVPF 111 103 104 9 0 8 106 105 13 110 112 113 126
not in the video m line.
m=video 9 UDP/TLS/RTP/SAVPF 96 97 98 99 100 101 102 121 127 120 125 107 108 109 35 36 124 119 123 118 114 115 116
The answering side is a Raspberry PI 32 bit, running a Python3 app, having GST 18.4, compiled from source. The answerer is having a pipeline providing a test video. The test video is displayed in the Chrome app, if the PI is the offerer. In this case the offer contains "sendonly", as designed.
PIPELINE_TEST_VP8 = '''
webrtcbin name=webrtcbin bundle-policy=max-bundle stun-server=stun://stun.l.google.com:19302
videotestsrc is-live=true pattern=ball ! videoconvert ! queue ! vp8enc deadline=1 ! queue ! rtpvp8pay !
queue ! application/x-rtp,media=video,encoding-name=VP8,payload=97 ! webrtcbin.
'''
The symptom is that there is no video on the offering side, streams are not provided by the answerer.
The behaviour is consistent, it also happens if I run the same python app on my MacBook.
I don't blame GST, I just would like to know, what I have to do in order get anything else except "recvonly". Do I have to munge the incoming answer, carve out the 0?