WebRTC P2P video stream from Android App & Chrome freeze every second

Question

I'm a newbie in WebRTC, creating a P2P video call. I'm not familiar with the WebRTC Internals's results.

Video streams from Android APP / Android Chrome are having freeze every second. Video streams from Desktop Browsers & Android Firefox does not have this problem, they just worked perfectly.

I've tried to google around and tried many fixes, unfortunately, none of them works.

For example, removing few lines of a=rtpmap:99 rtx/90000 from Sdp doesn't help with the freezing situation.

May I know how to fix this freezing problem?

Thanks in advance.

Below are my sdp sample and WebRTC Internals showing stream from Android Chrome:

sdp: "v=0
↵o=- 3972593082164766939 2 IN IP4 127.0.0.1
↵s=-
↵t=0 0
↵a=group:BUNDLE 0 1
↵a=msid-semantic: WMS EtmQlEiR4ZAgQ38QPrvlsfqvIW6y5jIO4rlX
↵m=audio 9 UDP/TLS/RTP/SAVPF 111 103 9 0 8 105 13 110 113 126
↵c=IN IP4 0.0.0.0
↵b=AS:50↵a=rtcp:9 IN IP4 0.0.0.0
↵a=ice-ufrag:w412
↵a=ice-pwd:qGY+GHRYFr1xVUacGk0HTwAP
↵a=ice-options:trickle
↵a=fingerprint:sha-256 7C:8C:5F:60:AB:DA:D0:9F:3B:69:84:3E:E2:42:60:43:DC:D7:83:B4:FD:A9:63:57:F4:8E:F5:97:34:93:58:A8
↵a=setup:actpass
↵a=mid:0
↵a=extmap:1 urn:ietf:params:rtp-hdrext:ssrc-audio-level
↵a=extmap:9 urn:ietf:params:rtp-hdrext:sdes:mid
↵a=extmap:13 urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id
↵a=extmap:14 urn:ietf:params:rtp-hdrext:sdes:repaired-rtp-stream-id
↵a=sendrecv
↵a=msid:EtmQlEiR4ZAgQ38QPrvlsfqvIW6y5jIO4rlX 6b9a5836-9a1f-4f9d-b3ea-d6fc5767ed36
↵a=rtcp-mux
↵a=rtpmap:111 opus/48000/2
↵a=rtcp-fb:111 transport-cc
↵a=fmtp:111 minptime=10;useinbandfec=1
↵a=rtpmap:103 ISAC/16000
↵a=rtpmap:9 G722/8000
↵a=rtpmap:0 PCMU/8000
↵a=rtpmap:8 PCMA/8000
↵a=rtpmap:105 CN/16000
↵a=rtpmap:13 CN/8000
↵a=rtpmap:110 telephone-event/48000
↵a=rtpmap:113 telephone-event/16000
↵a=rtpmap:126 telephone-event/8000
↵a=ssrc:1792162923 cname:Nhh1YQUo6/iSppuB
↵a=ssrc:1792162923 msid:EtmQlEiR4ZAgQ38QPrvlsfqvIW6y5jIO4rlX 6b9a5836-9a1f-4f9d-b3ea-d6fc5767ed36
↵a=ssrc:1792162923 mslabel:EtmQlEiR4ZAgQ38QPrvlsfqvIW6y5jIO4rlX
↵a=ssrc:1792162923 label:6b9a5836-9a1f-4f9d-b3ea-d6fc5767ed36
↵m=video 9 UDP/TLS/RTP/SAVPF 96 97 98 99 100 101 102 127 104
↵c=IN IP4 0.0.0.0
↵b=AS:300↵a=rtcp:9 IN IP4 0.0.0.0
↵a=ice-ufrag:w412
↵a=ice-pwd:qGY+GHRYFr1xVUacGk0HTwAP
↵a=ice-options:trickle
↵a=fingerprint:sha-256 7C:8C:5F:60:AB:DA:D0:9F:3B:69:84:3E:E2:42:60:43:DC:D7:83:B4:FD:A9:63:57:F4:8E:F5:97:34:93:58:A8
↵a=setup:actpass
↵a=mid:1
↵a=extmap:2 urn:ietf:params:rtp-hdrext:toffset
↵a=extmap:3 http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time
↵a=extmap:4 urn:3gpp:video-orientation
↵a=extmap:5 http://www.ietf.org/id/draft-holmer-rmcat-transport-wide-cc-extensions-01
↵a=extmap:6 http://www.webrtc.org/experiments/rtp-hdrext/playout-delay
↵a=extmap:7 http://www.webrtc.org/experiments/rtp-hdrext/video-content-type
↵a=extmap:8 http://www.webrtc.org/experiments/rtp-hdrext/video-timing
↵a=extmap:10 http://tools.ietf.org/html/draft-ietf-avtext-framemarking-07
↵a=extmap:12 http://www.webrtc.org/experiments/rtp-hdrext/color-space
↵a=extmap:9 urn:ietf:params:rtp-hdrext:sdes:mid
↵a=extmap:13 urn:ietf:params:rtp-hdrext:sdes:rtp-stream-id
↵a=extmap:14 urn:ietf:params:rtp-hdrext:sdes:repaired-rtp-stream-id
↵a=sendrecv
↵a=msid:EtmQlEiR4ZAgQ38QPrvlsfqvIW6y5jIO4rlX 2e2527ac-925e-4aca-8ffc-f33582d680a5
↵a=rtcp-mux
↵a=rtcp-rsize
↵a=rtpmap:96 VP8/90000
↵a=rtcp-fb:96 goog-remb
↵a=rtcp-fb:96 transport-cc
↵a=rtcp-fb:96 ccm fir
↵a=rtcp-fb:96 nack
↵a=rtcp-fb:96 nack pli
↵a=rtpmap:97 rtx/90000
↵a=fmtp:97 apt=96
↵a=rtpmap:98 VP9/90000
↵a=rtcp-fb:98 goog-remb
↵a=rtcp-fb:98 transport-cc
↵a=rtcp-fb:98 ccm fir
↵a=rtcp-fb:98 nack
↵a=rtcp-fb:98 nack pli
↵a=fmtp:98 profile-id=0
↵a=rtpmap:99 rtx/90000
↵a=fmtp:99 apt=98
↵a=rtpmap:100 H264/90000
↵a=rtcp-fb:100 goog-remb
↵a=rtcp-fb:100 transport-cc
↵a=rtcp-fb:100 ccm fir
↵a=rtcp-fb:100 nack
↵a=rtcp-fb:100 nack pli
↵a=fmtp:100 level-asymmetry-allowed=1;packetization-mode=1;profile-level-id=42e01f
↵a=rtpmap:101 rtx/90000
↵a=fmtp:101 apt=100
↵a=rtpmap:102 red/90000
↵a=rtpmap:127 rtx/90000
↵a=fmtp:127 apt=102
↵a=rtpmap:104 ulpfec/90000
↵a=ssrc-group:FID 1909059520 686539247
↵a=ssrc:1909059520 cname:Nhh1YQUo6/iSppuB
↵a=ssrc:1909059520 msid:EtmQlEiR4ZAgQ38QPrvlsfqvIW6y5jIO4rlX 2e2527ac-925e-4aca-8ffc-f33582d680a5
↵a=ssrc:1909059520 mslabel:EtmQlEiR4ZAgQ38QPrvlsfqvIW6y5jIO4rlX
↵a=ssrc:1909059520 label:2e2527ac-925e-4aca-8ffc-f33582d680a5
↵a=ssrc:686539247 cname:Nhh1YQUo6/iSppuB
↵a=ssrc:686539247 msid:EtmQlEiR4ZAgQ38QPrvlsfqvIW6y5jIO4rlX 2e2527ac-925e-4aca-8ffc-f33582d680a5
↵a=ssrc:686539247 mslabel:EtmQlEiR4ZAgQ38QPrvlsfqvIW6y5jIO4rlX
↵a=ssrc:686539247 label:2e2527ac-925e-4aca-8ffc-f33582d680a5
↵"

Answer 1

Your issue sounds similar to something I have been trying to debug for several days. Basically VP8 WebRTC video stream from Android device has micro freezes every 1-2 second during playback on desktop browser ( no turn, router not congested, tried several networks).

After having made a few experiments I feel confident that it is an android device issue. I have a xiaomi m2 lite which is mainly what I was using. After trying S9 , Pixel and other phones of friends and family, I figured out that these devices worked perfect under the same conditions where I see 1-2 sec constant freezes when I send from my xiaomi m2 lite.

I want to dig more into the underlying cause when I get a chance, but try to see if using another android device solves the issue for you.