1668028 - Intermittent frozen video using Jitsi

Status: RESOLVED DUPLICATE of bug 1674463

(Core :: WebRTC: Audio/Video, defect, P1)

Description

[Dan Minor [:dminor]]

Jitsi users are reporting intermittent frozen video using Firefox 80 and later:
https://community.jitsi.org/t/firefox-sends-video-for-first-few-seconds-then-intermittently-freezes-not-a-network-issue/78661

Bug 1663286 has what may be similar problems, in the context of screen sharing.

Comment 1

[Dan Minor [:dminor]]

I can reproduce something like this bug if I have three participants in a call, with at least two on the local network. Firefox's estimated bandwidth [1] drops from a healthy 2 - 5 Mbps to 10000bps, and Firefox will then stop sending video. I believe this to be a send side issue rather than a problem with the receiver reports generated, because it reproduces when Firefox is the sender, and the two receivers are Chrome, but does not reproduce if all three parties are Chrome.

With RTX disabled, the estimate goes down to 10000 bps, but video is still sent. With RTX enabled, if I hard code the target bitrate to something 2500000bps, I see similar video as I do with RTX disabled.

This reproduces for me, even if all participants are Firefox.

I've also seen a complete freeze with only two participants, one Firefox and one Chrome, with RTX enabled. In this case, the bitrate was still high.

It's not clear to me yet if there are two separate problems, or one problem with different ways of triggering it.

[1] https://searchfox.org/mozilla-central/rev/dfd9c0f72f9765bd4a187444e0c1e19e8834a506/third_party/libwebrtc/webrtc/modules/congestion_controller/send_side_congestion_controller.cc#381

Comment 2

[Byron Campen [:bwc]]

Just want to check; we wouldn't happen to be hitting bug 1667319 here would we?

Comment 3

[Dan Minor [:dminor]]

It doesn't seem to be, Jitsi is pretty consistent with VP8 on 100 and RTX on 96, and no other codecs, at least testing with Firefox and Chrome. It might be contributing to problems people are seeing, but doesn't seem to be the root cause.

Comment 4

[Paul Adenot (:padenot)]

Are we doing something with this?

Comment 5

[Nico Grunbaum [:ng, @chew:mozilla.org]]

Yes, mjf, and I are working on this. It appears to be an issue with simulcast in which one of the 3 simulcast streams will intermittently stop transmitting.

Comment 6

[Nils Ohlmeier [:drno]]

A patch landed via bug 1674463 which hopefully should address this issue. Let's open new issues for remaining issues with Jitsi.