1644577 - Jitsi communication broken after bug 1641600

Status: RESOLVED FIXED

(Core :: WebRTC: Signaling, defect, P1)

Description

[[:philipp]]

after bug 1641600 landed in 79.0a1 i can no longer open up a communication channel on jitsi with another user (i've observed this under win10 & don't know if other platforms are affected).

str for me:

• enter https://meet.jit.si/randomfxtest on a device and give permission to access the webcam
• enter the same url from a different device (in my case it has no cam, only a microphone - not sure if this matters for reproducing the issue)
• on each device i can see that there is another participant in the room, but it's displayed as muted and no sound or picture is received from the remote device

Comment 1

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

I am not able to reproduce this on 79.0a1 (2020-06-09). I have tried between two machines (Linux and OS X):
Nightly to Nightly,
Nightly to Chrome,
Nightly to Release.
I am getting low bandwidth warnings, which I do not suspect is an issue on my end.

philipp, could you add what the setup is on your second device?

Comment 2

[[:philipp]]

both of the devices run windows 10.
i first observed the issue with current nightly to current 68esr (each in a different network) but can also repro nightly to nighly in the same LAN.

Comment 3

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

I can reproduce under Windows 10 if and only if I have no camera. I will see if the same thing happens on Linux, though I am unable to test on OS X without a camera.

Comment 4

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

This reproduces on Linux without a camera.

Comment 5

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

I can confirm that adding ,*.jit.si to the media.peerconnection.video.use_rtx.blocklist preference corrects the issue.

Comment 6

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

Attachment: Bug 1644577 - add jit.si to RTX blocklist;r?dminor

Comment 7

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

Dan, I have added a commit to add *.jit.si to the blocklist. If you want to land that while looking for the issue feel free.

Comment 8

[Dan Minor [:dminor]]

With RTX enabled in Firefox, I'm seeing RTX codecs but no ssrc-group in the SDP coming from Jitsi. In the past, this has been problematic in Firefox, so I'm going to try to make Firefox more tolerant of this situation as a workaround. Oddly, with RTX disabled in Firefox, Jitsi offers RTX with a suitable ssrc-group.

Comment 9

[Dan Minor [:dminor]]

Jitsi has found a bug on their side and will be committing a fix today. I'll retest this tomorrow and close if things look good.

Comment 10

[jaya.allamsetty]

Jitsi bug as been fixed, it should be available in the next release of https://meet.jit.si

Comment 11

[Dan Minor [:dminor]]

I think there are two separate problems. I'm having the same symptoms on whereby.com with RTX enabled if the only input device is a microphone. So I think there was a bug on the Jitsi side, which is now fixed (thanks Jaya!), but there is still a problem with Firefox itself. I'll look into it.

Comment 12

[Dan Minor [:dminor]]

On Jitsi and whereby.com, the problem only seems to occur if the other party is Chrome.

Comment 13

[Dan Minor [:dminor]]

This is now working for me on https://beta.meet.jit.si. I still think there might be something going on with direct Firefox <-> Chrome calls, or it might just be a issue with my local testing set up. I'm going to resolve this bug, and I'll open a separate bug if I continue to see problems on whereby.