1670592 - doubling up of camera picture on Blackboard only on Firefox

Status: NEW

(Core :: WebRTC, defect, P3)

Description

[sheila]

Attachment: DoubleVideoFirefox.jpg

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:81.0) Gecko/20100101 Firefox/81.0

Steps to reproduce:

I am attending a course at UCL, London which uses Blackboard platform - https://eu.bbcollab.com

I log into and run the audio and video tests. Audio is fine bu on Video I show up as two faces side by side - see attched screen shot.

I'm on a Logitech Pro webcam V 2.51 Build 13.51.828, Firefox 81.0.1 , Windows 10 Home Build 19041.508 on HP XPS 8700 24GB, I do run with two screens on all the time .
This does not occur with Zoom, Skype etc where the webcam show one face as normal. My Viruschecker and Windows are all uptodate.

I've reproduced the issue, had UCL IT Support on the issue as well ( whose only solution is for me to use Chrome - but I prefer to drive my browser via the keyboard and therefore use Firefox)

Actual results:

double faces on webcam

Expected results:

It should have been the same as does happen with Chrome

Comment 1

[Andrei Purice]

Hello Sheila,

Can you test the issue while in Safe Mode? You can find helpful info here : https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode .
Also a fresh new profile could help. You can find more about creating a new profile here : https://support.mozilla.org/en-US/kb/troubleshoot-and-diagnose-firefox-problems#w_6-create-a-new-firefox-profile .
If possible, you can test this issue on the nightly build as well. Download the build from : https://www.mozilla.org/en-US/firefox/nightly/all/ .

Comment 2

[sheila]

Attachment: Nightly1604.jpg

Comment 3

[sheila]

Attachment: Double 1554.jpg

Comment 4

[sheila]

Hi Andrei

I've tried all of the suggested actions and still get the same issue

Sheila

Comment 5

[BugBot [:suhaib / :marco/ :calixte]]

Bugbug thinks this bug should belong to this component, but please revert this change in case of error.

Comment 6

[:Gijs (he/him)]

Sheila: sorry that this issue has been a bit lost. I'm going to attempt to get it to the right people to investigate, but it may take a little while because of incoming US-thanksgiving-related holidays.

Paul, do you know what could be the matter here, or how we could get more details?

Comment 7

[sheila]

Gijs, no problem. Happy Thanksgiving :)
Gijs, Paul, Just let me know if there is anything else you need from me.
S

Comment 8

[Andreas Pehrson [:pehrsons]]

Hi Sheila, I'd just like to do a final sanity check before we dig deeper. Could you please check also on https://mozilla.github.io/webrtc-landing/gum_test.html? Choose Camera and approve, then check whether the video from your camera is still displaying weirdly like in your screenshots.

We control this test site so if we see no issues here we know the site (bbcollab in this case) is doing something with the video. Or if we see issues, we know they're somewhere on our end.

Comment 9

[sheila]

Andreas, I did this a few times and it worked just fine!
Interestingly I repeated it with the Collaborate Blackboard open alongside in a separate window. The blackboard window showed double, but as soon as I hit the buttons on your test set it reset the blackboard to the normal single.
Tried to catch it on video for you
https://www.dropbox.com/s/vztmv0v7uhearyl/VID_20201201_170503.mp4?

Comment 10

[Andreas Pehrson [:pehrsons]]

That's interesting, and great video capture, thanks.

What happens when you start the second capture is that we stop and re-start the camera in our backend. Somehow this seems to fix the issue, suggesting it is caused by the camera and not us.

On that account I googled around a bit and found an old upstream bug for this camera with some more details.

Did you say you tried Chrome and it was fine? It's not entirely clear from comment 0. I wonder because Chrome has since the upstream bug was filed switched to their own camera backends, rather than the ones in libwebrtc (that we use forked variants of). If it works there consistently we could look at possible differences. Otherwise I think we're stuck with this, seeing that there's no upstream fix to cherry-pick, and only affecting an uncommon camera model.

Comment 11

[sheila]

Andreas,
Yes, Chrome works consistently in my experience and the college where I study specifically recommends Chrome BUT I just don't like it. I prefer the layout of controls in Firefox :) more familiar maybe ( I like the visibility of Firefox Menu bar with its keyboard access strokes, Chrome hides for example the Print command way down in its ...menu)

Yes, that older report you found seems to be the same issue - I've no experience of Hangouts or Whereby as mentioned therein.

I had a new higher resolution webcam on order which never arrived at the start of COVID, then they were really difficult to get hold of with everyone buying to Zoom , so am hanging fire till things settle down. In practice that will most certainly mean not this academic year and it might mean I just never get round to it as it is only with Blackboard that I have this issue, not for classes using Zoom or Skype . Being honest here because I do realise it's an older model and there is a workaround - use Chrome - and you have to prioritise what to address, but I have to say the camera works great and I have never had issues with it before this one. I do appreciate your time looking into this
S

Comment 12

[Andreas Pehrson [:pehrsons]]

One difference between Chromium and us is that they will use Media Foundation to interface with the camera if it's available, whereas we only have a DirectShow backend.

Apart from that there seem to be some timing differences in the DirectShow backend on when Run() is called on the media control, but unclear if that helps anything.