Logging into Discord with DRM streaming in other Firefox tab breaks sound.

[Benjamin Button]

What I expect to happen: seamless sound in multiple Firefox tabs

What happens instead:

While playing a certain youtube music stream with a clean browser history/cache:
https://www.youtube.com/watch?v=5qap5aO4i9A
I open another tab and log into Discord (in browser). As soon as I successfully log in, the sound from the youtube stream goes staticky and requires a pulseaudio -k (followed by a refresh of youtube) to remedy.

$ lsb_release -rd
Description: Ubuntu 20.04.3 LTS
Release: 20.04

$ apt-cache policy firefox
firefox:
  Installed: 94.0+build3-0ubuntu0.20.04.1
  Candidate: 94.0+build3-0ubuntu0.20.04.1

$ apt-cache policy pulseaudio
pulseaudio:
  Installed: 1:13.99.1-1ubuntu3.12
  Candidate: 1:13.99.1-1ubuntu3.12

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: firefox 94.0+build3-0ubuntu0.20.04.1
ProcVersionSignature: Ubuntu 5.11.0-40.44~20.04.2-generic 5.11.22
Uname: Linux 5.11.0-40-generic x86_64
AddonCompatCheckDisabled: False
ApportVersion: 2.20.11-0ubuntu27.21
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC1: username 36216 F.... pulseaudio
 /dev/snd/controlC2: username 36216 F.... pulseaudio
 /dev/snd/controlC0: username 36216 F.... pulseaudio
BuildID: 20211028161635
CasperMD5CheckResult: skip
Channel: Unavailable
CurrentDesktop: ubuntu:GNOME
Date: Wed Nov 10 20:15:31 2021
DefaultProfileExtensions: extensions.sqlite corrupt or missing
DefaultProfileIncompatibleExtensions: Unavailable (corrupt or non-existant compatibility.ini or extensions.sqlite)
DefaultProfileLocales: extensions.sqlite corrupt or missing
DefaultProfilePrefErrors: Unexpected character ',' before close parenthesis @ /usr/lib/firefox/omni.ja:greprefs.js:363
DefaultProfileThemes: extensions.sqlite corrupt or missing
ForcedLayersAccel: False
InstallationDate: Installed on 2021-11-11 (0 days ago)
InstallationMedia: Ubuntu 20.04.3 LTS "Focal Fossa" - Release amd64 (20210819)
IpRoute:
 default via 192.168.1.1 dev enp3s0 proto dhcp metric 100
 169.254.0.0/16 dev enp3s0 scope link metric 1000
 192.168.1.0/24 dev enp3s0 proto kernel scope link src 192.168.1.152 metric 100
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
Profile0Extensions: extensions.sqlite corrupt or missing
Profile0IncompatibleExtensions: Unavailable (corrupt or non-existant compatibility.ini or extensions.sqlite)
Profile0Locales: extensions.sqlite corrupt or missing
Profile0PrefErrors: Unexpected character ',' before close parenthesis @ /usr/lib/firefox/omni.ja:greprefs.js:363
Profile0PrefSources: prefs.js
Profile0Themes: extensions.sqlite corrupt or missing
Profiles:
 Profile1 (Default) - LastVersion=None/None (Out of date)
 Profile0 - LastVersion=94.0/20211028161635 (In use)
RunningIncompatibleAddons: False
SourcePackage: firefox
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 04/22/2021
dmi.bios.release: 5.17
dmi.bios.vendor: American Megatrends International, LLC.
dmi.bios.version: P1.80
dmi.board.name: B550M/ac
dmi.board.vendor: ASRock
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInternational,LLC.:bvrP1.80:bd04/22/2021:br5.17:svnToBeFilledByO.E.M.:pnToBeFilledByO.E.M.:pvrToBeFilledByO.E.M.:skuToBeFilledByO.E.M.:rvnASRock:rnB550M/ac:rvr:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.:
dmi.product.family: To Be Filled By O.E.M.
dmi.product.name: To Be Filled By O.E.M.
dmi.product.sku: To Be Filled By O.E.M.
dmi.product.version: To Be Filled By O.E.M.
dmi.sys.vendor: To Be Filled By O.E.M.

[Benjamin Button (afeod)]

Related: https://bugs.launchpad.net/ubuntu/+bug/1950539

[Benjamin Button (afeod)]

I cannot reproduce this error on an XPS 13. Suspect it may be hardware-specific.

[Olivier Tilloy (osomon)]

Thanks for the report Benjamin. This sounds similar to https://bugzilla.mozilla.org/show_bug.cgi?id=1719968. Could you test on the affected machine with an upstream build (as downloaded from https://www.mozilla.org/en/firefox/download/thanks/), and let us know whether you're observing the same problem? If so, can you comment on that upstream bug?

Also, is the XPS 13 also running Ubuntu 20.04, or a more recent release?

[Benjamin Button (afeod)]

Yes, the problem occurs with the upstream build as well. I have commented there, adding that my speakers are plugged into an audio jack (though I'm not yet convinced that's at the root of the problem)

The XPS is running 20.04 as well.

[Benjamin Button (afeod)]

The audio jack would appear to be a factor in the issue.
I plugged the speakers into my laptop. The bug didn't trigger.
With the speakers unplugged from the affected system, and bluetooth headphones connected, the bug also didn't trigger.
Should I continue posting here, or move to the Mozilla thread?