Firefox not loading gifv, gifs

[Craig Cole]

Firefox 86.0-3, fresh installation of Ubuntu 20.04 with no additional repositories added other than for Google Chrome, no third-party drivers, etc. Full dist-upgrade run, rebooted and otherwise working fine.

A version of firefox was pulled down using 'snap install firefox' and it did not have the same issues.

Some gifs work, but no gifv so far. Not sure of the pattern.

Example gifv from imgur.com: https://i.imgur.com/xFVwISe.gifv

I've disabled all restrictions in the privacy and security settings. I've also started in safe-mode so no extensions.

No reports of this issue on other operating systems or on https://bugzilla.mozilla.org

No huge impact to me personally, but maybe something to look at.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: firefox 86.0+build3-0ubuntu0.20.04.1
ProcVersionSignature: Ubuntu 5.8.0-44.50~20.04.1-generic 5.8.18
Uname: Linux 5.8.0-44-generic x86_64
AddonCompatCheckDisabled: False
ApportVersion: 2.20.11-0ubuntu27.16
Architecture: amd64
BuildID: 20210222142601
CasperMD5CheckResult: skip
Channel: Unavailable
CurrentDesktop: ubuntu:GNOME
Date: Thu Mar 4 16:40:12 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:348
DefaultProfileThemes: extensions.sqlite corrupt or missing
ForcedLayersAccel: False
InstallationDate: Installed on 2021-03-03 (1 days ago)
InstallationMedia: Ubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731)
ProcEnviron:
 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:348
Profile0PrefSources: prefs.js
Profile0Themes: extensions.sqlite corrupt or missing
Profiles:
 Profile1 (Default) - LastVersion=None/None (Out of date)
 Profile0 - LastVersion=86.0/20210222142601 (In use)
RunningIncompatibleAddons: False
SourcePackage: firefox
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 09/01/2020
dmi.bios.release: 5.17
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: GU502LW.309
dmi.board.asset.tag: ATN12345678901234567
dmi.board.name: GU502LW
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: 1.0
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK COMPUTER INC.
dmi.chassis.version: 1.0
dmi.ec.firmware.release: 3.8
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrGU502LW.309:bd09/01/2020:br5.17:efr3.8:svnASUSTeKCOMPUTERINC.:pnROGZephyrusM15GU502LW_GU502LW:pvr1.0:rvnASUSTeKCOMPUTERINC.:rnGU502LW:rvr1.0:cvnASUSTeKCOMPUTERINC.:ct10:cvr1.0:
dmi.product.family: ROG Zephyrus M15
dmi.product.name: ROG Zephyrus M15 GU502LW_GU502LW
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK COMPUTER INC.

[Craig Cole (phitbit)]

Downloaded the ubuntu-20.04.2.0-desktop-amd64.iso image and installed a virtual machine, updated it with apt update && apt dist-upgrade. Rebooted, tried firefox again and saw the same problem. Disabled most of the security and privacy restrictions in the firefox settings, same problem.

# apt info firefox
...
Version: 86.0+build3-0ubuntu0.20.04.1
...

[Craig Cole (phitbit)]

Installed VLC, problem is gone. This has been confirmed on multiple systems. Something about the way FireFox is handling media.