I can confirm the issue on a a rpi4 running 21.04 (arm64). The suggested workaround (setting gfx.webrender.force-disabled to True) works.
** Changed in: firefox (Ubuntu) Assignee: (unassigned) => Olivier Tilloy (osomon) ** Bug watch added: Mozilla Bugzilla #1714511 https://bugzilla.mozilla.org/show_bug.cgi?id=1714511 ** Also affects: firefox via https://bugzilla.mozilla.org/show_bug.cgi?id=1714511 Importance: Unknown Status: Unknown -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1930982 Title: Firefox 89: webrender breaks videos on Raspberry Pi To manage notifications about this bug go to: https://bugs.launchpad.net/firefox/+bug/1930982/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs