It’s been a long journey since the first VA-API implementation in Firefox. Two years ago Firefox 77.0 come to Fedora with accelerated video playback on Wayland which was more a tech preview than a working solution.
Since then X11 support was added, fixed many bugs, AV1 decoding was implemented so we can claim VA-API code as mature enough to enable it for testing in Firefox Nightly 103. As we don’t want to scare peaceful Ubuntu users and grandmas watching their favorite show, VA-API is enabled in Nightly channel only and stock Firefox 103 won’t be shipped with that.
But ‘Real Men‘ wants more challenge. ‘Quiche Eaters’ can use polished software, LTS distros or even Mac. That’s nothing for adventurers running on the edge. Thus new Firefox updates (Fedora 35, Fedora 36) has VA-API enabled by default ahead of upstream to get what you asked for, brave Fedorans.
Along with a bunch of upstream VA-API backports I also added a fix for mozbz#1735929 to make life easier for those who did a life mistake with NVIDIA hardware. I hope you’ve got a lesson and your next card will be AMD.
And how to fruitify it? It’s embarrassing it doesn’t need any complicated, cryptic, powerful, unforgiving and dangerous edits of Firefox about:config preferences, setting env variables on terminal or midnight vows. If VA-API is configured property Firefox just takes it and claims at about:support page.
More details are available at https://fedoraproject.org/wiki/Firefox_Hardware_acceleration