Yes, but more fixes are coming - https://bugzilla.mozilla.org/show_bug.cgi?id=1773377 for multiple GPU scenario and https://bugzilla.mozilla.org/show_bug.cgi?id=1774075 for radeon WebGL fixes.
Feel free to just test builds from koji, I'd like to submit all fixes together. And thanks for testing, it's very helpful!
Just quickly tested youtube playback on two different machines: Tigerlake (12th gen): VA-API seems to initialize just fine with the iHD_drv_video driver but no hardware acceleration This laptop does also have an RTX3050 with the nvidia driver loaded but that isn't used for Firefox.
It's because you hit https://bugzilla.mozilla.org/show_bug.cgi?id=1773377 On systems with more GPU the VA-API is broken now but should fall back to SW decode.
Okay, this build restored the video playback functionality but the performance is horrible running at only few FPS, now including other web-sites as well, like YouTube with vp9 and ac1 codecs. This is on RX 6700XT.
Please file that at bugzilla.redhat.com. I don't see that on RX 6600XT. Also we're supposed to switch to SW decode when VA-API fails.
I tested the update from 100 to 101 and the plugin is not changed. Looks like the change was made in some previous version. You need to go to about:config, find gmpopenh264 keys and reset them to default values. media.gmp-gmpopenh264.version needs to be system-installed. also make sure mozilla-openh264 package is installed (it's optional).