Youtube videos lagging/stuttering after pause and resume. Plays fine after jumping to another video position

[mmbossoni]

Whenever playing youtube videos, if I pause and then resume the video it starts stuttering, or in other words, playback is not smooth. If I skip the video (by pressing the back arrow to go back a few seconds or jump to another position) video plays smoothly again. Don't know if that is a general vaapi or firefox issue, but since it just happens when I enable vaapi, starting it here.

Operating System: Arch Linux KDE Plasma Version: 5.27.5 KDE Frameworks Version: 5.107.0 Qt Version: 5.15.10 Kernel Version: 6.3.8-x64v1-xanmod1-1 (64-bit) Graphics Platform: Wayland Processors: 16 × AMD Ryzen 7 5700X 8-Core Processor Memory: 15.5 GiB of RAM Graphics Processor: NVIDIA GeForce GTX 1070/PCIe/SSE2 Manufacturer: Micro-Star International Co., Ltd. Product Name: MS-7A37 System Version: 1.0

[elFarto]

I've not noticed any sort of issue like that. It might be worth using the Firefox profiler, with the 'Media' setting to get a profile of the issue.

[mmbossoni]

https://share.firefox.dev/44zCRcD Actions go like: 1 - Started viewing a video 2 - Started recording 3 - Count to 5 and pause 4 - Count to 5 and resume 5 - Count to 5 and pressed back

After that firefox drop's me to not accelerated? (I can't see the C+G on nvidia-smi if I keep video paused for too long and resume)

[mmbossoni]

I'll try to get a video

[elFarto]

Could you also capture the output of Firefox with NVD_LOG=1 set with this happening?

[elFarto]

I think I see the issue with that trace. I see references to the dav1d decoder, which means you're watching an AV1 video, which you 1070 can't decode, so it is falling back. I recommend setting the media.av1.enabled setting to false to prevent AV1 videos from being played back at all.

[mmbossoni]

I set the av1 to false I started video playback Opened a new tab checked on nvidia-smi that firefox was only with G (probably because new tab firefox was "saving" resources) switched back to video tab paused and resumed (got the stuttering) pressed back and suttering was gone

https://share.firefox.dev/3pmEhIm nvdlog.txt

[elFarto]

I can't quite figure out what's going on. It does seem to be taking a bit too long to initialise CUDA, but I don't see any obvious problems. I don't suppose you've got any CUDA debugging environment variables set (I see a number of references to 'dbg' in the stack traces)?

At this point, I would raise it with Mozilla, and see what they say.

[nahuel3pro]

I've got the same problem, could you find any fix?

[Glitch31415]

same issue here, but with an AMD graphics card. RX 6800

[mmbossoni]

OK, finally opened a bug on mozilla bugtracker https://bugzilla.mozilla.org/show_bug.cgi?id=1857106