When I am watching youtube video in firefox, in Task manager I can see its using "3D" part of my GPU, while video decode and video processing is idle. When I open the same video in edge, 3D part of my GPU is very low and its video processing unit taking the load.
This means I cannot watch 4k videos on my 4k laptop, as the GPU is dropping frames, 8k it renders just one single frame.
In edge, no issue playing 8k..
Drivers are up to date, vp9 codecs installed, hardware acceleration flipped x times.. Anyone got a lead?
Are you sure Youtube is serving you VP9 video? I've seen Youtube roll out AV1 to more and more devices so this may have something to do with that. You check check by right clicking the video and selecting "stats for nerds".
For me (Linux, Firefox) Youtube has been serving more and more AV1 content. Decoding speed for AV1 is very different between browsers if you don't have hardware support on your device.
I've personally never had too many frame drops on Youtube, but regardless of the quality I usually need to restart Firefox regularly because of memory leaks that cause massive browsing lag. Video content, specifically from Youtube, seems to cause this problem for me.
In case Firefox is your main browser, maybe check if the installed addons matter (try: menu -> help -> troubleshoot mode). I've run into a lot of browser crashes because of a seemingly unrelated addon messing with other pages; this took me a few months to find out.
I've never seen Youtube not drop frames. Best it seems to be able to do is about 1 dropped frame per second, regardless of OS and browser. It also seems to almost always use codecs which require CPU decoding, which is obviously terrible for power efficiency (though it might save them a little bit in bandwidth I guess).
I don't watch long videos on YT for this reason, I download them and use a real video player, which can play video without dropping frames at 2 % CPU. This also gives me my mandatory archival copy, as interesting things are often deleted or channels deleted / terminated.
It would be nice if some addon would intercept video page opening, initiated background download via youtube-dl, and plopped VLC window running the video (as it's downloading) inserted into the page.
This was possible before WebExtension. Unfortunately, it is not possible now. And your suggestion is a security nightmare as it could download malicious code that masked as video automatically.
My current setup is Video DownloadHelper + JDownloader 2. I have VDH set to copy the direct URL of the video only. And JD2 will detect the video url via clipboard monitoring and will prompt to download the video.
I believe it is still possible to do it in PaleMoon and WaterFox (fork of Firefox). They still uses XUL which it was before Mozilla decide to move to WebExtension. However a warning, they are not current with securities updates as Firefox are. I believe they are few version behind.
While not the issue you're running into, I think VP9 is required for anything over 1080P on Youtube. I used to have to run h264ify[0] because of certain GPUs not supporting it, and it putting it all on my (also aging) CPU.
The only thing you can really do is try enhanced-h264ify[1] and play around with the codecs to see if one works better for you with Firefox.
I also have an Intel 11th gen CPU, but desktop form of 11900K, so I may play around with this in Firefox to see if I can duplicate your results but I also have a Geforce 1060FE. I leave Intel Driver Support Assistant[2] installed on all of my machines. There is a conflict recently between it and the driver version that MS is pushing out over Windows Update, so I have hidden that driver for a couple months now. But you may want to at least give that driver a try as well and see if it changes anything.
I've consistently used Firefox since 2002, never having moved to Chrome, but made the switch to Microsoft Edge last month. There's a few reasons for that, which I won't bore you with here. But if you do decide to make the leap, I can say as a very longtime and formerly extremely dedicated Firefox advocate, I don't regret it.
Hopefully something here helps you, if not, Edge is Chromium Done Right.
This means I cannot watch 4k videos on my 4k laptop, as the GPU is dropping frames, 8k it renders just one single frame. In edge, no issue playing 8k..
Drivers are up to date, vp9 codecs installed, hardware acceleration flipped x times.. Anyone got a lead?
edit:Windows 10, iGPU of intel 11th gen i9-11950H