Fix YouTube Stuttering on Steam Deck with Firefox Using h264ify

If YouTube is stuttering on your Steam Deck when using Firefox, try the h264ify extension — it seems to fix the issue.

In a Reddit thread started by u/Kyokri reported the stuttering issue, and u/Usual-Neighborhood75 suggested using the h264ify extension as a fix. I tried it and it worked great.

You can find the extension here:
https://addons.mozilla.org/en-US/firefox/addon/h264ify/

Here’s some info from the extension’s page:

Try h264ify if YouTube videos stutter, take up too much CPU, eat battery life, or make your laptop hot.

By default, YouTube streams VP8/VP9 encoded video. However, this can cause problems with less powerful machines because VP8/VP9 is not typically hardware accelerated.

In contrast, H.264 is commonly hardware accelerated by GPUs, which usually means smoother video playback and reduced CPU usage. h264ify makes YouTube stream H.264 videos instead of VP8/VP9 videos.

Note: 4K and 1440p videos will not be available because YouTube no longer encodes those videos in H.264

Github: https://github.com/erkserkserks/h264ify