Greasy Fork

not work

?

What is your OS and browser? If your browser does not support AV1, you cannot use it.

And some old videos might not have AV1 codec.

firefox 121.0.1
Windows 11 22635

firefox 121.0.1Windows 11 22635

For windows 11, you have to install AV1 Video Extension from MS store.

https://www.microsoft.com/en-us/p/av1-video-extension/9mvzqvxjbq9v

( for details, see https://www.reddit.com/r/firefox/comments/u17udy/installedfirefox100betaandav1doesntseemto/ )

I already have it installed

I don't know. Any error message in the console log? (right click the page and click inspect)

Not every video have AV1 source. Try https://www.youtube.com/watch?v=dFlDRhvM4L0

You might also try to use another browser. It might be due to the settings in Firefox.

Try this as well.

https://www.tenforums.com/tutorials/121443-enable-disable-av1-video-codec-support-firefox.html