Consider enabling AV1 support for more mobile browsers

[manuquadrat]

This issue respects the following points:

• This issue is not already reported on GitHub (I've searched it).
• I agree to follow Jellyfin's Code of Conduct.
• This report addresses only a single issue; If you encounter multiple issues, kindly create separate reports for each one.

Describe the bug

Please consider enabling AV1 support for more mobile browsers.
Currently, Safari is the only mobile browser with enabled AV1 support in browserDeviceProfile.js. I've done some testing on a moderately recent Android device (Pixel 7 Pro, Android 15) and different browsers (Firefox 138, Cromite(Chromium) 135), and all could play hardware accelerated AV1 just fine. This was achieved by simply changing the user agents.

Reproduction Steps

1. Set AV1 as preferred transcode codec in playback settings
2. With mobile user Agent (Mozilla/5.0 (Android 15; Mobile; rv:138.0) Gecko/138.0 Firefox/138.0) h264 is selected as transcoding codec
3. With tablet user Agent (Mozilla/5.0 (Android 15; Tablet; rv:138.0) Gecko/138.0 Firefox/138.0) AV1 is selected and plays fine with HW acceleration

Expected/Actual behaviour

As AV1 support in hardware (devices) and software (browsers) is maturing, it should be issue-free enough to enable AV1 support in more mobile browsers.

Logs

No response

Server version

10.10.7

Web version

10.10.7

Build version

10.10.7

Platform

Android

Browser

Firefox, Chromium

Additional information

No response

[nyanmisaka]

Enabling AV1 in a mobile browser should ensure it has hardware acceleration, otherwise prioritize it behind a codec that has hardware acceleration. Otherwise many phones that don't support AV1 will drain their batteries faster than usual due to the software dav1d/libgav1 decoding.