Howto: Enable HTML5 HD/UHD video in firefox

Firefox by default doesnt enable some media extensions that are used by html5 video, specifically by youtube.

You can check what is enabled by going here: https://www.youtube.com/html5

Normally some options like mp4 H264 and MSE are disabled, this stops some videos from working, including HD and higher definition videos.

To fix this in Firefox you need to enable a few additional options.

Got to about:config

search for mediasource

In addition to the default settings,

make sure the following are set to true

media.mediasource.mp4.enabled
media.mediasource.enabled
media.mediasource.webm.enabled

Search for mp4

In addition to the default settings,

make sure the following are set to true

media.fragmented-mp4.exposed
media.fragmented-mp4.ffmpeg.enabled

The mp4 settings have changed since I last set them and my browser is slightly different. I didn't need to enable any extra options, but enabled all the mp4 options anyway in addition to the defaults. Mine looks like this

media.fragmented-mp4.enabled;true
media.fragmented-mp4.ffmpeg.enabled;true
media.fragmented-mp4.gmp.enabled;true
media.fragmented-mp4.use-blank-decoder;true
media.mediasource.mp4.enabled;true

@Baz Suggests in another topic to experiment with the media.fragmented-mp4.use-blank-decoder option as it may or may not cause some issues. Ive had no issues to far with it enabled, but it works with it disabled also.

Check the html5 page again you should have all options enabled: https://www.youtube.com/html5

You should be able to play this video in 4k

note: you may or may not have to install additional codecs depending on your distro.

ffmpeg is a dependency that will likely be required, make sure this is installed. Some distros do not ship with ffmpeg like Fedora, but it is available from rpmfusion in that case.

4 Likes

Opera has a similar issue, I might add a fix in a thread

Well it’s happening again.
This time with Firefox 60.5.1esr.

The media,mediasource stuff is there, but the media.fragmented stuff isn’t.
And the video put here doesn’t play.

So now what do we do?

OOPS!

opensuse leap 15
Kernel 4.20.12-lp150.7-defualtx86_64