To be fair, I've looked through the Bugzilla threads about this (here are some for reference: [0][1]) and it seems to be a very difficult thing to implement. It

To be fair, I've looked through the Bugzilla threads about this (here are some for reference: [0][1]) and it seems to be a very difficult thing to implement. It's a bit beyond my reach, but my understanding is the tricky part is compositing the frames decoded by ffmpeg onto the document, and getting that all to work with all possible CSS transformations and such. So it's not just a matter of the Firefox devs neglecting Linux. [0]: https://bugzilla.mozilla.org/show_bug.cgi?id=563206 https://bugzilla.mozilla.org/show_bug.cgi?id=563206 [1]: https://bugzilla.mozilla.org/show_bug.cgi?id=1210729 https://bugzilla.mozilla.org/show_bug.cgi?id=1210729