Within the nightly builds of the Firefox web browser is finally the ability to support playback of Matroska "MKV" content.

Enabled just within the Firefox Nightly builds for now or opting in within the media.mkv.enabled preference is the ability to support MKV playback. Initially just AVC/H.264 and AAC within MKV containers are supported but other codec support will be expanded over time.

For the past eight years there has been [1]this feature request for supporting Matroska/MKV playback support. This has been a common feature request and only now materializing within Firefox while Chrome/Chromium has enjoyed widespread support.

The latest [2]comment on the BugZilla for the feature tracking noted:

"A quick update: you can now watch AVC (H.264) and AAC in MKV on the latest Nightly. The preference is media.mkv.enabled (currently enabled by default only on Nightly). Feel free to try it out and report any issues if you encounter AVC or AAC in MKV failing to play.

Support for other codecs will be added gradually."

There is [3]this Matroska support technical brief around the Firefox support for it and their implementation plan. Eventually they hope for the MKV support to be as well versed as what is shipped by Chromium/Chrome.



[1] https://bugzilla.mozilla.org/show_bug.cgi?id=1422891

[2] https://bugzilla.mozilla.org/show_bug.cgi?id=1422891#c115

[3] https://docs.google.com/document/d/1SH5Pm1nRj9Qci9fBYVyE-5asj-GffL5evJa7OEZv3eY/edit?tab=t.0#heading=h.tfv43swtn2zr