Feature request: Matroska (MKV) video container

[jedenastka]

I would like to request a feature for the use of the Matroska video container (also called MKV) in <video> tags.

From my testing, it is supported in the latest versions of Chromium and GNOME Web (WebKit-based), but not in the latest version of Firefox.

WebM is based on MKV, but they are not the same format - WebM is already provided as a feature on caniuse.com, and support is present in latest versions of all major browsers.

Here's a page I made so I could test support myself: https://grzesiek11.stary.pc.pl/files/random/mkv.html. From top to bottom, this is:

• MP4 with H.264 + AAC
• WebM with AV1 + Opus
• Matroska with AV1 + Opus
• Matroska with H.264 + AAC

[marcing]

+1

[Schweinepriester]

Intent to prototype from Gecko/Firefox:

• https://groups.google.com/a/mozilla.org/g/dev-platform/c/0ib0_yqiBmk/m/lY27dMnOCgAJ
• https://bugzilla.mozilla.org/show_bug.cgi?id=1422891#c112

also, TIL

Note that MKV is now a standard: https://www.ietf.org/rfc/rfc9559.html

So, this isn't some "unofficial" container format anymore.

[Schweinepriester]

Intent to ship in Firefox 145:
https://groups.google.com/a/mozilla.org/g/dev-platform/c/hBU-Ea_aDZA/m/UHzFa8riAwAJ

[goodusername123]

Intent to ship in Firefox 145: groups.google.com/a/mozilla.org/g/dev-platform/c/hBU-Ea_aDZA/m/UHzFa8riAwAJ

If present on caniuse Firefox's support would have to be marked as partial in it's current state since they made the extremely strange decision to intentionally not expose the full set of web codecs to MKV unlike Chromium:
https://docs.google.com/document/d/1SH5Pm1nRj9Qci9fBYVyE-5asj-GffL5evJa7OEZv3eY/
https://bugzilla.mozilla.org/show_bug.cgi?id=1991746
https://bugzilla.mozilla.org/show_bug.cgi?id=1991747
https://bugzilla.mozilla.org/show_bug.cgi?id=1991748

Firefox's choice kinda goes against one of the main selling points of MKV and is likely to cause compat/interop issues down the road especially since one of the most popular pieces of software that produces MKV files (OBS Studio) provides users with a simple drop down box to easily select FLAC or PCM audio as options when recording to the default format of MKV.

[FooIbar]

Chromium < 145 would also need to be marked as partial because <source type="video/x-matroska"... was not supported:
https://chromiumdash.appspot.com/commit/d0813004e27eb2f679dd4a9e26a13baeac4be9f2