Add support for the webm media file format

[Raphexion]

I really love the feature that it is possible to attach images and videos to pull-requests and issues. However, I've noticed that the webm format isn't supported.

Would it be possible for Github to add support for the webm format?

[TheRadicalDreamer]

It is really silly, but it DOES support WEBM. If you rename your file to .mp4, you can upload it, and it will be properly played on the comments!

Come on @github-staff please do not filter WEBM when uploading it to comments

[apteryks]

Does not seem to work (failed to upload error); maybe my file is too large? (28 MiB).

[apteryks]

.webm looks supported now, the issue in my case was the video file size; a 10.4 MiB one could be uploaded just fine.

[qcasey]

I think WEBM support might be especially important now that Gnome 42 is rolling out broadly, in which the default screen recorder saves to .webm.

Renaming .webm to .mp4 seems to break playback in Safari, but does work in FF/Chromium.

[Drew-Daniels]

Bump

[joan38]

+1 Gifs are so inefficient

[TheRadicalDreamer]

Chromeos have its screenrecorder in WEBM, so it is already a standard in many devices

[mloskot]

Ubuntu default screencast produces WEBM too.

[phillip-kruger]

+1

[codingjoe]

And AVIF, it's 2025… AVIF is Baseline 2024.

[TheRadicalDreamer]

It does support webm like a year ago though :)
Screen recording 2026-11-10 21.31.09.webm

[TheRadicalDreamer]

Doesn't show as a video, but at least as a file.
It will great to have a video player though

[apteryks]

It did show a video player when posting in an issue.

[TheRadicalDreamer]

But mine here??
Screen recording 2026-11-10 21.31.09.webm