TinyMCE in classic editor does not support modern video formats

[blackstar1991]

WP does not support webp, avi formats for the classic editor. Can someone help and make them uwaliable like in Block Templates ?

[nabilaminhridoy]

Hi there 👋

I’ve reproduced this issue on WordPress 6.8.3 with the Classic Editor plugin (v1.6.3).

When inserting .webm or .avi video files through the Classic Editor (TinyMCE), they are not recognized or previewed properly. In contrast, the Block Editor supports these formats without any issue.

This indicates that the core media handler supports modern formats, but TinyMCE’s configuration or the allowed MIME types for the Classic Editor are limited to older formats (mp4, m4v, ogv, mov, wmv).

Possible fix direction:
Add support for additional MIME types in TinyMCE initialization or extend wp_get_mime_types() for Classic Editor to include:

• video/webm → .webm
• video/x-msvideo → .avi

I tested this on WP 6.8.3 and can confirm the issue still exists.
Happy to help test a patch if someone is working on this.

@nabilaminhridoy