Currently the WebM handling seems to assume there will be a video stream; however .webm files may be audio-only as well (in which case it's a Vorbis, or potentially maybe Opus audio track with no video).
Currently I can upload such a file, but I get some bad behavior as a result.
Compare audio-only .webm:
versus audio-only .ogg:
- Nasty warnings visible during display of the file page, and parsing of a page that embeds:
Notice: Undefined index: video in /srv/vagrant/mediawiki/extensions/TimedMediaHandler/handlers/WebMHandler/WebMHandler.php on line <i>123</i>
- File page's info marks it as 'audio/video file' and gives empty dimensions where it should be 'audio file' with no dimensions
"(WebM audio/video file, Vorbis, length 5 min 19 s, 0 × 0 pixels, 256 kbps overall)"
- Embedded player is marked as video, has a tiny audio icon thumbnail, and seems to be not initialized properly
- Media type returned from API is 'VIDEO', not 'AUDIO':
- No .ogg transcode is made (not sure if that's really necessary; I can extend ogv.js to support webm containers for the browsers that don't do WebM natively)