Motion-JPEG appears to be not patent-encumbered, and is produced by both some old cameras and some newer cameras too. It's notoriously space-inefficient (because there is no temporal compression between adjacent frames) but like large TIFF and PNG images, could be nice for supporting camera-original files.
ffmpeg & ffmpeg2theora should already handle converting such files into web-playable Ogg/WebM derivatives.
What would be needed:
- suitable type detection for .mov and .avi
- might need to add support to getid3, or do otherwise similar checks
- upload-time codec checks for .mov and .avi, extending plans from T155320
- whitelist for acceptable codecs
- ideally, pre-upload checking in JS so you don't waste time uploading a file that's not supported