Currently supported audio formats are: mp3, wav, m4a, 3gp, flac. Video formats are webm, mp4, and ogg. I don’t see a problem with the other audio formats as they cannot contain video, as far as I know.
Me either, but please see https://askubuntu.com/questions/518895/is-ogg-for-audio-or-for-video-format. Maybe we can assume ogg is for audio and ogv is for video.