See http://bugs.musicbrainz.org/ticket/2718 (PICARD-59 and PICARD-35)
Apparently .avi files would be more complicated to support, so I entered this ticket separately.
Support Resource Interchange File Format (RIFF)
Support Microsoft WAVE format (RIFF/WAVE) tagging with ID3
Better video track and file support
Support RIFF INFO chunks for WAVE files