WebM VP9/Opus marked as such:
WebM VP9/Opus unmarked:
WebM VP9 (no audio) unmarked:
MP4 VP9/MP3, marked as vp09.00.10.08, mp4a.6b:
MP4 VP9/MP3, marked as vp09.00.10.08, mp3:
MP4 VP9/MP3, marked as vp9, mp3:
MP4 VP9/MP3, unmarked:
MP4 VP9 (no audio), marked as vp09.00.10.08:
MP4 VP9 (no audio), marked as vp9:
MP4 VP9 (no audio), unmarked: