The VideoLAN Forums

Seems as if VLC requires an Opus Ogg header as extra data in the MKV stream header. While this is strictly not necessary, I understand that it is a little easier on the code to do it this way. Case closed.

I have webm containers with VP8 coded video and Opus audio. During playback, VLC reports "opus error: initial Opus header is corrupted" and "opus error: cannot read Opus header". A few minutes with the source code reveals that VLC is looking for an ogg header instead of raw opus ...