On Mon, 2010-05-24 at 16:43 -0700, OK OK wrote: > I'm having problem with mplay to replay one mkv file. The error I got > [mkv] Track ID 1: video (V_REAL/RV40), -vid 0 Looks like the realvideo extradata parsing in demux_mkv is buggy. The differences between muxers probably result from the muxers using somewhat different format for that (using larger than minimum size extradata should trigger the bug and break playback).