[MPlayer-users] A/V Sync drift in playback of MKV files

Samveen samveen at rediffmail.com
Thu Nov 25 06:30:57 CET 2010


hi all,

When I play some of my old MKV files (A:RM/COOK, 
V:RM/RV40) with mplayer on macosx (self compiled), the A/V sync drifts 
with the audio running ahead of the video. in the beginning, the video 
is ahead by a second, then the audio start to get ahead and the de-sync 
increases to more than a minute after 20 minutes of play. After 
searching around a lot, I got Nada in terms of working solutions from all
 the results including:
1) mplayer options: (http://lists.mplayerhq.hu/pipermail/mplayer-users/2009-October/077990.html and others) - Didnt affect playback one bit except make it worse at places.
2) Changing container to avi - mencoder failed with message that packing COOK audio into AVI not supported
3) Transcoding - Mplayer translated the problem into the transcoded file.

 Finally, in frustration, I unpacked the MKV into it's component streams
 with mkvextract from the mkvtoolnix package (v2.3.0) (ops: tracks f.mkv 1:f.cook.rm 2:f.rv40.rmv) and then joined 
them with mencoder (ops: f.rv40.rmv -audiofile f.cook.rm -ovc copy -oac pcm -o f.avi) . And voila, it worked.


My conclusion is that Mencoder cannot sync the A/V streams from the MKV 
container properly due to some bug in it's container handling code for 
MKV.

with hopes that this will help someone in the future.
Samveen  


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