[Matroska-devel] audio async when muxing MP4 files into MKV with mkvtoolnix 2.0.2

Christian HJ Wiesner chris at wiesneronline.net
Sat Feb 24 23:05:22 CET 2007



Hi Mosu, hi all,

i am converting MPEG captures from satellite into MP4 files, using VLC 
0.86a. Both the MPEG and the MP4 file are perfectly in sync. However, 
the final MKV, after being muxed from the MP4 with latest mkvtoolnix, 
will be async. I am not setting any time delays for the audio track, so 
i wonder why this is ?

The delay i have to use to get it into sync is between -200 to -1400 ms 
for the audio track, meaning the audio is normally too late after 
muxing. Here the warning that mmg is giving me during muxing :

''CTTS' atom is needed for getting the timecodes right. As it is missing 
the timecodes for this track might be wrong. You should watch the 
resulting file and make sure that it looks like you expected it to.'

Is there aynthing i can do to avoid this ? Maybe this is a problem of 
x264 or the MP4 muxer used in VLC ?

Thanks in advance for a short answer

Christian
matroska project admin




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