[MPlayer-users] DVD sound sync

Frank Leavis f.t.leavis at student.utwente.nl
Tue Jun 11 18:53:01 CEST 2002


>Hi,
>
>> > [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
>> >
>> > When I play back a DVD using mplayer, I usually have to set a sound
>> > delay of -200 or -300 ms to synchronise the picture and sound.
>>
>>
>> Me too ;-), and IIRC lots of others also seem to have sync problems when
>> playing DVDs. Although my machine (Celeron466) isn't fast at all, I do
>> not think it's a performance problem. My suspicion is that mplayer is
>> not paying attention to some kind of constant time offset specified in
>> the MPEG.
>
>there is NO such info in the mpeg headers
>
>maybe it is in the .ifo, but no one has detailed docs on .ifo file format
>the current rev.eng.-ed docs only cover navigation
>
>i have only 3 dvd disks, and none of them has such problem
>so eirther teh disk is badly mastered, or i'm just lucky...
>
>send me such disk with this problem than i can probably reproduce and try to
>find where is such info stored...
>
>anyway i still say that it's probably audio driver problem
>mpeg files has exact timestamps on both video and audio, and i've never
>heard about constant a-v offset used in mpeg files or dvd disks
>so, the only way to get a-v desynced is bad driver of slow system
>
>A'rpi / Astral & ESP-team

I also get a constant audio/video stream offset with some DVDs when playing with mplayer that can be get rid of by using + and - keys.

Further more, when I demux ac3 streams from a vob with the win32 program called dvd2avi, the program will output the audio/video delay for each stream in the 
filenames of the demuxed tracks. Often the offset is different from 0 with the vobs I tried. http://arbor.ee.ntu.edu.tw/~jackei/dvd2avi/
Sourcecode is also on the site, I think that the delay is calculated in the getbit.c file.

Best Regards,
Frank Leavis





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