[MPlayer-users] mkv to divx audio sync issues

[Bart de Boer]

Nico Sabbi wrote:
> Il Saturday 24 November 2007 12:25:17 Bart de Boer ha scritto:
>   
>> Dear mplayer people,
>>
>> Sorry if I'm double-posting. I think something went wrong with my
>> previous post. So here I go (again):
>>
>> I have a P4 2.8Ghz Celeron that isn't powerful enough to decode my
>> 720p H.264 mkv's. So I'm using mencoder to convert them to MPEG4
>> Divx. This works nicely performancewise. They only take up around
>> 30% CPU to decode on that machine now. :)
>>
>> I am however having another issue. There always seems to be a
>> slight A/V sync problem. (The original mkv's run perfectly in
>> sync.) I tried different mkv's. I also tried numerous parameters
>> without success. One thing that seemed to work (in most cases) is
>> to seek 1 second into the video using -ss 0:00:01 and start
>> converting from there. Therefore I conclude something goes wrong at
>> the beginning few frames of the video.
>>
>> These are the commands I'm currently using:
>>
>> mencoder ${inputFile} -ss 0:00:01 -oac copy -nosound -mc 0 -noskip
>> -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=4000:turbo:vpass=1
>> -passlogfile ${logFile} -o /dev/null
>>
>> mencoder ${inputFile} -ss 0:00:01 -oac copy -mc 0 -noskip -ovc lavc
>> -lavcopts vcodec=mpeg4:mbd=2:trell:v4mv:vbitrate=4000:vpass=2
>> -passlogfile ${logFile} -o $outputFile
>>
>> Is this an issue with mencoder or am I using the wrong method?
>>     
>
> copying one or more of the streams with -mc 0 -noskip is generally
> a recipe for disaster. remove -mc 0 -noskip and try also -demuxer lavf
>   

Well, I removed -mc 0 and -noskip and added -demuxer lavf... But that 
gave me all sorts of "duplicate frame" errors and finally completely 
failed with: "Too many audio packets in the buffer:"

Removing -demuxer lavf works without errors but that leaves me back to 
square one... I guess seeking into the video for 1 second helps... But 
that seems a bit of a workaround... It looks like mencoder is 
encountering "duplicate frames" and then failing to keep A/V sync after 
that?...

I'm using the backported mplayer-1.0~rc2 under Ubuntu by the way...