[MPlayer-users] [MEncoder] Synchonization lost when using Vorbis in a OGM

D Richard Felker III dalias at aerifal.cx
Tue Jun 17 18:17:15 CEST 2003


On Tue, Jun 17, 2003 at 12:01:33AM -0600, Rodolfo J. Quesada wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> Hi,
> 
> This is my first post to this list... As I had been looking for a long 
> time how to deal with a problem I got recently...
> 
> I'm trying to compress some VOBs copied with vobcopy, and after that, 
> dump the audio, convert it to Vorbis, and mux it all, with ogmmerge to 
> get a nice OGM.
> 
> The problem is, that those VOBs after starting mencoder, keeps saying 
> that there was duplicate frames, enters and leaves telecine mode, it 
> jumps from 23.976 to 29.970 in those changes... All of that things are 
> expected by the nature of the DVD, when I got to the final AVI, with an 
> AC3 audio track (-oac copy), the A-V sync is always around 0.000, with a 
> few tens of milliseconds changes... That's still fine...
> 
> Then I dump the PCM audio...
> 
> cat *.VOB | mplayer -vc null -vo null -ao pcm -aofile audio.wav
> 
> And I get a pretty big PCM file... Then I encode it...
> 
> oggenc -q0 audio.wav
> 
> And got an audio.ogg file...
> 
> Then, I merge it...
> 
> ogmmerge -A video.avi audio.ogg -o pelicula.ogm
> 
> And when I play it with MPlayer, the sync ratio jumps up to 15 seconds, 
> in some scenes where the telecine mode was enabled... It gets 
> desynchronized all the way, in the plain old 29.970fps scenes, the audio 
> is synced, but not in the 23.976 ones... I tried it in Windows Media 
> Player 6.4, and those scenes not synchonized get blurred or stoped, and 
> follows the audio synchronizations nicely, but the video quality is not 
> appealing at all... Pretty ugly in fact...
> 
> So, the question, somebody has faced this problem before? It can be 
> solved?... I really love OGM... The audio is so sweet, even at a -q0 
> ratio...
> 
> These are the lines of the encoding, I have tried the detc filter, and 
> othe options as well...
> 
> cat *VOB | mencoder -sws 1 -fps 29.970 -ofps 29.970 -sid 0 -vop 
> scale=512:384,pp=lb -aid 129 -oac copy -ovc lavc -lavcopts 
> vcodec=mpeg4:vhq:v4mv:vbitrate=650:vpass=1:vqscale=2 - -o /dev/null
> 
> cat *VOB | mencoder -sws 1 -fps 29.970 -ofps 29.970 -sid 0 -vop 
> scale=512:384,pp=lb -aid 129 -oac copy -ovc lavc -lavcopts 
> vcodec=mpeg4:vhq:v4mv:vbitrate=650:vpass=2 - -o video.avi

Have you tried -ofps 23.976???

Rich



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