[MEncoder-users] mencoder concatenation warps audio out of sync

[Reimar Döffinger]

On Fri, Nov 06, 2009 at 08:30:02AM -0800, mencoder at perlmeister.com wrote:
> On Wed, 4 Nov 2009, mencoder at perlmeister.com wrote:
> 
> > I have two videos, title.avi and soundtest.avi, which I'd like to
> > concatenate using mencoder. However, the audio gets out of sync with the
> > video in the process, and this happens both by copying or recoding it.
> 
> Hmm, it's been a while ... does anyone know the answer to this one? Is
> this the correct mailing list?

Well, it's rather simple, if you play the title.avi with -novideo you
will realize that the audio is 2.4 seconds long, the video is only 1.7
seconds, making a difference of 0.7 seconds.
The right fix is to make the audio of title.avi the right length, though
for this particular example -mc 100 works mostly fine, too (though you
still hear the issue, the noise audio starts too late, but it synced up
by the time the "clicks" start.