[MEncoder-users] ac3 mistaken for mp3 in recent versions of MEncoder

[Reimar Döffinger]

On Thu, Apr 29, 2010 at 08:41:33AM -0500, Laine Lee wrote:
> On 4/29/10 12:10 AM, "Reimar Döffinger" <Reimar.Doeffinger at gmx.de> wrote:
> > That's the wrong way of cutting it, like this it might be a bug in your
> > exporting program.
> > You should use the large files that fail and then use e.g. dd or some other
> > program
> > (there should be some GUI ones e.g. for splitting a file so you can burn it in
> > parts
> > on multiple CDs and often they can split them down to rather small sizes) to
> > just get the first part of _exactly_ these files.
> 
> Doing that isn't trivial, because my exporting program is the only way I can
> access the original capture with muxed audio and video in a single file. If
> I can remux the full-length exported files as they exist before encoding,
> then split them, that would yield what you suggest. But I'm not sure I can
> figure out a way to do that. Otherwise, I would have to guess how much of
> each file to cut so that I could get audio and video excerpts that are close
> enough to the same duration to be useful.

You are making a insurmountable mountain out of a rather trivial problem.
Why do you wan them to have the same duration, it does not matter for analyzing
the issue.
What you should do:
you run
mencoder 'Clip.mp4' -oac copy -audiofile 'Clip.ac3' ...
It fails.
Then you do
dd if=Clip.mp4 of=cut.mp4 bs=1024 count=4096
dd if=Clip.ac3 of=cut.ac3 bs=1024 count=4096
Then you make cut.mp4 and cut.ac3 somehow available to us (e.g. upload to
ftp://upload.mplayerhq.hu/MPlayer/incoming ).
The cut .mp4 may be useless, but maybe the ac3 file alone is enough to reproduce
the issue anyway.