[MEncoder-users] Solution: transcoding from MKV(AC3+H264) to anything keeping AC3 soundtrack

[The Wanderer]

Matthias Hopf wrote:

> On Mar 27, 07 10:43:23 +0200, Pierre Grimaud wrote:
> 
>> I have finally found a solution to this problem. As it turn out, it
>> is mencoder's muxer that is at fault (AFAIK).
> 
> Must be the demuxer, as this issue only occurs when transcoding mkv
> files.

>> 2. Extract AC3 soundtrack. The best way to do that is to use
>> mkvextract. I've not seen any other tool work (mplayer crashes, vlc
>> does weird things)
> 
> mplayer -dumpaudio -dumpfile blub.ac3 in.mkv
> works for me all the time.

...but, if the problem is in the demuxer as you suggest above, this
could produce an incorrect stream (because MPlayer has an incorrect idea
about what data is and is not part of the audio stream). I've run across
that problem before, with some MP4 files; there were constant artifacts
in the audio when played back with MPlayer, and dumping the (MP3) audio
and playing it back with a standalone MP3-playing program produced the
same artifacts, but other players were able to play the original file
with no artifacts.

(Not to mention that files resulting from -dump* are not necessarily
valid standalone files, because they are the raw audio data without any
container. Some formats are playable anyway, but IME others are not.)

-- 
       The Wanderer

Warning: Simply because I argue an issue does not mean I agree with any
side of it.

Secrecy is the beginning of tyranny.