[MEncoder-users] Skipping frames while copying video [BUGREPORT]

[Aaron Digulla]

RC wrote:

>> The key point: It doesn't. By skipping frames, I end up with more
>> audio than video. 
> 
> Well I could have said "trying to maintain sync", but I assumed that
> would be clear.  Most importantly, did you try disabling it by adding
> "-mc 0" (with/without -noskip)? You did not mention what effect
> it had, if any.

-mc 0 solved the problem and I ended up with a video where the audio and
the video had exactly the same "length".

> You said it was also duplicating frames, so it's not (just) shortening
> the video.  Do you know audio was exactly the same length as video in
> all your source files to begin with?  

The source material should have the same length for both streams; that's
why I was wondering why mencoder would want to drop/duplicate frames.

And it's dropping much more frames than it's duplicating.

>> Maybe this is a bug. Do you want to have a look at the input material?
>> I could upload a small file (4MB) which doesn't work.
> Always a good idea.

I uploaded a demo video as "copy-loosing-sync.mov" on the FTP server.
It's about 9MB and contains many skips and two duplicates.

The command I used to copy from Quicktime to an AVI container:

mencoder -ovc copy -oac pcm -o test.avi copy-loosing-sync.mov

Afterwards, I have 8.9s video and 9.5s audio. With "-mc 0", I get no
dropped or duplicated frames and the video and audio streams have the
same length.

I would expect mencoder not to drop or duplicate any frames while simply
copying a stream into a new container type.

Regards,

-- 
Aaron "Optimizer" Digulla a.k.a. Philmann Dark
"It's not the universe that's limited, it's our imagination.
Follow me and I'll show you something beyond the limits."
http://www.philmann-dark.de/