[LAU] OT - syncing partially out of sync video and audio in existing files

pshirkey at boosthardware.com pshirkey at boosthardware.com
Sat Jun 11 09:24:45 UTC 2011


 > Philipp <hollunder at lavabit.com> wrote:
>> >> >> >

<snip>

>> > So it seems mencoder can just drop video frames.
>>
>> That's good to know. For references sake, what was the commandline that
>> you ended up using?
>
> I wrote it in another post in this thread already, but here it is again:
>
>     1) Figure out the position at which the offset starts using mplayer.
>
>     2) Get the faulty part in a separate file, delay audio as necessary:
>     mencoder -ss 02:47:55 -oac copy -ovc copy -delay -9.55 file.avi -o
>     fileb.avi
>
>     3) Get the good part into another file:
>     mencoder -endpos 02:47:55 -oac copy -ovc copy file.avi -o
>     filea.avi
>
>     4) Put the parts back together again:
>     mencoder -oac copy -ovc copy filea.avi fileb.avi -o
>     filefixed.avi
>
>     filefixed.avi is the resulting fixed file.
>
> What I noticed though is that it's limited in granularity, maybe it has
> something to do with keyframes. In my previous case I had 13 seconds cut
> out instead of 9.55, but it seems like it can be more. I know far too
> little about video or mencoder to tell what's really going on.
> Well, it's ok for me to loose a couple of seconds and have synced audio.
>
>

I suspect you're not the only person who feels this tradeoff is a
reasonable *default* choice.

It's functionality like this that could be relatively easily added to
existing software and would make a huge difference to a lot of people over
the years. The problem is knowing how to achieve the goal and automating
that process. Seems like you have figured out a useful commandline method.
Hopefully that will get picked up and integrated into a GUI solution at
some point.


--
Patrick Shirkey
Boost Hardware Ltd





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