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

On Fri, 2011-06-10 at 18:57 +0200, Renato wrote:
> On Fri, 10 Jun 2011 17:58:46 +0200
> Philipp <hollunder@email-addr-hidden> wrote:
>
> > Hi,
> > sorry for abusing this list for a mostly video editing question, but I
> > didn't find a proper list and knew that we have some video people on
> > this list.
> >
> > I'd like to fix some videos that have partially out of sync video and
> > audio, meaning that beginning at a certain point in the video the
> > audio is suddenly out of sync by a couple of seconds. There's no
> > constant change, the delay seems fixed once it's there.
> >
> > I wonder how to fix such a thing. The files are xvid encoded videos
> > and vbr mp3 audio inside avi containers. I thought it should be
> > reasonably easy to cut and move the audio (re-encode if unavoidable,
> > but I know it's in principle possible without) and put it back in a
> > container, but I didn't manage.
> >
> > Can someone recommend a program/workflow that would allow this?
> >
> > I tried:
> > - Avidemux: seems like actual editing is not what this program was
> > written for, couldn't figure it out, but it seems close
> >
> > - openshot: couldn't figure out how to separate video/audio
> >
> > - kino: seems to only work with DV-files, apparently takes ages to
> > decode the file, doesn't seem to be what I need
> >
> > - openmovieeditor: I figured it might work by dragging the file to
> > both a video and an audio track, but I got extremely garbled audio
> > output, no idea what's wrong
> >
> > - cinelerra-cv: Doesn't start. No error message, it simply shows no
> > window, nothing. Well, it does something with the screen, but it
> > shows nothing.
> >
> > - pitivi: Doesn't seem like it can play back the video. I can drag the
> > video to the tracks and it starts to draw a waveform, I guess no
> > video thumbnails because of: gst.ElementNotFoundError: pngenc
> > Doesn't seem to be able to play the video.
> >
> > - kdenlive: would require me to install 30 additional packages, total
> > about 200MB, no thanks.
> >
> > I thought it would be a simple task, really nothing fancy. Seems like
> > I was wrong.
> >
> > Regards,
> > Philipp
> >
>
> Hi, unfortunately can't give you a full solution, but only a hint: in
> mplayer with "-" and "+" you can adjust audio/video syncronization by
> multiples of 100ms (maybe you cand do finer, but I'm not sure).
>
> maybe you could then somehow record the output to a new file?

I don't think so, assumed you can display the video without side effects
in a way, that you could 'record your desktop', than you only would be
able to record video, but AFAIK not audio.
An app like Cinelerra can separate the container's audio and video, but
using video apps on Linux can become a PITA ...

        21.9 Improving performance
        
        For the moment GNU/Linux is not an excellent desktop. It is more
        of a server. Most of what you will find on modern GNU/Linux
        distributions are faceless, network-only programs strategically
        designed to counteract one Microsoft server feature or another
        and not to perform very well at user interaction. There are a
        number of parameters on GNU/Linux, which ordinary people can
        adjust to make it behave more like a thoroughbred in desktop
        usage.
        21.9.1 Disabling swap space
        21.9.2 Enlarging sound buffers
        21.9.3 Freeing more shared memory
        21.9.4 Speeding up the hard drive
        21.9.5 Disabling cron
        21.9.6 Reducing USB mouse sensitivity
        21.9.7 Assorted X tweeks
        21.9.8 Speeding up the file system
http://cinelerra.org/docs/cinelerra_cv_manual_en.html

... if the app after editing should make a container again, it can
happen that the old man became a voice like Mickey Mouse or the
beautiful woman is transformed to a Conehead. After 12 hours using all
resources of your computer you will know if the video is ok or not. I
nearly have forgotten to mention, that it also can happen that audio and
video get out of sync during this process ;). YMMV.

On my machine Cinelerra always 'worked' OOTB! On Philipp's it doesn't
run.

Regards,

Ralf

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Received on Sat Jun 11 00:15:01 2011