On 06/10/2011 05:58 PM, Philipp 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.
If you're just interested to do it once during playback: with mplayer
you can set A/V offset (using '+' and '-' and 'o' for
on-screen-display). IIRC VLC can do it as well...
If you're up to compiling A3 + videotimeline: it's intended for this
kind of work:
http://rg42.org/wiki/a3vtl - basically it does the
following (but with a nice GUI);
1) separate A/V
ffmpeg -i INPUT.avi -vn audio.wav;
ffmpeg -i INPUT.avi -an -sameq video.avi
2) re-align A/V (by shifting/cutting the audio)
You could do this step with xjadeo & ardour2
3) Mux A/V
ffmpeg -i video -i audio.wav -vcodec copy -sameq output.avi
The A3-vtl video-export offers a lot more ffmpeg encoding options
optimizations.. but the above command should do; see `man ffmpeg` or
`ffmpeg --help` - though reading those is only for the faint-hearted.
google is your friend.
Sorry short reply. I'm a bit tied up this week-end and mostly offline.
HTH,
robin