[MEncoder-users] audio stream becomes longer than video stream

[Martin Collins]

On Sun, 14 Aug 2005 18:58:32 +0200
Grzegorz Nowak <gnowak at gmail.com> wrote:

> Okay thanks I will try that. What do you mean by altering its
> speed?? I just have to cut of a couple of ms of every soundstream.

You can do that with audacity too.

If your audio is longer because you have just lost some frames of
video in one place your movie will be in sync before the gap and out
of sync by a constant amount after it. Then cutting out the
corresponding section of audio will match up the lengths (and sync)
again.

If, however, you have lost frames over the length of the video your
movie will be in sync at the start but will get further and further
out of sync as time goes on. In effect the playback rate of the video
has been changed, but not of the audio. To fix this you need to change
the speed of the audio to match the video again (or replace the lost
frames with duplicates, which may introduce visible glitches).

Martin