[FFmpeg-user] Video and audio out of sync - general question

[Frank Häfemeier]

Am Sonntag, den 18.11.2012, 21:17 +0000 schrieb Carl Eugen Hoyos:
> Frank Häfemeier <ffmpeg <at> frank.haefemeier.eu> writes:
> 
> > I am converting HD video (H264, mp2/ac3, TS container) captured from
> > cable TV into mp4 container (x264, aac). I am also copy (if existing the
> > original ac3 stream as an additional stream into the mp4 container,
> > especially in case of a 5.1 audio.
> > 
> > Sometimes happens the audio is not in sync with video.
> 
> Command line and complete, uncut console output missing / 
> please share a sample.
I will send an example and related output, if I get one.

But in first place it is not the point, to get a audio out of sync.
I would like know (for my understanding) if it is in general necessary
to recode the audio stream if I want to use a filter graph.

More precisely: has a filter graph an effect in case of the parameter
'-codec:a copy'?

Bye
	Frank