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

[Roger Pack]

> 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. In this case I
> use the asyncts filter with 'first_pts=0'. This works well but only if I
> encode all audio streams.
>
> Is it really necessary to encode instead of copy? I tried to copy the
> stream and using the filter, but the audio was still not in sync. Is
> there a special order of parameter relevant?

So in your input the audio is in sync but not the output? Full command
line and console output please?
-r