Audio sync problems

[Dalboy1]

HI
I have 2 avi files with ac3 audio. When I join the two files with virtual dub the joined file plays OK up to the point where it is joined, then there is a click and the audio becomes barely audable. If I scroll foreward slightly the audio returns to normal volume. I have tried extracting the ac3 audio from the joined file and running thru ac3fix, after muxing the fixed file the audio level stays constant but is out of sync by 1800ms with video. If I adjust the interleaving with virtual dub the sync is OK but it reintroduces the same fault with audio at the joining point. Has anyone got some suggestions as to what I can do to fix this problem.

[Skelsgard]

have u considered decoding to wav, joining in this format (accepted by all audio editors) and reencoding to AC3?

[Dalboy1]

Yes I have tried decoding to wave, but both the resulting wave muxed with video and converted ac3 muxed with video were out of sync as before.

[Booji Boy]

I think during the splitting process parts of the audio was lost. There's not much you can do about it other than a re-rip. This time you might consider leaving the video in one piece.

[mod]

Have you checked that first audio and video streams have the same lenght?
If they haven't, you can introduce a silence before the joining frame, or cut the seconds that cause the gap (from the last valid keyframe).

[Dalboy1]

Hi
Thanks for the reply. It appears that the audio is slightly shorter than the video. But I am not to sure how to introduce silence as you suggest. Could you please explain in a bit more detail.