Help! Audio Sync goes off after I join avi files...

[morbius]

Greetz to all :)

I have 8 DIVX encoded avi files all with AC3 that I want to put together onto one DVD. I usually use TMPG DVD Author to create my menus and create the final structure after I have joined the avi files into one chunk.

BUT, on viewing the 8 files all of them are in perfect audio sync, but once I joined them (I used VirtualDub 1.5.10, set video and Audio to Direct Stream Copy and then appended the 7 extra files to the opened first one) the audio is miles away.

It does seem to be consistently off right from the start and to the same degree throughout the joined file, but what's gone wrong?

Can anyone advise whether I have done something wrong (or indeed suggest an alternative method, bearing in mind I want to preserve the AC3 audio)?

Many thanks in advance for looking

morbius

EDIT
I just looked at the File Info panel for each of the files, and the audio is a few seconds shorter on each (presumably as sig tune ends over the end credits or similar). Is there some compensation I should be making for this?

[cinco]

I had a similar problem with mp3 audio. It seems that audio tracks are added independently of video. So if audio and video are not exactly the same duration,you will get a bad sync. Here is how I've solve it with mp3 audio:

-Open the file in VirtualDub 1.5.10 or higher
-Set the audio delay (in audio/interleaving)
-Save with audio and video in direct stream copy (this should cut of the excessive audio)
-Open the file and check that audio and video are of thew same lenght (also check the framerate)
-Check the delay in some player (not in VDub 1.5.10 is seems to display sync offset of about 500 ms, while the same file plays fine in the DShow players)

[morbius]

cinco
Thanks for replying - I'll certainly try that method next time, as I managed to get around the problem by creating 8 .m2v files that, when added to the extracted AC3 audio files, makes up 4.3gig. I then built the project with TMPG DVD Author and it worked perfectly.

Cheers to all who looked.

morbius