audio sync issues in DVD lab pro

[goeth]

Hi all,
I am authoring some DVD and I have problems with one of the 4 movies I have placed on my own DVD. Only the third one gets the audio out of sync. I have tried all I could think of, I have read some stuff in teh forums, still without success!

Any pointers or hints will be appreciated. Here it goes...

I have perfectly correct avi files (no audio sync problems). I convert them to m2v and wav files using TmpGenc. I then trash the wav file and extract a ac3 file using ffmpeggui. At that point I multiplexed together the ac3 and the m2v to obtain a mpg to be used in dvdlab pro. I found out later that this is not required as dvdlab pro will take m2v file and ac3 files separately...

I did my menu, add my movies, build my transition, add subtitles and evrything works fine for 3 out of the 4 movies I am trying to add?!?!? I even tried to "delay" the time using the built in audio delay tool in dvdlab pro. I added a delay of 2000 ms (since my audio and video add a difference of 2 seconds) without any success.

Any idea before I give up? Thanks

[guns1inger]

When you play the mpg, are they in sync ?
Don't base you delay on the difference shown in the assets list. You are better off just doing trial and error, slowly increasing the dely until it matches.

Thankfully, I have never had sync problems arising from DVD Lab itself, although I have had to correct the occassional problem in DVD Lab.

[reboot]

You said you trash the audio. Why encode it in the first place?
You extract AC3...from what?

[goeth]

I trashed the wav file because I could not import it in encore (that I used before, something about linear PCM I think)

I extracted the ac3 file using ffmpeggui directly from the avi file.

I will try to re-encode the avi into mpg to see if I have sync problems. Also, dvdlab "splits" the file into m2v and ac3 when I import the mpg file. Would that cause the sync problem?

[reboot]

Try transcoding your .wav file in ffmpeggui.
Import the AC3 and m2v into dvdlab.

[goeth]

Everything works now!!!

Actually, I used the wav file that was extracted from TmpGenc. No need for the ac3 file. Everything is sunchronized now!

In the future, should I use wav files or convert to obtain ac3 files. I tried my DVD with both and both work (i.e. no audio sync problem). Which one is best?

[reboot]

AC3 is much smaller, leaving more rooom for video bitrate. AC3 is also DVD spec, although LPCM and mp2 are usually supported now. Older players may not like anything but AC3.