Serious AV synching problems

[Letricheur]

I have experienced severe AV synching problems with Harry Potter, Blade Runner, and Dr. No NTSC DVD rips and SVCD encoding. The audio is out by up to 10 seconds (usually faster than video). I use DVD2AVI (forced film) and demux to produce the ac3 file and BeSweet to make the mp2 file. SVCD (m2v) encoding is through CCE 2.64 via Avisynth. I use pulldown on this then bbMpeg to remux, splitting files at 700Mb.

I don't understand why the audio is so badly off. A half a second or so might be reasonable but 10 seconds?!! After searching the forums I have found that the only synching guides available deal with avi files (using Virtual Dub, for example). BTW I made an AVI of Dr. No with DivX 5 and the AV synching was fine.

Does anyone know how it this happens but more importantly how to fix such bad AV synching of MPEG-2 files?

[idbirch2]

I had the same problem with Deuce Bigalo PAL. Was out of sync by bout 3 seconds. I found that going into the BBMPEG tab and Advance Options then putting video delay up to 800ms worked a treat.

Hope this helps!

[Letricheur]

Thanks, but I think I may have solved the problem. I normally load all the vob files into DVD2AVI and make the d2v file without clipping any of the intro material or the stuff that appears at the end of the film (another FBI warning, etc.). In the case of Harry Potter, it opens with the Warner Brothers logo against blue, cloudy sky with accompanying music, then the MPAA rating screen for some seconds, which is silent. After that, the Warner Brothers Hollywood lot appears, shimmering in gold, with the Harry Potter music opening over this, finally followed by the opening scene of the movie.

I noticed in my SVCD that the Warner Brothers logo against blue, cloudy sky was in sync with the audio but then the Harry Potter music opened over the top of the MPAA rating screen, and not with the WB movie lot. Opening the ripped audio wav file in Cool Edit revealed that the opening music of Harry Potter appeared at about 14 seconds but I noticed that the video that accompanies it in the original vob file (when viewed in PowerDVD) appears at 21 seconds. So it seems that the original AC3 audio in the vob file is somehow stopped during the MPAA screen for about 7 seconds. My ripped audio does not include this instruction to pause (no doubt it's in the ifo file), hence after beginning in sync, it suddenly jumps ahead 7 seconds.

Delaying the whole audio by adding silence at the beginning or during remuxing in bbMPEG will not work. I must either place 7 seconds of silence when the MPAA logo is on or else, as I plan to, clip the first part of the vob file when making the DVD2AVI file so that it begins when the movie starts, leaving out all the WB promos and MPAA stuff.

I'll let you know how it works out.

[htc10825]

My suggestion: cutting off all the frames before the movie starts. So you will avoid the a/v asyncron issue.

To cut the mpg video you can use a mpg editor such as M2-Edit Pro. But the best method is to cut them in avisynth script before encoding. Example script for PAL movie:
...
Loadplugun(...)
Mpeg2Source(...)
trim(525,0) (525 frames = 21 sec)
....

To cut the mp2 oder wave audio, use the freeware tool "HeadAC3he",
select output type=source, change the start fram = 14 sec.

Finally multiplex them to a A/V syncron stream.