AC3 Audio Sync

[PandoraZboX]

Hi, I used DVD Decrypter to rip a tv episode disc. I opened the ripped files with Smartripper and ripped each episode to a seprate folder. Then I opened them with DGI Index, and made a D2V file and an AC3 file. Three of the four episodes turned out fine, and one had an audio sync problem. The same problem came up when I re-encoded the whole thing. I re-ripped with smartripper, same problem.

(This part seems to have been overlooked)
I demuxed the AC3 with smartripper instead of DGI index, same problem.

The really strange thing is that the AC3 is in sync until halfway through and then all of a sudden it falls 300ms behind. It does this during a brief spot that is silent and black (for a commercial). VirtualDub (and its contemporaries) only cut frames at keyframes, so I can't use it to fix the file.

Is there a tool that will let me cut the video apart without requiring it to be done at keyframes? Does anyone have an idea of how to fix this? Anything is greatly appreciated, thanks.

[Ark]

Err..what has this to do with XviD?

It's a DGIndex problem i guess, or the AC3 is badly done even in source, btw i think moderators should move this thread to DGIndex forum.

[PandoraZboX]

It doesn't much matter to me where this is. I just didn't know where to post this, because since I ripped the AC3 with smartripper and had the same probelem, its not a DGI Index problem.

I just figured since I did the standard XviD encoding routine someone would know what to do.

[powerslave]

I would say post this in the DGIndex threads since thats seemingly being updated every other day and you may have a buggy version which has been fixed. You may also want to try a known stable version like 1.1. Other then that, i would say the source is screwed up in some way.

[PandoraZboX]

For clarification: I am using DGI Index version 1.2.1

[Cyberia]

Does the latest beta exhibit the problem too? Have you tried cleaning and re-ripping the DVD?

[PandoraZboX]

Yeah, I tried ripping the audio straight from the dvd and it had the same problem. I could fix it by cutting the video into two parts and delaying the audio in the second part, and then putting them back together, but virtualdub (and the like) only let me cut at keyframes. Is there a program that lets me insert keyframes, or cut at non-keyframes?

[Cyberia]

This doesn't sound like a DGIndex problem, something is wrong with the source.

Sorry, I don't know how to fix it.

[jsoto]

I think you can manipulate only the ac3 file, and leave the video untouched.
Just cut the ac3, and join the two parts with an additional silence file of 300 msecs in between.

Is there any reason to do not do it in this way?

jsoto

[bugmenotwillyou]

I did solve this, and essentially by doing what jsoto suggested. I found a helpful tool called delay_cut that let me do this quite nicely. Incidentally, this is not hosted on doom9 and I think maybe it should be. The only thing is that after cutting the AC3 files at the right positions I had to go to the command line and do copy file1.ac3 and file2.ac3 so that windows would join them (just easier than finding another tool).