mpg is ok, vob is not... audio synch issues

[Brent212]

I have a .mpg file with an MPEG2, 6400 kbps VBR video stream and a 224 kbps MPEG1 layer 2 audio stream. I have tested it in media player. I can jump around to different positions or play the whole thing straight through and it plays fine, with the audio in video in synch. I have attempted to author it about 5 times in both ULead Movie Factory 2 and TMPGEnc DVD Author (using a rewriteable luckily).

The first several times I tried creating chapters, and each time the results were the same: the dvd would play fine until a specific chapter, and then the video would jump ahead of the audio about .5 seconds. It would remain that way for the rest of the dvd. Then I tried authoring it with TMPGEnc without any chapters. Just popped in the .mpg, hit author, and burned. The same result happened, at right about the same position in the video where that chapter would have been. So I'm guessing the chapter insertions didn't cause the problem. I was wondering if the burning had anything to do with it, so I checked the VIDEO_TS folder that was created on my hard drive, renamed the first .VOB (which contained the point of error) to .mpg, and played it in media player. Sure enough, the audio and video went out of synch at the expected spot. So now I'm pretty certain that when TMPGEnc DVD Author takes in the error-free (at least during media player playback) .mpg, it screws up the video/audio synch during the VOB creation process.

So I tried it one more time in ULead, without chapters, and without actually burning. I just wanted to test the authored VOBs. So I renamed the first .VOB to .mpg again, and opened it. Good lord it didn't go out of synch! Sweet! I tried playing all the .VOBs and they all played fine! Awesome! Annoying that Ulead works for this and TMPGEnc didn't, because I like TMPGEnc's interface and menu creation process better, but at least something actually sort of worked. My next step is to actually burn the chapter-free, Ulead-created VIDEO_TS folder and see if the dvd will play without synch problems. Then I'll try adding chapters and re-author and burn. I pray that will work.

I realize TMPGEnc DVD Author could be screwing up just because the .mpg may have errors that aren't noticeable in media player (I've heard software players can fix synch problems as they play), but if the VOBs it creates have errors that do show up in media player, then that at least proves that it does something bad during the .mpg-to-.vob conversion, which sucks.

Anyone have any comments or similar experiences? I'm interested to know if there's any way to fix these errors.

Thanks for any input,
Brent

[troyvcd1]

i would suggest demuxing your audio and video with virtualdub-mpg and then putting the individual streams into your authoring program.

[bottle-necked]

Play the original files in VirtualDubMPEG2, not those renamed vob files, and see if they are error free and in sync. Windows Media Player is not a good place to test.

By the way you explain it I would expect the capture dropped a few frames at that point the audio goes out of sync, but I don't know.

Good luck.

[Brent212]

I can't even get it to preview correctly in VirtualDubMod. It'll play in spurts of about .2 seconds. It'll play okay for a split second, pause, play for a split second, pause, etc., so it's hard to tell if it's in synch. VirtualDubMod crashes on me when I try to do just about anything in it, so I never use that program. It could be my system, although I feel like most of my other programs are fairly stable.

Is VirtualDubMod the same thing as virtualdub-mpg and VirtualDubMPEG2?

Also, when I said Media Player, I meant Media Player Classic, version 6.4.02.00, made by Gabest. It's like an older Media Player version, but with some additional features. I don't know if that makes a difference or not.

Thanks for the suggestions.

[bottle-necked]

I don't know why the program crashes etc but since it is a fairly small download and an easy install I would say to try and reinstall it. That may fix it, I don't know.

VirtualDubMPEG2 isn't much different, interface wise, from plain old VirtualDub. I find myself using it more than the Mod version but that is only my preference. They are both good programs.

Since chapter information isn't stored in a vob file I don't see how creating chapters effects the playback unless you just happen to place a chapter at the same point the file had an error. If that is the case then I can see the possibility of a problem showing up on and after that spot. To me this points back to a possible problem in the original file(s). That's where I would start looking.

Good luck.

[Brent212]

Yes, I doubt the chapter creation has anything to do with it as well. I think that TMPGEnc DVD Author creates the synch errors when it does the multiplexing during the VOB creation. ULead seems to be able to create the VOBs without errors.

This may be a result of error-containing mpg files (I've heard that the Hauppauge PVR 250 can't capture non-error-containing files). These errors probably don't show up when playing in a regular software media player. However, once de-muxed and re-muxed, the errors do show up, but only when the muxing is done with certain programs. The ideal solution would be to find a way to fix the errors in the original captured mpg, and then (hopefully) it would be able to be used successfully in any authoring tool. But until I find a way to do this (that works... I've heard several suggestions but none seem to work), I'll just use ULead with the captured, and possibly erroneous, mpg's to do the job.

Thanks for the tips, I might try messing around VirtualDubMPEG2.

[bottle-necked]

I agree with what you're saying and since you have a working dvd now this project is finished and all is well. I hate to plug Author but I still can't blame the program for a falty vob. Author does not have the ability to encode video so it can't 'change' a file. Yes it can encode audio and that may very well be what is happening here. I don't know.

Ulead, on the other hand, can encoded video and it has a process called "Smart Render" that it may be using. I look at smart render as being similar to VirtualDubs Direct Stream Copy routine. I think it can fix some errors along the way and this may be why Ulead can author the file properly when Tmpgenc cannot.

Good luck.