Theme of the month: audio sync problem

[litlfrog]

I'd written a thread earlier describing a problem with PAL to NTSC conversion using TMPGEnc. I've discovered that I have the same audio sync problem any time I tried to create an mpg file for an SVCD. For sh*ts and giggles, I tried making an mpg for a VCD last night and everything worked fine! Here are the details:

downloaded avi, VirtualDubMod tells me that there's an error in VBR encoding.
Using VirtualDub, I save the audio as a wav file using full processing instead of direct stream copy, then save a new avi using the wav as source audio.
(I know the last step isn't strictly necessary, but I now have a new avi with audio that I can watch on screen to confirm that the audio is fine.)
To keep things simple, I use the Project Wizard in TMPGEnc and click none of the extra settings--the only thing I change is the aspect ratio to Center (keep aspect ratio).
Converting the new avi to VCD (NTSC Film) gives me an mpg with good audio.
Converting the new avi to SVCD (NTSC Film) gives audio sync problems.

In a word--HELP!!

[Abond]

Well, my answer is the same as in your other topic.

[litlfrog]

Sorry, but it's still not working. I understand that it SHOULD work. Let me clarify something: I never had audio sync problems until a few weeks ago. I can still make regular VCDs with no problems. But any MPEG-2, no matter what the frame rate, comes out with bad audio. I can extract the audio as a .wav using full audio processing in VirtualDub, demux the audio and use BeSweet to convert it to an mp2 for later multiplexing with an m2v stream created with TMPGEnc Plus. I can use the demuxed original audio or a different type converted with BeSweet or HeadAc3he, and use dgpulldown to convert the video to 29.97 fps. The file always has out of sync audio.

Has anyone heard of a problem like this? Could I have a wonky setting somewhere in my system, or a bad codec, that would cause failures when trying to create an MPEG-2? If no one has any other ideas I'll try one more time by posting screenshots from GSpot, VirtualDub, BeSweet, and TMPGEnc to see if someone spots something unusual.

[dalek7]

>Using VirtualDub, I save the audio as a wav file using full processing instead of direct stream copy

Can you explain the steps you used here?
I am having similar problems, I think, on a PAL avi that I need to encode; my new wav files that I'm extracting using virtualdub are getting hiccups in them...
Please see my latest thread in this forum for details if you think you can help.
Thnx

[Abond]

How do you multiplexing?

[bugster]

downloaded avi, VirtualDubMod tells me that there's an error in VBR encoding.
Using VirtualDub, I save the audio as a wav file using full processing instead of direct stream copy,

I am confused. VirtualdubMod tells you the avi has VBR audio, but you saved it out as a wav file using virtualdub (not MOD?)

Make sure you save to a wav file using virtualdub, NOT virtualdub MOD. This solved a similiar problem for me.

If this doesn't work, try opening the avi in Goldwave and saveing to a wav file from there.

[Gurm]

VirtualdubMOD is a festering piece, or so I've discovered. It's too bad - it LOOKS like it ought to be nicer, but its audio handling is ... completely borked.

Here's what you do:

1. Load the AVI into virtualdub. It'll say "it has a broken header blah blah blah", DO NOT CORRECT IT.

2. Go to the file menu - don't f***ing touch the video or audio menu. On the file menu, pick "save wav". Wait a minute - it really only takes like one minute tops.

3. Don't remux it. That's stupid. Remuxing it makes a horrifying AVI file with uncompressed audio. I've NEVER had one of these work. I agree with you that it SHOULD work, but every time I do it, the sync is worse with this remuxed file than it was with the original borked VBR header file.

4. Under audio, pick NO AUDIO. Under video pick DIRECT STREAM COPY. Save it as a new file.

5. Load up your favorite converter, and use the two files as separate sources. Hit "go".

That's it.

Now, some caveats:

1. You are clearly working with some sort of pirated video. I'm not being the thought police here, I do my share of downloading TV shows that I miss as well. And yeah, every single one of them is encoded with broken VBR. I don't know what the deal is - maybe every video pirate in the western hemisphere has some borked pirated MP3 encoder. But they're ALL broken. Oh well.

2. I use Mainconcept. I always have to check the output video to make sure the audio runs all the way through. Mainconcept has a bug whereby if there's a glitch in the VIDEO, it'll drop the AUDIO. That's not good. I suppose I ought to run an AVI checker as an intermediary step to make sure there's no errors, but frankly I'm lazy and Mainconcept is so fast that I can afford to just go back and redo it if there's a problem.

[dalek7]

Wait.... You lost me about half-way thru. I myself am using virtualdub to create a wav that I am sticking into TMPGEnc to encode with the video, but I am getting major hiccups of the AUDIO wav file I created IN Virtualdub...

So...

Please re-explain exactly what you're doing from here down...

>4. Under audio, pick NO AUDIO. Under video pick DIRECT STREAM COPY. Save it as a new file.
Save WHAT as a new file? I'm saving the VIDEO as a new file as well? If so, why? What exactly am I saving it as (what command/file menu item, etc)??

>5. Load up your favorite converter, and use the two files as separate sources. Hit "go".
What exactly am I plugging into, say, TMPGEnc here? A new WAV (which is what I'm personally having problems with) and a new avi, both created in virtualdub...?? Please explain.
Thanks.

[Gurm]

Yes. Your goal is to have three files coming out of Virtualdub.

1. The original AVI
2. An AVI with no audio
3. A WAV file

Now, if you're having audio sync issues, it could be that the video file has errors. I'd try the guide on Doom9 (there might be one here as well) about fixing AVI glitches with Virtualdub.

[dalek7]

So how do I make an avi with virtualdub (never tried it, can't seem to figure it out)?

[Gurm]

Are you SERIOUS?

File->Save AVI

???

[litlfrog]

The problem, SHE IS SOLVED!!! I began to suspect a couple of weeks ago that the root of the problem wasn't the audio in the files, since I had successfully converted files from the same people before.

Long story short: I had a bad codec. I don't know which one it was or why it happened, but I went through the system and deleted most of my MPEG-2 codecs, then installed the latest ffdshow codecs from the videohelp site. The audio problem is solved and my conversions are fine.

A new, less annoying problem has arisen: using either Divx or the latest Windows Media Player, MPEG-2s look a little jerky on my system. Once I burn them to SVCDs they're fine, but I may need to tweak my video codecs a little more.

[dalek7]

Thanks very much for this post.
I am still having audio drift, though, but things are improving. Problem is that the only PC in my house that I can try this on is ancient in terms of processing power, so a 45 min. video took 4 hours to filter thru TMPGEnc, only to find that the drift kicked in somewhere before halfway thru. Dunno if it has anything to do with converting the PAL video to NTSC after converting the audio to a wav file from the PAL. Guess I'll keep trying.
Any further suggestions are appreciated.

[Gurm]

Yes, it definitely does. PAL->NTSC is a whole other barrel of worms. See the numerous topics posted about it in the past day/week/month/year.