Progressive loss of sync

[Atomic Dog]

OK, I followed the DivX -> VCD conversion guide (http://www.vcdhelp.com/divxtovcd.htm), but when I put the finished disc in my DVD player, I noticed it was slightly out of sync. As the video went on, it got worse and worse until the audio was trailing the video by about 3-5 seconds. This happened for all 3 files on the disc (ie, they each started out fine, and each got worse.) Note: In .avi format on the PC, they're sync'd perfectly.

Looked all around the site and through a portion of the messageboard posts, but I can't seem to find anything on this. I don't think it can be corrected using the "How do I fix audio sync in MPG" guide because it's a progressive loss, not a static one.

The only thing I can think of is I -might- have forgotten to check the "Source Range" box in the Advanced Settings tab in TMPG. Would that make any difference, leaving it unchecked (I don't have to split the file). Also, the fps was a little over 29.970 for all 3 files. I think the highest one as 30.110 - if that makes a difference, I still used VCD (NTSC). Either way, I'm stumped. Any ideas?

Thanks.
-AD

[Atomic Dog]

Question: Would disabling or changing the audio/video interleaving option make a difference? It says that it preloads the audio 500ms before the video starts, but my problem is the opposite - the audio is trailing.

Think changing the default 500 to something larger might help?

[Mirror_Image]

Every DivX capture from the cable TV (Radeon AIW, MMC 7.1) I do has the same problem - everything starts synched but the audio falls behind increasingly as the movie plays. Here's what I do:

Open the file in Virtual Dub (I do this to compress the audio with MP3 anyway).

Go to video...frame rate...select "change frame rate so audio and video match" (VDub will figure this amount for you).

Yep, change the audio interleave; I set it to "every 30 frames", but you can set it to every 500ms or whatever you like.

Set the video to "Direct Stream Copy".

Go to audio..."Full Stream Copy" and then choose your compression audio codec (I use MP3 96kHz 44,100k 16-bit stereo to smash my PCM audio) if you intend to compress the audio, if not, leave it set to "Direct Stream Copy".

OK, save the file as a new file and your sound should be synchronized with the video. It works for me; this used to drive me up a wall.

Best of luck!

EDIT: ACK! I just reread your post a little more closely. Disregard my post, it only applies to VirtualDub and AVI output. (Tired...must sleep...)

[Atomic Dog]

Another Question: I'm looking at a A/V Sync FAQ and it looks like changing it to PAL might work for animations (which I'm trying to burn). Will that work with the 29.970+ frame rate?

Also, I'm starting to suspect that checking that Source Range box might have been important, and that I might have forgotten it. Can anyone confirm?

[Atomic Dog]

OK, I've tried a couple more times and still the same result.

I used VCD (PAL) mode in TMPG, failed.
I tweaked the Audio settings in VirtualDub, failed.
I shouted profanity at it for a good 20 minutes, failed.

Any ideas? (I don't know if the audio sync theory will work since it's a progressive loss.)

I asked my buddy and he said that going from DIVX to MPG caused that almost every time with video animation. Am I just SOL on this?

[Gelo]

Hi,
I am having the same problem with my Divx --> VCD transformation.
I have reason to believe that this is a problem in the coding - decoding settings and some hardware incompatibility. Could you send me specs on your comp, and information on codecs installed (audio and video).

I am hunting for the sync error......
Thanks

[mr_seth_enslow]

I'm having the same issue with AT LEAST HALF of the movies that I try to encode.
- First, I split the AVI file using VirtualDub (1.4.8).
(Audio and Video are both set to Direct Stream Copy)
- Then I encode each half of the movie using TMPGEnc
(Always use VCD PAL template - regardless of frame rate)

The AVI audio synch was fine, but the MPGs tend to have progrsessive synch problems most of the time... It's driving me nuts!

Sometimes TMPGEnc (or tooLame) will hang when encoding the audio, so I extract a wave file first (44100 Hz using VirtualDub).
Then I encode using separate avi / wav files.
SOMETIMES this fixes sunch problems, but not usually.
My synch problems are ALWAYS progressive, never a fixed lead/delay.

[mr_seth_enslow]

bump...

There must be other people with this problem.
60% of the movies I try to encode are having the same type of synch problem.

[Chubs]

AHHHHHH, UGGGGGG!!!! Me too me too. I am trying to convert avi to MPEG2 with tmpeg and the audio is off. The avi audio is fine and if I convert with Ulead the audio is still fine. I am real intrested to hear the answer to this one. I have looked everywhere and can't find the answer.

[mr_seth_enslow]

bump

[Monetje]

I used to have the same problem and I was told it had something to do with the variable bitrate, I'm not sure how it works but I solved it by saving the audio as an uncompressed wav file in VirtualDub (full processing mode) and then converting the movie source and the wav file with TMPG.

[Chubs]

I think I may have figured it out. You can try the multiplex like the last guy mentioned but that didn't work for me. This did though. In my settings I made sure that field B was first and my aspect ratio was 4:3 NTSC This seemed to help for me. I am not totally done checking it out but so far (on shorter clips) it is doing it. Let me know if it works for ya because I am sure it is not just us having this problem. 8)

[Shuggie]

This is the best guide to Audio Sync problems I've ever found

http://nickyguides.digital-digest.com/audio-synch.htm

It contains a utility to fix AVI files which are out of sync. However - it does so by changing the framerate. If you want to eventually convert to a format with a specific framerate - you'll need to stretch or compress the audio, and for that you'll need something like cooledit.

It's an excellent guide and well written for the non-expert (like me!)

HTH

[Gelo]

I followed the DivX -> VCD conversion guide (http://www.vcdhelp.com/divxtovcd.htm), but I renamed the WAV file to MP3. !!!
Just change the extension!

After that I combined mpeg as it was described in the guide.

I did only one test and it is working!!.
Please try it and post the results.

Thanks
G

[Atomic Dog]

How long was your test video? I've been fooling around with various AVI files and it progressively loses sync at pretty much the same places in anything I make. I have a short 3 minute clip that doesn't lose anything, but when I go to a 10 minute clip, it gets worse, and when I go to a 22 minute clip, it's way off. I can't imagine what you guys trying to do whole movies are seeing

Chubs, When you're talking about changing the settings, that's in TMPG right? Where and how did you get to that menu?

Shuggie, I was looking at that url, just from the title I can't tell if it's going to help... The audio obviously isn't displaced, but it's not really stretched - at least by his definition. It seems like during encoding, it continually stretches the file, rather than just stretching the it all at once. I'll read it more closely later though. Right now, I've got to run.

I've got a lab to go to tonight, but when I get back I'm going to try that extension change method on a 22 minute file. I'll let you know what happens.

[Gillies]

after trying and trying i finally worked it out... i had a full length movie with the same prob so i did this.

open v-dub, open the file
audio -> full processing
audio -> compression, then select no compression or mp3... no compression is quicker but much bigger..
file -> save wav
open cool edit
open file
transform-> time/pitch-> stretch
gliding stretch tab
in initial% put 100 in the ratio or the original length of file in seconds.. which will be about 4380 in a 73 minute file.
in final% if the video is about a second behind audio put for example 4381 for example above... i used a ratio (eg 99.97)
click ok
file-> save
do not save as an mp3 save as wave
open tmpg
file-> mpeg tools
simple multiplex
video input -> select the mpeg file with the sync prob
audio input -> select the wav file from above
hit run..
now hopefully it should be back in sync... my take some trial and error..
it worked for me...
good luck
phew...

[Chubs]

Well, it didn't work on longer clips.....Sorry. I even tried two other encoders and they did the same thing. I am at a loss for words. I will keep reading and trying I guess.

[Atomic Dog]

Well, the file extention changing failed miserably. It was actually worse than doing it with the .wav files, for a 22minute animated .avi. I'm going to give Gilles method a try here tonight or tomorrow night.

[Gillies]

here's another method i was told..
open v-dub
open file
video-> direct stream copy
audio -> full processing mode
audio-> conversion
set sampling rate to 44100Hz
hit ok...
audio -> compression
no compression pcm
audio -> interleaving
enable interleaving
ok
save as avi..
encode in tmpgenc or some other encoder
this worked as well and much better cause its quicker and easier...
apparently tmpgenc sometimes cant handle some sound compressions too well, so we just take that out of the picture...
try that... that's what im using from now on... i'll use the cool edit thing from now on if i cant get anything else to work..
good luck

[Atomic Dog]

I'm still trying to wrap my brain around what actually happens using that CoolEdit approach... It seems like if you stretch it, you'll just get opposite sync problems...

When I encode, the final product has the video playing normal, with the audio playing catchup by about 1-3 seconds, increasing as the video progresses. If you stretch it, it seems like the audio will PRECEDE the video at the beginning and then get progressively better - which doesn't really solve the problem.

How big a file are you using when you do this? Is it only a couple minutes, or is it up to 20 minutes, or is it a full length film? And when you open the file the very first time (in VDub) is it in .avi format, or has it already been converted once (with tmpg or whatever) to .mpg format?

See, I'm taking 22min DivX cartoons and trying to put them on VCD. If I download a direct capture in .mpg format, it plays without a problem. But that's killing my HDD space too fast, so I want to go from .avi to .mpg.

And that tells me that the problem is either in A) The decoding of the audio or B) the encoding of the final product. But I'm drawing a blank about what to do about it. I'm going to give your method a try, as well as trying a few different audio compressions.

[Gillies]

the stretch program in cool edit is just what its called.... it shinks aswell... thats why u put an amount like 99.96% so its shorter...
no u use the gliding stretch and enter 100 in the initial% ratio box... so it starts the same but as it stretches/shinks it does it on a gradient, increasing its stretch/shrink rate as it goes, and eventually gets to the final ratio in the end... (eg initial% 100 final% 99.96= no change at start, 0.04% later at end)
understand?
im using a 73 minute file
originally in avi format

[Atomic Dog]

That didn't work for me either. Though I have to admit, despite stretching, the sound stayed very nice quality.

I have a feeling I might be doing it wrong though. When I saved it as an edited .wav file (from Cool Edit) I went to mulitplex and it wouldn't accept the .wav file as an audio input. Do I have to save it as an .mp2, because that was screwing the file up when I did.

[Gillies]

instead of multiplex just encode with the wav as the audio source

[Atomic Dog]

Argh, it's still not working.

I was wondering... Do you think my audio codecs have anything to do it? I'm using DivX 4.12 and the Tsunami Codec Pack.

[Atomic Dog]

OK, I think I may have found a handle on the problem, just no idea on how to fix it. I tried to encode it using XingMPEG Encoder and it gave me an error:

The video data rate is too low to encode this file. Try encoding again using a profile with a higher video data rate.

Can anyone tell me what this means and what I need to do to fix it?

[Gillies]

that may be either the frame rate or the bit rate im guessing... whats the bitrate and framerate of the file?

[Atomic Dog]

Using AVI File Info, I show a Framerate of 30.018 and using Bearson's Bitrate Calculator, I show a Bitrate of 666.38.

[Chubs]

Mirror, You are my hero. Thanks a million you saved me a lot of time. Tmpg works fantastico now. Although I have to admit I like the LSX better but it will only encode a 2GB file or less. Well I don't even know what a 2GB file is because mine typically say 20GB+. LOL