Log in

View Full Version : Audio sync problems with megui


280zx
11th July 2009, 04:57
Everything I've tried is way out of sync. The video turns out great compared to fairuse wizard but any suggestions on how to fix the audio sync problems?

I'm going from vobs ripped with dvdfab --->mp3 cbr 128k--->xvid avi container. For reference, autogk does the same thing, way out of sync audio. Fairuse wizard 2.9, perfectly in sync but it can't handle the hybrid film/interlaced source and the results look terrible.


Megui seems like it would be ideal if I could get this solved.

Inspector.Gadget
11th July 2009, 05:10
Is everything in sync after you rip? Is the desync constant or does it get worse over time?

7ekno
11th July 2009, 05:17
FairUse isn't changing the video framerate (hence the sync, but crap looking pics), but MeGUI is handling the video right, but you just haven't got the right Avisynth script to adjust the audio rate ..

You need to work out what the original frame rate is, what video frame rate MeGUI is producing that you are happy with, then convert the audio to the new framerate ...

The Avisynth functions and an example of how to calculate the sample rate you need for audio can be found in Wilbert's post here (http://forum.doom9.org/showthread.php?p=196422#post196422) ...

7ek

Inspector.Gadget
11th July 2009, 05:22
If you're doing IVTC, with or without blend decimation, then you shouldn't need to resample the audio.

280zx
11th July 2009, 05:26
Is everything in sync after you rip? Is the desync constant or does it get worse over time?

It seems to be constant, from start to finish.

FairUse isn't changing the video framerate (hence the sync, but crap looking pics), but MeGUI is handling the video right, but you just haven't got the right Avisynth script to adjust the audio rate ..

You need to work out what the original frame rate is, what video frame rate MeGUI is producing that you are happy with, then convert the audio to the new framerate ...

The Avisynth functions and an example of how to calculate the sample rate you need for audio can be found in Wilbert's post here (http://forum.doom9.org/showthread.php?p=196422#post196422) ...

7ek

Thanks I'll give that a shot.

sat-jokar
12th July 2009, 11:52
Man The only solution I found for this Problem is

open the avi in g-spot 2.60beta and check the audio. There is a good chance that the audio has been encoded with VBR MP3, which seems to cause sync issues with a lot of encoders. The latest version of ConvertXtoDVD (DivxtoDVD's big brother) has a lot less problems with it, but even it isn't immune.

If this is the case, open the avi in virtualdubmod (click OK to the VBR warning you will get), then go Streams->Stream List. Right click on the audio and select Full Processing. Right-click again and select Compression. Choose Uncompressed PCM. Click OK, then click Save WAV and create new file. The file size should be around 100mb per 10 minutes of footage (i.e. 90 minute file should produce a 900mb file, give or take a few MB). Once this completes, click on Add, and select your wav file. Click on the MP3 audio track, then click on the disable button. Click OK, then go File->Save as. Make sure it is set to Direct Stream Copy, and save a new avi file with just your new audio track. Finally, open this new avi file, and test it for audio sync. If everything is good, use this in DivxtoDVD and see how it goes.

Of course, if it isn't VBR MP3 audio, you have something else to worry about, so do a scan for bad frames in virtualdubmod at this point.

The Source
http://forum.videohelp.com/topic309224.html