How to make a good A/V synch

[cd090580]

Hi,

I've recorded some music videos from an old VHS tape but on some of the videos the sound is quite bad. So I decided to replace it by a new sound from the audio cd but 3 times / 4 the sound is out of synch after being multiplexed.

Here is what I do:

1. Get a better copy from audio cd or MP3
2. Resample to 48 khz
3. I open the new file and the original in soundforge.
4. I listen to the first sound to check for a good point to put a start reference.
Then I zoom in to have a more detailed vision of the waveform.
5. I do the same with the new file and when I found the same position, if compute the length difference between the points and I remove (or add silence) datas from the beginning of the new file. So both files starts at the same point.
6. I remove (if there are too uch sound) the excendent of samples at the end of the new file so they both have the same length.
7. I encode the new file and multiplex it with the video.

When I play the sound is often out of synch


Is there any better way to make sure the audio synch is perfect ?

[johns0]

There is no easy way to sync the audio,what you will need to do is sync it in smaller parts in that some parts will drift unevenly and you will need to match these parts.

That means splicing audio together and that will be a nightmare to do.

[cd090580]

I think I have found the problem.

The video was recorded with a standalone dvd recorder. When I play the dvd on my TV the audio is perfectly synched. But if I rip only a chapter with DVD decrypter and play the vob file, the audio is slightly out of synch.