.avi audio desync

[leimus]

an .avi movie file of mine desyncs audio towards the end of the movie. Towards the end, the audio is slightly ahead of the actions. Is there some tool that i can fix this desync?

[KingJohn]

Since you have an AVI, first scan it for any junk frames with Vdub

Video > scan video stream for errors
If it finds any

Video > direct stream copy
Audio > direct stream copy
SAVE AVI

If the scan fails, you need to download "vdub-mp3-freeze.exe" instead, this make a list of the bad frames at c:\badframes.log that can be used to remove the frames, starting with the highest blocks first.

Ok, the AVI has no junk frames, if the audio is fine up until the end, you need to save out the good part, using Vdub select start and end (end at keyframe) then once that section is marked, save it out, then press the delete key.

You should now have the good piece saved on your hard drive and the bad piece still in Vdub

You can now select Audio > Interleaving > Audio skew correction and adjust the skew to a delay or an increase. Save out and test, you can then join them back together.

Sometimes just saving out the audio in Vdub, and using it separate will also cure the problem. If there are junk frames, this glitch will cause the problem.

If you intend converting it later with TMPGEnc you can try using the saved audio and the original AVI to see if it will get passed the problem.

Using the audio separated from the video, means when you join them, if the bad video frames glitch, your audio will still remain constant.

Audio > Full processing mode
Audio > Conversion > 44.1Khz
SAVE WAV

[leimus]

i scanned it with vdub and there are no junk frames
So you're saying that i should marke the place where the audio starts to desync and cut out the audio where it is good and save it, then leave the desynced audio portion still in the movie?

how can I find the exact frame where it desyncs? Trial and error?

[KingJohn]

Ok, since you have not found any bad frames, try saving out the audio un-compressed, then work with them as AVI for video and the WAV for audio

Vdub > Audio > WAV audio

With the audio uncompressed, it may fix the problem. Using this method you would need to save out the AVI again to join the saved audio back to the AVI

If that fails, then you need to save the AVI with its original audio, up to the point it goes wrong, yes you need to play it a few times to get to the right spot. Then you should only have the un sync part loaded.

GGGGGGGGGGGGGGGGBBBBBBBBBBBBBB

Save the AVI GGGGGG
Then delete from Vdub, and only have BBBBBB left in the slide bar

If you can fix and save the BBBB, you can join it back later. There has got to be a glitch at the start, you could also try encoding in TMPGEnc at GBBBBBBBB (Source range) just to make sure that its not just the playback that’s causing the problem.

Sometimes AVI's with less key frames, can go out of sync during playback, but after conversion they are fine on a VCD