Vdub joining loses audio sync ?

[r3mix]

I encoded a DVB stream using AutoGK to xvid/mp3-CBR and the resulting AVI has a point at which audio sync goes out by 25ms for the rest of the video. This was due to a visible glitch in the capture.

I have used VirtualdubMod (and tried the MP3-freeze Version) to cut the AVI into these two sections and added the correct audio delay to the second so that the two separate AVI files each have audio sync.
The problem is when I use virtualdub to join these two AVIs using the append function the resulting AVI has the same sync problem the original file did.

The only thing I could find said that when using the append avi function to join files you need to remove the audio interleave setting for preloading 500ms of audio. This doesn't seem to help.

I've tried this a few ways now and it always ends up the same. Can anyone spot where the problem is in this process ?

1. AutoGK outputs an XVID/MP3-CBR AVI with a constant 25ms loss of audio sync starting at 22min.
2. I open this AVI in Virtualdub MP3-freeze - check all frames are good - resave the AVI as a direct stream copy with audio interleave settings of 0ms for preload and 0ms for audio delay.
3. Select the in-sync range and save this as first AVI segment - 0ms preload 0ms delay.
4. Select out-of-sync range and save this as second AVI segment - oms preload +25ms delay.
5. Check sync of both of these are find in a player.
6. Append these together with preload 0ms and delay 0ms.
7. Swear at AVI still out of sync just like it originally was.

Anyone ?

[manono]

I doubt the asynch is really 25ms, as it's usually said that you can't spot an audio asynch unless it's around 100ms or so (1/10th of a second).

If the audio is MP3, leave the interleaving settings at the default 500/1.

And to fix the asynch, make the second part asynch by the amount it's asynch after the join. It'll be asynch when played by itself, but back in synch after the join.