avi to mpeg sync probs, not for all movie just after certain bit

hi, I have downloaded a movie Trailer in avi and converted it to vcd (mpeg) with tmpgenc, when I view the new file the Audio starts great with the picture but then there is a bit where the picture goes funny for some seconds and it throws the whole thing right outa sync by quite a bit. I have tried stripping the 2 and using the mpeg tools and tried using goldwave! The thing is as well that the picture goes funny on the avi but the audio and picture stay in sync, it's only when I convert it that it goes out. Any help please Thanks!!! It's not a burning prob as this is when I view it on my pc! it's like the picture goes blocky and the audio keeps going and so puts it outa sync!

Thanks

 

Your source is corrupted. There really isn't any way to fix this other than re-downloading the trailer again.