mp4->xvid video moving too fast

[Snowcrystal]

Hi,

I have a bunch of mp4 files which I have converted to xvid with virtualdub and avisynth.
Now the problem is that many of the files have a speed problem. The image is moving alright in the first few minutes but afterward the image moves much faster than the sound and after 3/4 part of the movie the video is repeating itself. When I play the converted file the length is the same as the original mp4. I've watched the mp4 and there's nothing wrong when playing the file. And the converted sound is moving at the right speed only the image is wrong.

I've converted many mp4 to xvid using the same method and I have never encountered this problem before. Does anyone know a solution for this problem?

Thank you in advance.

[Baldrick]

what video codec in the mp4? it could be a x264 vfr problem.

You could also try latest alltoavi.