tried that got it to work.

convert all files to mpg using ffmpeg

then use copy /b to copy all files (concat) to a single mpg

then I convert the mpg to avi

I use "-qscale 6" when converting to mpg

but the final video is not the right length (combined length of other videos)

if i play it using windows media player also i see some clips and sometimes the audio is overlaid on wrong section of video image etc..

so whats wrong?

do ALL the input files have to be the same size and bit rate etc..?