Help With The Movies On Dreamcast Thingy

I have successfully made one movie....charlies angels...it was a mpeg file....i now have vertical limits....it is a .asf file and it wont work....how do i get it to work....or how can i convert it to mpeg? PLease help....while im at it....i have a bunch of audio files for a dc game...one of them is under 4 secs....i cant burn that....how do i make it longer or fix this problem???? please help me...peace out!