To convert video files to a resolution that is adequate for a PocketPC’s screen, use mencoder.
mencoder input.avi -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=200:abitrate=48 -vop scale=320:240 -oac copy -o output.avi
This will transform a typical 700MB AVI file into a ~200MB size file with a 320×240 pixel resolution.
mencoder -oac mp3lame -lameopts mode=3:preset=24 -ovc lavc -lavcopts vcodec=mpeg4:vhq:vbitrate=384:keyint=250 -vop expand=”320:240″ -o outout.avi input.avi
This will transform a 700MB AVI file into a video file small enough to be placed on a 512MB SD card.