you can use ffmpeg (a free command line tool for mac and linux and windows) to encode wmv to mp4. here is an example syntax:
ffmpeg -i [your_video.wmv] -r 20 -ar 44100 -ab 196 -b 300k -aspect 4:3 -s 320x240 -croptop 0 -cropbottom 0 -cropleft 0 -cropright 0 [your_video.mp4]
-r 20 is the framerate [frames/second]
-ar 44100 is the audio rate [samples/second]
-ab 196 is audio 196kbps
-b 300k is the video bitrate of 300kbps
-aspect 4:3 is the desired aspect ratio
-s 320x240 will scale to E8 screen resolution
