simple answer is ... u cant get videos directly from your file share to your computer.
this is because halo 3 videos are not in a video format at all. they are in a special format that the xbox uses and only the xbox can decode and understand.
to get your halo3 clips to your computer in a format you need you would have to buy whats called a 'capture card' which links your TV to a usb port, u would need to get some software (usually comes with the capture card) so you could play a halo clip on the TV and your computer would be saving whatevers on your TV into a computer readable video format,
if u couldnt understand this or just for more info or stuff i STRONGLY recommend you watch this video
http://www.youtube.com/watch?v=5ZpBlrsJn2Q
no seriously WATCH ALL OF IT it really hellps
