ok, ive got a powerbook and the 5g video ipod. i downloaded handbrake, and have ripped several dvds. they all went to the .mp4 format and they all look fine in iTunes. however, when i dragged the videos to the ipod icon, only some of them transfered. the ones that didn't included all the shows of a tv season i have on dvd, and two rented dvds (maybe they have some kind of lock?) but ya, why wont some of them work if theyre all the proper format?