I've got an Apple TV and was thinking about an iPod touch. I have a bunch of my favorite movies converted for playback on Apple TV. If I want to drop these on an iPod touch, do i need to create a new MP4? I would imagine if they were made for an iPod and I wanted to watch them on Apple TV, I would need to. But seeing as how I'm going from higher res to lower, do I still need to make an iPod specific copy? Thanks.