I'm starting to become more mobile and starting to watch video on my ipod more. However, I need to start converting my mp4 files for appletv to work on the ipod also. I know how to do this just fine with handbrake. My question is what file type do I use so that the same file can play on both devices? I will be purchasing an ipad with tax refund (thank you uncle sam) and I want the same file to work on that to. Any advice?