My ripped movies won't play on my iPad 2. They sync and play in iTunes, but when I try to transfer them to my iPad it says that my iPad cannot play the file. I thought that if the movie played in iTunes, it would play on all iDevices. I've tried both .mp4 and .m4v. Any suggestions? I'd like to only have one file so I won't have to have an iPad version, HD version, etc.