I can get some movies and tv shows to sync to Iphone 4s, but not all of them. I've deauthorized and then authorized the computer to no avail. I have the current versions of both Itunes and the os for the phone.
If the TV Shows in question are in HD, you may need to download a lower definition version of the show in order to sync it to your device.
iTunes: Sync purchased HD videos to iPod or iOS device
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