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I don't think this will work. You have to convert them into a format that the ATV can understand before iTunes will accept it. Visual Hub does this conversion quite nicely (which is what I use).

They *ARE* in a format :apple:tv can understand. They are H.264 and AAC-encoded .MOV files. Just make sure you download the 720p versions, not the 1080p versions. It's just that some exceed the specifications the :apple:tv can play.

From the :apple:tv Tech Specs page, emphasis mine:
Video formats supported
H.264 and protected H.264 (from iTunes Store): Up to 5 Mbps, Progressive Main Profile (CAVLC) with AAC-LC audio up to 160 Kbps (maximum resolution: 1280 by 720 pixels at 24 fps, 960 by 540 pixels at 30 fps) in .m4v, .mp4 and .mov file formats
 
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