HDCP is a new form of copy protection introduced with the HDMI platform, it stands for High-bandwidth Digital Content Protection. According to Jeff Carlson from TidBITS, movie rentals on the Apple TV require HDCP. This means if the TV/monitor you’re using your Apple TV with isn’t HDCP-compliant, you won’t be able to play rented movies. This is probably not the situation Apple wanted, but the movie studios likely insisted that their movies were protected from anyone copying them.
HDCP is like the DRM of video, it sucks, it’s pointless, but we have to put up with it. Fortunately, almost every HDTV out there has HDCP in it – and if you’re already watching Blu-ray movies through HDMI, then you’ll have no problem watching Apple TV movie rentals. Also, if you’re using your Apple TV through an analog connection that’s not high-definition, then you should have no problem with playback either. If you do find that you can’t play a movie you purchased, please contact Apple support – they should give you a refund.
Via [MacDailyNews]
Does the HDMI connection work with a non HDCP-compliant device if I'm playing my own videos through the Apple TV?
I'm thinking of purchasing an Apple TV and need it to work with an older projector by converting the HDMI signal to DVI: http://www.hdtvsupply.com/dvi-to-hdmi-adapter.html