Users of iTunes video can't play back their own content

The newest MacBooks and MacBook Pros are Apple's first devices with the Mini DisplayPort as their standard video out. But owners are discovering that display port comes with an extra added bonus, which they may not have asked for.

High definition content protection (HDCP) is being used to protect iTunes video purchases from being played through anything but direct Mini DisplayPort connections.

As a result, even when using Apple's Mini DisplayPort to VGA adapters, as Engadget, among others, recently found out, a lot of content from iTunes simply will not play back, even in QuickTime or through Boot Camp.

Any attempt to play back certain content through an external monitor will return the error message: "This movie cannot be played because a display that is not authorized to play protected movies is connected. Try disconnecting any displays that are not HDCP authorized."

Naturally, complaints in Apple's support forum have been coming in, one user began having problems just over a week ago:

"I updated my ATV the day 2.2 came out," the user wrote. "I have watched HD iTunes content fine up until 2 nights ago, when all of a sudden I started getting the HDCP error. Even shows I'd watched as early as 3 or 4 days ago are giving me the same error. Nothing has changed on my system and I've even done a factory restore and re-installed the 2.2 update. I've also switched cables, turned the ATV on/off/on/off with and without the HDMI cable connected."

HDCP has been the subject of criticism in the past, especially when Windows Vista was released, because it was not supported by the majority of PC monitors available at the time.