QuickTime 7.5.7 fixes iTunes SD DisplayPort blues

Stephen Withers
Thursday, 27 November 2008 01:53

IT Industry - Development

It looks like a software glitch may have been the cause of the recent problems some MacBook owners experienced when attempting to play standard-definition iTunes content on an external display.

There have been reports of current model MacBooks and MacBook Pros failing to play movies and TV shows purchased or rented from the iTunes Store when connected to a non-HDCP display.

The problem is that Apple's latest notebooks have a DisplayPort video connector which implements DPCP (DisplayPort Copy Protection, a standard  related to HDCP or High Definition Copy Protection).

DPCP will not allow the transmission of protected high-definition content to another device unless it also supports DPCP or HDCP - which recent Apple screens such as the 30in Cinema Display do not.

Curiously, there were user report that attempting to play some standard-definition content from the iTunes Store in this way also failed with a message saying "This movie cannot be played because a display that is not authorized to play protected movies is connected."

Even if the display didn't support HDCP, SD playback should be unaffected by the protection measure. Indeed, the standard behaviour of some HD sources connected to non-HDCP displays is to send a SD signal.

Apple has now released QuickTime 7.5.7, saying "This update is recommended for owners of MacBook, MacBook Air and MacBook Pro with Mini DisplayPort. The update addresses an issue where some standard definition purchases from the iTunes Store do not play on some external displays."

At this time it appears to be available only through Software Update, and only to affected hardware. The most recent version available from Apple's web site is 7.5.5.

According to some early user reports, the update does indeed allow the playback of SD content from the iTunes Store that would not previously work on an external, non-HDCP display.