Angry iTunes users are calling for a boycott of the Apple iTunes store after finding that certain video content they have purchased via download from iTunes can’t be played — even on their genuine Apple equipment.

They say they get an error message referring to “High Digital Content Protection” (HDCP), saying their external display device is not “HDCP-authorized”.

HDCP compatibility is apparently a condition imposed on Apple by the movie providers.

Apparently, HDCP limits the playing of iTunes-sources HD movies to displays that are HDCP compatible. A special connector, built into newer Mac computers, is required. The problem is, many HD displays — even genuine Mac displays prior to the current generation — don’t have the connector and, so, are not capable of showing the new HDCP movies.

“In other words,” laments Apple watcher Andy Foster in The Computer Blog, “the only way any of us can guarantee we can play the stuff we buy that is HD is to ensure we have the newest in hardware. … Forcing a user to buy new hardware to view your content will backfire, and no one will be able to predict at any point whether the explosion will be big or small.”

Stay tuned..