Yesterday, Amazon announced that they would begin streaming Amazon Prime movies in 4K Ultra HD, free of charge. This follows an announcement by Netflix in March that they would allow subscribers to stream 4K shows in Ultra HD for a small additional charge every month.

Of course, neither the iPhone, iPad, or the Apple TV support 4K video… but the new iMacs with Retina Display do. Yet despite this, Netflix and Amazon don’t actually stream 4K video to the Retina iMac. The best you can get is plain old 1080p.

What’s the deal? The same as it ever is. DRM.

Over at Macworld, writer Gordon Mah Ung spoke to Richard Doherty, research director at the technology-assessment and marketing-analysis firm Envisioneering, who told them that Netflix and Amazon can’t play 4K video on the Mac or any other PC because of DRM.

“It’s not anything against either platform or the processor,” Doherty told them. “It’s the matter of the security of the platform. The TV is secure and has no output to it. I and your readers on a PC or Mac could intercept the 4K [content] and therefore transmit it to a country that doesn’t have the rights.”

Ultra HD televisions, on the other hand, often have built-in DRM hardware that prevents the signal from being jacked on certain types of transmissions. Eventually, of course, the Mac will also get this hardware, or some equivalent software DRM backed right into OS X, but until then, those of us with Retina iMacs will continue to be S-O-L when we want to get our 4K on.

Source: Macworld