DisplayPort and HDCP in your Mac: What you need to know

Posted by Christian Zibreg

Chicago (IL) – Steve Jobs told us during the unibody Macbook keynote that Apple will integrate DisplayPort in all Mac hardware down the road, but he forgot to mention out that HDCP is part of the deal. Developed by Intel, HDCP stands for “High-bandwidth Digital Content Protection” and is generally viewed as the movie industry’s insurance policy against mass piracy of HD movies on Blu-ray media. Blu-ray playback requires a chain of HDCP-equipped devices, including an HDCP graphics card and HDCP monitor. But since we know that Apple will not adopt Blu-ray, why would Apple need HDCP? Some believe Hollywood is forcing Apple to integrate HDCP into iTunes content. Whatever the motivation may be, here is what you need to know about DisplayPort and HDCP in Macs.

DisplayPort (DP) is a royalty-free technology that has been adopted by Nvidia, AMD and Dell, which now sell DP video cards and monitors. HP, Philips, Samsung, Lenovo, Nvidia, Intel, Microsoft and other key IT players have pledged to support DP as well. Smaller than DVI or HDMI, the DP interface is easy to use, doesn't require screws to secure a connection and its pins don't bend easily. DP carries the clock signal in the data signal, unlike DVI or HDMI that carry the clock signal separately. It also supports more bandwidth than what is required for full HD resolution (1920 x 1080): DP 1.1 transfers a maximum of 8.64 Gb/s over a 2 m (6 ft), while version 1.2, slated for 2009, will double the bandwidth to support large display sizes with 120 Hz refresh rates.

Although Apple said that it supports DP as well, it is unclear whether the soon-to-be-refreshed desktop Macs will use DisplayPort or Apple's miniature variant called Mini DisplayPort (MDP) that is used in unibody Macbooks (Apple offers a royalty-free MDP license.) The MDP supports DP 1.1, which means that it can run a 30” Cinema Display at a 2560 x 1600 pixel resolution.

The MDP interconnect is one tenth the size of a full-sized DVI connector and carries digital audio and  video data, power, as well as a channel used for touch-panel data, USB, camera, microphone, etc. This enables owners of a 24” LED Cinema Display to attach up to three USB peripherals to the display instead of using USB ports on the MacBook, use the built-in camera, microphone and speakers and charge the notebook while it is connected to the display.

However, the transition to the new interconnect comes with a few downsides as well. A $99 Mini DisplayPort to DVI adapter is required to hook up unibody Macbooks with a 20- or 23-inch Cinema Display that use DVI. Owners of the 30” Cinema Display need a $29 Mini DisplayPort-to-Dual-link DVI adapter. But the adapter is bulky, it requires a USB port for power and does not ship until December 23, almost two months after the unibody Macbooks began shipping.

Those who wish to connect their new Macbooks to HDTVs will have to wait until a third party offers a Mini DisplayPort to HDMI adapter. Also, Apple is yet to introduce a DVI to Mini DisplayPort adapter to allow older Macs to connect to the new 24” LED Apple Cinema Display. Some users may dislike the fact that MDP comes with HDCP protection.

HDCP: Coming to a Mac near you

HDCP was originally developed and is currently licensed through Digital Content Protection, an Intel subsidiary. The technology is designed to prevent unauthorized copying and viewing of HD video content by encrypting video and audio as it travels across DisplayPort, DVI, HDMI, GVIF and UDI connections. HDCP made its debut when HD DVD and Blu-ray media became available and forced users who wanted to watch Blu-ray or HD DVD movies on their computers not only to buy a new optical drive, but also to upgrade their hardware that is carrying the audio/video signal with HDCP-equipped products.

Apple TV and unibody Macbooks already come with HDCP version 1.1 built-in that supports 128-bit AES encryption what may be surprising since DP has its own copy protection technology – the optional and AMD-developed DPCP (DisplayPort Content Protection), which uses 128-bit AES encryption as well.

Apple, however, does not need HDCP for Blu-ray, since it already stated that it won’t go the Blu-ray route. Instead, DP and HDCP are apparently required by iTS movies with HDCP protection. The combination of HDCP computers (Macs), HDCP content (iTS movies) and HDCP-compatible DisplayPort display creates the same daisy chain of copy protection as on a PC with an HDMI/HDCP graphics card and an HDMI/HDCP LCD.

One key problem is that the company offers HD movies for streaming and purchase only for Apple TV, while Mac users can only view the standard definition (SD) version of a movie. ArsTechnica learned that both SD and HD movies on the iTunes Store (iTS) are HDCP-flagged. This is not an issue if users watch such movies on an Apple TV. However, there is no question that hardware inconsistency does restrict the usage of HD content: For instance, an HD movie cannot be played on a unibody MacBook that is connected to an analog projector since the projector lacks the HDCP chip.

Of course, there are users who are unhappy about such a restriction, arguing that there is no need to use HDCP on SD movies since the technology is designed to protect HD content, not SD. Apple recently updated QuickTime for unibody Macbooks that removes playback restrictions for SD movies. But industry watchers are blaming movie studios for requiring Apple to create a secure environment. Indeed, Hollywood will likely not allow HD movie streaming or purchase on anything beyond Apple TV until Apple transitions the entire Mac lineup towards a DisplayPort+HDCP environment.