The case for VESA DisplayPort: Both open and shut

The Video Electronics Standards Association announced the next steps in its DisplayPort specification, but copy-protection features that can make it difficult for users to play back legitimately acquired content are still there.

First proposed in 2005, DisplayPort's advantage is that a single digital interface connects both internal and external displays. This means that DisplayPort can carry pixels directly from any display source to any LCD panel. Other advantages of DisplayPort over Digital Visual Interface (DVI) and VGA include a small USB-sized connector with available latching, two-way display connectivity, optional audio support, higher performance than dual link DVI at 10.8 Gbps, and a unique micro-packet architecture that enables new display features.

The specification is also a free and open standard, meaning no licensing fees as are required with High-Definition Multimedia Interface (HDMI), which is used in most digital television sets these days.

Consequently, the industry has been eager to adopt it. More than two dozen companies are participating in developing it, said Bob Myers, distinguished technologist for Hewlett-Packard's Displays Business Unit, and chairman of the VESA board of directors. These include such industry heavyweights as Intel, Hewlett-Packard, Dell, and Apple.

Bruce Montag, senior technical staff in the office of the CTO, Dell Inc., and chairman of the VESA DisplayPort Task Group, also discussed the development of the DisplayPort 1.2, which was mentioned at CES 2008 as well as this year. One planned improvement of this version was a doubling of the bandwidth, to 5.4 GB. The bandwidth increase allows for increased resolutions, higher refresh rates, deeper color depth, and 3D.

Other improvements include multiple streams -- meaning, multiple monitor support over a single connector, Montag said. A higher-speed auxiliary channel supports bi-directional bulk data transfer, such as USB peripheral device data transfer, microphone audio transfer, and camera video transfer, all over a single DisplayPort cable. Also included will be Apple's Mini DisplayPort connector, which it has donated to the effort. The DisplayPort 1.2 standard is expected to be adopted in 2009.

At this year's CES, ten products from eight vendors are being displayed, including PCs, notebooks, monitors, graphics cards, projectors, cables and connectors, and adapters.

Since 2007, though, the DisplayPort specification has also included High-bandwidth Digital Content Protection (HDPC), a copy-protection standard for Blu-ray and other high-definition video formats. (Technically it is an option; VESA was unable to say how many manufacturers implemented it in DisplayPort, but the DisplayPort Web site said it expects most vendors to implement it.)

Consequently, consumers who use any sort of non-DisplayPort connection or device -- such as using a DisplayPort to VGA adapter to make use of an older monitor -- have been finding themselves unable to play back content, even if they acquired it legitimately. For example, iTunes content will not play back from new Apple MacBook and MacBook Pros -- equipped with the Mini DisplayPort -- if there is a non-DisplayPort device connected anywhere.