DisplayPort – the HDMI killer?
With the war between BluRay and HD-DVD behind us, the world of HD wages yet another for the format of display, or more accurately, how the format gets transmitted within and between HD devices.
Put forth by VESA (Video Electronics Standards Association), the DisplayPort defines a license and royalty free digital audio + video interconnect that is also more eco-friendly and cheaper to implement.
You’ve most probably heard of the DisplayPort as a defacto display connection on the latest Apple range of notebooks and cinema displays, but in actual fact the DisplayPort has long been existing since as early as 2006, and had its last update earlier this year, with the mini version released and adopted by Apple last October.
Standing in line after the Digital Video Interface (DVI), which in turn was designed to replace the VGA, the DisplayPort is due to go head to head with the HDMI (High Definition Multimedia Interface) standard, most commonly used in HD consumer electronics.
But what benefits does the DisplayPort bring to the world of filmmaking? Looking at its specs, the DisplayPort seems set to be the next standard of displaying HD graphics, with its ability to transmit at 10.8GB/s and support for both RGB and YCbCr formats.
Translating this into figures that will compute – you can hook up a a 4k (4096 x 2160) source and transmit it at full 12-bit at 24 frames and you’ll still be well within the limits at 7.7Gbit/s. More realistically, a full HD image playing at 60 frames with a bit depth of 8-bits will only clock in at 3Gbit/s, which is what most people would be looking at.
And since the technology is based on the micro-packet protocol, the DisplayPort is scalable, so it can support multiple video streams over one connection in future versions.
Bruce Montag, chairman of the DisplayPort Task Group explains: “The major advantage of DisplayPort’s packet architecture is the variable possible number of wires in the cable.” Because of its small footprint, the DisplayPort also can be implemented internally in notebooks, effectively replacing the popular copper-based LVDS (Low-voltage differential signaling) links which expand in size as the screen resolution increases.
Additionally, LVDS only supports communication in one direction, but the DisplayPort is two-way, allowing its auxilary channel to transmit user controls such as touch panel data, on screen microphones and cameras, notebook backlight control etc.
This is not only good news for filmmakers, but manufacturers as well, since unifying the connectors keep costs low and increases unity across the industry. Even with HDMI’s head start, the DisplayPort may very well catch up on its cost effectiveness â€“ since it is royalty free, manufacturers do not have to pay the annual fee and royalty structure of US$0.04 per device price that HDMI comes with.
The DisplayPort is also practical, with no additional screws (unlike the DVI and VGA) needed for connection, and its pins are less likely to bend (also unlike the DVI and VGA). Like the size of a USB, four DisplayPorts will fit into one PCI-e bracket, and will never exceed a power consumption of 2V, so it is much more eco-friendly than its rival, HDMI, which runs at about 3.3V.
The latest version of the DisplayPort, version 1.1a, also features support for fibre optic cables as an alternative to copper, allowing for a much longer reach between source and display with minimal to no degradation. It also has HDCP, or High-bandwidth Digital Content Protection, which enables the viewing of protected content from Blu-ray sources.
Support for the DisplayPort standard is steadily expanding, with companies such as Nvidia, Samsung and Dell adopting the DisplayPort into their products. One notable adoption is by HP in their range of monitors, particularly the HP Dreamcolour LP2480zx (which I mentioned before) which makes full use of the DisplayPort’s high bitrate in displaying its billions of colours.