What is ultra-high definition?

Sometimes referred to as 4K, ultra-high definition TVs set a new standard in terms of depth of color, contrast detail and resolution and, unfortunately, price.

Sometimes referred to as 4K, ultra-high definition TVs set a new standard in terms of depth of color, contrast detail and resolution and, unfortunately, price.

The technology has received more than its fair share of publicity since the first TV sets debuted at exhibitions and electronics shows in 2011 and the buzz around ultra-high definition (UHD) is set to increase further as more and more TVs supporting the technology come to market throughout this year.

The excitement they're generating is due to the level of detail and the truly immersive viewing experience these TV sets offer, and, for the moment at least, their sheer size -- initial UHDTVs from Samsung, LG and Sony all boast a screen of 80 inches or more, in other words, over 2 meters in length from corner to corner.

UHD screens feature four times as many pixels horizontally than a high-definition display (hence they are also referred to as 4K) and as a result, the only way to appreciate just how crystal clear the resulting images are is to experience them in the flesh.

These displays are also generating a buzz because they are showcasing the future. Just as HD TV has become mainstream, so will UHD but, like high-definition TV sets and TV broadcasts, these changes will not happen overnight. As a result there is very little 'native' content -- TV shows, video clips or feature films that are truly UHD -- currently available. Early adopters will have to be satisfied with their sets' inbuilt processors and software that can take high definition content and stretch it to fit the screen (known as upscaling).

Broadcasters and video streaming services are still trying to overcome the obstacles of transmitting such detailed content. Whereas a high-definition feature film can fit on a 4GB Blu-ray disc, a native UHD film would fill more than 20 such discs. Then there's the fact that very little has been filmed in UHD to date. Recently video streaming and rental service Netflix revealed that its first in-house production, 'House of Cards,' has been shot in 4K and would be available to watch in UHD one day, but not before it has figured out how to stream such large file sizes to customers. Sony has gone one step further and is offering a UHD set-top box with its first UHD TVs that comes with pre-installed content, but on the whole, there is very little out there.

This dearth of content makes the second issue -- the cost of a UHDTV -- even more significant. The first TVs from Sony, LG and Samsung to support this technology all retail for around $20,000 or more, putting the technology way beyond the reach of the average consumer. And, until a technology receives mainstream consumer acceptance, don't expect it to receive mainstream Hollywood studio and TV broadcaster support.

There is also a third point worth considering. Current UHD TVs use an LCD screen, lit with LEDs. These LEDs are necessary to not only illuminate the screen, but to deliver the shades, depths of colors and contrasts. However, there is a superior screen technology called OLED which moves the bar again in terms of color, contrast and definition. Some argue that the difference between an OLED UHD TV and the current crop of UHD TVs that use an LCD screen is almost as great as the difference between standard and high definition. OLED screens are still proving more difficult to manufacture en masse than their LCD counterparts, but when the technology becomes more stable, those that decided to spend upwards of $20,000 on an earlier version of UHD may be disappointed.