Next-generation resolution - 4K, Ultra HD

UHD is an "umbrella term" that encompasses higher resolutions (more pixels) than HDTV, as well as more realistic color and higher frame rates. Today and this year, pretty much the only one of those improvements available in new TVs and content is 4K resolution.

Still, the shift from 1080p to 4K TV hardware is inevitable. This year 4K TVs will replace high-end 1080p models as the best-performing LED LCD-based sets on the market.

What's in a name? '4K' versus 'UHD'

In August 2012, the Consumer Electronics Association introduced the term Ultra High Definition, partly defined as resolutions of "at least 3,840x2,160 pixels". The idea was to replace the term 4K. The CEA's name lasted less than a day, as Sony then announced it was going to call the technology "4K Ultra High Definition". This is the term now used by most other TV manufacturers too, who seem interested in covering all the buzzword bases at the expense of brevity.

In practice, you will often see UHD used interchangeably with 4K, whether describing TVs, source devices, accessories or content. 

Digital resolutions: A primer

When used in a home context, 4K/UHD means the TV's screen has a minimum resolution of 3,840 pixels wide and 2,160 pixels high, making it the equivalent to two 1080p screens in height and two in length. This resolution was originally known as "Quad HD," and it's used by basically every 4K TV.

The latest in a line of broadcast and media resolutions, 4K is due to replace 1080p as the highest-resolution signal available for in-home movies and television.

With the arrival of 4K there are four main resolution standards for use in the home: standard definition (480p/540p) , high definition (720p), full high definition (1080i/p) and ultra high definition (2160p).

Four resolutions compared: standard definition; full high definition; and the two kinds of ultra high definition (Quad HD and 4Kx2K)

Another resolution, known as 4Kx2K (4,096x2,160 pixels), is used by some projectors and many professional cameras. It also falls under the umbrella of 4K/UHD. Other shooting resolutions are also employed in the pro realm, depending on the camera.

While 4K is relatively new, high definition (HD) itself has been with us for about a decade, and is the format used in Blu-ray movies and HD broadcasts. There are three main versions of HD: full high definition 1080p (progressive), 1080i (interlaced), and 720p (also called simply "high definition").

Despite the existence of HD and 4K, many television programs, online videos and all DVDs are still presented in standard definition, loosely defined as 480 lines. Standard definition began life as NTSC TV broadcasts before switching to digital with the introduction of ATSC in 2007.