What Is 4K Video?

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").While 4K is relatively new.

Ultra HD (4K), or Ultra High Definition, is the next big step in HDTV resolution. The Consumer Electronics Association (CEA) defines an Ultra HD television as one that displays at least 8 million active pixels, with a lower resolution boundary of at least 3,840 by 2,160. There are multiple varieties of 4K digital content ranging from 3,840 by 2,160 to 4,096 by 3,112, but the 3,840 by 2,160 resolution is the most consistent number we've seen and the standard resolution most UHD/4K HDTVs and monitors have settled on. It's a nice, even number, doubling the horizontal and vertical pixels offered by 1080p (1,920 by 1,080 pixels), which itself became the standard for high definition.

This format can't have the change in horizontal resolution, so change in aspect are made through the vertical resolution. For example, 4096×2304 is a frame size with aspect 16:9 and 4096×3072 — 4:3. The digital video resolutions examples:

Full Aperture 4k	4096 x 3112	12,746,752 pixels
Academy 4k	3656 x 2664	9,739,584 pixels
Digital Cinema 4k	4096 x 1714	7,020,544 pixels
Digital Cinema Aperture 4k	3996 x 2160	8,631,360 pixels

YouTube enabled 4K video support in the middle of 2010. Today, it's the highest resolution format available for consumers and it has great potential! It's quite possible that the demand for this format will increase in near future, especially by digital video data delivery services.