Ultra HD stands for ultra high definition. It is a prototype for a new digital video format and is also referred to as ultra high definition video (UHDV). This technology is the proposed replacement for existing high definition television (HDTV).
The highest-resolution HD monitors currently available offer 1,080 lines of resolution in a progressive-scan format — also known as 1080p video. These screens have 1,920 x 1,080 pixels and are theoretically capable of displaying every pixel of the highest-resolution HD broadcasts. These sets are sometimes called “ultra HD” as a marketing term, but in fact are part of the current HDTV standard.
True ultra HD is so named because it provides a video resolution containing 16 times as many pixels as current HD. Whereas HDTV uses 1,080 lines of resolution, ultra HD contains 4,320. It uses 7,680 x 4,320 pixels in a widescreen aspect ratio of 16x9, making for a total of approximately 33 million pixels (33 megapixels). The technology also offers improved sound quality: a 22.2 channel sound system reproduces 24 different channels of audio in three vertical layers of speakers, compared to currently available surround sound systems that use 5 or 6 channels.
Ultra HD was developed by a Japanese public broadcast company and research group called NHK Science and Technical Research Laboratories. Their aim in designing it is to present images and sound realistic enough to give viewers the sensation of being part of the scene — one reason the format is four times as high and four times as wide as HD. One screen built to demonstrate the technology spans 400 inches (1,016 cm). This provides viewers with a field of view perspective of about 100°, compared to 30° on commercially available screens. Some observers have even reported vertigo during demonstrations.
There are numerous practical problems for manufacturers seeking to bring the new format to consumers. The uncompressed video and audio recorded in ultra HD takes up high volumes of storage space — 3.5 terabytes for one 18-minute clip, requiring a hard disc weighing almost 600 pounds (272 kg). The prototype screen can use more electricity than an entire house might in one month. An early camera weighs more than 100 pounds (45 kg).
Because of these issues, ultra HD will likely be used in large venues such as museums before and if it becomes commercially available. As it is still at the concept stage, it will likely not be available to the public for some years. NHK has an internal goal of getting it to market by 2025.