Ultra-high-definition television (also known as 2160p, UHD-1, Super Hi-Vision, Ultra HD television, UltraHD, UHDTV, or UHD) includes 4K UHD (2160p) and 8K UHD (4320p), which are two digital video formats proposed by NHK Science & Technology Research Laboratories and defined and approved by the International Telecommunication Union (ITU).
The Consumer Electronics Association announced on October 17, 2012, that “Ultra High Definition”, or “Ultra HD”, would be used for displays that have an aspect ratio of 16:9 and at least one digital input capable of carrying and presenting native video at a minimum resolution of 3840×2160 pixels.
Ultra-high-definition television is also known as Ultra HD, UHD, and UHDTV. In Japan, 8K UHDTV will be known as Super Hi-Vision since Hi-Vision was the term used in Japan for HDTV.
In the consumer electronics market companies had previously only used the term 4K at the 2012 CES but that had changed to Ultra HD during the 2013 CES.
The Ultra HD term is an umbrella term that was selected by the Consumer Electronics Association after extensive consumer research.
Technical Details
Resolution
Two resolutions are defined as UHDTV:
- 4K UHDTV (2160p) is 3840 pixels wide by 2160 pixels tall (8.29 megapixels), which is four times as many pixels as 1920×1080 (2.07 megapixels).
- 8K UHDTV (4320p) is 7680 pixels wide by 4320 pixels tall (33.18 megapixels), which is sixteen times as many pixels and four times the spatial resolution of current 1080p HDTV, which brings it closer to the detail level of 15/70 mm IMAX. NHK advocates the 8K UHDTV format with 22.2 surround sound as Super Hi-Vision.
The suffix “p” in 2160p and 4320p stands for progressive scan or non-interlaced.
Colour space dynamic range and frame rate
The human visual system has a limited ability to discern improvements in the resolution below a certain size and beyond a certain distance.
At current consumer home viewing distances and TV sizes, increasing resolution to 4K may have a little perceptual impact, as consumers would not be close enough (the Lechner distance) to appreciate the differences in pixel count between 4K and HD. UHDTV also allows other image enhancements in dynamic range and colour, which can improve the perceived difference between 4KTV and HDTV.
UHDTV allows the future use of the new Rec. 2020 (UHDTV) colour space which can reproduce colours that cannot be shown with the current Rec. 709 (HDTV and most current 4KTV) colour space.
When dealing with CIE 1931 colour space coverage, the Rec. 2020 colour space covers 75.8%, whereas the digital cinema reference projector colour space covers 53.6%, the Adobe RGB colour space covers 52.1%, and the Rec. 709 colour space covers 35.9%.
UHDTV also allows for an increase in dynamic range, meaning brighter highlights but also increased detail in the greyscale. UHDTV also allows for frame rates up to 120 frames per second (fps).
Note that UHDTV potentially allows Rec.2020, higher dynamic range and higher frame rates to be applied to HD services, without necessarily increasing resolution to 4K.
4K UHD
4K resolution, also called 4K, refers to a display device or content having horizontal resolution on the order of 4,000 pixels. Several 4K resolutions exist in the fields of digital television and digital cinematography. In the movie projection industry, Digital Cinema Initiatives (DCI) is the dominant 4K standard. In television and consumer media, 4K UHD or UHD-1 is the dominant 4K standard. By 2015, 4K television market share had increased greatly as prices fell dramatically during 2014 and 2015.
By 2025, more than half of US households are anticipated to have a 4K-capable TV (2160p), which would be much faster than the adoption curve of FullHD (1080p).
The name “4K resolution” refers to a horizontal resolution of approximately 4,000 pixels. The use of width to characterize the overall resolution marks a switch from previous television standards such as 480i and 1080p, which categorize media according to its vertical dimension. Using that same convention, 4K UHD would be named 2160p.
There are two main 4K resolution standards:
- The DCI 4K resolution standard, which has a resolution of 4096 x 2160 pixels (256:135, approximately a 1.9:1 aspect ratio). This standard is widely respected by the film and video production industry. The DCI 4K standard has twice the horizontal and vertical resolution of DCI 2K.
- UHD-1, or ultra-high-definition television (UHDTV), is the 4K standard for television. UHD-1 is also called 2160p since it has twice the horizontal and vertical resolution of 1080p.
It has a resolution of 3840 x 2160 (16:9, or approximately a 1.78:1 aspect ratio). UHD-1 is used in consumer television and other media, e.g. video games.
Many manufacturers may advertise their products as UHD 4K, or simply 4K, when the term 4K is traditionally reserved for the cinematic, DCI resolution. This often causes great confusion among consumers.
YouTube and the television industry have adopted UHD-1 as its 4K standard and UHD-2 for NHK/BBC R&D’s 7680×4320 pixels UHDTV 2 with their basic parameter set is defined by the ITU BT.2020 standard. At present, 4K content from major broadcasters still remains limited.
8K UHD
8K resolution or 8K UHD is the current highest ultra high definition television (UHDTV) resolution in digital television and digital cinematography. 8K refers to the horizontal resolution in the order of 8,000 pixels, forming the total image dimensions of (7680×4320).
8K UHD has two times the horizontal and vertical resolution of the 4K UHD with four times as many pixels overall, or sixteen times as many pixels as Full HD.
High-resolution displays such as 8K allow the user to have each pixel be indistinguishable to the human eye from an acceptable distance to the screen. On an 8K screen sized 52 inches (132 cm), this effect would be achieved in a distance of 50.8 cm (20 inches) from the screen, and on a 92 inch (234 cm) screen at 91.44 cm (3 feet) away. 8K resolution can also be used with the purpose of enhancing lesser resolution videos with a combination of cropping technique and/or with downsampling technique used in video and film editing. Resolutions such as 8K allow filmmakers to shoot in a high resolution with a wide lens or at a further distance in case of a potentially dangerous subject (such as in wildlife documentaries), by intending to zoom and crop digitally in post-production. In this, a portion of the original image is cropped to match a smaller resolution such as the current industry standard for high-definition televisions (4K, 1080p, and 720p).
8K display resolution is the successor to 4K resolution. Full HD (1080p) is the current mainstream HD standard, with TV manufacturers pushing for 4K to become a new standard by 2017.
The feasibility of a fast transition to this new standard is often questionable in view of the absence of broadcasting resources.
As of 2015, few cameras have the capability to shoot video in 8K, with NHK being one of the only companies to have created a small broadcasting camera with an 8K image sensor.
Sony and Red Digital Cinema Camera Company are among the others to be working on bringing a larger 8K sensor in more of their product range in the coming years.
UHD Alliance
The UHD Alliance was created with the consumer in mind. It provides information on premium UHD devices and content to deliver best-in-class home entertainment. The Alliance is also focused on helping consumers build a seamless, integrated and high-quality UHD ecosystem from end-to-end. Premium UHD devices and content will be clearly marked so consumers can easily identify them in-store.
The UHD Alliance is a global coalition of leading film studios, TV brands, content distributors, post-production and technology companies that aim to create a unified criterion for premium UHD platforms, from devices to content including next-generation features like as 4K resolution, High Dynamic Range, Wide Color Gamut, High Frame Rate and Immersive Audio. The group is composed of DIRECTV, Dolby Laboratories, LG Electronics Inc., Netflix, Panasonic Corporation, Samsung Electronics Co., Ltd., Sharp Corporation, Sony Visual Product Inc., Technicolor, The Walt Disney Studios, Twentieth Century Fox, Universal Pictures and Warner Bros. Entertainment.
Vision
Provide consumers with a new differentiated entertainment experience that delivers a premium expression of creative intent using next generation audio‐visual technologies
Goals
Define a next-generation premium audio‐visual entertainment experience
Promote broad industry adoption
Promote consumer awareness
Reach consensus on quality criteria & a quality regime, assured by the UHD Alliance, across the ecosystem of premium content, devices and services
Enable new business opportunities in premium UHD leveraging cooperative efforts across the end‐to‐end ecosystem
Work Scope
Specify requirements for the Premium quality of UHD Content, Distribution,
Devices, and other elements of the ecosystem
Define criteria that distinguish premium quality ecosystem components while
preserving creative intent
Provide clear definitions, industry guidelines and best practices on emerging technologies, and collaborate with other standards organizations
Develop testing methodologies and certification programs based on the UHD Alliance specifications
Establish the UHD Alliance Logo program on certified products
Ensure UHDA‐branded content is guaranteed optimal presentation on UHDA‐branded devices
Promote UHD Alliance Brand and ecosystem to consumers
Establish consumer-facing naming and marketing messaging
Encourage consumers to choose UHDA‐branded products for a truly next‐generation experience
Website: www.uhdalliance.org
UHD Channels (4K)
Global
Fashion 4K
Festival 4K
Europe
4K UltraHD FunBox
Insight
Pearl TV
UHD-1
BT Sport Ultra HD
Tricolor Ultra HD
TRT 4K
Americas
NASA TV UHD
Asia
Airtel 4K
High 4K TV
UMAX[182]
SkyUHD 1
SkyUHD 2
UXN
