UHD & 4K FAQ

 

UHD4K UHD is a resolution of 3840 pixels × 2160 lines (8.3 megapixels, aspect ratio 16:9) and is one of the two resolutions of ultra high definition television targeted towards consumer television, the other being 8K UHD which is 7680 pixels × 4320 lines (33.2 megapixels). UHD has twice the horizontal and vertical resolution of the 1080p HDTV format, with four times as many pixels overall.

Televisions capable of displaying 4K resolutions are seen by consumer electronics companies as the next trigger for an upgrade cycle due to a lack of consumer interest in 3D television.

Besides resolution, the UHD standard and related technologies (e.g. HDMI 2.0) include other higher specifications such as a wider Rec. 2020 colour palette.

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.

 


 

What is 4K/UHD?

4K UHD GreyThe term 4K is derived from the movie industry format of 4096 x 2160 pixels, and refers to the roughly 4,000 pixels across the screen.
The terms 4K and Ultra HD are essentially used interchangeably. 4K is one type of UHD defined by a 2160p resolution (the minimum threshold for UHD), and is fast becoming the first widespread UHD standard.

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. A4K content from major broadcasters remains limited.


 

Where can I watch 4K/UHD Content?

Many major films and some TV shows are now shot using 4K cameras, though most of this video is downscaled  to HD resolution at present.
There are also a few UHD channels available on satellite, these are mostly test channels at present, availablity will depend on your location.

Streaming
Netflix 4KAmazon Prime Instant Video and Netflix now film and stream their original programmes in 4K/UHD. Search Netflix for  UHD content, Amazon is also streaming some programmes in HDR. These two subscription services, along with others such as M-Go, UltraFlix and Toon Goggles, offer 4K/UHD content from other sources — including Sony Pictures, Warner Bros., Lionsgate, 20th Century Fox and Discovery. YouTube and Vimeo also offer UHD streams.

Downloads
Sony has been most aggressive in promoting 4K/UHD. The company sells a $700 player that downloads 4K movies and TVs shows from Sony’s studio, Sony Pictures, including shows such as American Hustle and Breaking Bad. These can play on any 4K TV (not just Sony’s). About 300 titles are available, but that’s counting every episode of a show, such as The Blacklist, as a title. Films cost around $30 to buy and $8 to rent (for 24 hours), and are about 40GB in size; television episodes are available to purchase at $4 each.
Samsung offers its own media player with a sampling of titles from 20th Century Fox and Paramount, among others.

Discs
In 2015, the Blu-ray Disc Association announced that it had developed discs with greater capacity and finalized a format for UHD resolution, wide color gamut and HDR content. It remains to be seen which studios, if any, will produce Ultra HD Blu-ray discs (as they are formally known), and when.
Consumer electronics companies like LG and Sony have been cagey about plans to make Ultra HD Blu-ray players, simply saying that they are evaluating the technology.

Cable & Satellite
Some pay-TV providers are beginning to offer some on-demand 4K/UHD content. Dish Network in the US offer a set-top box called the 4K Joey that downloads programmes from the company’s satellite broadcasts. Comcast provides an app for Samsung TVs and offers a set-top box for its Xfinity customers.
Live broadcasts of 4K/UHD TV are probably a while off, simply because there isnot enough content to fill a channel lineup. But broadcasters such as Comcast say they will be able to handle broadcasts when the TV networks are ready. In the UK, Sky Q had launched offering some 4K content and the BBC is expected to launch a UHD channel in 2017.

Games
4K games are rare, and the top consoles — PlayStation 4 and Xbox One — are not powerful enough to support such content. But well-appointed PCs with multiple graphics cards can run some games at 4K/UHD resolution and at playable frame rates of about 30 fps, and sometimes higher. Still, 4K/UHD gaming has a long way to go before it’s a common capability, even on gaming-focussed PCs.


 

What are the Benefits of UHD/4K?

Philips 49PUS6401With UHD/4K TVs, you get a lot of detail. In a cityscape, for example, you may be able to see individual windows in the buildings, you can now make out the faces of people in the background. Even with HD content, a 4K TV with good up-conversion capability can fill in additional detail.

UHD/4K technology results in smaller pixels compared to HD screens of the same size, so you can sit about twice as close before you see the grid of individual pixels. This is important for large screens, whose pixels would be comparatively huge at 1080p resolution.
The Consumer Electronics Association estimates that in 2016, almost all TVs over 50 inches will have 4K/UHD resolution.
The addition of wide colour gamut and High Dynamic Range (HDR) provides further benefits, though currently only a smattering of very expensive 4K/UHD sets have these capabilities.


 

What Specifications should a UHD/4K TV have?

LG 58 Inch 58UH635V4K TVs started coming out before all the standards had been set. If you buy a TV (or monitor) made in 2015 or later, you should have all you need for ultra-high-def resolution, but you may not get the wide color gamut and high dynamic range capabilities. Here are the key specs you need to look for when buying.

HEVC/H.265: High Efficiency Video Coding, also known as HEVC or H.265, is the de-facto compression standard for squeezing 4K/UHD video into a stream or onto a hard drive or Blu-ray. Any new TV or monitor should support HEVC.

VP9: YouTube’s alternative to HEVC is used for most 4K/UHD streams on the video service. Any 4K/UHD TV with a YouTube app supports VP9 (as well as HEVC).

HDMI 2.0: The latest standard for combination digital-video/audio connections supports 4K/UHD at up to 60 frames per second, as well as the latest wide color gamut standard. Older 4K/UHD TVs may not have the latest HDMI support, meaning they are limited to 30fps video. Virtually no 4K/UHD content currently supports the higher specs, but it’s best to get a set with HDMI 2.0 so you are prepared for the future.

HDCP 2.2: Aside from videos you shoot yourself, most 4K/UHD content is copy protected using High-bandwidth Digital Content Protection (HDCP). If any of your devices don’t support HDCP 2.2, they won’t play premium 4K video. HDCP 2.2 is more or less standard on new 4K/UHD TVs, but only a few A/V receivers and soundbar speakers support it. If you plan to pass your video through one of these devices on the way to the TV, make sure they support HDCP 2.2, as well as HDMI 2.0.

HDR: HDR (High Dynamic Range) uses a panel technology to deliver a wider colour range and contrast, and it is very much about brightness and illumination.
To view HDR content, you need to have a TV that is compatible with HDR, it’s as simple as that. Although HDR has been talked about for a few years, there are now a set of standards for it, aiming to ensure that consumers are getting some sort of parity in HDR delivery across different devices.

Nanocrystals and quantum dots: These materials convert some of the deep-blue light from new LEDs into very saturated reds and greens. Combining the three colors yields a wide color gamut. Some TV makers are able to achieve a wide gamut by reconfiguring the LEDs themselves, without using nanocrystals or quantum dots.

OLED: Organic light-emitting diode screens are an expensive alternative to LCDs and don’t require a backlight. The OLED material itself glows when charged with electricity and goes completely black when turned off. This allows OLED TVs, such as the LG 55EC9300 ($2,499), to produce very dark shades and high dynamic range. These screens also produce a wide color gamut.


 

Dolby Vision

Dolby VisionDolby Vision™ transforms the way you experience movies, TV shows, and games with incredible brightness, contrast, and colour that bring entertainment to life before your eyes.
By fully leveraging the maximum potential of new cinema projection technology and new TVs’ display capabilities, Dolby Vision delivers high-dynamic-range (HDR) and wide-color-gamut content. The result is a refined, lifelike imag that will make you forget you are looking at a screen.

Current consumer video delivery and cinema standards are based on the limitations of old technologies and require altering the original content before it can be reproduced for playback—dramatically reducing the range of colours, brightness, and contrast from that captured by modern cameras.
Dolby Vision changes that, giving creative teams the confidence that images will be reproduced faithfully on TVs, PCs, and mobile devices that feature Dolby Vision.

Dolby Vision is a natural complement to Dolby Atmos®. It gives movie, television, and game creators the tools they need to create experiences that preserve the creative intent and let consumers experience truly immersive content without compromise.
For manufacturers of televisions, game consoles, personal computers, and mobile devices, Dolby Vision unlocks the full capabilities of their hardware and creates a premium experience that can increase use and enjoyment of these products.

 


 

HEVC/H.265

HEVC ResolutionsHigh Efficiency Video Coding (HEVC), also known as H.265, is a new video compression standard, developed by the Joint Collaborative Team on Video Coding (JCT-VC).  The JCT-VC brings together image and video encoding experts from around the world, producing a single standard that is approved by two standards bodies;

  • ITU-T Study Group 16 – Video Coding Experts Group (VCEG) – publishes the H.265 standard as ITU-T H.265, and
  • ISO/IEC JTC 1/SC 29/WG 11 Motion Picture Experts Group (MPEG) – publishes the HEVC standard as ISO/IEC 23008-2.

The initial version of the H.265/HEVC standard was ratified in January, 2013.

HEVC was developed with the goal of providing twice the compression efficiency of the previous standard, H.264 / AVC.  Although compression efficiency results vary depending on the type of content and the encoder settings, at typical consumer video distribution bit rates HEVC is typically able to compress video twice as efficiently as AVC.  End-users can take advantage of improved compression efficiency in one of two ways (or some combination of both);

  • At an identical level of visual quality, HEVC enables video to be compressed to a file that is about half the size (or half the bit rate) of AVC, or
  • When compressed to the same file size or bit rate as AVC, HEVC delivers significantly better visual quality.

 

High Dynamic Range (HDR)

HDR BalloonsHigh Dynamic Range (HDR), originates in photography, and refers to a technique that heightens a picture’s dynamic range – the contrast between the brightest whites and the darkest blacks. The theory is that the higher the dynamic range, the closer a picture gets to real life. HDR for televisions is basically the same idea.HDR Technical Details

HDR uses a panel technology to deliver a wider colour range and contrast, and it’s very much about brightness and illumination.
To view HDR content, you need to have a TV that is compatible with HDR, it’s as simple as that. Although HDR has been talked about for a few years, there are now a set of standards for it, aiming to ensure that consumers are getting some sort of parity in HDR delivery across different devices.

HDR-capable TVs are marketed as 4K televisions. Many HDR TVs have a backlight system that can output about 1,000 nits peak brightness, whereas standard HDTVs typically only output 100 nits, which is the level that Blu-ray and standard TV content is specified to.

Nits refers to the brightness, although this isn’t used uniformly when watching HDR content – this only refers to brightness in particular places, those highlights in a scene. Using an increased brightness range and a wider colour gamut, HDR can recreate visuals that werenot previously possible.

However this is not about absolute brightness it is about the range, so although you will see some LCD manufacturers talking about 1000 nit brightness, others, like OLED, might be offering 800 nits. Because both offer the wide range, they both have that ability to carry the HDR logo.

When it comes to colour standard HD TVs offer an 8-bit video specification known as Rec. 709, or BT.709. HDR steps up to 10- or 12-bit Rec. 2020, or BT.2020, which represents sixty times more colour combinations with smoother shade gradations. Those numbers do not really mean anything in themselves, they are just the standard defined by the ITU (International Telecommunications Union) and consumers will often hear TV manufacturers saying that they conform to BT.2020.

HDR is being bundled together with Ultra HD (4K). HDR is included in the Ultra HD Blu-ray spec, and the UHD Alliance has created a certification called Ultra HD Premium, which confirms that a device (e.g.: TV or Blu-ray player) meets particular standards for Ultra HD and HDR.


 

Hybrid Log-Gamma (HLG)

HLG teststreamHybrid Log-Gamma (HLG) is a high dynamic range (HDR) standard that was jointly developed by the BBC and NHK. The HLG standard is royalty-free and was approved as ARIB STD-B67 by the Association of Radio Industries and Businesses (ARIB). HLG is compatible with standard dynamic range (SDR) displays.

The BBC/NHK approach to HDR is to replace the gamma of Rec. 709 (which defines the relationship between the signal input coming into the display and the brightness of the output) with a new Electrical Opto Transfer Function (EOTF) that “splices” a log-curve onto the “high end” of Rec. 709. There is a white paper with more technical detail on the BBC R&D website.

The BBC points out that the BT.709 gamma works pretty well at low to mid levels of brightness, as seen on traditional CRTs. However, to match the HDR TVs that are starting to be available, better performance at high brightness is needed. The BBC believes that its proposal would support displays up to around 5,000 cd/m² with 10 bit grey scale data (it also has a 12 bit proposal for content creation). (Adam said that 1,000 cd/m² is likely to be a practical maximum brightness for a while for consumer TVs)

There are some huge advantages of the BBC proposal for broadcasters, no metadata is needed, which would be an advantage for live broadcast.

For more information see:
ARIB STD-B67 (PDF)
BBC WHP 309: A “Display Independent” High Dynamic Range Television System (PDF)


 

UHD Premium

UHD PremiumContent (4K Blu-ray discs) and devices (4K TVs/4K Blu-ray players) must meet or exceed a 4K resolution (3840 x 2160), up to 60 frames per second and support 10-bit colour depth, BT.2020 colour space representation and HDR.

Video is encoded under the High Efficiency Video Coding (HEVC) standard, and use 10-bit colour depth and the Rec. 2020 colour space.

TVs must also be capable of producing more than 90 per cent of the DCI P3 color standard and meet a certain brightness level (measured in nits).
4K TVs must have either a 1000-nit peak brightness and less than 0.05 nits black level (to cater for the high brightness of LCD TVs), or a 540-nit peak brightness and less than 0.0005 nits black level (to include the generally dimmer, yet stonking black depth, of OLEDs).

HDR pictures can be delivered in one of two ways: either using the BDA-developed “BD HDR” section of the new specification, or via compatible HDR formats such as Dolby Vision.

The disc specifications allows for discs in three sizes: 50GB with 82 Mbit/s, 66GB with 108 Mbit/s, and 100GB with 128 Mbit/s.
The discs support an optional digital bridge feature, which will allow the copying of Ultra HD Blu-ray content to an external hard disk drive and to portable devices, such as smartphones and tablets. The spec also mandates that all Ultra HD Blu-ray players will be able to play legacy Blu-ray discs.


 

UHD Terms Explained

ColorPrime
LG’s ColorPrime technology magnifies the range of colours that can be displayed on screen by utilising different LED phosphor colours, creating greater image depth and realism. Ultra Luminance technology continuously analyses the brightest and darkest parts of the displayed content in order to improve brightness and resolution. Equipped with LG’s 4K IPS panel, the TV renders detailed images at extremely wide viewing angles.

Nano Crystal Technology
Nano crystal or quantum dot technology is a new TV technology that uses nanoscopically small crystals (5 to 20 nanometers in size) as both a light and color source. In most TV applications, nano crystals of various sizes are spread across a thin film in the LCD display panel. When commanded, they emit light in various colors depending on the size of the crystal. The result is an LCD TV that is both brighter and features more enhances colors than a standard LED TV. Because a quantum dot TV still uses LED backlighting, these TVs essentially are a combination of both transmissive and emissive technology. While several companies, including LG, Sony, TCL and Samsung are putting nano crystals to work in new TVs, Samsung is probably the biggest backer of the technology and calls all its nano crystal TVs SUHD.

Peak Illuminator Pro
Peak Illuminator Pro heightens luminosity, increasing brightness by 1.5 times*. Peak Illuminator saves energy in the black areas to push the peak brightness levels even higher.

Precision Black
Precision Black technology enhances contrast by optimizing light emission, making everything you see more vivid and dramatic. With a PQI 2x that of conventional Samsung models, you get deeper black and purer white shades with more definition.

SUHD
What is SUHD? Samsung’s official answer is that the S does not stand for a specific word, the S is for the identification for their flagship products. It is not 8K or Super Hi Vision.

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