UHD Alliance Defines Premium 4K Ultra HD Experience

Alliance specs yield “almost a 3D experience without the glasses,” says Warner exec.
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Alliance specs yield “almost a 3D experience without the glasses,” says Warner exec.
The Ultra HD Premium logo is reserved for products and services that comply with the UHD Alliance’s minimum performance requirements.

The UHD Alliance (UHDA) came to CES with performance criteria that Ultra HD TVs and content must meet to deliver what the group calls a premium 4K experience.

The association also introduced a logo that will appear on certified content to guarantee to consumers “a premium experience that we defined,” alliance president and chairman Hanno Basse said at a Monday night press conference. The Ultra HD Premium logo is reserved for products and content that comply with minimum requirements for resolution, bit depth, high dynamic range (HDR), peak luminance, black levels, and wide color gamut, among other things, he said. (See details in fact sheet below.)

The collective requirements represent a “step change” in video quality, whereas past improvements were evolutionary, said Ron Sanders, president of home entertainment distribution at Warner Brothers Entertainment. The requirements yield “almost a 3D experience without the glasses,” he added.

The certification process began before the show, and the alliance has designated multiple independent centers around the world to do the testing.

Hardware, content launches: The certification process is already underway, and more than a dozen TVs have already been certified as meeting alliance requirements, Basse said. All of LG’s 2016 OLED TVs will meet all alliance performance criteria, some of them having already been certified, an LG spokesman told TWICE. Samsung said its entire 2016 SUHD TV lineup has been certified, and Panasonic was expected Tuesday to announce TVs meeting the requirements.

At least 100 movie titles will be available on physical 4K Blu-ray discs in 2016 from multiple studios, added Mike Dunn, president of 20th Century Fox Home Entertainment. Certified 4K discs from Fox will be available to coincide with the launch of Samsung’s first 4K Blu-ray player in the coming months, he noted.

For its part, Warner Brothers Entertainment will offer 35 certified 4K discs by the end of the year, said Sanders. Warner this year will offer a total of 60 certified titles in physical and digital formats combined, with some titles available in both 4K Blu-ray and 4K digital formats, he added. About a dozen 4K digital titles already available from Fox through Vudu meet alliance requirements.

Criteria: The alliance set criteria for content mastering as well as content-distribution methods, such as 4K Blu-ray discs, 4K streaming and downloads, and other distribution methods that could include pay-TV providers and broadcast TV. “The attributes are agnostic no matter how the content is distributed,” one alliance member told TWICE. The requirements apply regardless of distribution method, although “there can be differences in quality based on throughput,” he added.

All 4K Blu-ray players by definition will meet the alliance’s criteria because of the 4K Blu-ray spec’s high performance levels, the member noted. “4K Blu-ray will deliver it all,” he said.

Color gamut: For TVs, one key criteria is a wide-color-gamut display capable of reproducing more than 90 percent of the P3 color range, which is the standard used by digital cinemas.

The TVs must also be capable of accepting the ITU’s Rec. 2020 input-signal interface standard, which accommodates an even wider color gamut. “There’s a difference between the [Rec. 2020] interface standard, or container, and the display rendering,” a spokesman told TWICE. “To ensure interoperability, the content will be formatted in Rec. 2020, passed through distribution this way, and the displays will be able to understand such signal,” the spokesman told TWICE.

The use of Rec. 2020, however, will also enable step-up TVs with wider color gamut to display the full range of colors delivered by content that exceeds the display minimum.

HDR: For certified TVs, the criteria allow for a choice of two HDR ranges. The ranges are measured in nits, or candelas per square meter, each with a different minimum black level and different peak brightness level. The two ranges accommodate LCD displays and OLED displays. The latter deliver deeper blacks than LCD displays but aren’t as bright as LCD displays.

Also to meet alliance requirements, HDR systems must use SMPTE’s 2084 EOTF (Electro-Optical Transfer Function) standard, the spokesman added. Compliant systems include Dolby Vision, HDR10 as defined by CTA, and “any systems supported by Ultra HD Blu-ray,” which are also based on 2084, he said.  EOTF turns digital code into light.

Mastering, distribution: On the mastering and distribution side, one requirement is that content masters and distribution channels use the Rec. 2020 color-gamut “container,” 3840 by 2160 resolution, and minimum 10-bit signal. The alliance, however, is not requiring a minimum gamut or minimum dynamic range for the content master so as not to constrain the creative vision of the content producer, the spokesman said. Much of the alliance-certified content, however, is expected to meet the TV-display minimums, another movie-industry member said.

The alliance also “recommends” that any mastering display support at least 100 percent of P3 gamut, peak brightness of more than 1,000 nits, and a black level of less than 0.03 nits.

THX certification: Separately, THX told TWICE that it has developed a more stringent standard for HDR playback on TVs.

UHD Alliance Technical Specifications Overview

The UHD Alliance developed three specifications to support what it calls "the next-generation premium home entertainment experience." Three specifications cover the entertainment ecosystem in the following categories:

  • Devices (currently, television displays, with other devices under consideration)
  • Distribution
  • Content

Devices

The UHD Alliance supports various display technologies and consequently has defined combinations of parameters to ensure a premium experience across a wide range of devices. In order to receive the UHD Alliance Premium Logo, the device must meet or exceed the following specifications:

  • Image Resolution: 3840x2160
  • Color Bit Depth: 10-bit signal
  • Color Palette (Wide Color Gamut)
  • Signal Input: BT.2020 color representation
  • Display Reproduction: More than 90% of P3 colors
  • High Dynamic Range
  • SMPTE ST2084 EOTF
  • A combination of peak brightness and black level, either:
  • More than 1000 nits peak brightness and less than 0.05 nits black level    

         OR

  • More than 540 nits peak brightness and less than 0.0005 nits black level

Distribution

Any distribution channel delivering the UHD Alliance content must support

  • Image Resolution: 3840x2160
  • Color Bit Depth: Minimum 10-bit signal
  • Color: BT.2020 color representation
  • High Dynamic Range: SMPTE ST2084 EOTF

Content Master

  • The UHD Alliance Content Master must meet the following requirements:
  • Image Resolution: 3840x2160
  • Color Bit Depth: Minimum 10-bit signal
  • Color: BT.2020 color representation
  • High Dynamic Range: SMPTE ST2084 EOTF

The UHD Alliance recommends the following mastering display specifications:

  • Display Reproduction: Minimum 100% of P3 colors
  • Peak Brightness: More than 1000 nits
  • Black Level: Less than 0.03 nits

The UHD Alliance said its technical specifications "prioritize image quality and recommend support for next-generation audio.” 

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