|Media type||High-density optical disc|
|Encoding||H.265/MPEG-H Part 2 (HEVC)|
|Capacity||50 GB (dual-layer, 92 Mb/s)|
66 GB (dual-layer, 123, 144 Mb/s)
100 GB (triple-layer, 123, 144 Mb/s)
|Block size||2 KB sector, 64 KB block size|
|Read mechanism||405 nm laser|
|Developed by||Blu-ray Disc Association|
|Dimensions||120 mm (4.7 in) diameter|
|Extended from||Standard Blu-ray|
|Released||February 14, 2016|
Ultra HD Blu-ray (marketed as 4K Ultra HD) (UHD-BD), also referred as 4K Blu-ray, is a digital optical disc data storage format that is an enhanced variant of Blu-ray. Ultra HD Blu-ray discs are incompatible with existing standard Blu-ray players (though in most cases, a traditional Blu-ray and digital copy have been packaged with the Ultra HD Blu-ray discs). Ultra HD Blu-ray supports 4K UHD (3840 × 2160 pixel resolution) video at frame rates up to 60 progressive frames per second, encoded using High-Efficiency Video Coding. The discs support both high dynamic range by increasing the color depth to 10-bit per color and a greater color gamut than supported by conventional Blu-ray video by using the Rec. 2020 color space. 4K Blu-rays are supported on Microsoft's Xbox One X, One S, and PlayStation 5, while retail game releases on the Xbox Series X and PlayStation 5 video game consoles may be natively printed onto 100 GB UHD Blu-ray discs.
To differentiate Ultra HD Blu-ray titles on store shelves, the format usually uses a black opaque or slightly transparent keep case packaging format (as opposed to blue).
The specification allows for three disc capacities, each with its own data rate: 50 GB at 72 or 92 Mbit/s, and 66 GB and 100 GB at 92 Mbit/s, 123 or 144 Mbit/s. On 66 GB and 100 GB discs, the pits and lands are not narrower than those of a standard Blu-ray Disc, but shorter, which increases the capacity of each layer from 25 GB to 33 1/3 GB. This also means that each revolution of such a disc transfers more data than a revolution of a standard Blu-ray Disc, which means the transfer rate is higher despite the same linear velocity. In addition, the disc can be encoded to have the drive spin back up to the full 5,000 rpm starting from a point slightly away from the innermost part of the disc if an even higher transfer rate is needed. 50 and 66 GB use two layers, and 100 GB uses three layers. Ultra HD Blu-ray technology was licensed in mid-2015, and players had an expected release date of Christmas 2015. Ultra HD Blu-ray uses a new revision of AACS DRM: AACS 2. In addition, AACS 2.1 is used on certain titles (Stand by Me, Fury, The Patriot, Zombieland).
On May 12, 2015, the Blu-ray Disc Association revealed completed specifications and the official Ultra HD Blu-ray logo. Unlike conventional DVDs and Blu-rays, the new 4K format does not have region coding.
On February 14, 2016, the BDA released Ultra HD Blu-ray with mandatory support for HDR10 Media Profile video and optional support for Dolby Vision.
As of January 23, 2018, the BDA spec v3.2 also includes optional support for HDR10+ and Philips/Technicolor's SL-HDR2, also known as Advanced HDR by Technicolor. However, no Ultra HD Blu-ray player has ever supported SL-HDR2, and no discs encoded in SL-HDR2 were ever released.
The first Ultra HD Blu-ray Discs were officially released in the United States on February 14, 2016:
Sales of UHD Blu-ray players have been modest compared to older-generation video disc players, based on official US sales data from the Consumer Technology Association (CTA). Peak sales occurred in 2017 with 884,000 units sold, and sales have declined in the years since, as have all disc player sales. Meanwhile, previous generations of disc players sold in excess of four times as many units per year as did UHD Blu-ray.