10K resolution is any of a number of horizontal display resolutions of around ten-thousand pixels, usually double that of 5K resolutions: 9,600 or 10,240 pixels. Unlike 4K, 8K and 16K, it is not part of UHDTV broadcast standards. The first devices available featured ultra-wide "21:9" screens with the vertical resolution of 8K, which has a native 16:9 aspect ratio.
On June 5, 2015, Chinese manufacturer BOE showed a 10K display with an aspect ratio of 64:27 (≈21:9) and a resolution of 10240 × 4320.
In November 2016, the Consumer Technology Association published CTA-861-G, an update to their standard for digital video transmission formats. This revision added support for 10240 × 4320, a 10K resolution with an aspect ratio of 64:27 (≈21:9), at up to 120 Hz.
On January 4, 2017, HDMI version 2.1 was officially announced, and was later released on November 28, 2017. HDMI 2.1 includes support for all the formats listed in the CTA-861-G standard, including 10K (10240 × 4320) at up to 120 Hz. HDMI 2.1 specifies a new Ultra High Speed HDMI cable which supports a bandwidth of up to 48 Gbit/s. Display Stream Compression (DSC) 1.2a is used for video formats higher than 8K resolution with 4:2:0 chroma subsampling.