4K resolution
This resolution is used mainly in digital cinema production, and has a total of 8,847,360 pixels with an aspect ratio 256135 (≈1910). It was standardized as the resolution of the 4K container format defined by Digital Cinema Initiatives in the Digital Cinema System Specification, and is the native resolution of all DCI-compliant 4K digital projectors and monitors. The DCI specification allows several different resolutions for the content inside the container, depending on the desired aspect ratio. The allowed resolutions are defined in SMPTE 428-1: The DCI 4K standard has twice the horizontal and vertical resolution of DCI 2K (), with four times as many pixels overall.
DirecTV
In November 2014, DirecTV became the first television provider to begin offering 4K ultra-high definition content. On launch, 4K content was limited to renting a small library of on-demand films, downloaded to the subscriber's Genie DVR (some 4K content can also be pre-loaded automatically to the set-top box via the Genie Recommends feature). The 4K service could also only be used on "DirecTV 4K Ready" televisions, which support RVU protocol; this was limited to selected Samsung 4K televisions released in 2014.