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.
Digital cinema
The DCI specification calls for picture encoding using the ISO/IEC 15444-1 "JPEG2000" (.j2c) standard and use of the CIE XYZ color space at 12 bits per component encoded with a 2.6 gamma applied at projection. Two levels of resolution for both content and projectors are supported: 2K (2048×1080) or 2.2 MP at 24 or 48 frames per second, and 4K (4096×2160) or 8.85 MP at 24 frames per second. The specification ensures that 2K content can play on 4K projectors and vice versa. Smaller resolutions in one direction are also supported (the image gets automatically centered). Later versions of the standard added additional playback rates (like 25 fps in SMPTE mode). For the sound component of the content the specification provides for up to 16 channels of uncompressed audio using the "Broadcast Wave" (.wav) format at 24 bits and 48 kHz or 96 kHz sampling.