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 has 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 and One S; while re