Ultra HD 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. Ultra HD Blu-ray supports 4K UHD 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. Ultra HD Blu-Ray discs also support a 12-bit per color container via Dolby Vision. Dolby Vision content on 4K UHD Blu-Ray can also be mastered for 10,000 nits peak brightness, whereas standard HDR10 can only achieve a maximum of 4,000 nits of brightness. Moreover, Dolby Vision makes use of dynamic metadata, which adjusts the brightness and tone mapping per scene. In contrast, standard HDR10 only makes use of static metadata, which sets the same brightness and tone mapping for the entirety of the content.

An optical disc is a flat, usually disc-shaped object that stores information in the form of physical variations on its surface that can be read with the aid of a beam of light. Optical discs can be reflective, where the light source and detector are on the same side of the disc, or transmissive, where light shines through the disc to be detected on the other side.