Digital cinema refers to the use of digital technology to distribute or project motion pictures as opposed to the historical use of motion picture film. A movie can be distributed via hard drives, the Internet, dedicated satellite links or optical disks such as Blu-ray Discs. Digital movies are projected using a digital projector instead of a conventional film projector. Digital cinema is distinct from high-definition television and is not dependent on using television or high-definition video standards, aspect ratios, or frame rates. In digital cinema, resolutions are represented by the horizontal pixel count, usually 2K (2048×1080 or 2.2 megapixels) or 4K (4096×2160 or 8.8 megapixels).
As digital cinema technology has improved in early 2010s, most of the theaters across the world have converted to digital.
Digital media playback of hi-resolution 2K files has at least a 20-year history with early video data storage units (RAIDs) feeding custom frame buffer systems with large memories. Content was usually restricted to several minutes of material. Transfer of content between remote locations was slow and had limited capacity. It wasn't until the late 1990s that feature-length projects could be sent over the 'wire' (Internet or dedicated fiber links).