Blu-ray Disc is an optical disc storage medium. Also known as BD or Blu-ray, it was designed to supersede the standard DVD format. The storage medium mainly finds applications in storing high-definition video, PlayStation 3 video games and other data (with 25 GB per single layered and 50 GB per dual layered disc). The standard storage specification for Blu-ray drives is open-ended. These discs have same physical dimensions as standard DVDs and CDs.
Blue-violet laser is used to read the disc and that gives it its name. Blu-ray uses a 405 nm blue-violet laser, and the use of shorter wavelength allows for more data storage than a DVD. The storage medium was developed by the Blu-ray Disc Association.
Blu-ray Rom discs store high-definition video with up to 1920×1080 pixel resolution at up to 59.94 fields per second. The high storage capacity of these discs makes them hold and play back large quantities of high-definition data.
The discs are now backward compatible and are capable of reading standard DVDs and CDs. The earlier disc players could play standard DVDs but not CDs. The variants of Blu-ray Disc include Mini Blu-ray Disc, Blu-ray Disc recordable, BD9 and BD5, AVCHD and AVCREC.