Blu-ray Disc

Blu-ray Disc (also known as Blu-ray or BD) is an optical disc storage media format. Its main uses are high-definition video and data storage. The disc has the same dimensions as a standard DVD or CD.

The name Blu-ray Disc is derived from the blue-violet laser used to read and write this type of disc. Because of its shorter wavelength (405 nm), substantially more data can be stored on a Blu-ray Disc than on the DVD format, which uses a red (650 nm) laser. A dual layer Blu-ray Disc can store 50 GB, almost six times the capacity of a dual layer DVD.

Blu-ray Disc was developed by the Blu-ray Disc Association, a group of companies representing consumer electronics, computer hardware, and motion picture production. The standard is covered by several patents belonging to different companies. As of March 2007, a joint licensing agreement for all the relevant patents had not yet been finalized.

As of February 19, 2008, more than 450 Blu-ray Disc titles have been released in the United States, and more than 250 in Japan.

During the high definition optical disc format war, Blu-ray Disc competed with the HD DVD format. On February 19, 2008, Toshiba — the main company supporting HD DVD — announced it would no longer develop, manufacture and market HD DVD players and recorders, leading almost all other HD DVD supporters to follow suit.

Blu-ray Disc format finalized

The Blu-ray Disc physical specifications were finished in 2004. In January 2005, TDK announced that they had developed a hard coating polymer for Blu-ray Discs. The cartridges, no longer necessary, were scrapped. The BD-ROM specifications were finalized in early 2006. AACS LA, a consortium founded in 2004, had been developing the DRM platform that could be used to securely distribute movies to consumers. However, the final AACS standard was delayed, and then delayed again when an important member of the Blu-ray Disc group voiced concerns. At the request of the initial hardware manufacturers, including Toshiba, Pioneer and Samsung, an interim standard was published which did not include some features, like managed copy.

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