Blu-ray Disc

Blu-ray Disc (also known as Blu-ray or BD) is an optical disc storage medium. Its main uses are high-definition video and data storage. The disc has the same physical dimensions as standard DVDs and CDs.The name Blu-ray Disc is derived from the blue laser (violet-colored) used to read and write this type of disc. Because of the beam's shorter wavelength (405 nanometres), substantially more data can be stored on a Blu-ray Disc than on the DVD format, which uses a red (650 nm) laser. A two-layer Blu-ray Disc can store 50 gigabytes, almost six times the capacity of a two-layer DVD, or ten times that of a single-layer DVD.During the format war over high-definition optical discs, Blu-ray Disc competed with the HD DVD format. On February 19, 2008, Toshiba—the main company supporting HD DVD—announced that it would no longer develop, manufacture, and market HD DVD players and recorders,leading almost all other HD DVD companies to follow suit, effectively ending the format war.
Blu-ray Disc was developed by the Blu-ray Disc Association, a group representing makers of consumer electronics, computer hardware, and motion pictures. As of September 20, 2008, more than 850 Blu-ray Disc titles have been released in the United States and more than 500 Blu-ray Disc titles have been released in Japan.
There are expected to be over 1300 Blu-ray Disc titles released in the United States by the end of 2008.
In 1998, commercial HDTV sets began to appear in the consumer market; however, there was no commonly accepted, inexpensive way to record or play HD content. In fact, there was no medium with the storage required to accommodate HD codecs, except JVC's Digital VHS and Sony's HDCAM.Nevertheless, it was well known that using lasers with shorter wavelengths would enable optical storage with higher density. When Shuji Nakamura invented practical blue laser diodes, it was a sensation, although a lengthy patent lawsuit delayed commercial introduction.
Philips and Sony started two projects applying the new diodes: UDO (Ultra Density Optical) and DVR Blue (together with Pioneer), a format of rewritable discs which would eventually become Blu-ray Disc (more specifically, BD-RE).The core technologies of the formats are essentially similar.The first DVR Blue prototypes were unveiled at the CEATEC exhibition in October 2000.Because the Blu-ray Disc standard places the data recording layer close to the surface of the disc, early discs were susceptible to contamination and scratches and had to be enclosed in plastic cartridges for protection. In February 2002, the project was officially announced as Blu-ray,and the Blu-ray Disc Association was founded by the nine initial members.The first consumer devices were in stores on April 10, 2003. This device was the Sony BDZ-S77; a BD-RE recorder that was made available only in Japan. The recommended price was US$3800;however, there was no standard for pre-recorded video and no movies were released for this player. The Blu-ray Disc standard was still years away as a newer, more secure DRM system was needed before Hollywood studios would accept it, not wanting to repeat the failure of the Content Scramble System used on DVDs.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.