Blu Ray Disc – The ultimate disc storage for HD DVD – Plus
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 Blu-ray Disc can store 50 GB, almost six times the capacity of a dual layer DVD.
Blu-ray 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.
Long locked in a format war with HD DVD, Blu-ray Disc emerged the winner on February 19, 2008 when Toshiba — the main driving force behind HD DVD — announced it would no longer develop, manufacture and market HD DVD players and recorders. Some analysts believe that Sony’s PlayStation 3 video game console played an important role in the format war, believing it acted as a catalyst for Blu-ray Disc, as the PS3 was mainly based on Blu-ray technology. They also credited Sony’s more thorough and influential marketing campaign. It must also be noted, that Blu-ray players can reproduce AVCHD content, recorded by modern high definition camcorders, while HD DVD could not.
History
In the mid 1990s, commercial HDTV sets were finally starting to enter a larger market. However, there was no good, cheap way to record or play back HD content. Indeed, there was no medium that could store that amount of data, except JVC’s Digital VHS and Sony’s HDCAM. However, 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.
Origins
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 only made available in Japan. The recommended price was US$3800.However, there was no standard for pre-recorded video (BD-ROM) and no movies were released for this player. The Blu-ray Disc standard was still years away, since a new and secure DRM system was needed before Hollywood studios would accept it, not wanting to repeat the failure of the Content Scramble System for DVDs.
Competition from HD DVD
Comparison of high definition optical disc formatsThe DVD Forum (which was chaired by Toshiba) was deeply split over whether to go with the more expensive blue lasers or not. Although today’s Blu-ray Discs appear virtually identical to a standard DVD, when the Blu-ray Discs were initially developed they required a protective caddy to avoid mis-handling by the consumer (early CD-Rs also featured a protective caddy for the same purpose). The Blu-ray prototype’s caddy was both expensive and physically different from DVD, posing several problems. In March 2002, the forum voted to approve a proposal endorsed by Warner Bros. and other motion picture studios that involved compressing HD content onto dual-layer DVD-9 discs. However, in spite of this decision, the DVD Forum’s Steering Committee announced in April that it was pursuing its own blue-laser high-definition solution.
In August, Toshiba and NEC announced their competing standard Advanced Optical Disc. It was finally adopted by the DVD Forum and renamed HD DVD the next year, after being voted down twice by Blu-ray Disc Association members, prompting the U.S. Department of Justice to make preliminary investigations into the situation. Three new members had to be invited and the voting rules changed before the vote finally passed.
In the meantime, Sony spun off Professional Disc for DATA from the Blu-ray Disc project. It was essentially Blu-ray Disc with higher-quality media and components. The devices were too expensive for the consumer mass market. Instead, it was aimed at the professional data storage space market as a replacement for their line of 5.25″ MO drives. It was announced in October 2003, with the first devices shipping in December of the same year.
Blu-ray and HD DVD shared most of the same methods of encoding media onto disks with each other, using the same methods of encoding media onto disks as well as the default method of digital rights management, AACS. Blu-ray discs have a higher storage capacity than HD DVD discs had (50 GB vs. 30 GB) and Blu-ray discs also have higher bandwidth (48Mbit/sec vs. 30Mbit/sec), while including more DRM in the specification.
On 19 February 2008, Toshiba announced it was ending production of HD DVD devices, allowing Blu-ray Disc to become the industry standard.
Source : http://en.wikipedia.org/wiki/Blu-ray_Disc
