blu ray disc

Blu-ray Disc (official abbreviation BD) is an optical disc storage medium designed to supersede the DVD format. The format defines as its standard physical media a 12 cm (same as DVDs and CDs), 25 GB per-layer optical disc, being dual layer discs (50 GB) the norm for feature-length video discs, and the addition of more layers left open as a future possibility.

The name Blu-ray Disc refers to the "blue laser" used to read the disc, which allows for five times more storage than on a DVD.

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 June 2009, more than 1,500 Blu-ray Disc titles were available in Australia and the United Kingdom, with 2,500 in the United States and Canada.[2] In Japan as of July 2010 more than 3,300 titles were released.[3]

During the high definition optical disc format war, Blu-ray Disc competed with the HD DVD format. Toshiba, the main company that supported HD DVD, conceded in February 2008,[4] releasing their own Blu-ray Disc player in late 2009.



Media type High-density optical disc
Encoding MPEG-2, H.264/MPEG-4 AVC, and VC-1
Capacity 25 GB (single-layer)
50 GB (dual-layer)
100/128 GB (BDXL)
Block size 64 kb ECC
Read mechanism 405 nm laser:
1× @ 36 Mbit/s (4.5 MByte/s)
Developed by Sony
Blu-ray Disc Association
Usage

Data storage
1080p High-definition video High-definition audio
stereoscopic 3D
Future possibility:
Quad HD
Ultra HD

Blue Ray Disc Technology

Blu-ray, also known as Blu-ray Disc (BD), is the name of a next-generation optical disc format jointly developed by the Blu-ray Disc Association (BDA), a group of the world's leading consumer electronics, personal computer and media manufacturers (including Apple, Dell, Hitachi, HP, JVC, LG, Mitsubishi, Panasonic, Pioneer, Philips, Samsung, Sharp, Sony, TDK and Thomson). The format was developed to enable recording, rewriting and playback of high-definition video (HD), as well as storing large amounts of data. The format offers more than five times the storage capacity of traditional DVDs and can hold up to 25GB on a single-layer disc and 50GB on a dual-layer disc. This extra capacity combined with the use of advanced video and audio codecs will offer consumers an unprecedented HD experience.

While current optical disc technologies such as DVD, DVD±R, DVD±RW, and DVD-RAM rely on a red laser to read and write data, the new format uses a blue-violet laser instead, hence the name Blu-ray. Despite the different type of lasers used, Blu-ray products can easily be made backwards compatible with CDs and DVDs through the use of a BD/DVD/CD compatible optical pickup unit. The benefit of using a blue-violet laser (405nm) is that it has a shorter wavelength than a red laser (650nm), which makes it possible to focus the laser spot with even greater precision. This allows data to be packed more tightly and stored in less space, so it's possible to fit more data on the disc even though it's the same size as a CD/DVD. This together with the change of numerical aperture to 0.85 is what enables Blu-ray Discs to hold 25GB/50GB.