What is Blu-ray?
Blu-ray, also known as Blu-ray Disc (BD), is a next-generation optical disc format jointly developed by members of 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, as well as storing large amounts of data. The format offers more than five times the storage capacity of traditional DVD’s 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 codes offers consumers an unprecedented HD experience.
Why is it called Blu-ray?
A blue laser is used to read the media. Blue light has a shorter wavelength than red.
Blu-ray Disc specification
According to the Blu-ray Disc specification,the following formats are to be supported:-
BD-ROM that is read-only format for distribution of HD (High Definition) movies, games, software, etc.
BD-R that is recordable format for HD video recording and PC data storage.
BD-RE that is rewritable format for HD video recording and PC data storage.
According to the Blu-ray Disc specification, the base (1x) speed for read/write data is 36Mbps. Since Movies stored in BD-ROM require at minimum a 54Mbps data transfer rate, all discs are required to be read at 2x speed or 72Mbps. Because Blu-ray uses a very large numerical aperture (NA), it has the potential for much higher speeds and lower recording power.