Blu-ray (known also a Blu-ray Disc and BD) is a next-generation, massive optical storage medium. The disc measures the same as a regular Digital Versatile Disc (DVD) or Compact Disc (CD) (4.7 inches/120 mm in diameter), but the Blu-ray Disc format is of a far greater capacity than these two predecessors and is used particularly in the field of high-definition (HD) media. The disc takes its name from the violet or blue colored laser with which data is read and written. It is owing to the very short wave length of this laser that the Blu-ray format can store massive amounts of data. With a laser beam of just 405 nanometers, a single layer Blu-ray Disc has a maximum storage capacity of 25 gigabytes while a dual layer disc has a maximum storage capacity of 50 gigabytes.
The Blu-ray format was developed by a group of the world’s leading electronic manufacturers who came together under the umbrella organization known as the Blu-ray Disc Association (BDA). The express purpose of the group’s efforts was to develop a mass media storage format that would enable the recording, rewriting and playback of high-definition (HD) video and audio. The group also developed a series of advanced video CODECS to facilitate the delivery of the high definition media.
The Blu-ray Disc’s 45 nanometer blue laser is an improvement in the 65 nanometer red laser that is used with the DVD and CD formats. With a shorter wavelength, the laser beam can be focused more precisely and the data written more compactly. This means that while the Blu-ray Disc retains the same dimensions as its DVD and CD forbears it is able to use the optical storage space more economically. This means that a typical dual-layer Blu-ray Disc can store almost six times more data than a dual-layer DVD and ten times more than a single layer DVD.
The Blu-ray format is supported by the leaders of the electronic and digital media industries, with everyone from Apple, Hitachi and Hewlett Packard (HP) to Samsung, Sony, Thomson and TDK adopting the format. The movie industry has followed suit with Hollywood viewing the format as the natural successor to the DVD. The move by Hollywood studios such as Warner Brothers and Twentieth Century Fox to adopt the Blu-ray format at the expense of the competing HD format has meant that the former format has become the de facto optical media storage format of choice for the film and, most recently, the video game industries.