The specific design of Blu-ray DVD disk format lowers the manufacturing cost. Two disks of 0.6mm are molded in manufacturing the traditional DVD discs. The recording layer is sandwiched between these 0.6 mm disks. The manufacturing process of DVD disc is carried out very carefully so that birefringence could be avoided. Recording layer is added between the two molded disks which are then glued together. Injection molding process in blu-ray disk format is done on a single disk of 1.1 mm. Therefore this helps to reduce the production cost. This cost saving in blu-ray disk format compensates the additional cost on the protective layer.
In comparison with the DVD disk, the transfer rate in blu-ray disk format is much faster. The transfer rate of DVD format is 10 MB/s while that of blu-ray disk format is 36 MB/s. 25GB material can be recorded on a single side of blu-ray DVD disc. At first, the read-only formats of CD and DVD disks were introduced. Afterwards, their re-writable and recordable formats were introduced. The different formats of blu-ray are BD-R (recordable), BD-RE (rewritable), BD-RW (rewritable) and BD-ROM (read-only). BD-R and BD-RW are ideal for PC data storage while the other formats BD-ROM and BD-RE have been specifically designed for pre-recorded content and HDTV recording respectively. New blue-violet laser has been introduced in the blu-ray optical disc standard, while in DVDs & CDs red laser is used for reading and writing data.
So with the same amount of disk surface as that of DVD, the bluray disk can hold huge amount of data (25 GB on a single layer). Blu-ray name was given to this media format on the basis of its blue laser. The “blu” word came from the blue-violet diode while the other “ray” word was taken from the optical ray. The letter “e” was dropped and a new trademark “Blu-ray” was registered. Bluray DVD disk is also known as BD. Blu-ray disk format was developed in order to enable rewriting, recording, and playback of high-definition video HDV. Blu-ray recordable DVD disc can hold large amounts of data.
Blu-ray Disk Association is the founder of the blu-ray technology and now the worldwide members of this association are almost 180 companies. Blu-ray Disc Association’s Board of Directors is Sony Corporation, HP, Apple Computer, Dell, LG Electronics, Matsushita Electric Industrial Co., Hitachi, Pioneer Corporation, Mitsubishi Electric Corporation, Samsung Electronics, Royal Philips Electronics, Sun Microsystems, Sharp Corporation, Twentieth Century Fox, Warner Bros. Entertainment, Thomson Multimedia, Walt Disney Pictures and TDK. Combo disks of high definition DVD are also available whose one side comprises of standard DVD while the other side is the High-definition HD. All video formats including MPEG-4/AVC, VC-1 and MPEG-2 are supported by the bluray disk format.
Capacity of regular DVD disk is 4.36 GB and the capacity of single-layered bluray disc is approx. 25 GB. A dual-layer bluray will hold 50GB data. All major audio codec types are supported by the BD blu-ray format including eight channels of audio (un-compressed). The audio codecs supported by the bluray disk format includes Dolby Digital (DD), DTS Digital Surround, DTS-HD Master Audio, Dolby TrueHD, High Resolution Audio, Dolby Digital Plus (DD+) and LPCM (Linear PCM).