Blu-ray disc
Blu-ray disc is the next generation of optical-disc that was developed by the BDA (Blu-ray-Disc-Association - a world leading consumer of personal computer, electronics and also media manufacturers such as Dell, Apple, HP, Hitachi, LG, JVC, Panasonic, Mitsubishi, Thomson, Pioneer, TDK, Samsung, Sony and Sharp. The Blu-ray format was formed to enable rewriting, recording, and also high definition playback. In addition, it is also possible to store a huge amount of data on one single disc. The consumer is able to store 5 times more data on a single-layered Blu-ray disc, which is 25GB, and 50GB of data on a double-layered disc compared to the ordinary DVD. The capacity combined, and utilizing advanced audio and video codecs will bring consumers an extraordinary and breathtaking HD experience.
The current optical technologies: DVD, DVDñRW, DVD-RAM, and DVDñR depend on the red laser to write and read data, and the new Blu-ray format makes use of the blue-violet laser - showing exactly where the name comes from. In spite of all the different lasers, the products of Blu-ray can very easily be compatible with DVDs and CDs when using a DVD/BD/CD compatible-optical pickup unit. There are benefits when using the blue-violet (405nm) laser, and this is because the wavelength is shorter compared to the red (650nm) laser. The blue-violet laser is able to focus with great precision. Data is packed tighter than the red laser and less space is used. With this, more data can fit the disc although the DVD/CD and Blu-ray disc match in size. Because the numerical aperture is changed to 0.85, it allows a Blu-ray disc to store 25GB/50GB of data.
Around 180 world leading consumer personal computers, electronics, music, recording media and video game companies support Blu-ray. There are around 7 movie studios such as Fox, Disney, Paramount, Warner, Lionsgate, MGM, and Sony that have released some movies on the Blu-ray disc and only five: Fox, Disney, Lionsgate, MGM and Sony are releasing movies only on Blu-ray discs. There were also a few movie studios that have announced releasing the latest feature films in Blu-ray format, in addition, a catalogue of new titles each month.
When considering copying movies onto a Blu-ray disc and wondering how many hours of video will be able to fit on a double-layered disc, consider this: 9 hours HD (high-definition) video on a 50GB disc, and about 22-23 hours SD (standard-definition) video on a 50GB disc.

