Blu-RayBlu-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. Recent development by Pioneer has pushed the storage capacity to 500GB on a single disc by using 20 layers.
Blu-Ray Region Codes:
- A: East Asia (except Mainland China and Mongolia), Southeast Asia, the Americas, and their dependencies.
- B: Africa, Southwest Asia, Europe (except Russia), Oceania, and their dependencies.
- C: Central Asia, East Asia (Mainland China and Mongolia only), South Asia, central Eurasia (including Russia), and their dependencies.
HD DVD (short for High-Definition/Density DVD) is a now defunct high-density optical disc format for storing data and high-definition video. HD DVD is supported principally by Toshiba, and was envisaged to be the successor to the standard DVD format. However, in February 2008, after a protracted format war with rival Blu-ray, Toshiba abandoned the format, announcing it would no longer develop or manufacture HD DVD players or drives. HD DVD could store about 3¼ times as much data per layer compared to a standard DVD (maximum capacity: 15 GB per layer instead of 4.7 GB per layer).
Much like the VHS vs. Betamax format war during the late 1970s and early 1980s, HD DVD was competing with rival format Blu-ray Disc. In 2008, major content manufacturers and key retailers began withdrawing their support for the format. Toshiba's withdrawal from the format ended the high definition optical disc format war, effectively making rival Blu-ray Disc the dominant format for high definition video discs.