Blu-ray Basics

Cheryl Cain
There's a revolution underway in the world of DVD recording and playback and its name is "Blu-ray" – a reference to the new technology's use of a blue-violet laser beam to read and write data, as opposed to the red laser beam which is commonly used on current optical disc technologies, including DVD, DVD±R, DVD±RW and DVD-RAM.

Also known as Blu-ray Disc (BD), Blu-ray is the result of a joint development initiative involving over 150 computer, media and consumer electronics companies, including Apple, Dell, Hitachi, HP, JVC, LG, Mitsubishi, Panasonic, Pioneer, Philips, Samsung, Sharp, Sony, TDK and Thomson, under the auspices of the Blu-ray Disc Association (BDA), which was chartered to create this next-generation optical disc format.

The development of this new optical disc format is being driven primarily by the need to record, rewrite and playback high-definition video, as well as to provide an effective solution for those looking to flexibly store large amounts of data. With a capacity of 25GB, a single-layer Blu-ray Disc can contain more than two hours of HD programming or in excess of 13 hours of standard-definition video, with a 50GB dual-layer version capable of holding twice these amounts.

With this kind of performance, the Blu-ray format is slated to be widely used in next-generation HDTV DVD recorders and players, as well as in re-writable drives for computer data storage applications, replacing the CD/DVD drives commonly used today.

Blu-ray's use of a blue-violet laser rather than a red laser is due to the differences in wavelength between the two, with the former featuring a 405nm wavelength as opposed to the latter's 650nm. This shorter wavelength allows the blue-violet laser to be focused with greater precision than a red laser, making it possible to store more information on a disc the same size as a standard CD/DVD, or to allow increasingly useful amounts of data to be stored on even smaller media.

Even though there are two different laser types at play here, Blu-ray devices can be made backwards compatible with existing technologies by simply including an optical pickup designed for the older red laser devices, allowing for easy transitions from legacy systems.

Blu-ray also supports a 36Mbps data transfer rate as well as the MPEG-2 TS (Transport Stream) commonly used in digital television broadcasts, making it an attractive "VCR" replacement for HDTV owners who are looking to record broadcasts without any loss in quality. The technology is also an attractive option to current digital disk recorders, as it allows for simultaneous high-definition video recording and playback.

Given the rise of HDTV and the move to all-digital broadcasting, consumer demand for high-definition video recording and playback is on the increase and Blu-ray is poised to fill the need. Content producers and distributors would be wise to heed this trend and investigate ways in which they might best position themselves to fill the needs that this new format will provide.

A word of warning, however: Blu-ray is not the only technology vying for market dominance; facing stiff competition from Toshiba's HD-DVD format which is supported by both Microsoft and Intel. While only the future will tell which format comes out on top, in a potential replay of the VHS vs. Beta wars, some manufacturers are already planning on issuing equipment compatible with both – a move which should be reassuring to those trying to navigate the waters of this unfolding technological shift.