Blu-ray is an optical disc format which is set to rival HD-DVD in the race to be the de-facto standard storage medium for HDTV. The HD-DVD vs Blu-ray battle resembles that between Betamax and VHS and DVD+RW and DVD-RW.

Currently, the major Hollywood film studios are split evenly in their support for Blu-ray and HD-DVD, but most of the electronics industry is currently in the Blu-ray camp. The key difference between Blu-ray disc players and recorders and current optical disc technology is that Blu-ray, as its name suggests, uses a blue-violet laser to read and write data rather than a red one. Blue light has a shorter wavelength than red light, and according to the Blu-ray Disc Association (BDA), which is made up of, amongst others, Sony, Philips, Panasonic, and Pioneer, this means that the laser spot can be focussed with greater precision.

Blu-ray discs have a maximum capacity of 25GB and dual-layer discs can hold up to 50GB - enough for four hours of HDTV. Like HD-DVD, Blue laser discs don’t require a caddy and the players and recorders will be able to play current DVD discs. Codecs supported by Blu-ray include the H.264 MPEG-4 codec which will form part of Apple’s QuickTime 7, and the Windows Media 9 based VC-1.