The Blu-ray Disc enables the recording, rewriting and play back of up to 27 gigabytes (GB) of data on a single sided single layer 12cm CD/DVD size disc using a 405nm blue-violet laser. "Blu-ray Disc" Key Characteristics: 1) Large recording capacity up to 27GB 2) High-speed data transfer rate 36Mbps 3) Easy to use disc cartridge

Blu-ray is a new disk format that will provide much greater storage capacity than existing DVDs or the proposed (interim) HD-DVD format. A Blu-ray disk has a storage capacity of 25 GB, approximately five times the capacity of a single-layer DVD and and 67% more than HD-DVDs. Data can be read at 36 MB/s, compared to 19 MB/s for HD-DVD. Blu-ray disks will be available in dual layer and a quad-layer disk is in development. Blu-ray uses a shorter wavelength laser than do standard DVDs: 405 nm (blue-violet), the same as with HD-DVDs. Blu-ray and HD-DVD disks will use the MPEG-4 compression format, an offshoot of Windows Media 9. The larger initial size of a Blu-ray disk, in comparison to a HD-DVD disk, will allow content developers to use more or less compression at their option. MPEG-4, as with all MPEG algorithms, is a lossy compression format. It has been claimed that MPEG-4 will produce a better picture than the MPEG-2 format used for conventional DVDs at half the data rate. This has not yet been demonstrated in the market and is, in my opinion, highly unlikely. There is always a reduction in quality with lossy compression algorithms and the missing data cannot be restored. The Blu-ray disk is a step forward, while HD-DVD is a step sideways. When Blu-ray hits the market, HD-DVD will be obsolete. Again I ask: do you, as a consumer, want to pay for yet another industry format war? Oh, and by the way, a *third* new format has been proposed. This one will use the same laser as DVDs, will pack the data a little more tightly on the disk, and will use high compression rates to 'increase' storage. The worst of the lot, but the cheapest to implement. Someday soon an optical media player may have to manage several dozen formats. Sigh.

a high-definition DVD format, competing with HD-DVD. Playstation3 uses blu-ray while xbox 360 uses hd-dvd. It's kinda like VHS vs Beta. We'll see which wins.