The Blu-ray Format

Blu-ray is an optical disc storage technology. The name refers to the blue laser used (instead of the red laser used in DVD) — blue light has a shorter wavelength so more data can be stored in the same space.

Blu-ray competed with HD-DVD for the post-DVD high-definition market, eventually emerging as the winner in February 2008. See Blu-ray vs HD-DVD for a comparison.

A single-layer Blu-ray disc can hold 25GB of data, a dramatic improvement over DVD's 4.7GB. This is enough for approximately 2.5 hours of high-definition video or 13 hours of standard-definition video. A double-layer Blu-ray disc can hold 50 GB, enough for approximately 4.5 hours of high-definition video or 20 hours of standard-definition video.

Prototypes have been demonstrated which hold up to 100GB with a theoretical limit of 200 GB. However it should not be assumed that these specifications will be available any time soon (or at all).

Blu-ray supports 1080p resolution. This is touted as the best high-definition resolution for consumers, despite the fact that pre-recorded content is not yet widely available. However the inclusion of 1080p is another big tick for Blu-ray.

The Blu-ray format also allows you to:

• Record one program while playing back another
• Create playlists
• Edit and rearrange programs
• Search for empty disc space
• Access the Internet to download features such as subtitles

As far as the corporate game goes, Sony owns Columbia Pictures and MGM, and has the support of a number of big players. It also has PlayStation 3 on it's side which will play Blu-Ray DVDs.

Specifications at a Glance

See also:

• The DVD Format
• HD-DVD
• HD-DVD vs Blu-ray
• HD-VMD
• CH-DVD