Blu-ray information

A brief history

The 1980s witnessed an enormous leap in traditional storage media with the advent of the CD. Although its primary application was for audio, its 650MB storage capacity was crucial for the ever expanding storage requirements of the PC industry. This brought about a universal standard for storage media, and at very low costs. Although useful, the '90s demanded even more storage capacity which led to the evolution of the DVD specification, which gave a 5-10x increase in capacity. This also allowed high quality, standard definition video, and using the same form factor as CDs, allowed for a seamless migration to this new standard which offered full backwards compatibility. But just as we witnessed in the '80s and '90s, the 'naughty's' have also brought about further demands for high storage capacities, HD video, which like its predecessors, demanded a new solution.

This new format has arrived, the Blu-ray Disc. Just as we had a huge increase in storage capacity with DVD, Blu-ray yields a further five to ten times increase in storage capacity compared to DVD. Using a blue laser instead of the traditional red, and with improved lens spec, allows for a much smaller focal range which enables the medium to contain smaller density pits to store data.

Data on Blu-ray discs also have much higher tolerances and less distortion due the data layer being closer to the laser lens. As a result, Blu-ray discs, like CDs, are manufactured using a single substrate resulting in less production material, shorter production time, and lower costs per disc.

Blu-ray disc specifies the use of 'Universal disc Format' (UDF) 2.50 as a convergent friendly format for both PC and consumer electronics environments. It is used in latest specifications of BD-ROM, BD-RE and BD-R. All BD-ROM application files are stored under the 'BDMV' directory (shown below).

 AUXDATA: sound data and font files.
 BACKUP: backup files.
 CLIPINF: the database files for clips.
 PLAYLIST: playlists database files.
 STREAM: AV stream files.

 index.bdmv file: stores info describing the contents of the BDMV directory.

 MovieObject.bdmv file: stores info for one or more Movie Objects.

Blu-ray players sold in specific geographical regions are designed to only play discs authorised for that region. The Blu-ray Disc region coding scheme divides the world into 3 regions, labeled A, B, and C.

 

 Region A: includes most of North, Central and South American and Southeast Asian countries plus the Republic of China (Taiwan), Japan, Hong Kong, Macau and Korea.

 Region B: includes Europe, Africa, southwest Asia, Australia and New Zealand.

 Region C: includes central|south Asian countries, the People's Republic of China and Russia.