Blu-ray Disc

The Blu-ray Disc is an optical disc type primarily used for videos, created as a higher-capacity successor to the DVD. For a time it was in a format war with HD-DVD, ultimately winning out, but this victory came in a time when physical media were in decline in favor of streaming and downloads through networks as the preferred means of content distribution. This has slowed the adoption of Blu-ray compared to earlier media, but the format is widely supported nevertheless. Netflix has an option to receive Blu-ray Discs instead of DVDs when available, as part of the disc-in-the-mail subscriptions (which continue to have a wide range of material not presently available in streaming subscriptions).

Blu-ray Discs can be single-layer (25 GB capacity) or double-layer (50 GB). As with other optical disc types, they can be used for data, games, or audio, but the format is primarily marketed as a medium for video such as movies and TV shows. When used as a computer data storage medium, it may have a UDF filesystem.

The archival-quality M-Disc is available in BluRay form as well as DVD.

Blu-Ray video uses the M2TS format, with MPLS playlists, CLPI clip info files, and BDMV files for user interactivity. Subdirectories named BDMV and CERTIFICATE are used at the root level.

There is a Blu-ray 3D format as well for videos to be played in 3D (using special glasses) on supporting devices.

Standards and specs

 * White Paper on Blu-ray Disc Format: General
 * File System Specification
 * BD-RE physical format (rewritable)
 * BD-RE audo-visual application format 1
 * BD-RE audo-visual application format 2
 * BD-RE audo-visual application format 3
 * BD-R physical format (recordable)
 * BD-ROM physical format
 * BD-ROM audio-visual format
 * AVCREC rewritable format audio-visual spec

Other links

 * Wikipedia article
 * Blu-ray Disc Association website
 * Why Facebook thinks Blu-ray discs are perfect for the data center
 * More on Facebook's "Cold Storage"
 * Related patent application (European Patent Application EP1821310)
 * Article on UHD Blu-ray