Blu-ray

A high-capacity optical disc for HD movies that fits on the same size disc platter as a DVD. In 2008, Blu-ray became the bona fide successor to the DVD for high-definition content, although DVDs will be made for many years into the future.

Announced in 2002 by Sony, Hitachi, Philips and other vendors, the Blu-ray technology uses a blue-violet laser that reads pits a third the size of a DVD on tracks that are packed much tighter together. Blu-ray supports the more advanced H.264 and VC-1 video encoding algorithms (codecs) as well as MPEG-2, which is used for DVD. It also supports 1080p, the highest HDTV resolution. See H.264 and VC-1.

The first Blu-ray recorders, which also play CDs and DVDs, were introduced in Japan in 2003. A Blu-ray drive was one of the primary new features of Sony's PlayStation 3 video game console, introduced in 2006 (see PS3).

Blu-ray Is Built for Interactive Content
Blu-ray supports the Java programming language for adding menus and user interaction to movies and games. Every Blu-ray player includes a Java interpreter that executes Java programs (see Java Virtual Machine).

Blu-ray 1.1 (BonusView) and Blu-ray 2.0 (BD-Live)
Blu-ray features are cataloged in "profiles," with Blu-ray Profile 1.0 being the first feature set for discs and players. Profile 1.1 added picture-in-picture capability (BonusView), and players include a second audio and video codec and 256MB of non-volatile memory. Profile 2.0 (BD-Live) accesses the Internet for bonus content, and players must have 1GB of non-volatile memory. Players with older profiles play all Blu-ray discs, but do not support the extra features.

BD-ROM, BD-R and BD-RE
Like CD and DVD media, there are read-only, write-once and rewritable options. Used for HD movies, BD-ROMs (Blu-ray Disc-ROMs) are pre-recorded discs that cannot be changed. BD-R (Blu-ray Disc-Recordable) media can be "burned" once by the user, and BD-RE (Blu-ray Disc-RErecordable) disks can be rewritten over and over.

Blu-ray Hybrids
Hybrid Blu-ray disks are BD-ROMs that store a movie in Blu-ray on one side and standard DVD on the other. In late 2006, Warner Home Video announced a hybrid disc that held Blu-ray and HD DVD on one side and DVD on the other. In 2007, LG introduced the Super Blu, the first dual-format player, supporting both Blu-ray and HD DVD media. However, in early 2008, HD DVD was discontinued, leaving Blu-ray as the winner in the HD format battle. See HD DVD, DVD and DTV.

   FULL-SIZE BLU-RAY DISK (120 mm) CAPACITIES

            SINGLE SIDED       DOUBLE SIDED

                     HD                 HD
   Layers   Storage  Hours     Storage  Hours

   Single   25GB     4.5         50GB   9

   Dual     50GB     9