A high-capacity optical disc for high-definition (HD) movies. Developed primarily by Sony, Blu-ray and DVD discs have the same diameter and look similar, but Blu-ray's blue-violet laser reads pits a third the size of a DVD on tracks packed much tighter together. Blu-ray players support DVDs and CDs, plus resolutions up to 1080p and advanced video formats (see H.264 and VC-1). In addition, they support high-definition audio, including Dolby Digital Plus, TrueHD and DTS-HD (see Dolby Digital and DTS).
Blu-ray was designed for interactive content via the Java programming language, and every Blu-ray player executes Java programs for menus and user interaction (see Java Virtual Machine).
BonusView and BD-Live (Blu-ray 1.1 and 2.0)
Features are defined in "profiles," and all players support Profile 1.0. However, early Blu-ray 1.0 players do not support the extras in the later profiles.
BonusView (Profile 1.1) uses a second audio and video codec to enable picture-in-picture. Players have at least 256MB of non-volatile memory.
BD-Live (Profile 2.0) accesses the Internet for additional content; for example, an interview with the director of the movie might be available. BD- Live players have at least 1GB of non-volatile memory.
ROM, R and RE Formats
A Blu-ray disc (BD) comes in ROM (read-only memory), R (recordable) and RE (rewritable) formats. Used for commercial movies, BD-ROMs are pressed and cannot be changed. BD-Rs can be recorded only once by the user, and BD-RE discs can be rewritten over and over.
Blu-ray History
Blu-ray was announced in 2002 by Sony, Hitachi, Philips and other vendors, and the first recorders were sold in Japan a year later. In 2006, Sony's PlayStation 3 game console included a Blu-ray drive as one of its primary features.
From approximately 2005 up to 2008, Blu-ray competed with HD DVD, another high-def video format. However, having two similar technologies slowed adoption, and attempts to solve the problem by including both formats on a hybrid disc from Warner Home Video in 2006 or by creating the dual-format Super Blu player from LG in 2007 offered little help. In early 2008, HD DVD was discontinued, and Blu-ray became "the" HD format. See high-def DVD formats, 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
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