Optical disc composed of a phase change material, most often AgInSbTe, an alloy of silver, indium, antimony, and tellurium. Optical discs are most commonly used for storing music (e.g. for use in a CD player), video (e.g. for use in a Blu-ray player), or data and programs for personal computers (PC). The Optical Storage Technology Association (OSTA) promotes standardized optical storage formats. Although optical discs are more durable than earlier audio-visual and data storage formats, they are susceptible to environmental and daily-use damage. Libraries and archives enact optical media preservation procedures to ensure continued usability in the computer's optical disc drive or
China Blue High-definition Disc to 1 in China (due to heavy advertisement and favored backing from the government). In September 2009, Universal Studios and National Geographic announced their support for the format. Also adding support for the format are Paramount Pictures (US), Celestial (HK/CN) and BBC/Discovery (UK/US). China Blue High-definition Disc China Blue High-Definition (CBHD; ; alternatively "China High Definition DVD") is a high definition optical disc format announced in September 2007 by the Optical Memory National Engineering Research Center (OMNERC) of Tsinghua University in China. The format is a derivative of the HD DVD, a medium created by the DVD Forum designed to