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HD DVD (short for High Definition/Density Digital Versatile/Video Disc)〔(HD-DVD (High Definition Digital Versatile Disk) – blue laser optical disk ). Retrieved 16 April 2015.〕 is a discontinued high-density optical disc format for storing data and high-definition video. Supported principally by Toshiba, HD DVD was envisioned to be the successor to the standard DVD format. On 19 February 2008, after a protracted format war with rival Blu-ray Disc, Toshiba abandoned the format, announcing it would no longer develop or manufacture HD DVD players and drives.〔 The HD DVD Promotion Group was dissolved on March 28, 2008.〔(and the HD DVD Promotion Group officially dissolves in a high-res burst of tears ) (Engadget, March 28, 2008)〕 The HD DVD physical disc specifications (but not the codecs) were still in use as the basis for the China Blue High-definition Disc (CBHD) formerly called CH-DVD. Because all variants except 3× DVD and HD REC employed a blue laser with a shorter wavelength, HD DVD stored about 3.2 times as much data per layer as its predecessor (maximum capacity: 15 GB per layer compared to 4.7 GB per layer). ==History== In the mid 1990s, commercial HDTV sets started to enter a larger market, but there was no inexpensive way to record or play back HD content. JVC's D-VHS and Sony's HDCAM formats could store that amount of data, but were neither popular nor well-known. It was well known that using lasers with shorter wavelengths would yield optical storage with higher density. Shuji Nakamura invented practical blue laser diodes, but a lengthy patent lawsuit delayed commercial introduction. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「HD DVD」の詳細全文を読む スポンサード リンク
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