HD-DVD
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HD-DVD is a digital optical media format, and is one of the specifications being proposed as the standard for high-definition DVD. HD-DVD is similar to a competing format, the Blu-Ray disc, in that it uses a CD size (120 mm) optical data storage media and a blue laser at 405 nm wavelength. HD-DVD is promoted by Toshiba, NEC, and Sanyo, and backed by four major film studios, and is currently engaged in a format war with the Blu-ray Disc proposed by Sony.
HD-DVD has a capacity of 15 GB (for dual-sided HD-DVD, maximum capacity would be 30 GB) and does not use a caddy. The cover layer is, as in the case of the DVD, 0.6 mm thick (unlike the Blu-ray Disc at 0.1 mm). The numerical aperture of the optical pick-up head is accordingly the same as that of DVD player (0.65 mm). These factors indicate that HD-DVD media may be less expensive to manufacture. Moreover, existing DVD media are playable on HD-DVD drives without significant complications with respect to the optical pickup unit. It should be noted that Blu-ray Disc units also include DVD backward compatibility. The two formats employ nearly identical video compression techniques, including MPEG-2, Video Codec 1 (VC1) and H.264/MPEG-4 AVC.
On November 19, 2003, the DVD Forum decided with eight to six votes, that the HD-DVD will be the HDTV successor of the DVD. At this meeting they renamed it to HD-DVD, while it had been previously called the "Advanced Optical Disc". Note that Blu-ray Disc was never submitted to the DVD Forum for consideration.
The current specification version for HD-DVD-ROM and HD-DVD-Rewritable is version 1.0. The specification for HD-DVD-R is currently at 0.9. The first HD DVD-ROM drives are expected to be unveiled by Q4 2004, with mass production to start in Q1 2005.
Supporting film studios
See also
External link
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