HD-DVD
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HD-DVD (for High-Density Digital Versatile Disc) is a digital optical media format which is being developed as one standard for high-definition DVD. HD-DVD is similar to the competing Blu-ray Disc, which also uses the same CD sized (120 mm diameter) optical data storage media and 405 nm wavelength blue laser. HD-DVD is promoted by Toshiba, NEC, and Sanyo, and backed by four major film studios. The Blu-ray Disc is proposed by Sony.
HD-DVD has a single layer capacity of 15 GB and a dual-layer capacity of 30 GB. Toshiba has announced a triple-layer disc is in development, which would offer 45GB of storage. The surface layer of an HD-DVD disc is 0.6 mm thick, the same as DVD but thicker than the Blu-ray Disc's 0.1 mm layer. The numerical aperture of the optical pick-up head is 0.65, compared with 0.6 for DVD. These factors mean that HD-DVD media is less expensive to manufacture than Blu-ray Disc which require re-tooling of DVD disc production lines, and this has been critical in making HD-DVD the preferred choice of media companies. Existing DVD media are playable on HD-DVD drives with only minor modification of the optical pickup. Blu-ray Disc players however, are expected to include backward compatibility with DVDs. The two formats employ nearly identical video compression techniques, including MPEG-2, Video Codec 1 (VC1, based on the Windows Media 9 format) 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". 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 were expected to be unveiled by Q4 2004, with mass production to start in Q1 2005.
In April 2005, Apple Computer updated its version of DVD Studio Pro to support authoring HD content. DVD Studio Pro allows for the burning of HD-DVD content to both DVD and HD-DVD media (even though no burners are available).
Supporting film studios
See also
- Blu-ray Disc
- Enhanced Versatile Disc
- Versatile Multilayer Disc
- Digital Multilayer Disk
- Holographic Versatile Disc - a proposed next generation disc after HD-DVD and Blu-ray
External link
- DVD Forum (http://www.dvdforum.org)
- HD-DVD.org (http://www.hddvd.org/hddvd/)
- HD-DVD Central (http://www.hd-dvd-central.com/)
- Article detailing the battle between Blu-ray and HD-DVD (http://amishthrasher.blogspot.com/2005/06/hd-dvd-vs-blu-ray.html)
- BusinessWeek story detailing studio support for HD-DVD (http://www.businessweek.com/bwdaily/dnflash/oct2004/nf20041027_5297_db002.htm)af:HD-DVD