*** HD-DVD Information ***

[Scott]

HD DVD (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, Sanyo, and (most recently[1]) Microsoft, and backed by four major film studios.

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. This is smaller than its primary competitor Blu-ray Disc, which supports 25GB for one layer, 50GB for two and 100GB for four. 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, as HD DVD only requires modification of existing DVD disc production lines. Both formats will be backwards compatible with DVD's and both employ equal video compression techniques: 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 developed outside of the DVD Forum, and was never submitted to the 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).

[Scott]

HD DVD or High-Definition/Density Digital Versatile Disc is an obsolete high-density optical disc format for storing data and high-definition video. HD DVD was designed principally by Toshiba, and was envisaged to be the successor to the standard DVD format. However, in February 2008, Toshiba abandoned the format, announcing it would no longer develop or manufacture HD DVD players or drives.

Since all variants except the 3× DVD employed a blue laser with a shorter wavelength, HD DVD can store about 3¼ times as much data per layer as its predecessor (maximum capacity: 15 GB per layer instead of 4.7 GB per layer).

Much like the VHS vs. Betamax format war during the late 1970s and early 1980s, HD DVD was competing with rival format Blu-ray Disc. In 2008, major content manufacturers and key retailers began withdrawing their support for the format. Toshiba's withdrawal from the format ended the high definition optical disc format war, effectively making rival Blu-ray Disc the dominant format for high definition video discs. The HD DVD Promotion Group was dissolved on 28 March 2008.