The HD DVD disc is designed to be the successor to the standard DVD format. It can store about three times as much data as its predecessor (15 GB per layer instead of 4.7 GB). The HD DVD standard was jointly developed by a group of consumer electronics and PC companies, spearheaded by Toshiba. On November 19, 2003, the DVD Forum voted to support HD DVD as the high definition successor of the standard DVD. At this meeting, they also renamed it HD DVD. The format had previously been called the "Advanced Optical Disc" (AOD)...

more »At CES 2006, Microsoft announced that there would be an external add-on HD DVD drive for the Xbox 360 game console; this was released in November 2006. Also at CES [1]2006, companies backing HD DVD said that nearly 200 titles would be available for the format by the end of the year.

On March 31, 2006, Toshiba released their first HD DVD player in Japan at ?110,000 ($934).[2] HD DVD was released in United States on April 18, 2006,[3] with players priced at $499 and $799.

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 HD DVD-RAM is yet not fully finalized. The first HD DVD-ROM drives were expected to be unveiled by Q4 2006, with mass production to start in Q1 2007. The actual product launch of both CE and PC units occurred in late 2006.

HD DVD is currently in a format war with rival format Blu-ray Disc.

HD DVD stands for "High Definition Digital Versatile Disc"

The primary rival to HD DVD is Blu-ray, championed by Sony. Blu-ray has a higher disc capacity per layer (25 GB vs 15 GB). However the majority (70%[34]) of Blu-ray titles are in 25 GB single layer format while almost all (over 90%[35]) HD DVD movies are in 30 GB dual layer format. In 2007 only 46%[36] Blu-ray movies were released in 25GB Discs so far (03/2007).

In terms of audio/video compression, HD DVD and Blu-ray are similar on the surface: both support MPEG-2, VC-1, and H.264 for video compression. Virtually every HD DVD released uses an advanced codec (VC-1 or H.264) for video compression, reducing the required space for equivalent quality video. The first generation of Blu-ray Disc movies however used the legacy video codec MPEG-2, and many new titles still do. In terms of audio, there are many differences. With HD DVD support for the new Dolby Digital Plus audio codec is mandatory at a maximum of 3.0 Mbit/s, but for Blu-ray players it is optional at a maximum of 1.7 Mbit/s.[37] Furthermore HD DVD players must be able to decode the new lossless audio codec Dolby True HD, but this is optional for Blu-ray players.

Both HD DVD and Blu-ray Disc support the 24p (traditional movie) frame rate, but technical implementations of this mode are different among the two formats. Blu-ray Disc supports 24p with its native timing, while HD DVD uses 60i timing for 24p (encoded progressively, replacing missing fields with "repeat field flags"). Decoders can ignore the ?flags? to output 24p.[38] There is no impact on picture resolution or storage space as a result of this, as the HD DVD format uses the exact same video information ? it simply adds notational overhead.

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This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "HD DVD".