| HD DVD, High Density DVD, or High-Definition | | | | their house. The HD DVD format also can be |
| DVD is a high-density optical disc format | | | | applied to current red laser DVDs in 5, 9, 15 |
| designed for the storage of data and | | | | and 18 GB capacities which offers a |
| high-definition video. | | | | lower-cost option for distributors, this type |
| | | | of disk is often called 3x DVD as it has |
| History | | | | three times the bandwidth of regular DVD |
| | | | video. |
| The HD DVD disc is designed to be the | | | | |
| successor to the standard DVD format. It can | | | | Like the original DVD format, the data layer |
| store about three times as much data as its | | | | of an HD DVD disc is 0.6 mm below the |
| predecessor. (15 GB per layer instead of 4.7 | | | | surface. The numerical aperture of the |
| GB) The HD DVD standard was jointly developed | | | | optical pick-up head is 0.65, compared with |
| by a group of consumer electronics and PC | | | | 0.6 for DVD and 0.85 for Blu-ray aperture. |
| companies, spearheaded by Toshiba. On | | | | Both of the new formats are backward |
| November 19, 2003, the DVD Forum voted to | | | | compatible with DVDs and both employ the same |
| support HD DVD as the HDTV successor of the | | | | video compression techniques: MPEG-2, Video |
| standard DVD. At this meeting, they also | | | | Codec 1 (VC-1) and H.264/MPEG-4 AVC. |
| renamed it HD DVD. The format had previously | | | | |
| been called the "Advanced Optical Disc" | | | | File systems |
| (AOD). | | | | |
| | | | Like previous optical disc formats, HD DVD |
| At CES 2006, Microsoft announced that there | | | | supports several file systems, like ISO 9660 |
| would be an external add-on HD DVD drive for | | | | and Universal Disk Format (UDF). Currently, |
| the Xbox 360 game console; this was released | | | | all HD DVD titles use UDF version 2.5 as the |
| in November 2006. Also at CES [1]2006, | | | | file system, the same one used for Blu-ray |
| companies backing HD DVD said that nearly 200 | | | | releases. |
| titles would be available for the format by | | | | |
| the end of the year. | | | | Audio |
| | | | |
| On March 31, 2006, Toshiba released their | | | | HD DVD can be mastered with up to 7.1 channel |
| first HD DVD player in Japan at Y110,000 | | | | surround sound using linear (uncompressed) |
| ($934).[2] HD DVD was released in United | | | | PCM, Dolby Digital, Dolby Digital EX, DTS and |
| States on April 18, 2006,[3] with players | | | | DTS ES formats also used on DVDs. In |
| priced at $499 and $799. | | | | addition, it also supports Dolby Digital Plus |
| | | | and the lossless formats Dolby TrueHD and DTS |
| The current specification version for HD | | | | HD. Currently, most DVD movies are made with |
| DVD-ROM and HD DVD-Rewritable is version 1.0. | | | | 5.1 channels of surround sound. There are |
| The specification for HD DVD-R is currently | | | | relatively few titles that offer 6.1 channels |
| at 0.9. The first HD DVD-ROM drives were | | | | of surround sound. On HD DVD the Dolby |
| expected to be unveiled by Q4 2006, with mass | | | | formats are mandatory, meaning that a Dolby |
| production to start in Q1 2007. The actual | | | | Digital, Dolby Digital Plus or Dolby TrueHD |
| product launch of both CE and PC units | | | | track may be used as the sole soundtrack on a |
| occurred in late 2006. As of December 2006, | | | | disc, because every player will have a |
| more than 120,000 HD DVD's had been sold in | | | | decoder that can process any of these |
| the United States.[citation needed] | | | | bitstreams. For lossless audio in movies in |
| | | | the PCM, Dolby TrueHD or DTS-HD formats, HD |
| As of February 2007, HD DVD is in a format | | | | DVD discs support encoding in up to 24-bit |
| war with Blu-ray Disc. | | | | 192 kHz for two channels, or up to eight |
| | | | channels of up to 24-bit/96 kHz encoding. For |
| Technical specifications | | | | reference, even new big-budget Hollywood |
| | | | films are mastered in only 24-bit/48 kHz, |
| Hardware | | | | with 16-bit/48 kHz being common for ordinary |
| | | | films. |
| HD DVD has a single-layer capacity of 15 GB | | | | |
| and a dual-layer capacity of 30 GB. There is | | | | Video |
| also a double-sided hybrid format which | | | | |
| contains standard DVD-Video format video on | | | | The HD DVD format supports a wide variety of |
| one side, playable in regular DVD players, | | | | resolutions, from low-resolution CIF and |
| and HD DVD video on the other side for | | | | SDTV, all video resolutions supported by the |
| playback in high definition on HD DVD | | | | DVD-Video standard, and up to HDTV formats |
| players. These hybrid discs make retail | | | | such as 720p, 1080i and 1080p.[6] All movie |
| marketing and shelf space management easier. | | | | titles released so far have had the feature |
| This also removes some confusion from DVD | | | | encoded in 1080p, with supplements in 480i or |
| buyers since they can now buy a disc | | | | 480p. Most titles are encoded with VC-1. |
| compatible with any DVD/HD DVD player in | | | | |