[3.13] What about the HD-DVD and blue laser formats?

HD-DVD (HD stands for both high-density and high-definition) was under development before DVD came out. It finally emerged in 2003 (see 2.12 for general info). Some high-definition versions of HD-DVD use the original DVD physical format but depend on new video encoding technology such as H.264 to fit high-definition video in the space that used to hold only standard-definition video. High-density formats use blue or violet lasers to read smaller pits, increasing data capacity to around 15 to 30 GB per layer. High-density formats use high-definition MPEG-2 video (for compatibility with ATSC and DVB HD broadcasts, see 2.9 ) and may also use advanced encoding formats, probably supporting 1080p24 video.

As of early 2004 there are five proposals for HD-DVD, with the possibility of others. Here's a summary (more detail in the following sections):

* VC9 is the SMPTE standard based on Microsoft's Windows Media Series 9.

HD discs will not play on existing players. Even red-laser discs, which the player may be able to physically read, require new circuitry to decode and display the high-def video. Red-laser discs can play on DVD PCs with the right software (for example, HD versions of DVDs using Microsoft HD-WMV were available in 2003). Blue-laser discs require new optical assemblies and controllers. HD players will undoubtedly read existing DVDs, so your collection will not become obsolete when you buy a new player.

None of the HD formats will be used for movies until 2005 or 2006.

For a while there was a proposal being called HD-DVD-9, which put high-definition video on existing dual-layer DVD-9 discs. It has been combined with HD-DVD (AOD) in the sense that the application format is being designed to work on both current red-laser DVDs as well as future blu-laser DVDs. It's essentially a compatible-but-cheaper-to-replicate companion to blue-laser HD-DVD.

A 2-hour movie can fit on a DVD-9 at data rates of 6 to 7 Mbps. Given advances in video compression technology, it should be possible to get high-definition quality of at least 720p24 at these data rates (720 lines of progressive video at 24 frames/second). Shorter movies could be encoded in 1080p24 format. H.264 (MPEG-4 part 10) and VC9 (Windows Media 9) are the likely encoding standards.

The DVD Forum's next-generation DVD, once called Advanced Optical Disc (AOD), currently being called HD-DVD, but soon to have a new name. AOD is a modification of the existing DVD physical format to enable about 15 GB per layer using a blue-ultraviolet readout laser. The same 0.6-mm data depth is used. AOD is designed to improve data capacity while theoretically being able to use existing replication equipment. It is primarily supported by Toshiba and NEC.

Blu-ray is a new high-density physical format that will hold 23 to 27 GB per layer using a blue-ultraviolet laser and a 0.1-mm data depth. Because of the 0.1-mm cover layer it will require significant changes to production equipment. Blu-ray is initially intended for home recording, professional recording, and data recording. Mass-market distribution of pre-recorded movies will come later, after the read-only format, called BD-ROM, is developed and the details of video, audio, interactivity, and copy protection are hammered out. Blue-ray backers are LG, Panasonic, Philips, Pioneer, Hitachi, Mitsubishi, Samsung, Sharp, Sony, and Thomson. Sony released the first BD recorder in Japan in April 2003.

Technical details: up to 27 GB per layer using 0.1-mm recording depth (to reduce aberration from disc tilt), 405-nm blue-violet semiconductor with 0.85 NA (numerical aperture) lens design to provide 0.32 µm track pitch (half that of DVD) and as small as 0.138 µm pit length. Variations include 23.3 GB capacity with 0.160-µm minimum pit length (used by Sony's Professional Disc system) and 25 GB capacity with 0.149-µm minimum pit length. The physical discs uses phase-change groove recording on a 12-cm diameter, 1.2-mm thick disc, similar to DVD-RW and DVD+RW. 36 Mbps data transfer rate. Recording capacity on a single layer is about 2 hours of HD video (at 28 Mbps) or about 10 hours of standard-definition video (at 4.5 Mbps) . Cartridge size is 129 x 131 x 7 mm. Plans are to produce dual-layer recordable discs, holding about 50 GB per side, but such discs will take a few additional years to appear.

A government-backed consortium of companies in China, called eWorld, has developed a domestic version of DVD called EVD (Enhanced Versatile Disc). EVD uses red laser discs but with tighter tolerances than DVD to hold more data. Video is encoded in HD MPEG-2, although a future version will use the China-developed AVC compression format. EVD players first appeared in China at the beginning of 2004.

The Advanced Optical Storage Research Alliance (AOSRA), formed by Taiwan's Industrial Technology Research Institute (ITRI) has its own variations of blue-laser formats. FVD 1 uses a 0.6-mm data depth similar to AOD, and FVD 2 uses a 0.1-mm data depth similar to Blu-ray.