Information about Hd Dvd

HD DVD

Media type:	High-density optical disc
Encoding:	VC-1, H.264, and MPEG-2
Capacity:	15 GB (single layer) 30 GB (dual layer)
Read mechanism:	1x@36 Mbit/s & 2x@72 Mbit/s
Developed by:	DVD Forum
Usage:	Data storage, including high-definition video

Optical disc authoring
Optical disc Optical disc image Recorder hardware Authoring software Recording technologies Recording modes Packet writing
Optical media types
Laserdisc Compact disc/CD-ROM: CD-R, CD-RW MiniDisc DVD: DVD-R, DVD-D, DVD-R DL, DVD+R,  DVD+R DL, DVD-RW, DVD+RW,  DVD-RW DL, DVD+RW DL, DVD-RAM Blu-ray Disc: BD-R, BD-RE HD DVD: HD DVD-R: HD DVD-RAM UDO UMD Holographic data storage 3D optical data storage History of optical storage media
Standards
Rainbow Books File systems ISO 9660 Joliet Rock Ridge Amiga Rock Ridge extensions El Torito Apple ISO9660 Extensions Universal Disk Format Mount Rainier

HD DVD or High-Definition DVD is a high-density optical disc format designed for the storage of data and high-definition video.

Overview

The HD (High-Definition) DVD standard is designed to be the successor to the standard DVD format, and is derived from the same underlying technologies. It can store about 3 1/2 times as much data as its predecessor (Maximum capacity: 30 GB instead of 8.5 GB). A 51 GB triple-layer preliminary spec has been approved. However, no movies are currently scheduled for this disc type.

HD DVD is currently in a "format war" with rival format Blu-ray Disc, to determine which of the two formats will become the leading carrier for high-definition content to consumers.

As of October 16 2007, 311 HD DVD titles have been released in the USA.^[5] As of 15 September 2007, 133 HD DVD titles has been released in Japan, while 21 titles pending to be released.^[6]

History

The HD DVD standard was jointly developed by Toshiba and NEC.^[7] On 19 November 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).

On 31 March 2006, Toshiba released their first HD DVD player in Japan at ¥110,000 (US$934).^[8]. That was the first HD player available to consumers, beating Blu-Ray to the market.^[9] HD DVD was released in United States on 18 April 2006,^[10] with players priced at $499 and $799.

The first HD DVD titles were released on April 18 2006. They were The Last Samurai, Million Dollar Baby, The Phantom of the Opera by Warner Home Video and Serenity by Universal Studios.^[11] The first independent HD film released on HD DVD was One Six Right.^[12][13]

In December 2006, Toshiba reported that roughly 120,000 Toshiba branded HD DVD players have been sold in the U.S. along with 150,000 units coming in the form of HD DVD upgrade kits for the Xbox 360.^[14]

As of 18 April 2007, (on the first “birthday” of HD DVD),^[15] the HD DVD camp reported that they had sold 100,000 dedicated HD DVD units in the U.S. alone, (that is standalone players only, it does not include any computers with HD DVD drives or Xbox 360 add-ons drives—the latter was reported to have sold 92,000 units during the Christmas holiday season alone).^[16]

On January 29 2007, Microsoft released Windows Vista which supports the HD DVD format, including DRM requirements for playing back commercial content.

The first HD DVD Recorders were released mid 2007 in Japan.^[17]

Technical specifications

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 specification is not yet finalized.

Disc structure

HD DVD-ROM has a single-layer capacity of 15 GB, a dual-layer capacity of 30 GB, and a 51 GB single-sided triple-layer disc (which uses slightly bigger 17 GB layers), approved in September 2007 by the DVD Forum. Toshiba has claimed that all existing and future players should be compatible with the triple layer.^[18]

HD DVD-R and HD DVD-RW has a single-layer capacity of 15 GB, a dual-layer capacity of 30 GB. The HD DVD-RAM has a single-layer capacity of 20 GB.^[19] Like the original DVD format, the data layer of an HD DVD disc is 0.6 mm below the surface physically protecting the data layer from damage. The numerical aperture of the optical pick-up head is 0.65, compared with 0.6 for DVD. All HD DVD players are backward compatible with DVD and CD.

Physical size	Single layer capacity	Dual layer capacity	Triple layer capacity
12 cm, single sided	15 GB	30 GB	51 GB
12 cm, double sided	30 GB	60 GB	unknown
8 cm, single sided	4.7 GB	9.4 GB	unknown
8 cm, double sided	9.4 GB	18.8 GB	unknown

File systems

Like previous optical disc formats, HD DVD supports several file systems, like ISO 9660 and Universal Disk Format (UDF). Currently, all HD DVD titles use UDF version 2.5 as the file system.

Audio

HD DVD discs support encoding in up to 24-bit/192 kHz for two channels, or up to eight channels of up to 24-bit/96 kHz encoding.^[20] For reference, even new big-budget Hollywood films are mastered in only 24-bit/48 kHz, with 16-bit/48 kHz being common for ordinary films.

All HD DVD players are required to decode linear (uncompressed) PCM, Dolby Digital AC-3, Dolby Digital EX, DTS, Dolby Digital Plus and Dolby TrueHD.^[21] A secondary soundtrack, if present, can be stored in any of the aforementioned formats, or in one of the HD DVD optional codecs: DTS-HD High Resolution Audio and DTS-HD Master Audio.

For the highest-fidelity audio experience, HD DVD offers content-producers the choice of linear PCM, Dolby TrueHD and DTS-HD Master Audio. Due to the high-bandwidth requirements of linear-PCM, lossless audio on HD DVD movies has thus far been delivered in the lossless format Dolby True-HD.

Video

The HD DVD format supports a wide variety of resolutions, from low-resolution CIF and SDTV, all video resolutions supported by the DVD-Video standard, and up to HDTV formats such as 720p, 1080i and 1080p.^[20] HD DVD supports video encoded in MPEG2 which is what is used in DVDs as well as the new formats VC-1 and AVC which are more efficient. All movie titles released so far have had the feature encoded in 1080p, with most supplements in 480i or 480p. Almost all titles are encoded with VC-1, and most of the remaining titles encoded with AVC.

Digital rights management

Main article: Advanced Access Content System

HD DVD content is protected by the Advanced Access Content System (AACS) a standard for content distribution and digital rights management. It is developed by AACS Licensing Administrator, LLC (AACS LA), a consortium that includes Disney, Intel, Microsoft, Matsushita (Panasonic), Warner Brothers, IBM, Toshiba and Sony. One of the advantages over CSS, the content restriction system for DVDs, is that AACS allows content providers to revoke an individual player device if its cryptographic keys have been compromised (meaning that it will not be able to decrypt subsequently released content). There is no Region Coding in the existing HD DVD specification, which means that titles from any country can be played in players in any other country. This is likely to give the format some advantage in Europe and other places where consumers are now used to using multi-region players to play DVDs purchased in the US or through the extensive grey market.

Since appearing in devices in 2006, several successful attacks have been made on the format. The first known attack relied on the trusted client problem. In addition, decryption keys have been extracted from a weakly protected player (WinDVD). Notably, a Processing Key was found that could be used to decrypt all HD content that had been released at the time.^[22] The processing key was widely published on the Internet after it was found and the AACS LA sent multiple DMCA takedown notices in the aim of censoring it.^[23] This caused trouble on some sites that rely on user-submitted content, like Digg and Wikipedia, when administrators tried to remove any mentions of the key.^[24][25]

For more details on this topic, see AACS encryption key controversy.

AACS has also been circumvented by SlySoft with their program AnyDVD HD, which allows users to watch HD DVD movies on non-HDCP-compliant PC hardware. Slysoft has stated that AnyDVD HD uses several different mechanisms to disable the encryption, and is not dependent on the use of a single compromised encryption key.^[26]

Interactive content

HD DVDs use the HDi Interactive Format to allow interactive content to be authored for discs. HDi is based on web technologies such as HTML, XML, CSS, SMIL, and ECMAScript (JavaScript), so authoring in HDi should be a fairly easy transition for web developers. No existing DVD authoring experience is required. In contrast, Blu-ray Disc content is authored using either a scripting environment for basic content, or a Java-based platform (BD-J) for advanced content. DVD video discs utilize pre-rendered MPEG segments, selectable subtitle pictures, and simple programmatic navigation which is considerably more primitive.

Hardware

Compatibility

Backward compatibility will be available with all HD DVD players, allowing users to have a single player in their homes to play all types of HD DVD, DVD and CD discs. There is also a hybrid HD DVD format which contains both DVD and HD DVD versions of the same movie on a single disc, providing smoother transition for the studios in terms of publishing movies, and letting consumers with only DVD drives still use the discs. DVD disc replication companies can continue using their current production equipment with only minor alterations when changing over to the format of HD DVD replication. Due to the structure of the single-lens optical head, both red and blue laser diodes can be used in smaller, more compact HD DVD players.

List of HD DVD devices

Device name	Manufacturer	Type of device	Release date	Approximate price
Toshiba HD-A1	Toshiba	standalone player	April 18 2006
Toshiba HD-XA1 (also known as HDV5000)	Toshiba	standalone player	April 18 2006
Toshiba HD-A2	Toshiba	standalone player	2006 Q4	US$299.99
Toshiba HD-XA2	Toshiba	standalone player	2006 Q4	US$999.99[26]
Toshiba HD-A20	Toshiba	standalone player	January 7 2007	$499[27]
Toshiba HD-A3	Toshiba	standalone player	October 2007	US$299.99[28]
Toshiba HD-A30	Toshiba	standalone player	September 2007	US$399.99[28]
Toshiba HD-A35	Toshiba	standalone player	October 2007	US$499.99[28]
DV-HD805	Onkyo	standalone player	fall 2007	US$899
DV-HD805	Onkyo	standalone player	fall 2007	US$899
SHD7000	Venturer Electronics	standalone player	end of 2007[29]	US$199[30]
VidaBox MAX and VidaBox LUX	VidaBox	home theater PC (supports both Blu-ray and HD DVD)[31]
BH-100	LG Electronics	standalone player (supports both Blu-ray and HD DVD)	January 7 2007	US$1,199[32]
BH-200	LG Electronics	standalone player (supports both Blu-ray and HD DVD)	scheduled for October 2007	US$999[33]
BD-UP5000[34]	Samsung Group	standalone player (supports both Blu-ray and HD DVD)	scheduled for December 2007
Qosmio 35	Toshiba	Laptop computer	May 16 2006
HR-1100A	NEC	PC drive (OEM usage only)
HDV-ROM2.4FB	Buffalo Technology	PC drive	October 10 2006	US$320
GGW-H10N	LG Electronics (LGE)	PC drive (supports both Blu-ray and HD DVD)		US$1200[35]
Xbox 360 add-on external HD DVD drive	Microsoft	Video game console accessory (can be connected to PCs as well)		US$179
Qosmio G45	Toshiba	Laptop computer with DVD-R drive
Satellite X200	Toshiba	Laptop computer with DVD-R drive
HP Pavilion dv9500/9600t series	HP	Laptop computer (optional HD DVD-R drive)
HP Pavilion HDX series	HP	Laptop computer (optional HD DVD-ROM drive)	26 July 2007	ranging from $2,999
HP Pavilion PC series	HP	Desktop Computer (can be customised to include combo HD DVD-ROM/BD-RE)
Asus	Asus	Laptop computer
Acer	Acer	Laptop computer
Rock	Rock UK	Laptop computer (standard HD DVD-ROM drive for all DirectX 10 compatible)

Toshiba is expected to reveal the first portable HD DVD player at the 2008 CES show.

Xbox 360

Released at the end of November 2006, the Microsoft HD DVD drive for the Xbox 360 game-console gives the Xbox 360 the ability to play HD DVD movies. The drive was announced with an MSRP of US$199, and included Peter Jackson's King Kong on HD DVD along with a USB 2.0 cable for connection to the console. Many view the HD DVD add-on drive for the Xbox 360 as Microsoft's response to Sony's PlayStation 3 game-console, which plays competing Blu-ray Disc movies out of the box. The original Xbox 360 Core and Premium bundles did not offer HDMI/DVI-D outputs. In April 2007, Microsoft introduced the Xbox 360 Elite, which includes an HDMI 1.2 output port (and larger hard-drive). HD DVD Video output at the highest supported resolution (1080p) requires a display with HDMI or VGA input. For audio output, the Xbox 360 is limited compared to standalone players—the analog stereo-audio jack outputs a Pro-logic compatible downmix of the movie's audiotrack. The TOSLINK (S/PDIF) jack offers more choice: 2-channel LPCM 48 kHz/16-bit stereo (Pro-logic compatible), Dolby Digital (AC-3) @ 640 kbit/s, DTS @ 1500 kbit/s, or WMA Pro @ 1500 kbit/s. The console handles transcoding, if necessary, so a movie soundtrack of any type (Dolby TrueHD, Dolby DD+/AC-3, DTS, LPCM) will be output in the selected format. The HDMI-output on Xbox 360 Elite does not support multichannel LPCM—the Elite is limited to the same output choices as the non-HDMI 360 models.

The Xbox 360's add-on HD DVD drive can also be used with a desktop/laptop PC running Windows XP or Windows Vista. Although PC use is not officially supported, third-party player software can successfully play HD DVD movies using the add-on drive. A number of users buy the HD DVD add-on drive to use exclusively with their PCs because of the cheap price when compared to HD DVD drives made for PCs. For best experience, HD DVD player software requires a modern PC, with a DirectX 9 graphics adapter and dual-core or fast CPU. If the video is output to a DVI/HDMI port, then both the display and graphics processing unit must be HDCP-compliant.

The Xbox 360's add-on HD DVD is recognized on Macintosh computers running Mac OS 10.4, but support for UDF 2.5 does not exist for the platform. Standard DVDs and CDs can be read with the drive, but not HD DVDs. The beta version of Mac OS 10.5 "Leopard" includes Apple's UDF 2.5 driver.

The Xbox 360 HD DVD add-on drive is sold at retailers in the white color of the Xbox 360 Core/Premium. No announcements have been made by Microsoft to release this product in other colors to the general public.

Corporate and industry support

HD DVD Promotion Group Member List contains the main promoters of HD DVD, namely Toshiba, NEC, Sanyo, Microsoft, RCA, Kenwood, Intel, Venturer Electronics and Memory-Tech Corporation. The HD DVD format is also non-exclusively supported by Acer, HP, Hitachi Maxell, LG, Lite On, Onkyo, Meridian, Samsung,^[36] and Alpine.

In terms of major studios in North America, HD DVD is currently exclusively backed by Universal Studios (including subsidiaries Focus Features and Rogue Pictures), Paramount Pictures (including Paramount Vantage, Nickelodeon Movies, MTV Films, DreamWorks Pictures and DreamWorks Animation), The Weinstein Company (including Dimension Films), and First Look Studios.

The format is non-exclusively backed by Warner Bros. Pictures (it should be noted that a number of Warner's titles—Batman Begins, Constantine, Troy (excluding Troy: Director's Cut), V for Vendetta, The Perfect Storm, Poseidon, , The Matrix Trilogy—are HD DVD exclusive at the present), New Line Cinema (it should be noted that some of New Line Cinema titles, the first being Hairspray, are announced as Blu-ray exclusive for limited time due to lack of region coding in HD DVD^{[37] [38] [39]}. All catalog titles will be released simultaneously in both formats), HBO, and Image Entertainment (including the Discovery Channel),^[40] Magnolia Pictures,^[41] Brentwood Home Video, Ryko, Koch/Goldhil Entertainment.^[42]

In Europe HD DVD is currently supported either exclusively or non-exclusively by Medusa Home Entertainment, Studio Canal, Universum Films, Kinowelt Home Entertainment, DVD International, Opus Arte, MK2, Momentum Pictures, Twister Home Video, and many others ^[43]. Many titles that are Blu-ray exclusive in the United States are released on HD DVD in Europe, and can be played on any US player due to the absence of region coding on HD DVD^[44]. Likewise, movies that are HD DVD exclusive in the United States are released in either exclusive to a format or released to both formats in other region, to be made easier because some of region-coded discs are actually region-free^[45]. For example, Universal's Bruce Almighty, a European exclusive to Blu-ray, is compatible to region A player.

In the Music Industry, HD DVD is currently exclusively supported by EMI and non exclusively supported by Warner Music Group^[46] and Universal Music Group^[47]

In the adult-movie, HD DVD is currently exclusively backed by Wicked Pictures, Pink Visual, Bang Bros, Digital Playground Inc. and ClubJenna Inc. (which on 22 June 2006 was acquired by Playboy Enterprises). Contrary to many internet blogs, it has been reported by ABC News that the porn industry will not be a factor in the current format war.^[48]. The main reason is that many pornographic websites have movie downloads as an option, thus making the disc format less important.

Beginning July 2007, Blockbuster Video^[49] will be carrying Blu-ray Disc in 1,450 stores, in addition to the original 250 that carried both HD DVD and Blu-ray. Online they will still be offering both formats.^[50] Blockbuster will continue to offer both formats at its initial 250 stores that currently carry both high-definition formats.^[51]

On August 20, 2007, Paramount Pictures, DreamWorks Pictures, and DreamWorks Animation announced their exclusive support for the HD DVD format citing its cost benefits and superior features. However, in contrast to this the New York Times reported, citing two Viacom executives that a payoff had occurred for a sum of $150 million for a period of 18 months exclusivity. Paramount has neither denied or confirmed this, however Paramount's CTO Alan Bell said it was an indefinite commitment. Both Microsoft and Toshiba have denied that such a payoff occurred. Films directed by Steven Spielberg are excluded from this announcement as he controls the rights to his own works.^[52]

HD DVD / Blu-ray disc comparison

Main article: Comparison of high definition optical disc formats

The primary rival to HD DVD is Blu-ray Disc. Currently, Blu-ray has the advantage in maximum disc capacity, but in September 2007 the DVD Forum approved the triple layer 51GB HD DVD-ROM disc. As of 2007, the 51 GB HD DVD disc has only a preliminary specification, and no titles have been released. The first 50 GB dual-layer Blu-ray Disc release was movie Click, on October 10 2006, several months after the Blu-ray Disc format was released. As of September 2007 40% of Blu-ray titles use the 50 GB disc and 60% use the 25 GB disc^[53] while almost all HD DVD movies are in the 30 GB dual layer format.^[54]

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 older and less efficient 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 3.0 Mbit/s, but for Blu-ray players it is optional at 1.7 Mbit/s.^[21] 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.^[55] 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.

A Table Comparing the High-definition Optical Media Formats
DVD included for comparison

Mandatory codecs must be supported by the player. Each disc must use one or more of the mandatory codecs.

•  • [ e]			Blu-ray Disc	HD DVD	DVD
Laser wavelength			405 nm (blue-violet laser)		650 nm (red laser)
Numerical aperture			0.85	0.65	0.6
Storage capacity	single layer		25 GB	15 GB	4.7 GB
	dual layer		50 GB	30 GB	8.5 GB
Playback time in (video only)[1]	SD with MPEG-2 at 5 Mbit/s		22.2 hours	13.3 hours	3.8 hours
	HD with	AVC or VC-1 at 13 Mbit/s	8.5 hours	5.1 hours	N/A
		MPEG-2 at 20 Mbit/s	5.6 hours	3.3 hours	N/A
Mandatory Video codecs			MPEG-4 AVC (H.264) / VC-1 / MPEG-2		MPEG-1 / MPEG-2
Audio codecs	lossy	Dolby Digital	Mandatory @ 640 Kbit/s	Mandatory @ 504 Kbit/s	Mandatory @ 448 Kbit/s
		DTS	Mandatory @ 1.5 Mbit/s	Mandatory @ 1.5 Mbit/s	Optional @ 1.5 Mbit/s
		Dolby Digital Plus[2]	Optional @ 1.7 Mbit/s	Mandatory @ 3.0 Mbit/s	N/A
		DTS-HD High Resolution	Optional @ 6.0 Mbit/s	Optional @ 3.0 Mbit/s	N/A
	lossless	Linear PCM	Mandatory	Mandatory	Mandatory
		Dolby TrueHD	Optional	Mandatory[3]	N/A
		DTS-HD Master Audio	Optional @ 24.0 Mbit/s	Optional @ 18.0 Mbit/s	N/A
Maximum bitrate	Raw data transfer		53.95 Mbit/s	36.55 Mbit/s	11.08 Mbit/s
	Audio+Video		48.0 Mbit/s	30.24 Mbit/s	10.08 Mbit/s
	Video		40.0 Mbit/s	29.4 Mbit/s	9.8 Mbit/s
Secondary video decoder (PiP)			Optional (Profile 1.1)[4]	Mandatory	N/A
Secondary audio decoder			Optional (Profile 1.1)	Mandatory	N/A
Interactivity			Blu-ray Disc Java	HDi Interactive Format	N/A
Internet support			Optional (Profile 2.0)	Mandatory	N/A
Video resolution (maximum)			19201080 24p or 50/60i HDTV	19201080 24/25/30p or 50/60i HDTV	720480 60i and 720576 50i SDTV
Content protection system			AACS-128bit / BD+	AACS-128bit	CSS 40-bit
Region code			3 Regions	Region free	6 Regions
Hardcoating of disc			Mandatory	Optional	Optional

^ a Playback times are quoted for dual layer discs, for single layer discs divide by two. The numbers represent video only and the choice of audio codec and extra content also affects playback time.
^ b All HD DVD players are required to be able to decode Dolby TrueHD to two channels, however all current players support 5.1 channel decoding.^{[56] [57]}
^ c Secondary video decoder will become mandatory for new Blu-ray Disc players with Profile 1.1 on October 31 2007.
^ d On Blu-ray, Dolby Digital Plus (DD+) must be accompanied by a primary Dolby Digital (DD) 5.1 audiotrack. 640 Kbit/s is allocated to the primary DD 5.1 audiotrack (which is independently playable on players that do not support DD+), and 1 Mbit/s is allocated for the 'extension' DD+ bitstream. Furthermore, the DD+ audiotrack itself may only carry additional channel-information, and hence, Blu-ray DD+ may only be used for 6.1/7.1 audiotracks. On HD DVD, Dolby Digital Plus may be used in any legal channel configuration (up to 7.1), at any supported bitrate up to the maximum of 3 Mbit/s

Continuing development

Although the HD DVD standard is final, engineers continue developing the technology. At the CES 2007, Ritek revealed their high definition optical disc process extended both competing high definition formats to ten layers, increasing capacity to 150 GB for HD DVD, however, the major obstacle is that current reader-writer technology may not support the additional data layers.^[58]

NEC,^[59] Broadcom,^[60] Horizon Semiconductors, and STMicroelectronics^[60] have separately developed a single chip/laser that can read both the HD DVD and the Blu-ray disc standard. Broadcom and STMicroelectronics will be selling their dual-format single chip/laser solution to any OEM willing to develop a product based on the chip.

Variants

DVD / HD DVD hybrid discs

There are two types of hybrid formats which contain standard DVD-Video format video for playback in regular DVD players, and HD DVD video for playback in high definition on HD DVD players. The Combo disc is a dual sided disc with one side DVD and the other HD DVD, each of which can have up to two layers. The Twin disc is a single sided disc that can have up to three layers, with up to two layers dedicated to either DVD or HD DVD.^[61] These hybrid discs make retail marketing and shelf space management easier. Another advantage is hardware cross-compatibility. The average consumer doesn't have to worry about whether or not they can play a hybrid DVD disc: any standard home DVD player can access the DVD encoded content and any HD DVD player can access both the DVD and the HD DVD encoded content.

HD DVD / Blu-Ray hybrid discs

Warner Bros. officially announced Total Hi Def (THD) at CES 2007. Total Hi Def (Total HD) hybrid discs supports both HD DVD and Blu-ray, HD DVD on one side (up to two layers) and Blu-ray on the other side (up to two layers). Despite initially announcing that Total HD would be ready by the second half of 2007, on June 27 2007, Warner Bros. issued a press release stating that they would be delaying the launch of Total HD discs until early 2008. As of September 2007, no specific titles have yet been announced.

3x DVD

The HD DVD format also applies to current red laser DVDs, which offers a low-cost option for distributors; this type of disc is called "3x DVD", as it is capable of three times the bandwidth of regular DVD-Video.

3x DVDs are physically identical to normal DVDs, thus why the cost is lower for the physical medium. Although 3x DVDs provide the same high definition content, their playback time is less. For instance, on an 8.5 GB DVD you could fit about 85 minutes of 1080p video encoded with VC-1 or AVC at an average bitrate of 13 Mbit/s, suitable for short subjects (training films, home movies), but unsuitable for feature film-length content.

It is technically possible for consumers to create HD DVD compatible discs using low cost DVD-R or DVD+R media. At least one such guide exists.^[62]

HD REC

HD Rec is an extension of the HD DVD format for storing HD content on regular red laser DVDs using H.264/MPEG-4 AVC compression.^[63] It was approved by the DVD Forum on September 12 2007 ^[64]

See also

• List of HD DVDs
• Competing technologies: Blu-ray Disc, EVD, FVD
• Dolby Digital Plus, one of the mandatory audio codecs for HD DVD hardware.
• 1080p, high-definition resolution supported by HD DVD and Blu-ray.^[65]
• Format war
• Comparison of high definition optical disc formats
• MUSE LD – an earlier optical disc which contained analog HDTV signals
• D-VHS - a tape-based format that allows recording of 720 or 1080 high-def DTV, while remaining compatible with older VHS libraries
• Advanced Interactivity Consortium

Alternative disc technologies

• Blu-ray Disc
• Enhanced Versatile Disc (EVD)
• Forward Versatile Disc (FVD)
• Professional Disc for DATA (PDD or ProDATA)
• Versatile Multilayer Disc
• Fluorescent Multilayer Disc
• Digital Multilayer Disk
• Holographic Versatile Disc – a proposed next-generation disc after HD DVD and Blu-ray
• 3D optical data storage - another next-generation technology
• Tapestry Media
• Ultra Density Optical
• AVCHD
• LS-R - a "layer selection" technology designed to allow large numbers of data layers in one disc.

References

External links

• HD DVD Promotion Group – International site
• The Look and Sound of Perfect - Promotional
• The Authoritative HD DVD FAQ by Hugh Bennett