HD DVD - Caracteristicas

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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 Toshiba and NEC.[2] 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. HD DVD stands for "High Definition Digital Versatile Disc".[1] The format had previously been called the "Advanced Optical Disc" (AOD). At CES[2] 2006, companies backing HD DVD said that nearly 200 titles would be available for the format by the end of the year. On 31 March 2006, Toshiba released their first HD DVD player in Japan at ¥110,000 ($934).[3] HD DVD was released in United States on 18 April 2006,[4] with players priced at $499 and $799. In November 2006 Microsoft released an external add-on HD DVD drive for the Xbox 360 game console which was previously announced at CES 2006. 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 not yet fully finalized. The first HD DVD-ROM drives were released in late 2006. HD DVD is currently in a format war with rival format Blu-ray Disc.

Disc structure HD DVD has a single-layer capacity of 15 GB and a dual-layer capacity of 30 GB, the HD DVD-RAM has a single-layer capacity of 20 GB and a dual-layer capacity of 40 GB. 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.

Hybrid formats There are two types of hybrid formats which contains 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 which is a dual sided disc with one side DVD and the other HD DVD, each of which have up to two layers. The Twin disc which is a single sided disc containing up to three layers, with up to two layers dedicated to either DVD or HD DVD.[5] These hybrid discs make retail marketing and shelf space management easier. This also removes some confusion from DVD buyers since they can now buy a disc compatible with any DVD/HD DVD player in their house.

3x DVD The HD DVD format also can be applied to current red laser DVDs which offers a lower-cost option for distributors; this type of disc is called "3x DVD" as it is capable of up to three times the bandwidth of regular DVD-Video. 3x DVDs are physically identical to regular DVDs, which explains why the cost is lower for the physical media. While 3x DVDs provide the same high definition content, the trade off is that playback time is limited. 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 13Mbit/s. This makes the format suitable for subjects such as training videos and home movies, but not suitable for typical wide release studio movies. It is technically possible for consumers to create HD DVD compatible discs using low cost DVD-R or DVD+R media. At least one guide has been written that walks users through authoring these discs.[6]

Ongoing development Although the HD DVD standard has been finalized, engineers continue working to advance the technology. At the Consumer Electronics Show in January 7, 2007, Toshiba and TDK announced that they have created HD DVDs with 17 GB layers, and demonstrated a triple-layer 51 GB disc.[7] Toshiba aims to secure approval of the new disc by the DVD Forum within this year. There is no guarantee that the triple-layer format will work in existing players as it was not part of the original mandatory specifications. Also behind closed doors at CES 2007, Ritek has revealed that they had successfully developed a High Definition optical disc process that extends the disc capacity of both competing formats to 10 layers. That increases the capacity of the discs to 150gb for HD DVD and 250gb for Blu-Ray. However, they noted that the major obstacle is that current reader and writer technology does not support the additional layers.[8]

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.[9] 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.[citation needed] 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.[10] 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.[9] 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 Commercialized HD DVDs integrate copy protection technology specified by AACS LA (Advanced Access Content System License Authority). "Audio Watermark Protection" is also being considered by AACS for use on HD DVD. If Watermark is adopted by AACS, all HD DVD players will have a sensor that listens for inaudible audio watermarks in the soundtrack of movies. Studios may insert this invisible mark in the soundtracks of theatrical motion pictures. If an HD DVD player does not detect the invisible mark, it means the disc is playing back a copy made from a theatrical print (probably from illegal camcording), and will cause the player to refuse to play the disc. The mark is made by varying the waveform of speech and music in a regular pattern to convey a digital code. These variations are too subtle to be heard by the human ear. Another variation of this system can be used to prevent the playback of discs created by using a camcorder and microphone on a home entertainment center playing a legitimate disc purchased by a consumer. This variation for home entertainment utilizes a watermark that differs from the cinema mark in that it is permitted in normal, signed ROM discs, but generally not permitted on recordable discs. In addition, HD DVD players must follow AACS guidelines pertaining to outputs over analog connections. This is set by a flag called the Image Constraint Token (ICT), which restricts the resolution for analog outputs without HDCP to 960×540. The decision to set the flag to restrict output ("down-convert") is left to the content provider. Warner Pictures is a proponent of ICT, and it is expected that Paramount and Universal will implement down-conversion as well.[11] As of March 2006, 5 of the 6 studios releasing HD DVD content have announced they will not use ICT/down-conversion for the time being.[12] AACS guidelines require that any title that implements the ICT must clearly state so on the packaging. There is no Region Coding in the existing HD DVD specification.

Muslix64's exploit On December 26, 2006 a person using the alias muslix64 published a utility named BackupHDDVD and its source code for a working AACS decryptor on the Doom9's Forums.[13] The program is not an exploit or hack per se. Rather it is a tool that can be used to decrypt AACS protected content once one knows the encryption key. As such, it is no surprise or indication of vulnerability that such a program is possible and it can be seen as merely an implementation of the publicly available[14] standard AACS specification. However, Muslix64 claims to have found title and volume keys in main memory while playing HD DVD discs using a software player, and that finding them is not difficult.[15] Details of how to do this were revealed later (January 12, 2007) by other doom9.org forum members that also found title and volume keys of several movies in main memory of a software player called WinDVD. Ironically, WinDVD is a program that comes standard with most Toshiba PCs and Notebooks. On January 2, 2007 "muslix64" published a new version of his/her program, with volume key support.[16] Cyberlink, developers of PowerDVD maintain that their software was not used as part of the exploit.[17] The claimed attack (extraction of the encryption keys from a software player) highlights the inherent weakness of software movie players for the PC platform. The use of encryption does not offer any true protection in this scenario since the software player must have the encryption key available somewhere in memory[citation needed] and there is no way to protect against a determined hacker extracting the encryption key (if everything else fails the user could run the program in a virtual machine making it possible to freeze the program and inspect all memory addresses without the program knowing).[citation needed] Avoiding such attacks would require changes to the PC platform (see Trusted Computing) or that the content distributors do not permit their content to be played on PCs at all (by not providing the companies making software players with the needed encryption keys). Alternatively, they could use the AACS system's revocation mechanism to revoke a specific software player after it is known to have been compromised. In that case, the compromised players could still be used to break old titles but not newer releases as they would be released without encryption keys for the compromised software players requiring hackers to break other players. The latter alternative is not a desirable option, because it would result in legitimate users of compromised players being forced to upgrade or replace their player software in order to view new titles. On or about January 13, 2007 a title key was posted on pastebin.com in form of a riddle, which was solved by entering terms in Google search engine, which revealed a number of search results. By converting these results to hexadecimal, a correct key could be formed. This was also reported on by Slashdot.[18] Later that day, the first pirated HD DVD, Serenity, was uploaded on a private torrent tracker.[citation needed] On January 26, 2007 the Advanced Access Content System (AACS) Licensing Authority confirmed that the encryption on high-definition DVDs has been bypassed.[19] On March 4, 2007 the user "jx6bpm" on doom9.org's forums claimed to reveal Cyberlink's PowerDVD's key, claiming this was the key in use by AnyDVD.[20]

AnyDVD HD SlySoft has released AnyDVD HD which allows users to watch HD DVD movies on non-HDCP-compliant PC hardware. The movies can be decrypted on the fly directly from the HD DVD, or can be copied to another medium. AnyDVD HD is also capable of automatically removing any unwanted logos and trailers. Slysoft has stated that AnyDVD HD uses several different mechanisms to disable the encryption, and is not dependent on the use of compromised encryption keys. They have also stated that AACS has even more flaws in its implementation than CSS; this renders it highly vulnerable,[21] but they will release no details on their implementation. Users at Doom9 claim that the program makes use of the host certificate of PowerDVD version 6.5,[22] but SlySoft have claimed that the program would be unaffected by the AACS revocation system.[23] 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.

Xbox 360

Microsoft has also released an add-on HD DVD drive for the Xbox 360 which attaches to the console via a USB 2.0 cable. The drive was released at the end of November 2006 for US$199.99 and was sold out in both online and retail stores. As of January 2007 it has sold more than 100,000 units. Many view the add-on as Microsoft's answer to the PlayStation 3 which includes a Blu-ray Disc player, HD DVD's main competitor. The Xbox 360 does not currently offer HDMI or DVI outputs, but the Xbox 360 Elite updated hardware version (due for release in April 2007) will have an HDMI 1.2 output (and offer a DVI converter cable for that). HD DVDs can be viewed at 720p or 1080i through component cables and up to 1080p with VGA cables, (the previously mentioned "Xbox 360 Elite" will also support 1080p output via HDMI and DVI). The add-on HD DVD drive does support TrueHD lossless audio and DTS found on some HD DVD's, but all audio is transcoded to 640kbps Dolby Digital. The add-on HD DVD drive for the Xbox 360 can also connect to a PC using the supplied USB 2.0 cable. Using this, combined with a software that supports playing HD DVDs (such as Cyberlink PowerDVD Ultra or WinDVD 8) and hardware that meets minimum requirements (HDCP-compliant graphics processing unit and display if using DVI or HDMI, relatively high-performance PC), it is possible to use the drive for 1080p HD DVD playback on a PC. Though the Xbox 360 HD DVD add-on is sold at retailers in the White color of the Xbox 360 Core/Premium, there were a few Black HD DVD add-ons made for Microsoft employees. This matched the color of the Xbox 360 Elite. The Universal media remote was also in black. No announcements have been made by Microsoft to release this product to the general public, although a few units have been leaked onto ebay, though it would cost more than the $199.99 price of the white one.

Corporate and industry support HD DVD is promoted by Toshiba, NEC, Sanyo, HP, Microsoft, RCA, Hitachi, Kenwood, and Intel. The HD DVD format is also non-exclusively supported by LG, Lite On, Onkyo, Meridan, Samsung[39], and Alpine. In terms of major studios In North America, HD DVD is currently exclusively backed by Universal Studios (including subsidiaries Rogue Pictures, Focus Features and Polygram Filmed Entertainment) , The Weinstein Company/Dimension Films (through Genius Products), and First Look Studios. The format is non-exclusively backed by Paramount Pictures, DreamWorks, Warner Bros. Pictures (Although it should be noted that a number of Warner's titles (Batman Begins, V for Vendetta, The Perfect Storm, Troy, Poseiedon, Terminator 3: Rise of the Machines and The Matrix Trilogy) are HD DVD exclusive till further notice), Warner Music Group, New Line Cinema, HBO, Studio Canal, and Image Entertainment (including the Discovery Channel),[40] Magnolia Pictures,[41] Brentwood Home Video, Ryko, Koch/Goldhil Entertainment,[42] . HD DVD does have more studio support worldwide, especially in Europe. Also with history as a reference, the adult-movie/pornography industry may have a big influence in the HD DVD versus Blu-ray format war, at least when it comes to home rental and retail purchases or pressed movies as it generates multi-billion annual revenue worldwide, (with US$57 billion in annual revenue worldwide reported in May, 2006).[43] HD DVD is currently exclusively backed by several adult-movie/pornography studios/publishers, including Wicked Pictures, Pink Visual, Bang Bros, Digital Playground Inc. and ClubJenna Inc. (which on 22 June 2006 was acquired by Playboy Enterprises), and HD DVD is also non-exclusively backed by Vivid Entertainment. Hybrid player technology NEC,[44] Broadcom,[45] and STMicroelectronics[46] 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 anyone willing to OEM a product based on the chip. Hybrid media/discs On the media disc side, 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). Warner Bros. stated at their press conference that first Total HD releases will come out in the second half of 2007, no specific titles have yet been announced. HD DVD / Blu-ray disc comparison Main article: Comparison of high definition optical disc formats 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 of Blu-ray titles released before 2007 are in the 25 GB single layer format while almost all HD DVD movies are in the 30 GB dual layer format. [47] The first 50GB release for Blu-Ray was not made until November 2006. So far in 2007 approx half of the new releases for Blu-ray movies were released in 25GB Discs with the other half being released in 50GB dual layer format.[48] 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.[10] 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.[49] 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.