Blu Ray VS HD DVD

Blu-ray Disc
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Blu-ray Disc


Media type:
High-density optical disc
Encoding:
MPEG-2, MPEG-4 AVC (H.264), and VC-1
Capacity:
25 GB (single layer), 50 GB (dual layer)
Read mechanism:
1x@36 Mbit/s & 2x@72 Mbit/s
Developed by:
Blu-ray Disc Association
Usage:
Data storage, High-definition video and PlayStation 3 Games
A Blu-ray Disc is a high-density optical disc format for the storage of digital information, including high-definition video.
Contents[hide]
1 Overview
2 History
3 Disc structure
3.1 Laser and optics
3.2 Hard-coating technology
4 Software standards
4.1 Codecs
4.2 Java software support
4.3 Region codes
4.4 Digital rights management (DRM)
5 Player profiles
6 Backward compatibility
7 List of Blu-ray devices
8 Corporate support
9 Blu-ray Disc / HD DVD comparison
10 Ongoing development
11 Variants
11.1 BD9 / Mini-Blu-ray Disc
11.2 AVCREC
11.3 Blu-ray Disc recordable
11.4 HD DVD / Blu-Ray hybrid discs
12 See also
12.1 Alternative disc technologies
13 References
14 External links
14.1 News
//

[edit] Overview
Optical disc authoring
Optical disc
Optical disc image
Optical disc drive
Authoring software
Recording technologies
Recording modes
Packet writing
Optical media types
Laserdisc
Compact disc (CD): CD-Audio, PhotoCD, CD-R, CD-ROM, CD-RW, Video CD, SVCD, CD+G, CD-Text, CD-ROM XA, CD-Extra, CD-i Bridge, CD-i
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-RW, 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

A blank rewritable Blu-ray disc (a BD-RE)
The name Blu-ray Disc is derived from the blue-violet laser used to read and write this type of disc. Because of its shorter wavelength (405 nm), substantially more data can be stored on a Blu-ray Disc than on the DVD format, which uses a red (650 nm) laser. A single layer Blu-ray Disc can store 25 gigabytes (GB), over five times the size of a single layer DVD at 4.7 GB. A dual layer Blu-ray Disc can store 50 GB, almost six times the size of a dual layer DVD at 8.5 GB.
Blu-ray was developed by the Blu-ray Disc Association, a group of leading companies representing consumer electronics, computer hardware, and motion picture production. The standard is covered by several patents belonging to different companies. As of March 2007, a joint licensing agreement for all the relevant patents has not yet been finalized.[1]
As of October 23, 2007, 351[2] titles have been released on Blu-ray Disc in the United States (32 of those titles have since been discontinued). As of October 9, 2007, 179 titles have been released in Japan, with 55 titles planned for release.[3]
The Blu-ray standard is currently in a format war with its rival HD DVD, to determine which (if either) of the two formats will become the leading carrier for high-definition content to consumers.

[edit] History
In the mid 1990s, commercial HDTV sets were finally starting to enter a larger market. However, there was no good, cheap way to record or play back HD content. There was no cheap storage medium that could store that amount of data, except JVC's Digital VHS and Sony's HD Betacam.[4] However, it was well known that using lasers with shorter wavelengths would yield optical storage with higher density. When Shuji Nakamura invented practical blue laser diodes, it was a sensation, although a lengthy patent lawsuit delayed commercial introduction.[5]
Sony started two projects applying the new diodes: UDO (Ultra Density Optical) and DVR Blue (together with Pioneer), a format of rewritable discs which would eventually become Blu-ray (more specifically, BD-RE).[6] The core technologies of the formats are essentially similar.
The first DVR Blue prototypes were unveiled at the CEATEC exhibition in October 2000.[7] Because the Blu-ray Disc standard places the data recording layer close to the surface of the disc, early discs were susceptible to contamination and scratches and had to be enclosed in plastic cartridges for protection. In February 2002, the project was officially announced as Blu-ray,[8] and the Blu-ray Disc Association was founded by the nine initial members.
The first consumer devices were in stores on April 10 the next year. It was the Sony BDZ-S77 a BD-RE recorder that was only made available in Japan. The recommended price was US$3800.[9] However, there was no standard for pre-recorded video (BD-ROM); no movies were released for that player. That standard was still years away, since a new and secure DRM system was needed before Hollywood studios would accept it. Nobody wanted to repeat the failure of the Content Scramble System for DVDs.
The DVD Forum (which was chaired by Toshiba) was deeply split over whether to go with the more expensive blue lasers or not. In March 2002, the forum voted to approve a proposal endorsed by Warner Bros. and other motion picture studios that involved compressing HD content onto dual-layer DVD-9 discs.[10][11] However, in spite of this decision, the DVD Forum's Steering Committee announced in April that it was pursuing its own blue-laser high-definition solution.[12] In August, Toshiba and NEC announced their competing standard Advanced Optical Disc.[13] It was finally adopted by the DVD forum and renamed to HD DVD the next year,[14] after being voted down twice by Blu-ray Disc Association members, prompting the U.S. Department of Justice to make preliminary investigations into the situation.[15][16] Three new members had to be invited and the voting rules changed before the vote finally passed.[17][18]
In the mean time, Sony spun off Professional Disc for DATA from the Blu-ray project. It was essentially Blu-ray with higher-quality media and components. The devices were too expensive for the consumer mass market. Instead, it was aimed at the professional data storage space market as a replacement for their line of 5.25" MO drives. It was announced in October 2003, with the first devices shipping in December of the same year.[19][20]
The costs of a format war are large, both for consumers and for the industry. In an attempt to avoid that, Blu-ray Disc Association and DVD Forum started to negotiate a compromise in early 2005. One of the issues was that the Blu-ray camp wanted to use a Java-based platform for interactivity (BD-J), while the DVD Forum was promoting Microsoft's "iHD" (which became HDi).[21] A much larger issue, though, was the physical formats of the discs themselves; the Blu-ray member companies did not want to risk losing billions of dollars in royalties as they had done with standard DVD.[22] An agreement seemed close, but negotiations proceeded slowly.[23]
At the end of June 2005, Sun announced that the Blu-ray Association had chosen the Java-based BD-J interactivity layer instead of Microsoft's HDi. This was based on a BDA board vote favouring BD-J 10 to 4, despite a technical committee previously favouring HDi by a vote of 7 to 5.[24] At the same time, Microsoft and Toshiba jointly announced that they would cooperate in developing high-definition DVD players.[25] In a top-level meeting in July, Microsoft's Bill Gates argued that the Blu-ray standard had to change to "work more smoothly with personal computers". The Blu-ray Disc Association's representatives defended the technology.[26]
On August 22, 2005, the Blu-ray Disc Association and DVD Forum announced that the negotiations to unify their standards had failed.[27] Rumours surfaced that an "unnamed partner" had pressured Toshiba to stick with HD DVD—in spite of Blu-ray's strong support among Hollywood studios and some analysts saying that HD DVD's days were numbered—but these rumours were denied by the parties involved; instead, the same reasons of physical format incompatibility were cited.[22][26] At the end of September, Microsoft and Intel jointly announced their support for HD DVD.[28]
HP made a last attempt to broker a peace between with Blu-ray Disc Association and Microsoft. The company demanded that the Blu-ray association adopted Microsoft's HDi instead of its own Java solution, and that Blu-ray would adopt a mandatory managed copy feature. If the demands weren't met, HP threatened to support HD DVD instead.[29] In a research report, Gartner analysts Van Baker, Laura Behrens and Mike McGuire wrote that if HP's proposal was accepted, Blu-ray would become the winner of the format war.[30] However, the Blu-ray disc group did not accept HP's offer.[31]
The Blu-ray physical specifications were finished in 2004.[32] In January 2005, TDK announced that they had developed a hard coating polymer for Blu-ray discs.[33] The cartridges, no longer necessary, were scrapped. The BD-ROM specifications were finalized in early 2006.[34] AACS LA, a consortium founded in 2004,[35] had been developing the necessary DRM platform that could securely distribute movies to consumers. However, the final AACS standard was delayed,[36] and then delayed again when an important member of the Blu-ray group voiced concerns.[37] At the request of Toshiba, an interim standard was published which did not include some features, like managed copy.[38]
The first BD-ROM players were shipped in the middle of June 2006, though HD DVD players beat them in the race to the market by a few months.[39][40]
The first Blu-ray Disc titles were released on June 20, 2006. The earliest releases used MPEG-2 video compression. This is the compression method used on DVDs. The first releases using the newer VC-1 and AVC codecs were introduced in September 2006.[41] The first movies using dual layer discs (50 GB) were introduced in October 2006.[42]
The first mass-market Blu-ray rewritable drive for the PC was the BWU-100A, released by Sony on July 18, 2006. It recorded both single and dual layer BD-R as well as BD-RE discs and had a suggested retail price of US$699.
HD DVD had a head start, and the Blu-ray market was slow at first. The first Blu-ray player was perceived as expensive and buggy, and there were few titles available.[43] That changed when PlayStation 3 launched, since every PS3 unit also functioned as a Blu-ray player. In February 2007, Blu-ray discs had outsold HD DVDs.[44] During the first three quarters of 2007, BD discs outsold HD DVDs by about two to one.[45]
In May 2007, Target Technology sued Sony, claiming that Blu-ray technology infringed on their patent on reflective-layer materials for optical discs.[46]

[edit] Disc structure

[edit] Laser and optics
Like its rival format HD DVD, Blu-ray uses a "blue" (technically violet) laser operating at a wavelength of 405 nm to read and write data. Conventional DVDs and CDs use red and infared lasers at 650 nm and 780 nm respectively.
The blue-violet laser's shorter wavelength makes it possible to store more information on a 12 cm CD/DVD sized disc. The minimum "spot size" on which a laser can be focused is limited by diffraction, and depends on the wavelength of the light and the numerical aperture of the lens used to focus it. By decreasing the wavelength, using a higher numerical aperture (0.85, compared with 0.6 for DVD), higher quality, dual-lens system, and making the cover layer thinner to avoid unwanted optical effects, the laser beam can be focused much more tightly at the disk surface. This produces a smaller spot on the disc and allows more information to be physically contained in the same area. In addition to the optical improvements, Blu-ray Discs feature improvements in data encoding, allowing for even more data to be packed in. (See Compact disc for information on optical discs' physical structure.)

[edit] Hard-coating technology
Since the Blu-ray data layer is closer to the surface of the disk, compared to the DVD standard, it was at first more vulnerable to scratches. The first discs were housed in cartridges for protection. Advances in polymer technology eventually made the caddies unnecessary.
TDK was the first company to develop a working scratch protection coating for Blu-ray discs. It was named Durabis. Both Sony and Panasonic replication methods include proprietary hard-coat technologies. Sony's rewritable media are sprayed with a scratch-resistant and antistatic coating. Verbatim recordable and rewritable Blu-ray Disc discs use their own proprietary hard-coat technology called ScratchGuard.

[edit] Software standards

[edit] Codecs
Codecs are compression schemes that reduce data storage requirements; both lossy and lossless compression techniques have been developed and are being used. Depending on the application, either can be used to greatly increase the amount of audio or video storable on fixed-bit-capacity media.
The BD-ROM specification mandates certain codec compatibilities for both hardware decoders (players) and the movie-software (content). For video, all players are required to support ISO MPEG-2, H.264/AVC, and SMPTE VC-1. MPEG-2 video allows decoder backward compatibility for DVDs. H.264, sometimes called MPEG-4 part 10, is a more recent video codec. VC-1 is a competing MPEG-4 derivative codec proposed by Microsoft (based on Microsoft's previous work in Windows Media 9). BD-ROM titles with video must store video using one of the three mandatory codecs (multiple codecs on a single title are allowed).
The initial version of Sony's Blu-ray Disc-authoring software shipped with support for only 1 video-codec: MPEG-2.[citation needed] Consequently, all launch titles were encoded in MPEG-2 video.[citation needed] A subsequent update allowed the content producers to author titles in any of the 3 supported codecs: MPEG-2, VC-1, or H.264.[citation needed] The choice of codecs affects the producer's licensing/royalty costs, as well as the title's maximum runtime (due to differences in compression efficiency).[citation needed] Discs encoded in MPEG-2 video typically limit content producers to around two hours of high-definition content on a single-layer (25 GB) BD-ROM. The more advanced video codecs (VC-1 and H.264) typically achieve a video runtime twice that of MPEG-2, with comparable quality.
For audio, BD-ROM players are required to support Dolby Digital AC-3, DTS, and Linear PCM (up to 7.1 channels). Dolby Digital Plus, and lossless formats Dolby TrueHD and DTS HD are player optional. BD-ROM titles must use one of mandatory schemes for the primary soundtrack (linear PCM, Dolby Digital, or DTS). A secondary audiotrack, if present, may use any of the mandatory or optional codecs.[47] If Dolby Digital Plus is used, it must be accompanied by an AC-3 soundtrack (which provides the "core" bitstream). For uncompressed PCM and lossless audio in Dolby TrueHD or DTS-HD Master Audio formats, Blu-ray Discs support encoding in up to 24-bit/192 kHz for a maximum of six channels, or up to eight channels with at most 24-bit/96 kHz sampling.[48]
For users recording digital television programming, the recordable Blu-ray Disc standard's datarate of 54 Mbit/s is more than adequate to record high-definition broadcasts from any source (IPTV, cable/satellite, or terrestrial). For Blu-ray Disc movies the maximum transfer rate is 48 Mbit/s (1.5x) (both audio and video payloads together), of which a maximum of 40 Mbit/s can be dedicated to video data. This compares favorably to the maximum of 36.55 Mbit/s in HD DVD movies for audio and video data.[49]

[edit] Java software support
Main article: BD-J
At the 2005 JavaOne trade show, it was announced that Sun Microsystems' Java cross-platform software environment would be included in all Blu-ray Disc players as a mandatory part of the standard. Java is used to implement interactive menus on Blu-ray Discs, as opposed to the method used on DVD video discs, which uses pre-rendered MPEG segments and selectable subtitle pictures, which is considerably more primitive and less seamless. Java creator James Gosling, at the conference, suggested that the inclusion of a Java Virtual Machine as well as network connectivity in BD devices will allow updates to Blu-ray Discs via the Internet, adding content such as additional subtitle languages and promotional features that are not included on the disc at pressing time. This Java Version is called BD-J and will be a subset of the Globally Executable MHP (GEM) standard. GEM is the world-wide version of the Multimedia Home Platform standard.

[edit] Region codes

Regions for Blu-ray standard[50]
Blu-ray discs may be encoded with a region code intended to restrict the area of the world in which they can be played, similar to the DVD region codes. Blu-ray players sold in a certain region should only be able to play discs encoded for that region. The purpose of this system is to allow motion picture studios to control the various aspects of a release (including content, date and, in particular, price) according to the region. Discs can also be produced without region coding, so they can be played on all devices.
Region code
Area[51]
A
North America, Central America, South America, Japan, Taiwan, North Korea, South Korea, Hong Kong and Southeast Asia.
B
Europe, Greenland, French territories, Middle East, Africa, Australia and New Zealand.
C
India, Bangladesh, Nepal, Mainland China, Pakistan, Russia, Central and South Asia.
This arrangement puts the countries of the major Blu-ray manufacturers (Japan, Korea, Malaysia) in the same region as the U.S., thus ensuring early releases of U.S. content to those markets, whereas they weren't before. Reportedly early BD releases (including Casino Royale) are "ALL" region and therefore compatible in various BD players around the globe.

[edit] Digital rights management (DRM)
The Blu-ray Disc format employs several layers of Digital rights management.[52][53] They have been at least partially circumvented.
Advanced Access Content System is 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 Bros., IBM, Toshiba and Sony.
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). However, even though some AACS cryptographic keys have been compromised, new releases will use new, uncompromised keys.
BD+ was developed by Cryptography Research Inc. and is based on their concept of Self-Protecting Digital Content.[54] BD+ is effectively a small virtual machine embedded in authorized players. It allows content providers to include executable programs on Blu-ray Discs. Such programs can:[52]
examine the host environment, to see if the player has been tampered with. Every licensed playback device manufacturer must provide the BD+ licensing authority with memory footprints that identify their devices.
verify that the player's keys have not been changed.
execute native code, possibly to patch an otherwise insecure system.
transform the audio and video output. Parts of the content will not be viewable without letting the BD+-program unscramble it.
If a playback device manufacturer finds that its devices have been hacked, it can potentially release BD+-code that detects and circumvents the vulnerability. These programs can then be included in all new content releases.
The specifications of the BD+ virtual machine are only available to licensed device manufacturers. A list of licensed adopters is available from the BD+ website.
BD+ was made available for content publishers in June 2007.[55] The first titles using BD+ were released in October the same year. Several players had problems playing back those titles.[56] BD+ has been circumvented by the developers of the program AnyDVD as of version 6.1.9.6 beta.[57]
BD-ROM Mark is a small amount of cryptographical data that is stored physically differently from normal Blu-ray Disc data. Bit-by-bit copies that do not replicate the BD-ROM Mark are impossible to decode. A specially licensed piece of hardware is required to insert the ROM-mark into the media during replication. Through licensing of the special hardware element, the BDA believes that it can eliminate the possibility of mass producing BD-ROMs without authorization.
When the first AACS keys were leaked, some Blu-ray titles became available on file-sharing networks. There is also a commercial PC software player (AnyDVD HD) that allowed users to watch Blu-ray Disc movies on non-HDCP compliant PC hardware or copy them.

[edit] Player profiles
The BD-ROM specification defines four profiles of Blu-ray Disc players; in addition to the three listed in the table below, there is a fourth audio-only profile that does not require video decoding or BD-J.[citation needed] All the video-based profiles are required to have a full implementation of BD-J, but with varying levels of hardware support.
Feature[58]
BD-Video (Grace Period Profile – Profile 1.0)
Bonus View (Final Standard Profile – Profile 1.1)
BD-Live (Profile 2)
Built-in persistent memory
64 KB
64 KB
64 KB
Local storage capability[a]
–
256 MB
1 GB
Secondary video decoder (PiP)
Optional
Mandatory
Mandatory
Secondary audio decoder[b]
Optional
Mandatory
Mandatory
Virtual file system
Optional
Mandatory
Mandatory
Internet connection capability
No
No
Mandatory
^ a This is used for storing audio/video and title updates. It can either be built in memory or removable media, such as a memory card or a USB flash memory.
^ b A secondary audio decoder is typically used for interactive audio and commentary
On November 1, 2007, the Grace Period Profile was superseded by "Bonus View" as the minimum profile for new players released to the market.[59] With the possible exception of the PS3, profile 1.0 players cannot be upgraded to be Bonus View compliant.[60] Notably, A Sony VP has stated that Playstation 3 will receive an update that will enhance upon the console's Blu-ray Disc interactivity, however has not indicated that it will become 1.1 compliant nor has a date been provided.[61] When software authored with interactive features dependent on "Bonus View" hardware capabilities are played on profile 1.0 players some features may not be available or may offer limited capability. Profile 1.0 players will still be able to play the main feature of the disc, however.[citation needed]

[edit] Backward compatibility
While it is not compulsory for manufacturers; the Blu-ray Disc Association recommends that Blu-ray Disc drives should be capable of reading standard DVDs for backward compatibility. For instance, Samsung's first Blu-ray Disc drive can read CDs, regular DVDs, and Blu-ray Discs. All other Blu-ray Disc players released support DVD playback as well, however not all support CD playback. This includes Sony, Panasonic, Philips, LG, Pioneer and PC-based players from Alienware, Sony, and Dell.

[edit] List