.
During the high definition optical disc format war, Blu-ray Disc competed with the HD DVD format. On February 19, 2008, Toshiba — the main company supporting HD DVD — announced it would no longer develop, manufacture, and market HD DVD players and recorders,[2] leading almost all other HD DVD companies to follow suit, effectively ending the format war.

Blu-ray Disc was developed by the Blu-ray Disc Association, a group representing consumer electronics, computer hardware, and motion picture production. As of August 27, 2008 more than 780 Blu-ray Disc titles have been released in the United States and more than 480 Blu-ray Disc titles have been released in Japan.[3][4] By the end of 2008, there is expected to be a total of 1220 Blu-ray Disc titles released in the United States.[5]


Optical media types

* Laserdisc (LD), Video Single Disc (VSD)
* Compact Disc (CD): Red Book, 5.1 Music Disc, SACD, PhotoCD, CD-R, CD-ROM, CD-RW, CD Video (CDV), Video CD (VCD), SVCD, CD+G, CD-Text, CD-ROM XA, CD-i
* MiniDisc (MD) (Hi-MD)
* DVD: DVD-R, DVD+R, DVD-R DL, DVD+R DL, DVD-RW, DVD+RW, DVD-RW DL, DVD+RW DL, DVD-RAM, DVD-D
* Ultra Density Optical (UDO)
* Universal Media Disc (UMD)
* HD DVD: HD DVD-R, HD DVD-RW
* Blu-ray Disc (BD): BD-R, BD-RE
* High-Definition Versatile Disc (HVD)
* High definition Forward Versatile Disc (HD-FVD)

Standards

* Rainbow Books
* File systems
o ISO 9660
+ Joliet
+ Rock Ridge
+ El Torito
+ Apple ISO 9660 Extensions
o Universal Disk Format (ISO 9660) (UDF)
+ Mount Rainier

Further reading

* History of optical storage media
* High definition optical disc format war




 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 some 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 is a subset of the Globally Executable MHP (GEM) standard. GEM is the world-wide version of the Multimedia Home Platform standard.

 Region codes
Regions for Blu-ray standard A: East Asia (except Mainland China and Mongolia), Southeast Asia, North America, South America and their dependencies. B: Africa, Southwest Asia, Europe (except Russia and Kazakhstan), Oceania and their dependencies. C: Central Asia, East Asia (Mainland China and Mongolia only), South Asia, Europe (Russia and Kazakhstan only) and their dependencies.
Regions for Blu-ray standard[44]
A: East Asia (except Mainland China and Mongolia), Southeast Asia, North America, South America and their dependencies. B: Africa, Southwest Asia, Europe (except Russia and Kazakhstan), Oceania and their dependencies. C: Central Asia, East Asia (Mainland China and Mongolia only), South Asia, Europe (Russia and Kazakhstan only) and their dependencies.

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 in principle to the DVD region codes, although the used geographical regions differ. Blu-ray Disc players sold in a certain region may only 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 may also be produced without region coding, so they can be played on all devices. The countries of the major Blu-ray manufacturers (Japan, Korea, Malaysia) are in the same region as North America. As of early 2008, about two-thirds of all released discs were region-free.[45]

Major studios have different region coding policies. Paramount Pictures and Universal Studios have released all of their titles region free.[46][47] Sony Pictures and Warner Bros have released most of their titles region free, but titles released by Warner's New Line division are region-coded.[48][49] Lionsgate and Walt Disney Pictures have released a mix of titles that were region free and region coded.[50][51] 20th Century Fox has released all but one of their titles region coded.[52]

However, since the demise of the HD-DVD format which did not support Region Coding, the majority of Blu-ray releases are now region coded.

In the Blu-ray region coding system, the United States is placed in region A while regions B and C are used for countries which can experience localization delays before U.S. titles are officially released. The opposite, though, is sometimes true and a few new titles such as Harry Potter and the Goblet of Fire and Running Scared were released in certain European countries before the U.S. release.[53] In response to the DVD region system, multi-region and region-free DVD players became dominant in certain markets; certain Blu-ray player models have been modified to allow for playback of Blu-ray and DVD discs with any region code.[54]

 Digital rights management (DRM)

The Blu-ray Disc format employs several layers of digital rights management.[55][56]
AACS decryption process
AACS decryption process

Advanced Access Content System (AACS) is a standard for content distribution and digital rights management. It is developed by AS 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). New releases will use new, uncompromised keys.[57] However, now (August 2008) all decryption keys are available on the Internet.[citation needed]

BD+ was developed by Cryptography Research Inc. and is based on their concept of Self-Protecting Digital Content.[58] 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:[55]

* 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.

If a publisher desires BD+ has the ability to limit playback of a Blu-Ray Disc to the first Blu-Ray playback device in which the disc is played.[citation needed]

The specifications of the BD+ virtual machine are available only 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.[59] The first titles using BD+ were released in October the same year. Players from Samsung and LG had problems playing back those titles until the manufacturers updated their firmware, but this problem was later identified as being related to BD-Java use, not BD+.[60] BD+ protection was fully circumvented with the release 6.4.0.0 of AnyDVD HD program.

BD-ROM Mark is a small amount of cryptographic data that is stored separately 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.

 Player profiles

The BD-ROM specification defines four Blu-ray Disc player profiles which includes an audio only player profile (BD-Audio) that does not require video decoding or BD-J.[61] All three of the video based player profiles (BD-Video) are required to have a full implementation of BD-J, but with varying levels of hardware support.
Feature BD-Audio BD-Video
Grace Period [d] Bonus View [e] BD-Live
Profile 3.0 [c] Profile 1.0 Profile 1.1 Profile 2.0
Built-in persistent memory No 64 KB 64 KB 64 KB
Local storage capability[a] No Optional 256 MB 1 GB
Secondary video decoder (PiP) No Optional Mandatory Mandatory
Secondary audio decoder[b] No Optional Mandatory Mandatory
Virtual file system No Optional Mandatory Mandatory
Internet connection capability No 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 USB flash memory.
^ b A secondary audio decoder is typically used for interactive audio and commentary.
^ c Profile 3.0 is a separate audio only player profile. As of 2008-06-26, only one known Blu-ray record has been released and it has been confirmed to work on the PS3.[62][63]
^ d Is also known as Initial Standard profile.
^ e Is also known as Final Standard profile.

On November 1, 2007, the Grace Period Profile was superseded by Bonus View as the minimum profile for new BD-Video players released to the market.[64] When Blu-ray software authored with interactive features dependent on Bonus View or BD-Live hardware capabilities are played on Profile 1.0 players they will be able to play the main feature of the disc but some extra features may not be available or may offer limited capability.[65]

Except the LG-BH100, the LG-BH200, the PlayStation 3, and the Samsung BD-UP5000, Profile 1.0 players can not be upgraded to be Bonus View or BD-Live compliant.[66][67][68]

 Backward compatibility

Though not compulsory, the Blu-ray Disc Association recommends that Blu-ray Disc drives should be capable of reading standard DVDs and CDs for backward compatibility.[69] A few early Blu-ray Disc players released in 2006 could play DVDs but not CDs (the LG BH100, Pioneer BDP-HD1, and Sony BDP-S1)[70][71][72] but all current Blu-ray Disc players are capable of both DVD and CD playback.[73]

 Ongoing development
Front of an experimental 200GB rewritable Blu-ray Disc

Although the Blu-ray Disc specification has been finalized, engineers continue working to advance the technology. Quad-layer (100 GB) discs have been demonstrated on a drive with modified optics (TDK version) and standard unaltered optics ("Hitachi used a standard drive.").[74][75] Hitachi stated that such a disc could be used to store 7 hours of 32 Mbit/s video (HDTV) or 3.5 hours of 64 Mbit/s video (Cinema 4K). Furthermore TDK announced in August 2006 that they have created a working experimental Blu-ray Disc capable of holding 200 GB of data on a single side, using six 33 GB data layers.[76]

Also behind closed doors at CES 2007, Ritek revealed that they had successfully developed a High Definition optical disc process that extends the disc capacity to 10 layers. That increases the capacity of the discs to 250 GB. However, they noted that the major obstacle is that current reader and writer technology does not support the additional layers.[77]

JVC has developed a three-layer technology that allows putting both standard-definition DVD data and HD data on a BD/DVD combo. If successfully commercialized, this would enable the consumer to purchase a disc which could be played on current DVD players, and reveal its HD version when played on a new BD player.[78] This hybrid disc does not appear to be ready for production and no titles have been announced that would use this disc structure.

In January 2007, Hitachi showcased a 100 GB Blu-ray Disc, which consists of four layers containing 25 GB each.[79] Unlike TDK and Panasonic's 100 GB discs, they claim this disc is readable on standard Blu-ray Disc drives that are currently in circulation, and it is believed that a firmware update is the only requirement to make it readable to current players and drives.[80]

As of April, 2008 a joint licensing agreement for Blu-ray Disc has not yet been finalized.[81] A joint licensing agreement would make it easier for companies to get a license for Blu-ray Disc without having to go to each individual company that owns a Blu-ray Disc patent. For this reason a joint licensing agreement was eventually made for DVD by the DVD6C Licensing Agency.[82]

 Variants

 Mini Blu-ray Disc

The Mini Blu-ray Disc (also, Mini-BD and Mini Blu-ray) is a compact 8cm (~3in) diameter variant of the Blu-ray Disc that can store approximately 7.5 GB of data. It is similar in concept to the MiniDVD.

Recordable (BD-R) and rewritable (BD-RE) versions of Mini Blu-ray Disc have been developed specifically for compact camcorders and other compact recording devices.[83]

 BD9/BD5 Blu-ray Disc

See also: 3× DVD

BD9 and BD5 are lower capacity variants of the Blu-ray Disc that contain Blu-ray compatible video and audio streams contained on a conventional DVD (650 nm wavelength / red laser) optical disc. Such discs offer the use of the same advanced compression technologies available to Blu-ray discs (including MPEG-4-AVC/H.264, SMPTE-421M/VC-1 and MPEG-2) while using lower cost legacy media. BD9 uses a standard 8152MB DVD9 dual-layer disc while BD5 uses a standard 4489MB DVD5 single-layer disc.[84]

Given that Blu-ray Discs are assumed to have a minimum transfer rate of 30.25 Mbit/s, BD9/BD5 discs must be spun at high speed, equivalent to a 3× DVD drive speed or greater.

BD9 and BD5 discs can be authored using home computers for private showing using standard DVD±R recorders. AACS digital rights management is optional.[85]

The BD9 format was originally proposed by Warner Home Video, as a cost-effective alternative to regular Blu-ray Discs.[86] It was adopted as part of the BD-ROM basic format, file system and AV specifications. BD5 and BD9 are similar to 3× DVD.

[edit] AVCREC

See also: HD REC

AVCREC is an official[87] lower capacity variant of the Blu-ray Disc used for storing Blu-ray Disc compatible content on conventional DVD discs. It is being promoted for use in camcorders, distribution of short HD broadcast content and other cost-sensitive distribution needs. It is similar to HD REC for HD DVD.

Note that AVCREC is not the same as AVCHD content stored on DVD. The latter is a media independent format and is used presently in tapeless camcorders that record onto DVD and Blu-ray disks, as well as onto SecureDigital and MemoryStick memory cards. Playing back AVCHD content on a Blu-ray player may require modification of AVCHD directory structure, but does not require re-encoding of video files themselves.[88]

Blu-ray Disc recordable

Main article: Blu-ray Disc recordable

Blu-ray Disc recordable refers to two optical disc formats that can be recorded with an optical disc recorder. BD-R discs can be written to once, whereas BD-RE can be erased and re-recorded multiple times. The theoretical maximum speed for Blu-ray Discs is about 12× as the speed of rotation (10,000 rpm) causes too much wobble for the discs to be read properly, similar to the 20× and 52× respective maximum speeds of DVDs and CDs.

Since September 2007, BD-RE was also available in the smaller 8 cm Mini Blu-ray Disc diameter size.[83][89]

On September 18, 2007, Pioneer and Mitsubishi co-developed BD-R LTH ("Low to High" in groove recording), which features an organic dye recording layer that can be manufactured by modifying existing CD-R and DVD-R production equipment, significantly reducing manufacturing costs.[90]

In February 2008, Taiyo Yuden, Mitsubishi and Maxell released the first BD-R LTH Discs,[91] and in March 2008, Sony's PlayStation 3 gained official support for BD-R LTH Discs with the 2.20 firmware update.[92]

Unlike the previous releases of 120 mm optical discs (i.e. CDs and DVDs), Blu-ray recorders hit the market almost simultaneously with Blu-ray's debut (at least in Japan).

[
* Blu-ray Disc authoring
* Blu-ray Disc Association
* Blu-ray Disc recordable
* Comparison of high definition optical disc formats
* PlayStation 3
* High definition optical disc format war
* List of Blu-ray Disc devices
* Optical disc

 Alternative disc technologies

* HD DVD (primary competitor, now discontinued)
* HD VMD/Versatile Multilayer Disc (new low-profile competitor)
* AVCHD
* Digital Multilayer Disk — the successor technology to Fluorescent Multilayer Disc
* Enhanced Versatile Disc (EVD)
* Forward Versatile Disc (FVD) — Taiwanese backed red laser format
* Fluorescent Multilayer Disc
* Holographic Versatile Disc — standards with 3.9 TB storage are under development
* 3D optical data storage — a next-generation technology expected to provide TB-capacity discs
* Protein-coated disc
* Ultra Density Optical
* LS-R — a "layer selection" technology allowing the stacking of very large numbers of DVD-like data layers in a single disc.
* Professional Disc for DATA (PDD or ProDATA)