Disc Formats | Blu-ray Disc (BluRay)

The name blu-ray Disc (BD) is derived from the blue-violet laser it uses to read and write in high definition. A Blu-ray Disc can store substantially more data than the common DVD format, because of the shorter wavelength (405 nm) of the blue-violet laser (DVDs use a 650-nm-wavelength red laser and CDs use an infrared 780 nm laser), which allows more information to be stored digitally in the same amount of space. In comparison to HD DVD, which also uses a blue laser, Blu-ray Disc has more information capacity per layer (currently 25 GB, but test media is up to 200 GB). Sony has released 50 GB recordable BDs and will soon be releasing 50GB BD media discs.[1] In August 2006, TDK developed a Blu-ray Disc with a 200 GB capacity.

The Blu-ray Disc is a similar format to PDD, another optical disc format developed by Sony (which has been available since 2004) but offering higher data transfer speeds. PDD was not intended for home video use and was aimed at business data archiving and backup, although currently it is gaining popularity as an HD video format media and Playstation 3 media. The UDO format is also aimed for similar purposes. It is currently in a format war against the HD DVD disc.

The Blu-ray Disc standard was jointly developed by a group of consumer electronics and PC companies called the Blu-ray Disc Association (BDA). It is currently competing with the HD DVD format for wide adoption as the preferred next generation optical standard, similar to the videotape format war between JVC's VHS and Sony's Betamax. As of 2006, neither the Blu-ray Disc nor the HD DVD has succeeded in supplanting the present home video standard, the DVD.

The Blu-ray Disc Association unveiled their plans for a May 23, 2006 release date at the Consumer Electronics Show (CES) in January 2006. Since then, Blu-ray Disc was delayed, but eventually shipped in the U.S. on June 20, 2006.

Currently available BD-ROM and recordable discs store up to 50 gigabytes (using 2 layers.)

TDK recently announced that they have created a working experimental Blu-ray Disc capable of holding 200 GB of data on a single side (six 33 GB data layers).
Physical size Single layer capacity Dual layer capacity Quad layer capacity Sextuple layer capacity
12 cm, single sided 25GB (23.3GiB) 50 GB (46.6GiB) 100 GB (93.2GiB) 200 GB (186.4GiB)
12 cm, double sided 50 GB (46.6GiB) 100 GB (93.2GiB) 200 GB (186.4GiB) N/A
8 cm, single sided 7.8 GB (7.3GiB) 15.6 GB (14.5GiB) N/A N/A
8 cm, double sided 15.6 GB (14.5GiB) 31.2 GB (29GiB) N/A N/A

The Blu-ray Disc system uses a blue-violet laser operating at a wavelength of 405 nm, similar to the one used for HD DVD, to read and write data. Conventional DVDs and CDs use red and infrared lasers at 650 nm and 780 nm respectively.

Because the Blu-ray Disc standard places the data recording layer closer to the surface of the disc, early discs were susceptible to contamination and scratches and had to be enclosed in plastic caddies for protection. The consortium worried that such an inconvenience would hurt Blu-ray Disc's market adoption in the face of the rival HD DVD standard, as HD DVDs place the data layer farther away from the surface like DVDs. Blu-ray Discs now use a purpose-developed layer of protective material over the reflective data backing (i.e. on the label side).

TDK also announced a way to remedy the problem in January 2004 with the introduction of a clear polymer coating that gives Blu-ray Discs substantial scratch resistance. The coating was developed by TDK and is called 'Durabis'. It allows BDs to be cleaned safely with only a tissue. The coating is said to successfully resist 'wire wool scrubbing' according to Samsung Optical technical manager Chas Kalsi. It is not clear, however, whether discs will use the Durabis coating or if the use of the coating will prove too expensive.

Verbatim announced in July 2006 that their Blu-ray Disc recordable and rewritable discs would incorporate their hard-coat ScratchGuard technology which protects against scratches, abrasion, fingerprints, and traces of grease.

For video, ISO MPEG-2, H.264/AVC, and SMPTE VC-1 are player-mandatory. (This means all BD-ROM players must be capable of decoding all three video codecs.) 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 legal).

Initial versions of Sony's Blu-ray Disc-authoring software only included support for MPEG-2 video, so the initial Blu-ray Discs were forced to use MPEG-2 rather than the newer codecs, VC-1 and H.264. An upgrade was subsequently released supporting the newer compression methods so the second wave of Blu-ray Disc titles were able to make use of this. The choice of codecs affects disc cost (due to related licensing/royalty payments) as well as program capacity. The two more advanced video codecs can typically achieve twice the video runtime of MPEG-2. When using MPEG-2, quality considerations would limit the publisher to around two hours of high-definition content on a single-layer (25 GB) BD-ROM.

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 audiotracks for the primary soundtrack (linear PCM 5.1, Dolby Digital 5.1 or DTS 5.1.). A secondary audiotrack, if present, may use any of the mandatory or optional codecs. For lossless audio in movies in the PCM, Dolby TrueHD or DTS-HD formats, Blu-ray Discs support encoding in up to 24-bit/192 kHz for up to six 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.

For users recording digital television broadcasts, the Blu-ray Disc's baseline datarate of 36 Mbit/s is more than adequate to record high-definition broadcasts. Support for new codecs will evolve as they are encapsulated by broadcasters into their MPEG-2 transport streams, and consumer set-top boxes capable of decoding them are rolled out. For Blu-ray Disc movies the maximum transfer rate is 54 Mbit/s (1.5x) for the combined audio and video payload, 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.

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 will be 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 will be 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.

There is some concern about the cost of implementing and licensing the Multimedia Home Platform standard. The first generation Blu-ray players are only required to implement a subset of the Java layer, and are not required to support certain features such as Picture-in-Picture, persistent storage, or network connections.

The Blu-ray movie region codes are different from the DVD region codes.
The following are the region codes for Blu-ray discs :
Region code -> Area
A/1 North America, Central America, South America, Korea, Japan and South East Asia.
B/2 Europe, Greenland, French territories, Middle East, Africa, Australia and New Zealand.
C/3 China, Russia, Central and South Asia.

Blu-ray Disc has an experimental digital rights management (DRM) feature called BD+ which allows for dynamically changing keys for the cryptographic protections involved. Should the keys currently in use be 'cracked' or leaked, manufacturers can update them and build them into all subsequent discs, preventing a single key discovery from permanently breaking the entire scheme. Blu-ray Disc also mandates a Mandatory Managed Copy system, which allows users to copy content a limited number of times, but requiring registration with the content provider to acquire the keys needed; this feature was originally requested by HP . The lack of a dynamic encryption model is what has made DeCSS a disaster from the industry's perspective: once CSS was cracked, all DVDs from then on were open to unauthorized decryption (commonly known as 'ripping'). However this controversial technology, together with Self-Protecting Digital Content (SPDC), can allow players judged 'bad' to be effectively disabled, preventing their use by their purchaser or subsequent owners.

The Blu-ray Disc Association also agreed to add a form of digital watermarking technology to the discs. Under the name 'ROM-Mark', this technology will be built into all ROM-producing devices, and requires a specially licensed piece of hardware to insert the ROM-mark into the media during replication. All Blu-ray Disc playback devices must check for the mark. Through licensing of the special hardware element, the BDA believes that it can eliminate the possibility of mass producing BD-ROMs without authorization.

In addition, Blu-ray Disc players must follow AACS guidelines pertaining to outputs over non-encrypted interfaces. This is set by a flag called the Image Constraint Token (ICT), which would restrict the output-resolution without HDCP to 960�540. The decision to set the flag to restrict output ('down-convert') is left up to the content provider. According to CED Magazine, Sony/MGM and Disney currently have no plans to down-convert, and Fox is opposed to it as well. Warner Pictures is a proponent of the ICT, and it is expected that Paramount will also implement it. Other studios releasing Blu-ray Disc content have not yet commented on whether or not they will use down-conversion. AACS guidelines require that any title that implements the ICT must clearly state so on the packaging.

While it is not compulsory for manufacturers, the Blu-ray Disc Association recommends that Blu-ray Disc drives should be capable of reading DVDs for backward compatibility. For instance, Samsung's first Blu-ray Disc drive can read and write CDs, DVDs, and Blu-ray Discs.

JVC has developed a three layer technology that allows putting both standard-definition DVD data and HD data on a BD/DVD combo disc. 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. This hybrid disc does not appear to be ready for production and no titles have been announced that would utilize this disc structure.

The first Blu-ray Disc recorder was demoed by Sony on March 3, 2003, and was introduced to the Japanese market in April that year. On September 1, 2003, JVC and Samsung Electronics announced Blu-ray Disc-based products at IFA in Berlin, Germany. Both indicated that their products would be on the market in 2005.

In June 2004 Panasonic became the second manufacturer to launch a Blu-ray Disc recorder to the Japanese market. Launching in July the DMR-E700BD was one of the first few units to support writing to existing DVD formats, and to single-side dual-layer Blu-ray Discs with a maximum capacity of 50 gigabytes. The launch price of the recorder was $2780 USD, with 50 GB disc costing around $69 USD and the 25 GB disc costing around $32 USD.

Sony has announced that the PlayStation 3 will be shipped with a 2x Blu-ray Disc drive, likely read-only as is the case with most game console optical drives. According to Sony's press releases, it will support DVD (8x), CD (24x), and SACD (2x) formats in addition to BD-ROM, BD-R, and BD-RE. The Japanese release date for PS3 is on November 11, 2006. The release date of the PS3 in North America has been announced for November 17, 2006, and everywhere else in March, 2007. Sony also announced in March 2006 their first consumer Blu-ray Disc player the BDP-S1, would be available in stores by July 2006.

On January 4, 2006, at the Consumer Electronics Show Samsung and Philips announced their first Blu-ray Disc consumer products to the U.S. market. Samsung launched the first Blu-ray Disc player for the U.S. market, the BD-P1000, retailing for $1000 USD and sporting HDMI output with backward support for most of today's standard DVD formats (DVD-RAM, DVD-RW, DVD-R, DVD+RW, and DVD+R), while Philips launched the BDP-9000 player. Both players were expected to arrive in stores sometime in 2nd and 3rd quarters of 2006.

On September 13, 2006, Panasonic announced a Blu-ray Disc (BD) recorder capable of playing back BD discs. The Blu-ray DIGA DMR-BW200 and DMR-BR100 can record high-definition imagery on BD-RE rewritable discs and dub from the built-in hard-disk drive.

On October 18, 2006, VidaBox announced the first Dual HD player / media center capable of playing back both Blu-ray Disc (BD) & HD DVD Disc formats. The VidaBox MAX and VidaBox LUX can have both drives upgraded to play both high-definition formats up to their native 1080p resolutions at 24-bit color.

PC data storage

Originally, Blu-ray Disc drives in production could only transfer approximately 36 Mbit/s (54 Mbit/s required for BD-ROM), but 2x speed drives with a 72 Mbit/s transfer rate are now available. Rates of 8x (288 Mbit/s) or more are planned for the future.

Hewlett Packard has announced plans to sell Blu-ray Disc-equipped desktop PCs and laptops. In December 2005, HP announced that they would also be supporting the rival HD DVD technology. Philips was scheduled to debut a Blu-ray computer drive in the second half of 2005, but it was also delayed. On March 10, 2005 Apple Computer joined the Blu-ray Disc Association.

In July 2005, information was leaked about an upcoming Pioneer Blu-ray Disc drive; the OEM BDR 101A. On December 27, 2005, Pioneer formally announced the drive which was released in the late second quarter of 2006. The drive writes at 2x on BD-R and BD-RE, 8x on DVD+R and DVD-R, and 4x on DVD-RW and DVD+RW.

On January 4, 2006, at the Consumer Electronics Show Philips announced its SPD7000 Triplewriter Blu-ray Disc internal drive for the PC and Blu-ray Disc BD-R/BD-RE media discs would be available in 2nd quarter of 2006.

In April 2006 Panasonic said it would be releasing a Blu-ray Disc internal PC drive in the summer, the LF-MB121JD, priced at $850 USD. The new drive would be able to comprehensively read and/or write 13 BD / DVD / CD formats, which includes both BD-R/RE formats. It will read both 25 GB and 50 GB dual layer discs and write to them at 2x speeds.

In June 2006 LiteOn announced their first internal Blu-ray Disc drive LH-2B1S would be released August 2006 for the UK market. Also in June Plextor announced their first internal 2x Blu-ray drive PX-B900A would be released in 3rd quarter of 2006.

Corporate support

The Blu-ray Disc has gained a large amount of support in the corporate world, with companies like Apple Computer, Dell, and Panasonic supporting it.

Wikipedia information about Blu-ray Disc. This article is licensed under the GNU Free Documentation License . It uses material from the Wikipedia article 'Blu-ray Disc'