A Blu-ray Disc is a high-density optical disc format for the storage of digital media, including high-definition video.

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Overview

The name Blu-ray Disc is derived from the blue-violet laser used to read and write this type of disc. Because of this shorter wavelength (405 nm), substantially more data can be stored on a Blu-ray Disc than on the common DVD format, which uses a red, 650 nm laser. 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 33 GB). Several manufacturers have released 50 GB recordable BDs and rewritable discs.^[1] All supporting studios have either already released or have announced release of movies on 50GB discs.

Blu-ray Disc is similar 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. Blu-ray Disc is currently in a format war with rival format HD DVD.

 

Technical Specifications

• About 9 hours of high-definition (HD) video can be stored on a 50 GB disc.
• About 23 hours of standard-definition (SD) video can be stored on a 50 GB disc.
• On average, a single-layer disc can hold a High Definition feature of 135 minutes using MPEG-2, with additional room for 2 hours of bonus material in standard definition quality. A double-layer disc will extend this number up to 3 hours in HD quality and 9 hours of SD bonus material.

Physical size Single layer capacity Dual layer capacity 12 cm, single sided 25 GB (23.3 GiB) 50 GB (46.6 GiB) 12 cm, double sided 50 GB (46.6 GiB) 100 GB (93.2 GiB)   8 cm, single sided 7.8 GB (7.3 GiB) 15.6 GB (14.6 GiB)   8 cm, double sided 15.6 GB (14.5 GiB) 31.2 GB (29 GiB)  

Laser and optics

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.

Hard-coating technology

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 caddies for protection. The consortium worried that such an inconvenience would hurt Blu-ray Disc's market adoption.^[2] Blu-ray Discs now use a layer of protective material on the surface through which the data is read.

Both Sony and Panasonic replication methods include proprietary hard-coat technologies. Sony's rewritable media are sprayed with a scratch-resistant and antistatic coating.^[3]

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.^[4][5]

Ongoing development

Although the Blu-ray Disc specification has been finalized, engineers continue working to advance the technology. Quad-layer (100 GB) discs have been demonstrated. And 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.^[6] Such discs would almost certainly not work on some of today's Blu-ray Disc players, as these devices are only designed and tested on discs that meet the current specification.

Software standards

Codecs

Codecs are compression schemes that can be used to store audio and video information on a disc. The BD-ROM specification places requirements on both hardware decoders (players) and the movie-software (content).

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 allowed).

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.^[7] 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 up to six channels, or up to eight channels of up to 24-bit/96 kHz encoding.^[8] 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 54 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.^[9]

Java software support

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.

The BD-ROM specification defines four profiles of Blu-ray players. All video-based profiles are required to have a full implementation of BD-J. The 1st generation players are based on the Profile 1 (BD-Video) specification that does not require support of certain features such as Picture-in-Picture, secondary audio, local storage, and network connections. Profile 1.1 makes PIP, secondary audio and local storage mandatory. Profile 2 (BD-Live) adds network connectivity to the list of mandatory functions. Profile 3 is meant for an audio-only player and does not require video decoding or BD-J.

Region codes

The Blu-ray movie region codes are different from the DVD region codes.^[10] The following are the region codes for Blu-ray discs:^[11]

Region code Area A/1 North America, Central America, South America, Korea, Japan, Taiwan, Hong Kong and South East Asia. B/2 Europe, Greenland, French territories, Middle East, Africa, Australia and New Zealand. C/3 India, Nepal, Mainland China, Russia, Central and South Asia.

Digital Rights Management

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.^[13]

The lack of a dynamic encryption model is what made standard DVD's Content Scramble System a disaster from the industry's perspective: once CSS was cracked, all standard DVDs from then on were open to unauthorized decryption. However this controversial technology, together with Self-Protecting Digital Content (SPDC), can allow players judged "bad" to be effectively disabled,^[14] preventing their use by their purchaser or subsequent owners.^[15] See Advanced Access Content System (AACS).

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.^[16] Other studios releasing Blu-ray Disc content have not yet commented on whether or not they will use down-conversion. None of the titles released as of Dec 2006 include the use of the ICT. AACS guidelines require that any title that implements the ICT must clearly state so on the packaging.

Applications

Compatibility

The blue ray disc was first invented by T. Collesso and ceo Dean Collesso. in december5, 2003.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 and write CDs, regular DVDs, and Blu-ray Discs. All other Blu-ray Disc players released support DVD playback as well. This includes Sony, Panasonic, Philips, LG, Pioneer and PC-based players from Alienware, Sony, and Dell. LG has also produced a player that is capable of playing both Blu-ray and HD DVD formats.

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.^[17] This hybrid disc does not appear to be ready for production and no titles have been announced that would utilize this disc structure.

Stand-alone recorders and game consoles

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 announced Blu-ray Disc-based products at IFA in Berlin, Germany.

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.^[18][19]

The home video game console system PlayStation 3 (Sony) is shipped with a 2x Blu-ray Disc drive. The drive is read-only as is the case with most game console optical drives. According to Sony's press releases, it supports DVD (8x), CD (24x), and SACD (2x) formats in addition to BD-ROM, BD-R, and BD-RE.
November 11, 2006 PlayStation 3 released in Japan.
November 17, 2006 PlayStation 3 released in North America, Hong Kong and Taiwan. Sony also announced in March 2006 their first consumer Blu-ray Disc player the BDP-S1, would be available in stores by July 2006.^[20]

On January 4, 2006, at the Consumer Electronics Show Philips announced their first Blu-ray Disc consumer product to the U.S. market.

On April 13, 2006, Panasonic announced its first Blu-ray Disc player for the U.S. market, the DMP-BD10 would be shipping together in late 2006 along with their first commercially available plasma 1080p HDTVs.^[21]

On September 13, 2006, Panasonic announced a Blu-ray Disc (BD) recorder capable of playing back BDs. The Blu-ray Disc 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.^[22]

On October 18, 2006, VidaBox announced the first Dual HD player / media center capable of playing back both Blu-ray Disc (BD) & HD DVD 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.^[23]

On December 4, 2006, Sony launched their first standalone Blu-ray Disc player, the BDP-S1, to the U.S. market for $1000 USD.

PC data storage

Originally, Blu-ray Disc drives in production could only transfer approximately 4.5 MB/s or 36 Mbit/s (54 Mbit/s required for BD-ROM), but 2x speed drives with a 9 MB/s or 72 Mbit/s transfer rate are now available. Rates of 8x (288 Mbit/s) or more are planned for the future. First devices used AT Attachment but newest ones support Serial ATA.

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.^[24] Philips was scheduled to debut a Blu-ray computer drive in the second half of 2005, but it was also delayed.^[25][26] 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.^[27] 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.^[28][29]

Optical heads allowing the reading of CDs/DVDs/Blu-ray Discs have already been developed and are expected to be included after first release of DVD/Blu-ray Disc-only drives.^[30]

The Panasonic Blu-ray Disc SW-5582 is the first drive to support all three formats.^[31]

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.^[32]

In March 2006 Sony announced a Blu-ray Disc player, a VAIO desktop PC with a Blu-ray Disc recorder, and a Blu-ray Disc internal PC drive would be released in the summer of 2006.^[33]

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.^[34]

As of June 2006 Sony sold the first commercially available VAIO AR laptop and RC desktop PCs with a built in Blu-ray Disc recorder.^[35][36]

In June 2006 LiteOn announced their first internal Blu-ray Disc drive LH-2B1S would be released August 2006 for the UK market.^[37] Also in June Plextor announced their first internal 2x Blu-ray Disc drive PX-B900A would be released in 3rd quarter of 2006.^[38]

In July 2006 BenQ announced they will be selling a Blu-ray Disc device for the Europe, China and Taiwan markets.^[39]

Sony's first after-market Blu-ray Disc drive was announced in July 2006 with shipment due in August.^[40]

In August 2006 LiteOn announced their first triple-laser internal Blu-ray Disc drive for the U.S. market would be available in 3rd quarter of 2006.^[41]

In January 2007, LG announced the GGW-H10N. Like the BH100, it's due for a Q1 2007 release. While it supports all the DVD and CD recordable and re-writeable formats, along with BD-R and BD-RE, it's read-only as far as HD DVD goes.^[42]

Corporate support

The Blu-ray Disc has gained a large amount of support in the corporate world,^[43] with companies like Apple Inc., Dell, and Panasonic supporting it.

In a recent interview with gamespot, when quized on the new LG HD DVD/Blu Ray combo players, Sir Howard Stringer had this to say: "It's an expensive way of showing universal discs. The three biggest box-office winners of this year were, in order: Sony, Disney, and Fox. Those are the three Blu-ray players. When you consider that those three successful studios will be delivering last year's successful box office in home video this year, then that's an enormous advantage. The fourth is Warner, and they release in both formats, so it doesn't hurt. If you are going to be buying discs, you are going to be buying an awful lot of Blu-ray discs going forward--if you want Pirates of the Caribbean or James Bond or Da Vinci Code or Spider-Man. Universal is the only one with HD DVD. I don't feel terribly intimidated."

BD / HD DVD comparison

The primary rival to Blu-ray Disc is HD DVD, championed by Toshiba, NEC Corporation, Microsoft, and Intel. HD DVD has a lower theoretical disc capacity per layer (15 GB vs 25 GB). The Blu-ray Disc version of the Adam Sandler movie Click was released on October 10, 2006 as the first ever dual-layer release. Sony's goal is to use 50 GB dual-layer discs to store up to nine hours of HD video content. Alternatively, studios releasing movies on Blu-ray Disc can choose to use VC-1 or H.264/AVC instead of MPEG-2 as an alternative way to put four hours of high-definition content on a (single layer) BD.

In terms of audio/video compression, Blu-ray Disc and HD DVD are similar on the surface: both support MPEG-2, VC-1, and H.264 for video compression, and Dolby Digital (AC-3), PCM, and DTS for audio compression. The first generation of Blu-ray Disc movies released used MPEG-2 (the standard currently used in DVDs, although encoded at a much higher video resolution and a much higher bit rate than those used on conventional DVDs), while initial HD DVDs releases used the VC-1 codec. Due to greater total disc capacity, the Blu-ray Disc may choose in the future to utilize a higher maximum video bit rate, as well as potentially higher average bit rates. In terms of audio, there are some differences. Blu-ray Disc allows conventional AC-3 audiotracks at 640 kbit/s, which is higher than DVD/HD DVD's maximum, 448 kbit/s. Nevertheless, Dolby Digital Plus support is mandatory for standalone HD DVD players at a maximum of 3 Mbit/s, while optional for BD players and support up to a higher bitrate of 4.736 Mbit/s.^[44]

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 30i timing for 24p (replacing missing frames with "repeat field flags"). Decoders can ignore the “flags” to output 24p.^[45] 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.

On November 29, 2004 four Hollywood studios (New Line Cinema, Paramount Pictures, Universal Studios and Warner Bros.) announced non-exclusive agreements to support HD DVD. Since that time, Paramount and Warner have chosen to release titles in both Blu-ray Disc and HD DVD, while only Universal has since announced exclusive support for HD DVD. Currently Sony Pictures, MGM, Disney and 20th Century Fox have all exclusively backed Blu-Ray.

Disc BD-ROM HD-DVD ROM 3X DVD ROM DVD ROM Laser wavelength 405 Nanometers 405 Nanometers 650 Nanometers 650 Nanometers Numerical aperture 0.85 0.65 0.6 0.6 Storage capacity single layer 25 GB 15 GB 4.7 GB 4.7 GB Storage capacity dual layer 50 GB 30 GB 8.5 GB 8.5 GB Playback time on two layers (Standard Definition) 23 hours 13.8 hours N/A 4 hours Playback time on two layers (High Definition) 9 hours 5.4 hours 2 hours - Video codecs MPEG-4 AVC (H.264) / VC-1 / MPEG-2 MPEG-4 AVC (H.264) / VC-1 / MPEG-2 MPEG-4 AVC (H.264) / VC-1 / MPEG-2 MPEG-2 Audio codecs lossless (mandatory) Linear PCM Linear PCM/MLP(TRUE HD)[2-ch] Linear PCM/MLP(TRUE HD)[2-ch] Linear PCM[2ch] Audio codecs lossless (optional) DTS HD (lossless)/7.1 PCM/MLP (lossless) DTS HD (lossless) DTS HD (lossless) N/A Audio codecs lossy (mandatory) Dolby Digital Plus/DTS/Dolby Digital/MPEG Audio Dolby Digital Plus/DTS/Dolby Digital/MPEG Audio Dolby Digital Plus/DTS/Dolby Digital/MPEG Audio Dolby Digital/MPEG Audio (Europe) Maximum data transfer rate 54.0 Mbit/s 36.55 Mbit/s 36.55 Mbit/s 11.08 Mbit/s Content protection system Advanced Access Content System (AACS-128bit) Advanced Access Content System (AACS-128bit) Advanced Access Content System (AACS-128bit) CSS 40-bit Video systems (maximum) 1920x1080 50/60 Progressive HDTV 1920x1080 50/60 Progressive HDTV 1920x1080 50/60 Progressive HDTV 720x480 and 720x576 50/60 Progressive SDTV

Other optical data storage technologies

• HD DVD
• AVCHD
• Digital Multilayer Disk – the successor technology to Fluorescent Multilayer Disc
• Enhanced Versatile Disc
• Forward Versatile Disc – Taiwanese backed red laser format
• Fluorescent Multilayer Disc
• Holographic Versatile Disc - standards with 200 and 300 GB storage are under development and prototypes expected in 2008
• Protein-coated disc
• Tapestry Media
• Versatile Multilayer Disc
• Ultra Density Optical
• Professional Disc for DATA (PDD or ProDATA)

Released titles

The first Blu-ray Disc titles released on June 20, 2006 were Hitch, The Fifth Element, House of Flying Daggers, Underworld: Evolution, 50 First Dates, XXX by Sony; and The Terminator by MGM.

As of January 2007, more than 137 titles have been released and more are being released weekly. While the earliest releases used MPEG-2 video compression, later releases are more often using VC-1 and AVC.

On August 15, 2006, Memento was remastered for BD. This could possibly be the first independent film release for Blu-ray Disc.^{[citation needed]}

On September 5, 2006, Warner released the first 3 titles using VC-1 encoding, Blazing Saddles, Firewall, and Lethal Weapon. A further 6 VC-1 encoded titles, Tim Burton's Corpse Bride, Swordfish, Space Cowboys, The Fugitive, Lethal Weapon 2, and House of Wax, were released on September 26.[1]

On September 19, 2006, Disney released the first two titles to be encoded using AVC, namely Dinosaur and Eight Below.

On September 26, 2006, Warner released, The Lake House which is the first movie to be released simultaneously on Blu-ray Disc, HD DVD, and DVD.

On October 10, 2006, Columbia Pictures released the first dual-layer Blu-ray Disc title, Click.

On November 14, 2006, Fox released their first 50 GB dual-layer Blu-ray Disc title, Kingdom of Heaven: Director's Cut. Other titles, Ice Age: The Meltdown, Fantastic Four and the recent remake of The Omen were released on the same day and used AVC encoding and DTS HD Lossless Master Audio. The first shipments of the PlayStation 3 in the United States included a Blu-ray Disc version of Talladega Nights: The Ballad of Ricky Bobby.[2]

On February 27, 2007, rock band Nine Inch Nails will release Beside You In Time, a compilation of video recordings of live performances documenting the 2006 "With Teeth" tour, simultaneously in Blu-ray, DVD, and HD-DVD formats.

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