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Topics Pages

1.Review of Litrature 3
2.Introduction 4
3.History & Origin 6
4.Blu-ray Association & Members 7
5.Cotributors 9
6.Launch and Sales Development 10
7.Competion from HD DVD 10
8.Technical Specification 11
9.Laser Optics 12
10.Hard-Coating Technology 12
11.Verson & Speed 13
12.Technical Details 14
13.Capacity/Codes 17
14.Interacivity 18
15.Disc Construction 19
16.Hybrid Discs 19
17.Software Standards 22
18.Digital Right Management 24
19.Player Profile 27
20.Variant 27
21.Blu-Ray Recordability 28
22.Bibliography 30


Review Of Litrature

1. Jeremy Reimer (2007-10-07). "New Blu-ray discs with BD+ DRM failing to play on some devices". arstechnica.com. Retrieved on 2007-11-02.
2. Zyber, Joshua (2007-11-23). "High-Def FAQ: Blu-ray Profiles Explained". highdefdigest.com. Retrieved on 2007-12-1
3. Yam, Marcus (2007-01-10). "Three HD Layers Today, Ten Tomorrow" (in English). DailyTech. Retrieved on 2007-04-24.
4. Christian Lysvåg (2008-05-29). "Music on Blu-ray". Music Information Centre Norway. Retrieved on 2008-06-26
5. ^ Joshua Fruhlinger. "First Blu-ray record, Divertimenti, released". engadget. Retrieved on 2008-07-05
6. ^ Zyber, Joshua (2007-11-23). "High-Def FAQ: Blu-ray Profiles Explained". highdefdigest.com. Retrieved on 2007-12-18.




Introduction

Blu-ray Disc (also known as Blu-ray or BD) is an optical disc storage medium. Its main uses are high-definition video and data storage. The disc has the same physical dimensions as standard DVDs and CDs.

The name Blu-ray Disc is derived from the blue laser (violet-colored) used to read and write this type of disc. Because of the beam's shorter wavelength (405 nanometers), substantially more data can be stored on a Blu-ray Disc than on the DVD format, which uses a red (650 nm) laser. A two-layer Blu-ray Disc can store 50 gigabytes, almost six times the capacity of a two-layer DVD, or ten times that of a single-layer DVD.

During the format war over high-definition optical discs, Blu-ray Disc competed with the HD DVD format. On February 19, 2008, Toshiba—the main company supporting HD DVD—announced that it would no longer develop, manufacture, and market HD DVD players and recorders, 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 makers of consumer electronics, computer hardware, and motion pictures. As of September 20, 2008, more than 850 Blu-ray Disc titles have been released in the United States and more than 500 Blu-ray Disc titles have been released in Japan. There are expected to be over 1300 Blu-ray Disc titles released in the United States by the end of 2008.






Reverse side of a Blu-ray Disc


Media type : High-density optical disc
Encoding : MPEG-2, H.264/MPEG-4 AVC, and VC-1
Capacity : 25 GB (single layer), 50 GB (dual layer)
Read : 405 nm laser:
Mechanism 1× at 36 Mbit/s
2× at 72 Mbit/s
4× at 144 Mbit/s
6× at 216 Mbit/s
8× at 288 Mbit/s
12× at 432 Mbit/s

Developed by : Blu-ray Disc Association
Usage : Data storage,
High-definition video
High-definition audio
PlayStation 3 games



History

In 1998, commercial HDTV sets began to appear in the consumer market; however, there was no commonly accepted, inexpensive way to record or play HD content. In fact, there was no medium with the storage required to accommodate HD codecs, except JVC's Digital VHS and Sony's HDCAM.Nevertheless, it was well known that using lasers with shorter wavelengths would enable 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

Origins
Philips and 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 Disc (more specifically, BD-RE).The core technologies of the formats are essentially similar.
The first DVR Blue prototypes were unveiled at the CEATEC exhibition in October 2000.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, and the Blu-ray Disc Association was founded by the nine initial members.
The first consumer devices were in stores on April 10, 2003. This device was the Sony BDZ-S77; a BD-RE recorder that was made available only in Japan. The recommended price was US$3800; however, there was no standard for pre-recorded video and no movies were released for this player. The Blu-ray Disc standard was still years away as a newer, more secure DRM system was needed before Hollywood studios would accept it, not wanting to repeat the failure of the Content Scramble System used on DVDs.
Blu-ray Disc Association
The Blu-ray Disc Association (BDA) is the industry consortium that develops and licenses Blu-ray Disc technology and is responsible for establishing format standards and promoting business opportunities for Blu-ray Disc. The BDA is divided into three levels of membership: the Board of Directors, the Contributors, and the General Members.
The "Blu-ray Disc Founder group" was started in May 2002 by nine leading electronic companies: Sony, Matsushita, Pioneer, Philips, Thomson, LG Electronics, Hitachi, Sharp, and Samsung. Spearheaded by Sony Corporation, on February 19, 2002 the companies announced that they were the "Founders" of the Blu-ray Disc and later changed their name to the "Blu-ray Disc Association" on May 18, 2004 to allow more companies to join their development. Some examples of companies that signed in include Apple, TDK, Dell, Hewlett Packard, The Walt Disney Company, Warner Bros. and Universal Music Group. As of December 2007, there are more than 250 members and supporters of the Association.



Members
Board of Directors
The Blu-ray Disc Association website describes the role of the Board of Directors as follows:
"Companies participating in the Board of Directors are active participants of the format creation and key BDA activities. They are selected from the Contributors by election. The board sets an overall strategy and approves key issues. A board member can participate in all activities and attend all meetings. The Blu-ray Disc Founder companies will make up the initial Board of Directors. Annual fee: $ 50,000"
The current 18 board members (as of January 2008) are:[4]
• Apple Inc.
• Dell Inc.
• Hewlett-Packard Company
• Hitachi, Ltd.
• LG Electronics
• Mitsubishi Electric
• Panasonic (Matsushita Electric)
• Pioneer Corporation
• Royal Philips Electronics
• Samsung Electronics
• Sharp Corporation
• Sony Corporation
• Sun Microsystems
• TDK Corporation
• Thomson SA
• Twentieth Century Fox
• Walt Disney Motion Pictures Group / Walt Disney Studios Home Entertainment
• Warner Bros. Entertainment, Inc.


Contributors
Contributors are active participants of the format creation and other key BDA activities. They can be elected to become a member of the Board of Directors. A contributor can attend general meetings and seminars, and can participate in Technical Expert Groups (TEGs), regional Promotion Team activities, and most of the Compliance Committee (CC) activities. Membership requires execution of Contribution Agreement and must be approved by the Board of Directors. Annual fee: $ 20,000

General Membership
"General membership provides access to specific information from Committee discussions. A general member can attend general meetings and seminars. They can participate in specific Regional Promotion Team activities and specific CC activities. Annual fee: $3,000"
Blu-ray Disc format finalized
The Blu-ray Disc physical specifications were finished in 2004. In January 2005, TDK announced that they had developed a hard coating polymer for Blu-ray Discs. The cartridges, no longer necessary, were scrapped. The BD-ROM specifications were finalized in early 2006. AACS LA, a consortium founded in 2004, had been developing the DRM platform that could be used to securely distribute movies to consumers. However, the final AACS standard was delayed, and then delayed again when an important member of the Blu-ray Disc group voiced concerns. At the request of the initial hardware manufacturers, including Toshiba, Pioneer and Samsung, an interim standard was published which did not include some features, like managed copy.
Launch and sales developments
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.
The first Blu-ray Disc titles were released on June 20, 2006. The earliest releases used MPEG-2 video compression, the same method used on DVDs. The first releases using the newer VC-1 and AVC codecs were introduced in September 2006. The first movies using dual layer discs (50 GB) were introduced in October 2006.The first audio-only release was made in March 2008.
The first mass-market Blu-ray Disc 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.
Competition from HD DVD
The DVD Forum (which was chaired by Toshiba) was deeply split over whether to develop the more expensive blue laser technology 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. In spite of this decision, however, the DVD Forum's Steering Committee announced in April that it was pursuing its own blue-laser high-definition solution. In August, Toshiba and NEC announced their competing standard Advanced Optical Disc. It was finally adopted by the DVD Forum and renamed HD DVD the next year, 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.
HD DVD had a head start in the high definition video market and Blu-ray Disc sales were slow at first. The first Blu-ray Disc player was perceived as expensive and buggy, and there were few titles available. This changed when PlayStation 3 launched, since every PS3 unit also functioned as a Blu-ray Disc player. At CES 2007 Warner proposed Total Hi Def which was a hybrid disc containing Blu-ray on one side and HD DVD on the other but it was never released. By January 2007, Blu-ray discs had outsold HD DVDs, and during the first three quarters of 2007, BD outsold HD DVDs by about two to one. In February 2008, Toshiba withdrew its support for the HD DVD format, leaving Blu-ray as the victor.
Some analysts believe that Sony's PlayStation 3 video game console played an important role in the format war, believing it acted as a catalyst for Blu-ray Disc, as the PlayStation 3 used a Blu-ray Disc drive as its primary information storage medium. They also credited Sony's more thorough and influential marketing campaign. More recently Twentieth Century Fox has cited Blu-ray Disc's adoption of the BD+ anti-copying system as the reason they supported Blu-ray Disc over HD DVD.
Technical specifications
Type Physical size Single layer capacity Dual layer capacity
Standard disc size 12 cm, single sided 25 GB (23.28 GiB) 50 GB (46.56 GiB)
Mini disc size 8 cm, single sided 7.8 GB (7.26 GiB) 15.6 GB (14.53 GiB)

Laser and optics
Blu-ray Disc 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 near infrared 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, increasing the numerical aperture from 0.60 to 0.85 and making the cover layer thinner to avoid unwanted optical effects, the laser beam can be focused to a smaller spot. This allows more information to be stored in the same area. For Blu-ray Disc, the spot size is 580 nm. In addition to the optical improvements, Blu-ray Discs feature improvements in data encoding that further increase the capacity.
Hard-coating technology
Because the Blu-ray Disc data layer is closer to the surface of the disc, compared to the DVD standard, it was at first more vulnerable to scratches. The first discs were housed in cartridges for protection.
TDK was the first company to develop a working scratch protection coating for Blu-ray Discs. It was named Durabis. In addition, both Sony and Panasonic's replication methods include proprietary hard-coat technologies. Sony's rewritable media are spin-coated with a scratch-resistant and antistatic coating. Verbatim's recordable and rewritable Blu-ray Disc discs use their own proprietary hard-coat technology called Scratch Guard.
Version
BD-RE Versions
There are three versions of rewritable Blu-ray Discs (BD-RE):
Version 1.0
• unique BD File System
• not computer compatible
Version 2.0
• UDF 2.5 file system for computer use
• the use of AACS
• BD-R Version 1.0 follows this specification
Version 3.0
• camcorder (8 cm) discs added
• backward compatible with Version 2.0
• BD-R Version 2.0 follows this specification
BD-R Versions
Version 1.2
• Add BD-R Low to High (BD-R LTH) standard.
Speed
Drive speed Data rate Single layer BD write time
1X 36 Mbit/s 4.5 MB/s 4.39 MiB/s
95 min.
2X 72 Mbit/s 9 MB/s 8.78 MiB/s
47 min.
4X 144 Mbit/s 18 MB/s 17.56 MiB/s
24 min.
6X 216 Mbit/s 27 MB/s 26.34 MiB/s
16 min.
8X 288 Mbit/s 36 MB/s 35.12 MiB/s
12 min.
12X 432 Mbit/s 54 MB/s 52.63 MiB/s
8 min.

BD-R LTH (Low To High)
BD-R LTH is a write-once Blu-ray disc format that features organic dye recording layer. The advantage of BD-R LTH is it can protect a manufacturer's investment in DVD-R/CD-R manufacturing equipment. Only modifications are required to current equipment; no investment in new production lines is required. It is believed this can lower the cost of discs.
Old Blu-ray players and recorders can't utilize BD-R LTH, however, a firmware upgrade could enable the device to access BD-R LTH. Panasonic has already released such a firmware update last November for its DMR-BW200, DMR-BR100 and the MR-BW900/BW800/BW700 models. Pioneer is also expected to ship the first LTH BD drives in Spring of 2008. Furthermore, Sony's PlayStation 3 received firmware upgrade to enable BD-R LTH reading in March, 2008.
Technical details
A Table Comparing the High-definition Optical Media Formats
DVD included for comparison
Mandatory codecs must be supported by the player. Each disc must use one or more of the mandatory codecs.
Blu-ray Disc
HD DVD
DVD

Laser wavelength
405 nm (blue-violet laser) 650 nm (red laser)
Numerical aperture
0.85 0.65 0.6
Storage capacity
(single side) per layer/maximum 25/50 GB 15/30 GB 4.7/8.5 GB
Maximum
bitrate
Raw data transfer 53.95 Mbit/s 36.55 Mbit/s 11.08 Mbit/s
Audio+Video+Subtitles 48.0 Mbit/s 30.24 Mbit/s 10.08 Mbit/s
Video 40.0 Mbit/s 29.4 Mbit/s 9.8 Mbit/s
Mandatory video codecs
H.264/MPEG-4 AVC / VC-1 / MPEG-2
MPEG-1 / MPEG-2

Audio
codecs
lossy
Dolby Digital
Mandatory @ 640 kbit/s Mandatory @ 504 kbit/s Mandatory @ 448 kbit/s
DTS
Mandatory @ 1.5 Mbit/s Optional @ 1.5 Mbit/s
Dolby Digital Plus
Optional @ 1.7 Mbit/s Mandatory @ 3.0 Mbit/s N/A
DTS-HD High Resolution
Optional @ 6.0 Mbit/s Optional @ 3.0 Mbit/s N/A
lossless
Linear PCM
Mandatory Optional
Dolby TrueHD
Optional Mandatory N/A
DTS-HD Master Audio
Optional N/A
Secondary video decoder (PiP)
Mandatory for Bonus View players Mandatory N/A
Secondary audio decoder Mandatory for Bonus View players Mandatory Optional
Interactivity BDMV and Blu-ray Disc Java
Standard Content and Advanced Content
Rudimentary
Internet support Mandatory for BD-Live players Mandatory N/A
Video resolution (maximum)
1920×1080 720×480 (NTSC), 720×576 (PAL)

Frame rates at maximum resolution 24p, 50/60i
25/30p, 50/60i
50/60i

Digital Rights Management
AACS-128bit / BD+ / ROM-Mark
AACS-128bit CSS 40-bit

Region codes
Three area codes
Region free 8 Regions (6 commercial)
Hard coating of disc Mandatory Optional
Capacity/codecs
Blu-ray has a higher maximum disc capacity than HD DVD (50 GB vs. 30 GB for a single sided disc). In September 2007 the DVD Forum approved a preliminary specification for the triple-layer 51GB HD DVD (ROM only) disc though Toshiba never stated whether it was compatible with existing HD DVD players. In September 2006 TDK announced a prototype Blu-ray Disc with a capacity of 200GB. TDK was also the first to develop a Blu-ray prototype with a capacity of 100GB in May 2005. In October 2007 Hitachi developed a Blu-ray prototype with a capacity of 100GB. Hitachi has stated that current Blu-ray drives would only require a few firmware updates in order to play the disc.
The first 50 GB dual-layer Blu-ray Disc release was the movie Click, which was released on October 10, 2006. As of July 2008, over 54% of Blu-ray movies are published on 50 GB dual layer discs with the remainder on 25 GB discs. 85% of HD DVD movies are published on 30 GB dual layer discs, with the remainder on 15 GB discs.
The choice of video compression technology (codec) complicates any comparison of the formats. Blu-ray Disc and HD DVD both support the same three video compression standards: MPEG-2, VC-1 and AVC, each of which exhibits different bitrate/noise-ratio curves, visual impairments/artifacts, and encoder maturity. Initial Blu-ray Disc titles often used MPEG-2 video, which requires the highest average bitrate and thus the most space, to match the picture quality of the other two video codecs. As of July 2008 over 70% of Blu-ray Disc titles have been authored with the newer compression standards: AVC and VC-1. HD DVD titles have used VC-1 and AVC almost exclusively since the format's introduction. Warner Bros., which used to release movies in both formats prior to June 1, 2007, often used the same encode (with VC-1 codec) for both Blu-ray Disc and HD DVD, with identical results. In contrast, Paramount used different encodings: initially MPEG-2 for early Blu-ray Disc releases, VC-1 for early HD DVD releases, and eventually AVC for both formats.
Whilst the two formats support similar audio codecs, their usage varies. Most titles released on the Blu-ray format include Dolby Digital tracks for each language in the region, a DTS-HD Master Audio track for all 20th Century Fox and many upcoming Universal titles, Dolby TrueHD for Disney and Sony Pictures and some Paramount and Warner titles, and for many Blu-ray titles a Linear PCM track for the primary language. On the other hand, most titles released on the HD DVD format include Dolby Digital Plus tracks for each language in the region, and some also include a Dolby TrueHD track for the primary language.
Interactivity
Both Blu-ray Disc and HD DVD have two main options for interactivity (on-screen menus, bonus features, etc.).
Blu-ray's basic mode is known as HDMV or BDMV ("High Definition Movie Mode" or "Blu-ray Disc Movie Mode"), whilst HD DVD's is known as "Standard Content". Both offer modest upgrades from standard DVD, such as the use of more buttons on-screen, a larger colour palette, and expanded programming environment. BDMV is more powerful than Standard Content, and has been used on many Blu-ray disc titles. Standard Content has been used less on HD DVDs. HD DVD's Standard Content is a minor change from standard DVD's sub picture technology, while Blu-ray's BDMV is completely new. This makes transitioning from standard DVD to Standard Content HD DVD relatively simple-- for example, Apple's DVD Studio Pro has supported authoring Standard Content since version 4.0.3. For more advanced interactivity Blu-ray disc supports BD-J while HD DVD supports Advanced Content.

Disc construction
Blu-ray Discs contain their data relatively close to the surface (less than 0.1 mm) which combined with the smaller spot size presents a problem when the surface is scratched as data would be destroyed. To overcome this, TDK, Sony, and Panasonic each have developed a proprietary scratch resistant surface coating. TDK trademarked theirs as Durabis, which has withstood direct abrasion by steel wool and marring with markers in tests.
HD DVD uses traditional material and has the same scratch and surface characteristics of a regular DVD. The data is at the same depth (0.6 mm) as DVD as to minimize damage from scratching. As with DVD the construction of the HD DVD disc allows for a second side of either HD DVD or DVD.
A study performed by Home Media Magazine (August 5, 2007) concluded that HD DVD discs and Blu-ray discs are essentially equal in production cost. Quotes from several disc manufacturers for 25,000 units of HD DVDs and Blu-rays revealed a price differential of only 5-10 cents. (Lowest price: 90 cents versus 100 cents. Highest price: $1.45 versus $1.50.) Another study performed by Wesley Tech (February 9, 2007) arrived at a similar conclusion. Quotes for 10,000 discs show that a 15 gigabyte HD DVD costs $11,500 total, and 25 gigabyte Blu-ray or a 30 gigabyte HD DVD costs $13,000 total. For larger quantities of 100,000 units, the 30 gigabyte HD DVD was more expensive than the 25 gigabyte Blu-ray ($1.55 versus $1.49).
Hybrid discs
At the January 8, 2007 Consumer Electronics Show, Warner Bros. introduced a hybrid technology, Total HD, that would reportedly support both formats on a single disc. The new discs would overlay the Blu-ray and HD DVD layers, placing them respectively 0.1 mm and 0.5 mm beneath the surface. The Blu-ray top layer would act as a two-way mirror, reflecting just enough light for a Blu-ray reader to read and an HD DVD player to ignore. But the following September, Warner President Ron Sanders said that the technology was on hold due to Warner being the only one that would publish on it.
As of January 4, 2008, Warner Bros. announced that they will be supporting the Blu-ray format exclusively after June 1, 2008. This news along with the end of the format war would indicate that the hybrid discs once announced by Warner Bros. will not be put into production.
Copy protection
The primary copy protection system used on both formats is the Advanced Access Content System (AACS). Use of AACS is optional for HD DVD, but mandatory for Blu-ray, which can add thousands of dollars to production costs. Other copy protection systems include:
Blu-ray Disc
HD DVD

• HDCP encrypted digital output
• ROM-Mark watermarking technology (physical layer)
• BD dynamic crypto (BD+)
• HDCP encrypted digital output

Region coding
The Blu-ray specification and all currently available players support region coding. As of July 2008 about 66.7% of Blu-ray Disc titles are region-free and 33.3% use region codes.
The HD DVD specification has no region coding, so an HD DVD disc from anywhere in the world will work in any player. The DVD Forum's steering committee has discussed a request from Disney to add it, but many of the 20 companies on the committee actively oppose it.
Many film titles that are exclusive to Blu-ray in the United States such as Sony's xXx, Fox's Fantastic Four: Rise of the Silver Surfer and Disney's The Prestige, are available on HD DVD in other countries due to different distribution agreements (in fact, The Prestige was released outside the US by once format-neutral studio Warner Bros. Pictures). Because of this, film titles that are exclusive to Blu-ray in the U.S. can be bought on HD DVDs by U.S. consumers purchasing them online from Europe or Asia. Since there is no region coding in HD DVDs, there are no restrictions playing these foreign-bought HD DVDs in an HD DVD player. Similarly, European customers can obtain HD DVD discs from American online retailers for titles that are Blu-ray exclusive or haven't yet been released in their own countries.
Retail price of consumer-writable discs
Disc BD-R
BD-R DL
HD DVD-R
HD DVD-R DL
DVD-R
DVD-R DL

Capacity 25GB 50GB 15GB 30GB 4.7GB 8.5GB
Bulk-Bought Cost $7.99 $21.27 $10.74 $19.85 $0.47 $2.00
Cost Per GB (full disc) $0.44 $0.47 $0.67 $0.62 $0.10 $0.23
Price/Cost Per GB (as of 21.02.2008) $11.99 / $0.48 $36.81 / $0.74 $7 / $0.47 $17.60 / $0.59 $0.47 / $0.10 $2.00 / $0.23
Disc being compared 1 non-rewritable single-layer disc (Verbatim 25GB 2X BD-R) 1 non-rewritable dual-layer disc (Panasonic 50GB 2x BD-R) 1 non-rewritable single-layer disc (Verbatim 15GB 1X HD DVD-R) 1 non-rewritable dual-layer disc (Verbatim 30GB 1X HD DVD-R DL) generic pack of discs generic pack of discs

Software standards
Codecs
Codecs are compression schemes that store audio and video more efficiently, optimizing for either low space usage or quality per megabyte. There are both lossy and lossless compression techniques.
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 MPEG-2, H.264/AVC, and SMPTE VC-1. MPEG-2 is the codec used on regular DVDs, which allows backwards compatibility. H.264/AVC was developed by MPEG and VCEG as a modern successor of H.263 . VC-1 is another MPEG-4 derivative codec mostly developed by Microsoft. BD-ROM titles with video must store video using one of the three mandatory codecs. Multiple codecs on a single title are allowed.
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. 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.
MPEG-2 was used by many studios, including Paramount Pictures (which initially used the VC-1 codec for HD DVD releases) for the first series of Blu-ray discs that were launched throughout 2006. Modern releases are now often encoded in either H.264/AVC or VC-1, allowing film studios to place all content on one disc, reducing costs and improving ease of use. Using these codecs will also free many GBs of space for storage of bonus content in HD (1080i/p) as opposed to the SD (480i/p) typically used for most titles. Some studios (such as Warner Bros.) have released bonus content on discs encoded in a different codec than the main feature title; for example the Blu-ray release of Superman Returns uses VC-1 for the feature film and MPEG-2 for bonus content (presumably because it is simply ported from the DVD release).
For audio, BD-ROM players are required to support Dolby Digital, DTS, and linear PCM. Players may optionally support Dolby Digital Plus and DTS-HD High Resolution Audio, as well as lossless formats Dolby TrueHD and DTS-HD Master Audio. BD-ROM titles must use one of the mandatory schemes for the primary soundtrack. A secondary audiotrack, if present, may use any of the mandatory or optional codecs.
For users recording digital television programming, the recordable Blu-ray Disc standard's initial data rate of 36 Mbit/s is more than adequate to record high-definition broadcasts from any source (IPTV, cable/satellite, or terrestrial). BD-Video movies have a maximum data transfer rate of 54 Mbit/s, a maximum AV bitrate of 48 Mbit/s (for both audio and video data), and a maximum video bitrate of 40 Mbit/s. This compares to HD DVD movies which have a maximum data transfer rate of 36 Mbit/s, a maximum AV bitrate of 30.24 Mbit/s, and a maximum video bitrate of 29.4 Mbit/s.

Digital rights management
The Blu-ray Disc format employs several layers of digital rights management.
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). Since keys can be revoked in newer releases, this is only a temporary attack and new keys must continually be discovered in order to decrypt the latest discs. This cat-and-mouse game has gone through several cycles and as of August 2008 all current decryption keys are available on the Internet.
BD+ was developed by Cryptography Research Inc. and is based on their concept of Self-Protecting Digital Content. 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:
• 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 available only to licensed device manufacturers. A list of licensed adopters is available from the BD+ website.
The first titles using BD+ were released in October 2007. 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+.BD+ protection was fully circumvented with the release 6.4.0.0 of Any DVD 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. 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 Bonus View BD-Live
Profile 3.0 Profile 1.0 Profile 1.1 Profile 2.0
Built-in persistent memory No 64 KB 64 KB 64 KB
Local storage capability No Optional 256 MB 1 GB
Secondary video decoder (PiP)
No Optional Mandatory Mandatory
Secondary audio decoder No Optional Mandatory Mandatory
Virtual file system
No Optional Mandatory Mandatory
Internet connection capability No No No Mandatory


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.
BD9/BD5 Blu-ray Disc
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 4482MB DVD5 single-layer disc.
BD9/BD5 discs can be authored using home computers for private showing using standard DVD±R recorders. AACS digital rights management is optional. The BD9/BD5 format was originally proposed by Warner Home Video, as a cost-effective alternative to regular Blu-ray Discs. It was adopted as part of the BD-ROM basic format, file system, and AV specifications. BD9/BD5 is similar to 3× DVD for HD DVD.
AVCREC
AVCREC is an official 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 tape less camcorders that record onto DVD and Blu-ray disks, as well as onto Secure Digital and Memory Stick 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.
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 wobbles 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.
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.
In February 2008, Taiyo Yuden, Mitsubishi and Maxell released the first BD-R LTH Discs, and in March 2008, Sony's PlayStation 3 gained official support for BD-R LTH Discs with the 2.20 firmware update.
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).




























Bibliography

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