4.1 What specifications govern BD discs?
4.2 What BD formats are available?
4.3 What are hybrid discs?
4.4 What file systems are used on BD discs?
4.5 What is the BD-R/RE AV format?
4.6  What is the BD-ROM AV format?
4.7 What is a Total Hi Def disc?
4.8 Are double-sided BD and BD/DVD Combo discs available?
4.9 What is a BD9 disc?
4.10 What are BD-Video, BD-Live, Blu-ray 3D and Ultra HD Blu-ray profiles?
4.11 How do BD, HD DVD and DVD video formats and player requirements compare?
4.12 What is the directory structure of a BD-ROM AV disc?
4.13 What is the directory structure of a BD-R/RE AV disc?
4.14 Can all BD players display BD-J content?
4.15 How long does it take a BD player to load and execute BD-J content?

4.1 What specifications govern BD discs?
All BD disc formats are governed by a variety of system descriptions (books) defining their mechanical properties, optical signal characteristics, physical arrangement, writing methods and testing conditions as well as file systems and applications (see figure 4.1).

Specifications for BD physical formats (BD-ROM, BD-R, BD-RE and BD Hybrid) and applications (BD-R/RE AV and BD-ROM AV incorporating HDMV and BD-J modes) were established and are continually updated by the Blu-ray Disc Association (BDA), an alliance of manufacturers founded in 2002 by Hitachi, LG Electronics, Matsushita Electric, Pioneer, Philips Electronics, Samsung Electronics, Sharp, Sony, and Thomson.

Currently, there are no plans to develop BD specifications into ECMA International or ISO/IEC standards.

4.2 What BD formats are available?
BD comes in prerecorded (BD-ROM), recordable (BD-R) and rewritable (BD-RE) configurations (see table).

Similar to familiar CD and DVD-ROM, BD-ROM discs have information permanently molded (pressed) into them at the factory and is typically used to distribute commercial content (movies, games, software, etc.).

Akin to CD-R and DVD±R, BD-R is the recordable format used for data storage as well as audio/video recording. It is write-once employing an inorganic material (or organic dye) recording layer to which information is written by means of a laser.

Resembling CD-RW and DVD±RW, BD-RE is the rewritable format incorporating a recording layer composed of a phase-change alloy that can be rewritten at least 1,000 times.

Initial BD-RE (rewritable) specifications (version 1.0) were released in 2002 to define 1x recording speed to single (SL) and dual-layer (DL) discs storing 23.3 GB/layer, 25 GB/layer and 27 GB/layer (reserved as a future possibility) in open or sealed cartridge types. In 2003 Sony marketed the first set-top BD-RE recorder designed to capture HD television broadcasts (Japan only). Due to various technological and manufacturing limitations, discs originally arrived in only sealed cartridges and were limited to 23.3 GB. Sealed cartridges were abandoned in late 2003 (version 1.1) with bare discs for most applications then mandated in 2004 (version 2.0) after suitable disc protective hard coatings became available. At the same time, 2x recording was established with 25 GB (SL) and 50 GB (DL) discs introduced to market.

In 2004 both BD-ROM (prerecorded) and BD-R (recordable) specifications (version 1.0) were released with single and dual-layer discs storing 23.3 GB/layer, 25 GB/layer and 27 GB/layer and with BD-R defining 1x and 2x recording. The first generation of drives, players and recorders were released in 2006.

In 2010, High Capacity BD (BDXL) was introduced in both BD-RE XL (rewritable) and BD-R XL (recordable) configurations. BD-RE XL specifications (version 4) define triple-layer (TL) discs storing 33.33 GB/layer with 2x recording speed. BD-R XL (version 3) defines triple-layer (TL) and quadruple-layer (QL) discs storing 33.33 GB/layer and 32 GB/layer respectively, with 2x and 4x recording speeds.

4.3 What are hybrid discs?
Manufacturers are experimenting with combining multiple physical formats in a single multilayer disc (BD Hybrid). Theoretically, a BD Hybrid disc could contain one or two BD layers (BD-ROM/R/RE) as well as one CD (CD-ROM/DA/R/RW) and/or one or two DVD layers (DVD-ROM/±R/±RW/RAM). Formally, an Intra-Hybrid Blu-ray Disc (IH-BD) combines different BD format layers while an Inter-Hybrid adds CD or DVD layers. Such combinations are possible because each format shares many physical characteristics (radius, thickness, spiral and rotational directions, etc.) but with, however, important differences (data layers residing at different depths, written and read using different wavelength lasers, etc.).

Realistically speaking, it’s unclear if hybrid discs can be cost effectively mass-produced (manufacturing challenges, multiple format patent royalties, etc.) and even if there is sufficient market need or interest to warrant their development and introduction.

4.4 What file systems are used on BD discs?
While it is possible for BD discs to employ any number of file systems, the Universal Disc Format (UDF) developed by the Optical Storage Technology Association (OSTA) is specified for most applications. UDF version 2.5 applies to BD-ROM and BD-RE and both UDF version 2.5 and 2.6 to BD-R.

Be aware that, unlike Windows Vista and Windows 7, Windows XP does not natively support these UDF versions. Thus, it is necessary with XP to install a compatible driver or packet writing software (e.g. CyberLink’s InstantBurn, Nero’s InCD, Software Architects’ WriteUDF!, etc.) to access the directories and files contained on most BD discs.

4.5 What is the BD-R/RE AV format?
BD-R/RE Audio Visual (BD-R/RE AV) is an application format designed to record and play back full quality high (HD) and standard (SD) definition digital television broadcasts on BD-R (recordable) and BD-RE (rewritable). It can also be used to capture SD material from analog sources and direct transfers from HDV camcorders. Typically, up to 2 hours of HD material can be stored on a 25 GB single-layer (SL) disc or 12 hours of VHS-quality SD material (double that on dual-layer discs). A basic framework for navigating the recorded material as well as destructive and non-destructive editing is also provided. Occasionally, BD-R/RE AV is incorrectly identified as BD-AV or BDAV.

Whereas DVD-Video employs the ISO/IEC 13818-1 MPEG-2 Program Stream (PS) as its video and audio multiplexing format, BD-R/RE AV, however, adopts MPEG-2’s Transport Stream (TS). With its smaller 188-byte packet size, ability to multiplex multiple channels and electronic program guide (EPG) information, MPEG-2 TS is better suited for recording and playing digital broadcasts. Since a digital broadcast can contain multiple television and audio channels in a full transport stream, BD-R/RE AV allows individual channels to be selected, extracted and recorded to form a partial transport stream (without the need to re-encode the audio or video).

Structurally (see figure 4.2), the BD-R/RE Transport Stream (BDAV MPEG-2 TS) encapsulates Packetized Elementary Streams (PES) of audio and video inside a series of Source Packets (192 bytes each). Clusters of 32 Source Packets are then grouped together to form Aligned Units (6144 bytes each), which are, in turn, stored in sequences of three consecutive logical sectors on a BD disc (2048 bytes per sector x 3 sectors each).

In addition to digital broadcasts, BD-R/RE AV incorporates a Self-Encoded Stream Format (SESF) for recording SD analog broadcasts and other material. With SESF, the source video signal is encoded in MPEG-2 (MP@ML) format and multiplexed with its audio (MPEG-1 Layer 2, LPCM, Dolby Digital AC-3), teletex information (PAL option only) and Tip data (video aspect ratio, copy control, coding, etc.) to again create a partial transport stream (see tables).

BD-R/RE AV also accepts material captured by an HDV camcorder. HDV streams are already MPEG-2 format so they do not have to be re-encoded to create the partial transport stream and can be directly transferred for recording by using a standard IEEE 1394 (FireWire/i.LINK) interface.

BD-R/RE AV employs a two layer (Clip and PlayList) organizational structure to manage captured audio and video. The Clip Layer is concealed from the user and contains the partial transport streams (stored as clip AV stream files) as well as an equal number of clip information files, each consisting of descriptive details (type, sequence, program and timing) directly corresponding to each stream. The combination of each AV stream and associated information file is called a clip.

The Playlist Layer allows the user to view, edit and stitch together clips through a system of playlists (stored as playlist files). A playlist can be either real or virtual and contains one or more playitems, each consisting of a set of start and end pointers to define a range of playback time within a clip.

When each clip is initially recorded a matching real playlist (containing a playitem delimiting the clip’s entire playback time) is automatically generated. Real playlists can also be divided or combined by the user and deleting an entire real playlist or segment will erase the associated clip or clip portion from the disc.

In contrast, a virtual playlist is always created by the user and contains playitems that point to segments of real playlists. Thus, changes made to a virtual playlist do not affect the original clips so multiple real playlists can be segmented and grouped in any order to form continuous playback sequences. Seamless connection is possible by creating and referencing an optional bridge clip inserted at the edit point between two clips. Virtual playlists also enable audio dubbing to add sound to a clip after it has been recorded. Here, a playitem points to the real playlist of one clip (main path) and a subplayitem to the real playlist of a second clip (sub path). Video from the main path can then be played simultaneously with audio from the sub path.

Other BD-R/RE AV features include thumbnails (display images representing the disc and playlists), marks (bookmarks for jumping to specific clip locations, resuming from a location after stopping playback, etc.), naming (assigning titles to discs and playlists), write protection (to prevent modifying or deleting playlists), password protection (PIN required to initiate playback) and others.

4.6 What is the BD-ROM AV format?
BD-ROM Audio Visual (BD-ROM AV) is an application format designed to meet the requirements of the film industry for distributing high definition (HD) commercial movies on BD-ROM (prerecorded). Through its High Definition Movie (HDMV) mode, BD-ROM AV offers the most recognizable features of DVD while adding support for HD video, the latest multi-channel audio technologies as well as more sophisticated navigation and elaborate visual possibilities. An additional Blu-ray Disc Java (BD-J) mode extends these capabilities still further through a fully programmable application framework enabling multifaceted interactivity as well as optional Internet and network connection. Occasionally, BD-ROM AV has been incorrectly called BD-MV or BDMV.

BD-ROM AV adopts the same MPEG-2 Transport Stream (TS) format as BD-R/RE AV. When a disc is initially authored and encoded each component (video, audio, text subtitle and graphics) elementary stream (ES) is packetized and multiplexed (muxed), along with other information, to form the transport stream (maximum bitrate 48Mbps).

HDMV Mode:  HDMV mode can supplement the multiplexed stream with individual streams stored separately but decoded at the same time (out-of-mux) to enable additional features (text subtitle, pop-up menu, button sounds, browsable slideshow) without consuming valuable space in the main stream and allowing for possible additions and substitutions.

The playback image is formed by simultaneously overlaying five independent (primary video, secondary video, presentation graphics, interactive graphics, BD-J background) image planes, each up to full HD resolution (1920×1080) and fed by their own streams (see figure 4.3). Dual video planes enable picture-in-picture (PiP) playback with the secondary plane (typically displaying supplemental material) scaled, positioned and superimposed (luma keying is optional) over the primary plane (displaying the main feature).

Even a single hour of high-definition video can occupy hundreds of gigabytes of space. To allow a serviceable amount of material to fit on a single BD disc, video is compressed using one of three codecs: MPEG-2, MPEG-4 AVC/H.264, and VC-1. Though the choice of scheme is made while encoding the source material before or while authoring the disc, every BD playback device is designed to decode all three codecs.

Specifically, BD-ROM AV supports up to nine video streams (including the primary and secondary) encoded in MPEG-2, MPEG-4 AVC and VC-1 with a maximum bitrate of 40 Mbps (see table). Depending upon the codec, resolutions ranging from 720×480 (SD) to 1920×1080 (HD) are supported, as are 4:3 and 16:9 aspect ratios as well as interlaced and progressive scan (see tables).

BD-ROM AV allows for 32 audio streams (including a primary and secondary associated with corresponding primary and secondary video streams) in up to eight channels and up to 24-bit/192kHz quality to accompany the video. Audio can be compressed using one or more of a variety of specified constant (CBR) and variable bitrate (VBR) codecs with the scheme(s) chosen while encoding the source material before or while authoring the disc.

The primary audio stream supports Linear Pulse Code Modulation (LPCM), Dolby Digital (AC-3), Dolby Digital Plus (DD+), Dolby Lossless (a superset of Dolby TrueHD), DTS Digital Surround (DTS), DTS-96/24, DTS-ES and DTS-HD (formerly DTS++) which includes DTS Core, DTS-HD High Resolution Audio (DTS-HD HR) and DTS-HD Master Audio (DTS-HD MA), as well as DigiRise DRA (added Mar. 2009 in BD-ROM 2.0 Part 3 v.2.3 specifications). For the secondary audio stream, Dolby Digital Plus and DTS Express (formerly DTS-HD LBR) are defined while interactive audio exclusively employs LPCM (see tables).

Each BD playback device is designed to decode LPCM, Dolby Digital and DTS Digital Surround with the other codecs available as options. Since a BD device might be equipped with only the mandatory Dolby Digital and DTS Digital Surround decoders, the optional Dolby Digital Plus, Dolby Lossless and DTS-HD Master Audio streams additionally incorporate companion Dolby Digital or DTS Digital Surround bitstreams to ensure at least minimum playback compatibility. Further, any BD-ROM AV disc that employs DigiRise DRA must also include an accompanying LPCM, Dolby Digital or DTS Digital Surround stream.

The presentation graphics plane (HDMV and BD-J modes) displays graphic or text-based subtitles separately while the interactive graphics plane (HDMV mode) carries graphic menus. Graphics are full color bitmaps with various visual effects available (fade, wipe, scroll, etc.) while text subtitles (HDMV mode) consist of vector-based international characters with font, style, color and position information along with similar effects (see tables). An HDMV mode movie title can also be authored to offer users a choice of text sizes, colors and display positions. The text subtitle stream is stored and read out-of-mux so multiple subtitle streams can be made available and accessed without consuming space in the main AV stream.

HDMV mode incorporates several types of visual menus (pop-up, multi-page, always-on) to contain information and assorted buttons for navigation and feature control. A pop-up menu can be activated over top of a playing (or paused) movie without interrupting the audio and video underneath as can a multi-page menu consisting of interconnected screens. Each is stored as an out-of-mux stream and is preloaded into the BD player’s buffer before playback begins. An always-on menu is akin to that on conventional DVD and is preloaded or multiplexed with the video stream.

Menu buttons can have three states (normal, selected, activated), each with its own appearance and attributes. Buttons can be made visible or invisible on the fly as they are enabled or disabled and, in selected and activates states, trigger brief out-of-mux sounds (clicks, voice, music, etc.) then mixed with any underlying audio.

Another feature of HDMV mode is the browsable slideshow consisting of still images with optional accompanying audio (out-of-mux). Users can view and navigate pictures or photos without interrupting the music, sounds or voices playing in the background.

BD-J Mode: BD-J mode builds on HDMV mode’s features, adding a fully programmable application environment, frame accurate animation, interactive audio (up to eight simultaneous channels), Internet and network connection (TCP/IP, HTTP) as well as control over local storage devices such as flash memory or hard drives. This enables sophisticated interactivity and content extension for an entire disc or individual titles on a disc. For example, a commercial film might employ BD-J mode to offer resident games and puzzles with access to online bonus material, new theatrical previews, alternate endings, additional languages or commentaries (downloaded as new clips and playlists) and still others.

BD-J mode is based on several established interface and object oriented programming standards. Specifically, it is fully compliant with Java 2 Micro Edition (J2ME) Personal Basis Profile (PBP 1.0) and incorporates the package media target profile extension of the Globally Executable Multimedia Home Platform (GEM 1.0.2). The framework for BD-J’s graphical user interface (GUI) employs Java’s Abstract Window Toolkit (AWT), mechanisms from GEM 1.0.2 as well as extensions to the Home Audio Video Interoperability (HAVi) user interface (UI) device model and widget set.

Organizational Structure: BD-ROM AV employs a four layer (Clip, PlayList, Object, Index Table) organizational structure to manage its video, audio, text subtitle and graphics elements (see figure 4.4). The first two layers mirror those of BD-R/RE AV.

The Clip Layer contains the transport streams (stored as clip AV stream files) as well as an equal number of clip information files, each consisting of descriptive details (type, sequence, program and timing) directly corresponding to each stream. The combination of each AV stream and associated information file is called a clip.

The PlayList Layer contains multiple playlists (stored as playlist files) holding one or more playitems and subplayitems, each consisting of sets of start and end pointers to define ranges of playback times within any number of clips. This structure enables out-of-mux presentation of supplementary material (text subtitles, button sounds, accompanying audio streams, etc.). The playitem points to the playlist of the main AV clip (main path) and the subplayitem to the playlist of a separate clip (sub path) that can be synchronized with or treated independently of audio and video on the main path.

The Object Layer contains various Movie Objects (HDMV mode) and/or BD-J Objects (BD-J mode) stored, respectively, as movie object or java object files. A Movie Object is a set of navigation commands that initiate playlist playback upon user instruction and executes another Movie Object. A BD-J Object is a table of Java applications or command programs (Xlets) that trigger playlist playback, other Movie or BD-J Objects and Java programs.

The Index Table (stored as an index table file) is the highest level of organization. It defines all Titles (movies, video programs, music albums, etc.) and defines their entry points as well as those for optional First Playback and Top Menu functions (each is linked to a corresponding Movie or BD-J Object). First Playback designates a specific Movie or BD-J Object to be automatically executed when the disc is first loaded into the BD player. Top Menu points to a Movie or BD-J Object referencing a clip containing a menu (typically the main menu) and can be accessed by a user triggering the BD player’s Menu Call feature. The BD player calls on the Index Table whenever it accesses a Title or Menu (Title Search, Menu Call, etc.) in order to identify the correct Movie or BD-J Object to be executed.

4.7 What is a Total Hi Def disc?
Total Hi Def (THD) brings together prerecorded Blu-ray Disc (BD-ROM) and HD DVD-ROM physical formats in a single disc. THD is double-sided (DS) containing one or two prerecorded BD-ROM layers (25 GB or 50 GB) on its top side and one or two HD DVD-ROM layers (15 GB or 30 GB) on its flip side. Warner Bros. (Warner Home Video, HBO Video, New Line Home Entertainment) originally planned to offer THD discs in the second half of 2007 but has since put those plans on hold indefinitely.

4.8 Are double-sided BD and BD/DVD Combo discs available?
While all currently available prerecorded BD-ROM discs are single-sided (SS) it is technically possible to manufacture double-sided (DS) varieties such as those that incorporate DVD-ROM, BD-ROM or HD DVD-ROM (e.g. Total Hi Def) layers on each side.

Realistically speaking, it’s unclear if double-sided BD discs of any type can be cost effectively mass-produced (manufacturing challenges, multiple format patent royalties, etc.) and even if there is sufficient market need or interest to warrant their development and introduction.

4.9 What is a BD9 disc?
A BD9 is a prerecorded DVD-ROM disc designed for playback in BD players that contains audio and video authored in the same format employed in commercial BD-ROM movies (BD-ROM AV). BD9 is part of the official BD family and defined in the BD-ROM basic format (part 1), file system (part 2) and AV (part 3) specifications.

Physically, a BD9 is simply a 12 cm DVD-ROM disc with standard 4.7 GB (single-layer) or 8.5 GB (dual-layer) capacities but is fabricated to somewhat tighter specification for dynamic imbalance. It is also spun at three times the normal speed of a DVD resulting in a proportionally higher data transfer rate (33.24 Mbps vs. 11.08 Mbps).

In terms of its logical and application formats, BD9 employs the same file system (UDF 2.5), content protection (AACS, BD+, ROM Mark) and structure (BD-ROM AV HDMV/BD-J) used by commercial BD-ROM movies. As such BD9 offers identical features to BD-ROM although there are some restrictions (transport stream maximum data rate 28 Mbps vs. 48 Mbps) arising from its somewhat lower performance (user data rate 33.24 Mbps vs. 53.948 Mbps).

BD9 is intended to leverage existing DVD manufacturing infrastructure in order to potentially provide a lower cost vehicle for publishing budget and lesser quality high definition titles, short studio and independent movies and presentations, television shows, music albums as well as bonus content. However, given its lower capacity and rapidly declining BD-ROM production costs, BD9 is not widely promoted and may remain a seldom-used curiosity. As of Oct. 2009, no BD9 titles have yet been announced.

4.10 What are BD-Video, BD-Live, Blu-ray 3D and Ultra HD Blu-ray profiles?
Features obviously vary among models and versions from different manufacturers and publishers but there are four basic types of BD consumer electronics (CE) players and computer playback software (BD-Video, BD-Live, Blu-ray 3D and Ultra HD Blu-ray).

In specific terms, the BD-ROM AV format (used by commercial movies) defines separate BD-Video, BD-Live, Blu-ray 3D and Ultra HD Blu-ray profiles, each outlining several advanced capabilities that must be supported in their respective conforming players and software. These include local (persistent) storage, Virtual File System (VFS), picture-in-picture (PiP), audio mixing (secondary audio), Internet connection through a network as well as stereoscopic 3D and Ultra High-Definition (Ultra HD) video (see table).

BD-Video 1.0 (profile 1 Final Standard Profile) players and software must have available at least 256 MB of local storage (built-in or removable flash memory, hard drive, etc.) and incorporate VFS, secondary audio mixing and PiP. Be aware that an initial grace period (ended Oct. 31, 2007) allowed manufacturers to forego these features. Manufacturers and content publishers are strongly encouraged (but not required) to use the name BONUSVIEW on products, packaging and marketing material to identify players, software and movie titles compliant with Final Standard Profile specifications. BD-Live (profile 2) includes these capabilities but expands local storage to at least 1 GB while adding the ability to access the Internet. Blu-ray 3D (profile 5) and Ultra HD Blu-ray (profile 6) go even further and enable stereoscopic 3D and Ultra High-Definition (Ultra HD) video playback.

For a list detailing the profile compliance of various BD consumer electronics players see: 17.3 How much do consumer electronics BD players cost?

4.11 How do BD, HD DVD and DVD video formats and player requirements compare?

4.12 What is the directory structure of a BD-ROM AV disc?
BD-ROM AV content is arranged on a disc in a straightforward hierarchy of mandatory and optional file directories and subdirectories (see figure 4.5). These include:

ROOT: Disc root directory containing index table (index.bdmv) and movie object (MovieObject.bdmv) files as well as all directories (BDMV, PLAYLIST, CLIPINF, STREAM, AUXDATA, META, BDJO, JAR, BACKUP, CERTIFICATE, AACS, BDSVM)

BDMV: Parent directory containing all BD-ROM AV subdirectories

PLAYLIST: Subdirectory containing movie playlist files (xxxxx.mpls)

CLIPINF: Subdirectory containing clip information files (xxxxx.clpi)

STREAM: Subdirectory containing clip AV stream files (xxxxx.m2ts)

AUXDATA: Subdirectory containing interactive graphics sounds (sound.bdmv) as well as font (xxxxx.otf) and font index (bdmv.fontindex) files for text subtitles

META: Subdirectory containing metadata disc library (dlmt_000.xml) and title scene (esmt_000_xxxxx.xml) search files

BDJO: Subdirectory containing BD-J Object files (xxxxx.bdjo)

JAR: Subdirectory containing BD-J Java Archive files (xxxxx.jar)

BACKUP: Subdirectory containing backup copies of primary files (index.bdmv, MovieObject.bdmv) and subdirectories (PLAYLIST, CLIPINF, BDJO, JAR)

CERTIFICATE: Directory containing BD-J root certificate (app.discroot.crt) and ID information (id.bdmv)

AACS: Directory containing AACS decryption files (Content000.cer, Content001.cer, ContentHash000.tbl, ContentHash001.tbl, ContentRevocation.lst, CPSUnit00001.cci, CPSUnit00002.cci, mcmf.xml, MKB_RO.inf, MKB_RW.inf, SKB1.inf, SKB2.inf Unit_Key_RO.inf) and DUPLICATE subdirectory

BDSVM: Directory containing BD+ content code files (xxxxx.svm) and BACKUP subdirectory

4.13 What is the directory structure of a BD-R/RE AV disc?
BD-R/RE AV content is arranged on a disc in a straightforward hierarchy of mandatory and optional file directories and subdirectories (see figure 4.6). These include:

ROOT: Disc root directory containing all directories (BDAV, AACS, BDAV1, BDAV2, BDAV3…)

BDAV: Parent directory containing management and playlist information (info.bdav), menu thumbnail index (menu.tidx), menu thumbnail (menu.tdt1, menu.tdt2), mark thumbnail index (mark.tidx) and mark thumbnail (mark.tdt1, mark.tdt2) files and all BD-R/RE AV subdirectories (PLAYLIST, CLIPINF, STREAM)

PLAYLIST: Subdirectory containing real (xxxxx.rpls) and virtual (xxxxx.vpls) playlist files

CLIPINF: Subdirectory containing clip information files (xxxxx.clpi)

STREAM: Subdirectory containing clip AV stream (xxxxx.m2ts) and DV stream (xxxxx.dvsd) files

BDAV1, 2, 3: Directories containing backups of all BDAV management information files and subdirectories

AACS: Directory containing Read/Write Media Key Block (MKB_RW.inf) file and AACS decryption subdirectory (AACS_av)

AACS_av: Subdirectory containing AACS CPS Unit Key (Unit_Key_RW.inf), CPS Unit Key backup (BAK_Unit_Key_RW.inf) and CPS Unit Usage (CPSUnit00001.cci, CPSUnit00002.cci…) files

4.14 Can all BD players display BD-J content?
Blu-ray specifications require all BD players and playback software to be fully compatible with discs authored in the BD-ROM AV format. They must, therefore, display content authored in both its BD-Java (BD-J) and High Definition Movie (HDMV) modes. Sometimes, BD-ROM AV’s BD-J mode is incorrectly confused with its profiles (BD-Video, BD-Live, Blu-ray 3D, Ultra HD Blu-ray), which define various advanced features such as Internet/network connection, local storage, Picture-in-Picture (PiP), stereoscopic 3D, Ultra HD and others.

4.15 How long does it take a BD player to load and execute BD-J content?
The speeds at which BD players load and execute BD-Java (BD-J) content vary among models and versions from different manufacturers. Initially, there were no official requirements for BD-J mode but now Blu-ray players and playback software conforming to BD-ROM 2.0 Part 3 v.2.3 specifications (released Mar. 2009) must meet minimum standards for video and audio start times, image loading and drawing (JPEG/PNG graphics), font rendering (Roman/CJK characters) and animation, as well as microprocessor performance (measured by EEMBC’s GrinderBench).