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Authoring
The process of designing, creating, capturing, editing, and integrating information for a CD or DVD. Or, creating a database for a CD or DVD using tagging and indexing that generates a search and retrieval document.
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Bit
One binary information element having the value ZERO or ONE.
Bit Error Rate (BER)
Probability that a read bit does not match the written bit.
Block
Group of contiguous recorded characters treated as a unit and containing one or more logical records. A logical block contains 512x28 bytes, where n is an integer (0, 1, 2, ...) Normally used to characterize a DVD ECC block or a CD subcode block, or section, but can also refer to a CD frame.
Block Error Rate (BLER)
Number of blocks, each containing one or more erroneous bits, per unit of time (usually seconds).
Blu-ray Disc (BD)
120 mm optical disc achieving very high density through use of 405 nm blue-violet lasers, high numerical aperture optics, and, optionally, multiple information layers.
Blue Book
Proprietary Philips/Sony specification (blue cover) for Enhanced Music CD.
Burn
To record data to a removable disc. Typically used to record a music playlist to a recordable CD or a video production to a recordable CD or DVD.
Byte
Contiguous set of eight data bits, represented by an equal or greater number of channel or recorded bits.
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CD-DA
CD-Digital Audio using 16 bits of linear coding to represent each digital sample of an audio channel. First specified in the Red Book, later in IEC 908 (also see Digitize.)
CD-R
CD-Recordable, write once-read many disc specified by Orange Book Part II using a pre-stamped, wobbled groove to guide a write laser that irreversibly changes regions of a dye polymer layer to an optically absorbing state. A special drive is required for writing.
CD-ROM
CD-Read Only Memory, first specified in the Yellow Book, later in ISO/IEC 10149 (Second Edition 1995).
CD-RW
CD-ReWritable phase change media specified by Orange Book Part III that can be reversibly recorded, erased, or overwritten. Uses a pre-stamped groove to guide a write laser. Data is contained in an alloy layer that can be converted by a laser from a reflective crystalline state to a non-reflective amorphous state or erased back to the crystalline state, depending on laser power. A special drive is required for writing, but CD-RW recorded media can be read in modified CD-ROM drives capable of detecting the low light levels resulting from CD-RW reflectivity of 15-25%. (Formerly CD- Erasable or CD-E.)
Closed-Caption
Text characters invisibly buried within a video signal, which can be decoded and displayed decoded and displayed as subtitles by the television set. Independent of any subtitle streams included in a DVD-Video track.
Compact Disc (CD)
An optical digital disc format used both for prerecorded content, especially music (CD-Audio), and as recordable media for consumer devices and computers (CD-R and CD-RW). The full-size 120mm (12cm) diameter disc originally stored 650MB, or 60 minutes of CD-Audio, now also available in 700MB/80-minute capacity. Also available in smaller sizes and specialty shapes (business cards, for example). See also CD-R, CD-ROM, CD-RW, DVD, Video CD.
Compression
Decreasing the size of stored information by reducing the representation of the information without significantly diminishing the information itself, usually by removing redundancies. Requires decompression upon retrieval. Lossless compression allows the original data to be recreated exactly. Lossy compression sacrifices some accuracy to achieve greater compression. Fixed rate compression, such as MPEG-1, has been superceded by variable bit rate compression methods, such as MPEG-2, that dynamically adjust the compression ration between fixed upper and lower bounds depending on the complexity of the original information. Compression ratios can reach 175:1 depending on the specific coder/decoder (codec).
Conversion
Data transfer from one type of media to anotherþ often using DLT or 8 mm tape or CD-R as input.
Copy Protection
Mechanisms designed to protect DVD content from being copied. These include the Macrovision APS to prevent copying the analog video signal and the Copy Generation Management System (CGMS) to specify how many copies may be made of the disc.
CSS
Acronym for Content Scrambling System. The DVD Video copy-protection mechanism that encrypts the DVD digital data to prevent it from being read without the proper decryption key. See also content protection.
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Data Area
Logical sectors in a volume containing descriptors, path tables, and files.
Data Bit
Information received from the host for storage or transmitted to the host after retrieval.
Data Field
A fixed length field containing the user information in a sector.
Digitize
Conversion of a sampled analog or continuous signal into a series of binary ones and zeros. Used for audio, graphic images, or physical measurements. Sampling frequency and number of binary elements affects accuracy of conversion back to analog form.
Directory
A file in a single extent belonging to only one directory hierarchy that contains contiguous records, each of which describe a file section or another directory.
Directory Hierarchy
One set of path tables and a multilevel set of directories defined by a volume descriptor and having a common character set and other properties.
Disc
Term commonly used to refer to optical storage devices such as DVD and CD. See also disk.
Disc Image
A single file that contains the data for a complete DVD production. A disc image can be burned very efficiently to a DVD disc because it is in exactly the format that the data will be stored on a DVD. The disc image can be recorded directly to DVD to create the proper data structures and DVD volume directories. It also can be transferred to DLT tape to be used at a replication facility to manufacture multiple copies of the disc.
Disk
Term commonly used to refer to magnetic storage devices such as hard disks. See also disc.
DLT
Acronym for Digital Linear Tape. A half-inch magnetic tape format used extensively for computer file backup and retrieval. Commonly used for transferring premastered DVD productions to a replication facility for manufacturing.
Dropout
Significant loss of signal amplitude capable of affecting data and servo accuracy, usually related to a physical defect.
Duplication
Production of a copy using sequential, serial transfer of information elements from an original image to a duplicate. Low mastering and equipment costs and short preparation times are offset by low throughput, often limiting use to low volumes. Examples would be CD-R duplication from a digital master, or making copies of text using a line printer.
DVD
Originally an acronym for Digital Versatile Disc (or Digital Video Disc). A family of optical disc formats used both for prerecorded content, especially movies, and as recordable media for consumer devices and computers (that is, DVD-ROM, DVD-R, DVD-RW, DVD-RAM). A family of data format standards for video, audio, and data storage (that is, DVD-Video and DVD-Audio) for consumer electronics products and computers. DVD discs are the same diameter as CD discs (120mm. or 12 cm, in diameter), and most formats hold 4.7GB (actually billion bytes) of data on a side. A smaller size mini-DVD disc is also used, especially in camcorders.
DVD-5
Single-sized DVD disc format, with a storage capacity of 4.7GB (actually billion bytes).
DVD-9
Dual-layer DVD disc format, with a storage capacity of 8.5GB (actually billion bytes).
DVD-10
Double-sided DVD disc format, with a storage capacity of 9.4GB (actually billion bytes).
DVD-R
DVD Recordable. The DVD Forum-defined write-once DVD format. Because the data cannot be erased, the DVD-R is useful for making permanent backups. Recordable discs are more compatible with set-top DVD players than rewritable discs.
DVD+R
Alternate DVD - Recordable write-once format developed by the DVD+RW Alliance.
DVD-ROM
DVD Read-Only Memory. The DVD Forum-defined, read-only DVD format. Used for prerecorded audio and data. Also the computer-readable content on a DVD-Video disc.
DVD-RW
DVD ReWritable. The DVD Forum-defined, re-recordable DVD format. Like CD-RW, rewritable discs can be reused, but are more expensive than recordable, and are less compatible with set-top players.
DVD+RW
Alternate DVD ReWritable format developed by the DVD+RW Alliance. Intended to replace the capabilities of DVD-RW and DVD-RAM and also provide higher compatibility with set-top players.
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Enhanced Music CD
Multisession CD-DA and CD-ROM disc specified in Blue Book playable as an audio CD without data-generated static.
Entrance Surface (Readout Surface)
Substrate surface nearest to the optical pickup head where the laser beam enters and, after reflection, exits.
Equalizer
Electronic circuit that compensates for low read signal amplitudes from short pits (marks) and lands that result from optical bandwidth limits related to diffraction limited spot sizes and other effects.
Erasure Byte
Byte of known location containing one or more erroneous bits flagged by error detection for processing in a subsequent operation.
Error Byte
Byte of unknown location containing one or more erroneous bits.
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Father
The first electroformed part made from a glass master and containing a reversed data image of the final disc.
File
Named collection of information stored in one or more extents.
File Section
Part of the file that is stored in any one extent and identified by a descriptor in a directory.
Finalization
Action in which lead-in and lead-out areas are recorded that must be performed at the end of a recording operation if the disc is to be readable in a conventional drive. Also referred to as closure.
Format
Structure used to organize data for information storage and retrieval.
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GB
Gigabyte, 1 GB equals 1024 megabytes. Gb may denote gigabits.
Glass Master
Data image of the final CD or DVD disc generated by a Laser Beam Recorder (LBR), normally consisting of a thin photosensitive organic layer supported by a polished, optically flat glass substrate.
Green Book
Proprietary Philips/Sony specification (green cover) for CD.
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HD DVD
120 mm optical disc achieving very high bit density through of 405 nm blue-violet lasers, high numerical aperture optics, and, optionally, multiple information layers.
Header
Area appended to and preceding user data containing addressing, format, and other information.
HF
Analog signals containing High Frequency data information in contrast to low frequency servo information.
HFS
Hierarchical File Structure defining the native Apple MacIntosh format for mass storage.
Hybrid
Disc containing both an ISO 9660 (MS-DOS) partition and an HFS partition. Or, a disc containing both ISO 9660 and UDF volume and file structures. Or, may indicate that the first session of a multi- session CD-R or CD-RW disc is a mastered session followed by recorded sessions.
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Image
Fully premastered data assembled in the exact format for recording.
Index
Searchable points within a CD track, up to 99 index points per track.
Indexing
Creation of a data index to speed up search and retrieval.
Information Area
One area of a physical track consisting of one lead-in (with TOC), one program area, and one lead- out.
Information Layer
Physical layer of a CD or DVD disc that contains optically recoverable data after replication or recording.
Injection Molding
Replication involving injection under pressure of molten plastic into the cavity of a mold followed by cooling and removal of the solidified part that retains a replica of the mold.
Interchange
Capability of media to function properly in various systems.
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kB
Kilobyte, 1 kB equals 1024 bytes. kb may be used to denote kilobits.
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Laser
Light Amplification by Stimulated Emission of Radiation generates monochromatic, coherent light, usually from an excited gas or semiconductor.
Lead-In
Area at the beginning of a disc or session containing the Table of Contents (TOC) and other important information. Lead-in is followed by the Program Area.
Lead-Out
Buffer area following the Program Area used in case the player reads past the track.
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Master
Physical entity containing an image for duplication or replication (also see Glass Master.)
Mastering
The process of recording pre-mastered data on a master. The data source is sometimes referred to as a gold master.
MB
Megabyte, 1 MB equals 1024 kB. Mb may denote megabits.
Menu
The main mechanism for navigating DVD productions. Typically consists of a background (still image or motion video), title text, buttons to link to different elements of the DVD (menus or video tracks), and background audio. The viewer interacts with the menu by pressing the up, down, left, and right keys on the Remote Control to cycle through the buttons; and then presses Select to activate the currently-highlighted button.
Mini-DVD
A smaller-diameter DVD disc format, especially for use in portable camcorders. The disc diameter is 8cm (80mm), compared to 120mm (12cm) for full-size DVD discs.
Mixed Mode
CD-ROM and CD-DA on the same disc, data on track 1, audio on tracks 2 up to 99.
Modulation
Conversion of data bits to channel bits that normally enhances storage capacity and minimizes low frequency components of recorded information that might interfere with servomechanism functions.
Mother
The electroformed part made from a father and containing a data image of the final disc.
MPEG
Motion Pictures Expert Group compression methods for video, graphics, or audio information. MPEG-1 uses a fixed compression ratio while subsequent methods, such as MPEG-2 and MPEG-4, use variable bit rate compression.
Multimedia
Integration of more than one form of information, such as text, graphics, audio, video, animation, and computer data.
Multisession
Multiple incremental recording events, or sessions, using non-incremental session-at-once or incremental track-at-once writing, each recording event resulting in a new lead-in (with TOC), program area, and lead-out. Multiple recording events at different times result in multiple sessions with a distinct TOC for each session.
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NTSC
National Television Systems Committee organized by the Electronic Industries Association for the development of NTSC commercial television standards used in the United States and also Canada, Japan, and other countries. Black-and-white TV uses a scanning system of 525 lines at 60 fields per second. Color uses 525 lines at 59.94 fields per second with a 3.58 MHz color subcarrier.
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Optical Disc
Removable storage medium, such as DVD and CD, that is read (and written) with laser light.
Orange Book
Proprietary multipart Philips/Sony specification (orange cover) for magneto-optical, CD-R, and CD- RW optical discs.
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Packet
Integral number of sectors forming a single unit of information that can be incrementally written or overwritten.
PAL
Phase Alternate Line video standard used in Europe and other parts of the world for composite color encoding, using 625 lines at 50 fields per second with a 4.438 MHz color subcarrier, although other scanning systems may be used.
Partition
An extent of logical sectors within a volume; partitions may be allowed to overlap.
Photo CD
Proprietary Eastman Kodak method of storing photographs on CD described in the Beige Book, using elements of Yellow Book, Orange Book, and CD-ROM XA.
Pit
Information area viewed as a depression from the label surface that can be sensed by an optical system.
PQ Information
Subcode information determining track start points, control bits, timing, and other information.
Pre-Gap
Two second first part of a CD program area or track, normally encoded as null data or audio silence, but should contain track descriptor blocks if session-at-once or incremental track-at-once recording is used.
Premastering
Generating an image ready for mastering and replicating by formatting data into the exact sector, volume, and file structure required by the applicable standard.
Protective Coating
Layer applied over the metal coating. Often a spin-coated UV-curable polymer.
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Record
A sequence of bytes treated as a unit of information.
Recordable
Storage medium that can only be read, not modified, after information is initially written.
Red Book
Proprietary Philips/Sony specification (red cover) for CD-Audio, subsequently published as IEC 908.
Record
A sequence of bytes treated as a unit of information.
Recordable
Storage medium that can only be read, not modified, after information is initially written.
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Sample
Value of an analog or continuous signal at a single point of time (see Digitize.)
Section
CD information group containing 98 consecutive frames of interleaved bytes from scrambled sectors, plus C1 and C2 CIRC, subcode, and frame sync. Also referred to as a subcode block.
Sector
Smallest addressable entity in the information area that can be addressed independently of other addressable parts.
Session
Single recording event that creates a single information area (lead-in - program area - lead-out.)
Single Session
Single recording event resulting in one lead-in (with TOC), program area, and lead-out for the entire disc.
Spindle
Mechanical means of coupling a disc to a rotating device.
Stamper
The electroformed part made from a mother and containing a reversed data image of the final disc. Becomes part of a mold for the injection molding replication process.
Subcode
Ninety-eight-bit codes used in the CD format. P and Q codes contain flag and control information. Codes R,S,T,U,V,W are available and may be used for CD+G or other specialized applications.
Substrate
Transparent physical layer providing mechanical support through which the laser can access an information layer.
Sync
Unique bit pattern appended to and preceding information that establishes a reference point for decoding of that subsequent information.
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Table of Contents (TOC)
Lists number of CD tracks, their starting locations, total length of data on the disc, and identification of type of disc. The TOC is placed in Q-subcode in the lead-in area of a CD disc.
Track
A physical track consists of one contiguous physical spiral area from inner diameter to outer diameter containing information (dual layer DVD discs have two physical tracks.) Or, the information contained within a single 360 ° rotation of the disc. Or, one contiguous logical element of information, such as a single CD audio track (a song) or computer data region (an information track.) One CD session contains from one up to 99 such logical tracks, each consisting of a pre-gap, user data, and a post-gap.
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USB (Universal Serial Bus)
A digital data interface standard providing a Plug-and-Play interface for personal computers. Typically used for lower-speed peripherals such as mice, keyboards, printers, and scanners. Also used for interfacing to digital cameras. The existing USB 1 standard provides up to 12Mbps (million bits per second) data rate. The new USB 2 standard supports up to 480Mbps data rate.
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Variable Bit Rate (VBR)
Data compression technique that produces an output data stream varying between fixed minimum and maximum rates, with bandwidth decreasing or increasing depending on the complexity of the fixed rate incoming data.
Verification
Process of matching information on a copy to that on the original.
Video CD (VCD)
A consumer format for storing video presentations on CD discs. VCD can fit 74 minutes of "VHS-quality" video on a CD, but at lower video resolution than DVD using the older MPEG-1 compression format. The VCD format is especially popular in Asia as format for distributing commercial movies and videos. Many DVD authoring tools provide the option to author to VCD format, and most DVD players can play the format. This provides an inexpensive option for sharing productions with most computers. Many set-top DVD players also can play VCDs.
Volume
A dismountable CD-ROM disc. A mountable sector address space consisting of a single set of sector addresses, usually as a continuous sequence of sectors, and containing one or more directory hierarchies.
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White Book
Proprietary Philips/Sony specification (white cover) for VIDEO CD.
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Yellow Book
Proprietary Philips/Sony specification (yellow cover) for CD-ROM, subsequently published as ISO/IEC 10149 (Second Edition 1995.)
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