A:B:C notation (n.) The standard way to describe relationships in digital video formats. Three numbers are used to represent ratios as follows:
(A) The basic sample rate compared to the color clock rate.
(B) The color horizontal downsampling rate compared to the basic sampling rate.
(C) The color vertical downsampling rate plus 1.
A standard 4:2:2 format indicates that sampling is done at four times the color clock, which is 3.58 megahertz (MHz); two horizontal chroma samples are taken for every four luminance samples; there is no reduction in vertical color resolution (1+1).
abend (n.) Abnormal end; an error message that indicates unexpected termination of a program or signal, which may be either recoverable or unrecoverable.
ABI (n.) Application binary interface; the emulation in software of a hardware/software platform other than the native one, which allows foreign applications to run. An example would be running a Windows application under the UNIX operating system.
ABIOS (n.) Advanced Basic Input/Output System; service routines built into IBM-compatible computers that support multitasking.
ablation (n.) Using a laser beam, the burning of pits into thin metal film for optical data storage.
abort (v.) To cancel a computing procedure while in progress.
A-B roll (n.) An editing process in which videotape is played from two tape machines. The tapes are rolled sequentially, in order to dub portions of each onto a third tape, the composite master. Video editors use this technique to import footage from multiple sources. The resulting product is often enhanced by placing transitions between the cuts and using special effects.
absolute time (n.) The time elapsed from the exact beginning of an audio CD or a digital audio tape (DAT) to any given point in the program material that follows. It is useful to determine the start and stop times of sound segments. The term refers to the time elapsed from the beginning of an entire sequence or group of events rather than a single piece.
abstract class (n.) In object-oriented programming, a class without instances. Instead it has concrete classes as subclasses. For example, mammal is an abstract class, and cow is a concrete class.
AC (n.) Alternating current; in the United States, 120-volt electricity that is delivered by utility companies and changes polarity from positive to negative 60 times per second. In other countries, the rate of alternation is often 50 cycles per second. Direct current, by contrast, is a continuous stream of current in one direction with constant polarity. The regular pulse of AC can be picked up by audio systems that are not well grounded, introducing a 60-cycle hum.
accelerator card (n.) A circuit board inserted into a slot on the motherboard that increases the processing speed and performance of the CPU. Graphics accelerators are used to increase the productivity of artists.
acceptable use policy See AUP.
access (v.) To seek and retrieve information from a hard disk, floppy disk, CD-ROM, or any other digital or analog storage medium.
access time (n.) The time required to locate and load data from storage after the seek command. Typically, this measurement includes the time it takes the reading head to move between the most distant segments of the media.
ACD (n.) Automatic call distribution; in telecommunications, a method of routing and tracking telephone signals.
ACID test (n.) A test of the atomicity, consistency, isolation, and durability of transaction processing. Passing the ACID test exhibits a high degree of resilience and recoverability. The term is derived from the process of testing metals with strong acid to determine gold content.
ACK (n.) An acknowledgment character that is returned to a sending device by a receiving device to indicate that the data has been received correctly.
ACM (n.) Association for Computing Machinery; a group dedicated to the advancement of computing knowledge.
acquisition (n.) The process of capturing assets or transferring information from an analog to a digital format.
Acrobat (n.) A program developed by Adobe for cross-platform document exchange in which files are created in Portable Document Format (.pdf) from PostScript files. The full complement of Acrobat tools consists of the Distiller, the Exchange package, the Catalog package, and the Reader. The Reader is freely distributed so that it can be installed and used on any computer along with an Acrobat document.
ActionMedia II (n.) An early video capture card developed by Intel that employs their Digital Video Interactive (DVI) compression technology. It has been replaced by the Intel Smart Video Recorder.
active-matrix display (n.) An LCD panel that has three transistors (R,G,B) for each pixel and yields better color and resolution than a passive-matrix display. Thin film transistor (TFT) technology makes this possible.
active video lines (n.) Lines of video that are scanned on the screen between the horizontal and vertical blanking intervals. About 483 lines are visible or active in the NTSC 525-line system used in the United States.
active window (n.) The portion of the screen that is prepared to accept input from an input device.
adapter (n.) An interface card that connects to peripherals or a network.
Adaptive Data Compression See ADC.
adaptive differential pulse code modulation See ADPCM.
ADB (n.) Apple Desktop Bus; the standard I/O port and protocol used on a Macintosh to connect the keyboard, mouse, and other devices.
ADC 1. (n.) Adaptive Data Compression (a Hayes modem protocol). 2. (n.) Analog-to-digital converter.
ADCCP (n.) Advanced Data Communications Control Procedures; a standard protocol used by the United States government for communications.
ADCIS (n.) Association for the Development of Computer-Based Instruction Systems.
A/D converter (n.) Analog-to-digital converter; a circuit that converts changes in voltage, pressure, or motion over time into a stream of digits that defines an event with time-based binary data.
additive color mixing (n.) The process of creating hues by mixing colors of light rather than pigments. Mixing the additive primary colors in equal proportions results in white.
additive color mixing
additive synthesis (n.) The production of a composite waveform by summing multiple individual waveforms.
address 1. (n.) Any label that identifies the location of data in either static or dynamic memory, such as a frame number on coded videotape. 2. (v.) To send a message to a particular location.
address code 1. (n.) Time code stamped on a tape that identifies each frame of video. The hour, minute, second, and frame numbers are expressed by eight digits in the format hh:mm:ss:ff. 2. (n.) The cue code placed in the vertical blanking interval of a videodisc frame as a point of reference.
addressable converter (n.) A device connected to a cable television receiver to give the program provider the capacity to send or block services to individual subscribers.
Address Resolution Protocol See ARP.
Adobe Type Manager See ATM.
ADPCM (n.) Adaptive differential pulse code modulation; the IMA version of this standard is used for storing audio information in a digital format in multiple-session CD-ROM XA and CD-i. The procedure reduces the amount of data needed by examining previously encoded data and adaptively predicting future encoding, eliminating some redundancy, and storing the differences between successive digital samples rather than full values. It is an extension of the PCM audio encoding format. Standardized by the CCITT for telecommunications applications, another version of this audio encoding process can transmit a voice over a 32-kilobit per second (Kbps) digital channel. Each sample is defined by three or four bits that represent the difference between adjacent samples.
ADR (n.) Automatic dialog replacement; in audio sweetening, an automated process for substituting a new voice track for the original.
ADSL (n.) Asynchronous Digital Subscriber Line; a communications protocol that allows the transfer of high data rates over twisted-pair telephone wire connections. It is useful for networking compressed video and audio at up to 1.5 megabits per second (Mbps).
ADSR (n.) Attack, decay, sustain, release; refers to a common way of shaping synthesized sounds and the circuit that performs the process. ADSR stands for four stages in the envelope of a sound. In sound synthesis, the ADSR settings define the shape of a note or its amplitude over time, not the pitch.
ADSR curve
Advanced Data Communications Control Procedures See ADCCP.
Advanced Research Projects Agency See ARPA.
Advanced RISC Machine See ARM.
Advanced SCSI Programming Interface See ASPI.
advanced wave effects See AWE.
AECT (n.) Association for Educational Communications and Technology.
AES/EBU (n.) Audio Engineering Society/European Broadcast Union; the two groups that developed similar digital audio transmission standards, specifying transmission of data in a stream with encoded stereo audio signals along with optional information.
AF (n.) Audio frequency; sounds within the normal range of human hearing, approximately 20 hertz (Hz)-20 kilohertz (kHz).
AFC (n.) Automatic frequency control; the process of locking a receiver to a TV or FM station's frequency.
affordance (n.) A tangible aspect of an object that allows action or manipulation. Examples are handles, buttons, and scroll bars.
AFSK (n.) Audio frequency-shift keying. In telecommunications, a method of modulating a carrier wave with audio frequencies (AF) to send digital signals.
AGC (n.) Automatic gain control; a limiting circuit used in audio playback systems to prevent damaging high volume levels.
AI (n.) Artificial intelligence; software that makes decisions based on accumulated experience and information. Functions normally associated with human intelligence, such as learning, adapting, reasoning, and self-correction are features of the software.
AIFF (n.) Audio interchange file format; a sound file format defined by Apple Computer and others that can include both sampled sound and MIDI data. The AIFF-C variation stores the data in compressed form. AIFF files may be imported by most multimedia authoring programs for the Macintosh and by some programs running on IBM-compatible computers.
A-law (n.) A digital audio encoding method for telephony used primarily in Europe. Defined by the CCITT G.711 standard, it is based on the 2048-kilobit (Kb), 30-channel PCM system. It compresses at a 2:1 ratio and is similar to the mu-law encoding scheme used in the United States and Japan.
algorithm (n.) A type of formula that defines a sequence of steps necessary to perform a process.
algorithmic (adj.) Describes a program structured like a mathematical procedure that solves a problem in a limited number of steps.
alias (n.) In a Macintosh system 7.0 and higher, an icon that represents or points to the original file. Multiple aliases may be created and placed where they may provide convenient access to the original file.
aliasing 1. (n.) The appearance of unwanted visual effects, known as "jaggies," in digitized images. An example is the stair-step effect on raster display systems without high enough resolution to reproduce smooth diagonal lines or circles. 2. (n.) In audio sampling, all frequency components higher than half the sampling frequency are reflected in the lower range. This distortion-producing reflection is referred to as aliasing, and it results in artifacts. It can be avoided by processing the waveform to be sampled with a low-pass filter at half the sample rate before digitizing.
alignment 1. (n.) In a tape recorder, the positioning of the head in relation to the tape path. 2. (n.) In a word-processed or graphic document, the horizontal and vertical relationships of elements.
alpha blending (n.) A technique used to produce atmospheric effects in three-dimensional graphics. Alpha values determine the degree of transparency of a pixel.
alpha channel (n.) In video production, a separate signal used to control visual effects such as overlay and transparency. In a digital graphics environment, the bits that control the percentage of visibility between upper and lower layers, or foreground and background elements.
alphanumeric (adj.) Describes a combination of alphabet letters, numerals, and other symbols used for codes and computational expressions.
alpha test (n.) The initial testing on software that evaluates general functionality. It occurs prior to a beta test, in which it is field-tested by users.
AM (n.) Amplitude modulation; the process of adding information to a constant carrier signal by modulating or changing its amplitude in direct correlation to another signal.
ambient (adj.) Describes a natural state, such as room temperature. Ambient sounds are referred to as "environmental" because they exist in a natural environment.
American Society of Composers, Authors, and Publishers See ASCAP.
American Standard Code for Information Interchange See ASCII.
America Online See AOL.
Amiga (n.) A computer system based on the Motorola 68000 family of processors and similar in design to a Macintosh. It was developed by Commodore International, which is no longer in existence. A popular application for the Amiga is the Video Toaster, a digitizing card that facilitates titling and effects for digital video production. The presence of onboard genlock capabilities made the Amiga system unique among microcomputers.
A-mode (n.) The mode a video editing system is in while it is assembling the segments in the order listed on the edit decision list (EDL). This process usually involves multiple changes of source reels.
ampere (n.) A measurement of electrical current equal to one volt applied to one ohm of resistance.
amplifier (n.) An electronic device that boosts signal strength. Amplifiers, or amps, are required to drive speakers for audio output. They are also required at regular intervals in a cable television system between the headend and the subscriber, approximately every 1500 feet.
amplify (v.) To increase the amplitude or power of a given signal. Related to audio, to increase the sound pressure level (SPL). Amplitude is the height of a waveform, or the measurement of a signal from trough to peak.
amplitude modulation See AM.
amplitude-shift keying See ASK.
analog (n.) A method of representing physical variables, such as voltage, pressure, or motion, that flow and change continuously and are values expressed as the quantitative magnitude of the variables. Analog devices are often controlled by knobs and sliders, and their output is shown by dials, gauges, and meters.
analog RGB (n.) A video signal that sends separate signal lines for red, green, and blue picture information. Each of the signals is encoded as a proportional voltage rather than as digital bits. Video systems for microcomputers employ this system.
analog-to-digital converter See A/D converter.
analog video (n.) A continuous electronic signal generated by a camera or a videotape source that represents an infinite number of smooth gradations between video levels. By contrast, a digital video signal assigns a finite series of steps in the gradations and is stored as data.
anchor (n.) In a hypertext environment, such as an HTML document, a word or icon that is colored or underlined and links to another document or location. By clicking on the hypertext link, a user is transported to the new location.
anchor point (n.) In a drawing program, the beginning or ending point of a Bezier curve. See Bezier curve.
animatic (n.) A compilation of key scenes used to plan and lay out video spots and motion pictures.
animation (n.) The rapid display of a series of still images or objects that are repositioned in each frame to achieve the effect of movement on a still background.
anonymous FTP (n.) A procedure that downloads files from a public FTP server to the user. It is possible to log on to an anonymous FTP server by using "anonymous" as the login name and an e-mail address as the password.
ANSI (n.) American National Standards Institute.
anti-aliasing (n.) Software alterations in the representation of data that help diagonal or curved lines appear smooth and continuous when displayed from computer-generated sources. In audio applications, the smoothing of steps between discrete samples to reduce the undesirable effects of low bit-rate capture.
anti-aliased letter on left, aliased letter on right
AOL (n.) America Online; a commercial networking service for individual users who have a computer and a modem.
APDA (n.) Apple Programmers and Developers Association; the source for all the tools needed to conduct high-level multimedia development using the Macintosh platform. They may be contacted at 1-800-282-2732 in the United States, or 1-800-637-0029 in Canada.
API (n.) Application Program Interface; software that defines the interface with an operating system or another program via a set of calls or special messages.
Apple Desktop Bus See ADB.
Apple Programmers and Developers Association See APDA.
Apple Remote Access See ARA.
applet (n.) A small application program that performs a specific function or handles media.
AppleTalk (n.) A local area network (LAN) protocol developed by Apple Computer for connecting peripherals and computers. It is a part of the system software from Apple Computer and operates over a variety of wiring types. Technically, it is a CSMA/CD network running at 230 kilobits per second (Kbps) that can connect up to 32 devices using shielded, twisted-pair cable for a distance of approximately 1000 feet.
AppleUNIX See A/UX.
Apple Video Compressor (n.) Developed by Apple Computer, this is the original compression and decompression codec used for QuickTime. These algorithms have been updated.
application 1. (n.) A software program that creates or reads a data file. 2. (n.) The set of data and program software contained on a compact disc.
application binary interface See ABI.
Application Program Interface See API.
application-specific integrated circuit See ASIC.
ARA (n.) Apple Remote Access; a communications protocol through which a user can dial up a host Macintosh from a remote modem and share the desktop of the host on the remote computer. Files can be downloaded or uploaded between the two connected computers.
Archie (n.) Available as a UNIX command via Telnet, this tool allows users to search a database of anonymous FTP sites.
architecture (n.) The general design of a computer hardware and software system. A system with "open architecture" allows the addition of internal cards and external peripherals.
archival (adj.) Describes a storage medium that preserves data for an extended period. Archival media must remain stable without degradation over time.
archive (v.) To record information in long-term storage.
archiving (n.) The process of moving data from online storage to nearline (optical disk) or offline (tape) storage. A directory is stored along with the data.
ARCnet (n.) Attached Resource Computer Network; a local area network (LAN) configuration that operates at 2.5 megabits per second (Mbps) over coaxial cable using a token-passing protocol. It features a distributed star topology and is reliable and easily expanded.
ARM 1. (n.) Advanced RISC machine; a miniature reduced instruction set computing processor, such as the one used in the Apple Newton PDA. 2. (n.) Asynchronous response mode; in an unbalanced data connection, a mode in which the secondary station may begin transmission to the primary station without obtaining permission.
ARP (n.) Address Resolution Protocol; a standard used on the Internet that assigns IP addresses to workstations on a local area network (LAN).
ARPA (n.) Advanced Research Projects Agency; a United States government organization that developed packet-switching techniques and created the network that was the precursor to the Internet.
ARQ (n.) Automatic request for retransmission; a case in which the receiver asks the transmitter to resend a frame or a block of information, generally as a result of error correction.
array (n.) A set of coordinates that define rows and columns. A two-dimensional array is described with x and y coordinates, while a three-dimensional array requires x, y, and z coordinates.
artifact (n.) An undesirable distortion that appears in digitized audio or video files as a result of inaccurate information introduced during capture or compression.
artificial intelligence See AI.
artwork (n.) Any type of graphics prepared for computer display, printing, or video. This may include drawings, paintings, photographs, maps, graphs, charts, captions, titles, and all elements in which artistic design considerations are of primary concern.
ASCAP (n.) American Society of Composers, Authors, and Publishers; a licensing agency that controls the rights for broadcast and performance of musical compositions.
ASCII (n.) American Standard Code for Information Interchange; developed by ANSI, the standardized data character system used internationally to code letters, numbers, and other symbols into the binary values used in most microcomputer applications. It is a seven-bit-plus-parity character code in which each bit can be a one or a zero, and it is capable of representing only 128 items. ASCII files contain text characters only: letters, numbers, and punctuation with no formatting. The other major method of encoding is EBCDIC, an 8-bit code used by mainframe computers. (Pronounced as-kee.) See table.
ASIC (n.) Application-specific integrated circuit; a gate array or logic array. This type of chip has its gates configured to perform a particular function.
ASK (n.) Amplitude-shift keying; a form of digital modulation in which discrete changes in the amplitude of the carrier signal convey a digital signal.
aspect ratio (n.) The resolution expressed in relative height and width values. The standard ratio for computer screens is 3:4. This is the basis for the standard resolutions of 120:160, 180:240, 240:320, 480:640, or 600:800 used by video monitors. The aspect ratio for television monitors is wider, and the problem of overscan introduces variables related to the safe viewing area around the edges. The ratio of modern motion pictures varies from 3:5 to 3:7, creating a problem when a wide-format motion picture is transferred to a 3:4-ratio screen. A 35mm photograph has dimensions of 24 × 36mm, resulting in a 2:3 ratio. A letterbox effect occurs when photos are ported to the computer screen. See illustration.
ASPI (n.) Advanced SCSI Programming Interface; developed by Adaptec, a protocol used to configure devices and media on a SCSI chain.
assemble editing (n.) The placement of video sequences back-to-back without a constant reference signal, a process that is prone to minor timing errors. Insert editing, or placing sequences on top of an existing reference track, is more stable.
assembly (n.) The conversion of instructions and data written in a computer programming language into lower-level machine code.
assembly language (n.) A lower-level programming language that consists of words and phrases that are used to control a microprocessor. An assembler converts the subroutines of assembly language into machine code that a computer can read. The source code consists of statements, while machine code consists of binary digits.
asset (n.) Any piece of data used in a multimedia program, such as an audio, graphic, text, or video file.
Association for Computing Machinery See ACM.
asymmetrical compression (n.) Any video or audio compression process in which more time and resources are required to encode than to decode.
asynchronous 1. (adj.) Describes the performance of computer operations in sequential stages, rather than in a continuous variable stream. 2. (adj.) The opposite of "real-time" conferencing in e-mail applications, where more than one person can participate in a conversation at the same time from different locations. In asynchronous communication they must take turns. 3. (adj.) In telecommunications, a mode in which two devices are free to send data in a continuous stream at any time. Each byte begins with a start bit and ends with a stop bit. It is the most common mode of communication between computer modem users.
Asynchronous Digital Subscriber Line See ADSL.
Asynchronous Response Mode See ARM.
Asynchronous Transfer Mode See ATM.
ATAPI (n.) AT Attachment Packet Interface; an enhancement to the original ATA hard disk controller system that allows packets to be sent to a CD-ROM player.
ATDT (n.) Attention dial tone; a modem command.
ATM 1. (n.) Adobe Type Manager; a utility that extrapolates a screen-resolution character (72 dots per inch) from a PostScript character. 2. (n.) Asynchronous transfer mode; a means of transmitting data that combines different data types (audio, video, or text) with a sophisticated formula for allocating bandwidth and shuttling packets, or cells, of a fixed length (53 bytes). It provides a common means of transporting all types of data, some of which exist as streams that are reassembled on reception.
Attached Resource Computer Network See ARCnet.
attachment (n.) Any file linked to an e-mail message that can be opened and viewed by an application resident on the recipient's computer.
attachment unit interface See AUI.
attention dial tone See ATDT.
attenuate (v.) To reduce the strength of a signal. In audio applications, attenuators often appear as faders or sliding switches that control the decibel levels of output channels on mixing boards.
audio (adj.) Related to sound, as in audio tape, audio track, or audio file.
audio bridge (n.) An electronic device that controls multiple telephone lines connected for two-way audio and data transmission; commonly used for audioconference applications.
audioconference (n.) A meeting over telephone lines with participants in different geographic locations who speak with one another simultaneously. Full-duplex systems allow users to hear other voices while they speak into their headsets. Half-duplex systems allow either reception or transmission of a signal at any given moment, but not synchronous two-way communication.
Audio Engineering Society/European Broadcast Union See AES/EBU.
audio frequency See AF.
audio frequency-shift keying See AFSK.
audio graphics (n.) A hardware and software system that permits computer users in different locations to connect over telephone lines and share data, graphics, and audio information. With an audiographic connection, users can work on the same application or document simultaneously, both can see the data on their computer screens, and they can discuss their progress over a voice channel. In the most basic application, it refers to any single-frame transmission of graphics with audio signals.
audio interchange file format See AIFF.
audio track (n.) The section or layer of an audio/videotape or disc that contains the sound signal that accompanies the video signal. Systems with two separate audio tracks can produce stereo sound or two independent tracks.
audio-video interleaved See AVI.
AUI (n.) Attachment unit interface; a 15-pin connector used to couple computers on an Ethernet network.
AUP (n.) Acceptable use policy; an Internet service provider's statement of permissible uses.
author 1. (v.) To create an interactive computer program with the use of an authoring language or system. Developers without formal programming skills can prepare applications for computer systems or CD-ROMs by "scripting" commands. Authoring requires a disciplined approach to preparing the elements of a multimedia program with careful planning and design. 2. (n.) A person who participates in the creation of a multimedia program or an interactive CD-ROM.
authoring software (n.) A program that facilitates the development of interactive multimedia. Systems vary widely in their capabilities, and factors such as the platform, audience, and desired results are taken into consideration when selecting the appropriate tool. It requires less time to develop interactive multimedia with the aid of an authoring system than it does to program it in compiled code. The methods used to develop graphics, text, video, audio, animation, and other media objects generally are not affected by the choice of an authoring system. Software designed for the creation and editing of specific media types is used to refine objects to be imported into the authoring environment, although an authoring tool may have some rudimentary editing features. The following is a description of the primary types of authoring paradigms:
Scripting language: An approach similar to traditional programming. File names identify multimedia elements, sequencing, and hot spots. An object-oriented version of the scripting language is usually implemented.
Flow control with icons: Rapid proto typing and short development time are characteristic. A palette of icons presents the tools for interaction, and a flow line connects the icons. Runtime speed may be slower than with other development tools.
Frame-based system: Uses screens, frames, or cards as the work place and brings media types onto each frame. A way to control the timing of a presentation and the layering of assets generally is provided. An icon palette is available, and conceptual links are made between objects that represent media types, such as graphics, audio, and video files. A scripting language is provided to set up interaction. With this type of tool it is difficult to see the connections while building a program. Some frame-based systems provide a matrix, or a score, that shows the progression of frames on the horizontal axis and the media channels, or tracks, on the vertical axis.
Hierarchical object: A system that defines relationships with metaphors represented by embedded objects (media types or events) and iconic properties (controls or conditional statements), similar to an object-oriented programming language.
Hypermedia linking: A tool that allows conditional relationships to be built between elements and gives the author a means to direct traffic. Most programs show the relationship between elements but do not offer a visual map of the connections.
The table on the following page lists widely used authoring programs, identifies the publisher, indicates the platforms on which programs may be developed or run, and describes the authoring paradigm and prominent features. Programs that offer a cross-platform "player" require that the authoring be done in the original environment. After development, the program may be ported to the player platform as a self-contained module. See table on following page.
auto-assembly (n.) In video post-production, the use of an edit decision list, or EDL, as well as a computerized edit controller to automate the process of making a final edited master tape.
autochanger (n.) An optical media system that can store and retrieve data from multiple discs; similar to a jukebox that plays phonograph records.
Autodesk Animator (n.) Developed by Autodesk, a collection of PC animation tools that create files in the Autodesk proprietary "FLC" and "FLI" formats.
autoexec.bat (n.) A batch file, or command set, that is automatically executed by a PC running MS-DOS whenever the system is turned on or booted.
autofeed (n.) A mode in which a scanner can operate continuously. A new page is loaded automatically when the scan of the previous page is completed.
automatic call distribution See ACD.
automatic dialog replacement See ADR.
automatic frequency control See AFC.
automatic gain control See AGC.
automatic request for retransmission See ARQ.
AutoPlay (n.) A CD-ROM standard developed by Microsoft that allows Windows 95 to detect a disc and load its program automatically.
auto-repeat (n.) A feature of many media playback devices, this is a mode that allows continuous replay of program material until interrupted.
A/UX (n.) Apple UNIX; a version of UNIX that runs on networked Apple computers.
auxiliary data field (n.) A 288-byte field that precedes the data field in a CD-ROM sector. It contains error-correction codes in a Mode 1 disc, but it may contain data on a Mode 2 disc.
AVC (n.) Association of Visual Communicators.
AVI (n.) Audio-video interleaved; developed by Microsoft, this is a digital video architecture for use in Microsoft Windows. It is a common standard for synchronized audio/video delivery on IBM-compatible computers, known as Video for Windows. In this file format, blocks of audio data are woven into a stream of video frames.
AWE (n.) Advanced Wave Effects; a proprietary method of sound synthesis employed by the 32-bit Sound Blaster card.