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Compact videocassette format, popularized by camcorders, employing 8-millimeter-wide videotape. [See Hi8.]

A-B roll Two video sources played simultaneously, to be mixed or cut between.

action axis Imaginary line drawn between two subjects or along a line of motion as an aid in maintaining continuity of screen direction. Sometimes referred to as the "180-degree rule."

ad-lib Unrehearsed, spontaneous act of speaking, performing, or otherwise improvising on-camera activity without preparation.

AFM See audio frequency modulation.

AGC See automatic gain control.

ambient sound (ambience) Natural background audio representative of a given recording environment. On-camera dialog might be primary sound; traffic noise and refrigerator hum would be ambient.

animation Visual special effect whereby still progressive images displayed in rapid succession creates the illusion of movement.

aperture See iris.

artificial light Man-made illumination not limited to "indoor" variety: fluorescent bulbs, jack-o'-lanterns, a car's headlights. Has lower color temperature than natural light, and thus more reddish qualities. [See color temperature, natural light.]

aspect ratio Proportional height and width of picture on screen. Current standard for conventional receiver or monitor is three by four (3:4); 3:5 for HDTV.

assemble edit Recording video/audio in sequence immediately following previous material. Consecutive edits form complete program. [See edit, insert edit.]

ATV Acronym forAmateur TeleVision. Specialized domain of ham radio, transmits standard TV signals on UHF radio bands.

audio dub Result of recording over prerecorded videotape soundtrack, or a portion, without affecting prerecorded images.

audio frequency modulation (AFM) Method of recording hi-fi audio on videotape along with video signals.

audio mixer Device with user-adjustable controls to blend multiple sound inputs into desired composite output. [See mix.]

automatic exposure Circuitry that monitors light levels and adjusts camcorder iris accordingly, compensating for changing light conditions.

automatic gain control (AGC) Camcorder circuitry that adjusts incoming signal levels automatically, alleviating excessive image brightness and distortion of loud sound.

available light Amount of illumination normally present in a particular environment: natural light, artificial, or a combination.

AVI Acronym for Audio Video Interleaved. This is the standard format for digital video in Windows.

back light Illumination from behind, creates sense of depth by separating foreground subject from background area. Applied erroneously, causes severe silhouetting. [See fill light, key light, three-point lighting.]

barndoors Accessory for video lights, two- or four-leaf folding flaps that control light distribution.

Betamax More commonly known as "Beta," half-inch videotape format developed by Sony, eclipsed by VHS in home video market popularity. [See ED Beta.]

bidirectional Microphone pickup pattern whereby sound is absorbed equally from two sides only. [See omnidirectional, unidirectional.]

black box Generic term for wide variety of video image manipulation devices with perceived mysterious or "magical" capabilities, including proc amps, enhancers, SEGs, and TBCs.

bleeding Video image imperfection characterized by blurring of color borders; colors spill over defined boundaries, "run" into neighboring areas.

BNC (bayonet fitting connector) Durable "professional" cable connector, attaches to VCRs for transfer of high-frequency composite video in/out signals. Also used by BetaSP machines to route R-y, B-y, Y color channel information, and sometimes RGB. Connects with a push and a twist.

boom Extension arm used to suspend a microphone or camera over sound or subject(s) being recorded. Objective is to keep production gear out of camera's view.

booming Camera move above or below subject with aid of a balanced "boom arm," creating sense of floating into or out of a scene. Can combine effects of panning, tilting, and pedding in one fluid movement.

C See chrominance.

cable/community access Channel(s) of a local cable television system dedicated to community-based programming. Access centers provide free or low-cost training and use of video production equipment and facilities.

cameo lighting Foreground subjects illuminated by highly directional light, appearing before a completely black background.

Cannon See XLR.

cardioid The most common type of unidirectional microphone; pickup pattern resembles a heart-shaped figure.

CCD (Charge Coupled Device) Light-sensitive computer chip in video cameras that converts images into electrical flows. Less prone to image irregularities -- burn-in, lag, streaking -- than are older image sensors. [See pickup.]

CDROM Mass storage media for digital data, such as digital video.

character generator Device which electronically produces letters, numbers, symbols, and other graphic displays for on-screen video titling.

chroma Characteristics of color a videotape absorbs with recorded signal, divided into two categories: AM (amplitude modulation) indicates color intensity; PM (phase modulation) indicates color purity.

chroma key Method of electronically inserting the image from one video source into the picture of another. Wherever a selected "key color" appears in the foreground shot, background image replaces. Frequently used on news programs to display graphics behind talent.

chrominance Portion of video signal that carries color information (hue and saturation, but not brightness); frequently abbreviated as "C." [See luminance.]

clapstick Identification slate with hinged, striped top that smacks together for on-camera scene initiation. Originally used to synchronize movie sound with picture. [See lip-sync.]

closeup Tightly framed camera shot in which principal subject is viewed at close range, appearing relatively large and dominant on screen. Extent of view may be designated "medium closeup" or "extreme closeup." [See long shot, medium shot.]

CODEC Acronym for COmpressor/DECompressor. Reduces file size by compressing the data it contains. Also used to decompress compressed files.

color bars Standard test signal containing samples of primary and secondary colors, used as reference in aligning color video equipment. Generated electronically by a "color bar generator," often viewed on broadcast television in off-air hours. [See test pattern.]

color corrector Electronic device that dissects the colors of a video signal, allowing them to be adjusted individually.

color depth Number of bits containing color information for each pixel in an image. A color depth of 1 bit displays only black and white: a color depth of 8 bits displays up to 256 colors: a color depth of 24 bits displays up to 16,277,216 colors.

color palette Number of colors the graphics system can generate.

color temperature Relative amount of "white" light's reddish or bluish qualities, measured in "degrees Kelvin." Desirable readings for quality videomaking are 3200 -- K indoors, 5600 -- K outdoors. [See artificial, natural light.]

comet tailing Smear of light resulting from inability of camera's pickup to process bright objects -- especially in darker settings. Object or camera in motion creates appearance of flying fireball. [See lag.]

component video Signal transmission system, resembling S-video concept, employed with professional videotape formats. Separates luminance and two chrominance channels to avoid quality loss from NTSC or PAL encoding. Encoding all image information in a single pixel.

composite video Signal combining luminance and chrominance signals through an encoding process, including image's separate RGB (red, green, blue) elements and sync information.

compositing Superimposing multiple layers of video. Each layer may move independently.

compression Reducing the digital data in a video frame, typically from nearly one megabyte to 50 kilobytes or less, by throwing away information the eye can't see. Compression makes it possible to store reasonably large amounts of video on a hard disk. JPEG, Motion-JPEG, MPEG, DVI, Indeo, Fractals and Wavelets are all compression schemes.

composition Visual makeup of a video picture, including such variables as balance, framing, field of view, texture -- all aesthetic considerations. Combined qualities form image that's pleasing to view, and effectively communicates.

condenser Microphone with built-in amplifier, the type installed on camcorders. Also called capacitor or electret condenser, requires battery or external power source. [See electret condenser.]

continuity [1:visual] Logical succession of recorded or edited events, necessitating consistent placement of props, positioning of characters, and progression of time. [2:directional] Consistency in camera-subject relationships, to avoid confusing a viewer's perspective.

contrast Difference between a picture's brightest and darkest areas. When high, image contains sharp blacks and whites; when low, image limited to variations in gray tones.

Control-L A two-way communication system used to coordinate tape transport commands for automated editing. Primarily found in 8mm camcorders and VCRs. (See Control-S, RC, synchro edit).

Control-S A one-way communication system that treats a VCR or camcorder as a slave unit, with edit commands emanating from an external edit controller or compatible deck. Primarily found on 8mm VCRs and camcorders. (See Control-L, synchro edit).

control track Videotape area containing information to synchronize playback and videotape editing operations.

cookie See cucalorus.

crawl Text or graphics -- usually special announcements -- that move across screen horizontally, typically from bottom right to lef t. Produced with character generator. [See roll.]

cropping Selecting a portion of the visible image and discarding the unselected portion.

cross-fade Simultaneous fade-in of one audio source or lighting effect as another fades out; may overlap temporarily. Transition analogous to video dissolve. [See dissolve, fade.]

cucalorus (cookie) Lighting accessory consisting of random pattern of cutouts that forms shadows when light passes through it. Used to imitate shadows of natural lighting.

cue [1] Signal to begin, end, or otherwise influence on-camera activity while recording. [2] Presetting specific starting points of audio or video material so it's available for immediate and precise playback when required.

cut [1] Instantaneous change from one shot to another. [2] Director's command to immediately terminate on-camera action and recording.

cutaway Shot of other than principal action (but peripherally related), frequently used as transitional footage or to avoid a jump cut.

cuts-only editing Editing limited to immediate shifts from one scene to another, without smoother image transition capabilities such as dissolving or wiping. [See cut, edit.]

D1, D2 Entirely digital "professional" videotape recording formats (component and composite, respectively) capable of multigeneration duplication without picture degradation.

data rate Amount of data transferred from or to a hard disk or other storage medium. Normally measured in the data transferred per second.

DCT Acronym for Discreet Cosine Transformation. Part of the JPEG image data compression. The brightness and color imformation is stored as the frequency coefficient.

decibel (Db) Measure of audio signal strength based on a logarithmic scale. Also the unit of measure for sound pressure level (loudness).

depth of field Area in which all objects, located at different distances from the camera, appear in focus. Varies with subject-to-camera distance, focal length of camera lens, and camera's aperture setting.

desktop video (DTV) Fusion of personal computers and home video components for elaborate videomaking capabilities rivaling those of well-financed broadcast facilities.

diffused light Illuminates relatively large area indistinctly; often created with floodlights, produces soft shadows. [See directional light.]

diffuser Gauzy or translucent material that alters the quality of light passing through it to produce less intense, flatter lighting with weaker, less noticeable shadows.

diffusion filter Mounted at front of camcorder lens, gives videotaped images a foggy, fuzzy, dreamy look. [See filter.]

digital audio Sounds that have been converted to digital information.

digital video Digital video stores information bit-by-bit in a file, as opposed to analog video storage medium.

digital video effects (DVE) Electronic analog-to-digital picture modification yielding specialty image patterns and maneuvers: tumbling, strobing, page turning, mosaic, posterization, solarization, etc.

digitization The process of converting a continuous analog video or audio signal to digital data (ones and zeros) for computer storage.

digitizer Device that captures and imports video image into a computer by converting it into digital information.

directional light Illuminates relatively small area with distinct light beam; usually created with spotlight, yields harsh, defined shadows. [See diffused light.]

dissolve Image transition effect of one picture gradually disappearing as another appears. Analogous to audio and lighting cross-fade. [See cross- fade.]

distribution amp Divides single video or audio signals, while boosting their strength, for delivery to multiple audio/video acceptors. Allows simultaneous recording from same source, especially useful for tape duplication.

dolly Camera support mounted on wheels enabling smooth movement in any direction.

dollying Camera movement toward or away from a subject. Effect may appear same as zooming, which reduces and magnifies the image, but dollying in or out maintains perspective while changing picture size.

dropout Videotape signal voids, viewed as fleeting white specks or streaks. Usually result of minute "bare spots" on a tape's magnetic particle coating, or tape debris covering particles and blocking signals.

DTV See desktop video.

dub [1] Process or result of duplicating a videotape in its entirety. [2] Editing technique whereby new audio or video replaces portion(s) of existing recording.

DVE See digital video effects.

dynamic Microphone type, also called "moving coil." Works much like a loudspeaker in reverse, employing a simple magnet and wire coil to convert sound waves into an electrical signal.

ED Beta Acronym for Extended Definition Beta. Improved version of the original half-inch Betamax video format, yielding sharper pictures with 500-line resolution. [See Betamax.]

edit Process or result of selectively recording video and/or audio on finished videotape. Typically involves reviewing raw footage and transferring desired segments from master tape(s) onto new tape in a predetermined sequence. [See assemble edit, in-camera editing, insert edit.]

edit controller Electronic programmer used in conjunction with VCRs/camcorders to facilitate automated videotape editing with speed, precision, and convenience.

edit control protocols Types of signals designed to communicate between computers and tape decks--record, pause, rewind and so on.

edit decision list (EDL) Handwritten or computer-generated compilation of all post-production edits to be executed in a video work.

edited master See master.

EDL See edit decision list.

EFP Acronym for Electronic Field Production. Film-style production approach using a single camera to record on location. Typically shot for post-production application, non-live feed.

electret condenser Microphone type incorporating a precharged element, eliminating need for bulky power sources. [See condenser.]

encoder "Combiner" device that translates a video signal into a different format - - RGB to composite. Horizontal and vertical sync information joins individual red/green/blue components.

ENG Acronym for Electronic News Gathering. Use of portable video cameras, lighting and sound equipment to record news events in the field quickly, conveniently, and efficiently.

enhancer See image enhancer.

EP Acronym for Extended Play. Slowest tape speed of a VHS VCR, accommodating six-hour recordings. [See LP, SP.]

equalization Emphasizing specific audio or video frequencies and eliminating others as signal control measure, usually to produce particular sonic qualities. Achieved with equalizer.

essential area Boundaries within which contents of a television picture are sure to be seen, regardless of size differences in receiver displays. Also called "critical area" and "safe title area," encompasses 80 percent of total screen.

establishing shot Opening picture of a program or scene. Usually a wide and/or distant perspective, orients viewer to overall setting and surroundings. [See long shot.]

extra Accessory talent not essential to a production, assuming some peripheral on-camera role. In movie work, performers with fewer than five lines are called "under fives."