links page

[A] B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A

A/B roll.

Technique of placing one scene on one video tape (and VTP) and another scene on another and then rolling (playing) both VTPs together, along with the editing VTR, in order to fade, dissolve or do a special effect using both scenes at once

A/B roll editing.

Editing from two source VCRs (" A and B to third (recording) VCR. Typically switcher or mixer such as the Digital Video is used provide transition effects between sources. Control over machines process can be done manually automatically using an edit controller.

A/B switch.

Electrical switch which selects either the signal from cable A or the signal from cable B and feeds the results to a TV, VCR, or other destination.

A/B/C roll.

An edit employing 3 video players where the image comes from player A, then through some special effect transitions to B, and then to C.

AC.

Alternating Current, which comes from the wall outlet (not DC-Direct Current which comes from a battery).

AC adaptor.

Device that connects to a wall outlet (AC), and sends power to a device to: charge its batteries, or operate without using battery power. A/V (Audio/Video).

AC-3.

AC-3 is a proprietary digital compression scheme developed and licensed by Dolby Laboratories.

Accelerometer Servo.

A technology used on speakers (mostly subwoofers and notably on some Velodyne subwoofer lines) to correct driver movement for decreased distortion.

Access Time.

The time taken from a computer's request for data stored on disk or in memory to the data being delivered. Normally measured in nanoseconds (memory) or milliseconds (disk).

Acoustic Suspension.

A type of speaker enclosure that is completely sealed with no port or other device to let air inside the enclosure flow outside the enclosure.

Acoustics.

The physical properties of sound as they pertain to a particular situation.

ACPI

Advanced configuration and power interface. The latest standard that specifies how PC or Laptop power can be effeciently managed. Features include activating devices only when required and reducing clock speed when full processing power is not needed.

Active Crossover.

Uses electronics supplied with a power source and acting on the sound to shift sound reproduction tasks from one speaker driver to another.

Active Sensing.

A method by which a MIDI device detects disconnection. A message is sent to the receiver around three times per second, and if no message is received during this period, the unit assumes the MIDI connection has been broken. It then begins a routine to reestablish normal operation.

Active Speaker.

A speaker using drivers powered by their own internal amplifiers.

ActiveX.

Set of interactive technology developed by Microsoft, combining OLE (Object Linking & Embedding) and COM (Component Object Model). Unlike Java, ActiveX is not a programming language, but a set of instructions on how an object should be used.

Adaptor Card.

see expansion card.

ADC.

Analog-to-Digital Converter. An electronic device used at the input of digital audio equipment to convert analog electrical signals to digital values whose numbers represent the level and frequency information contained in the original analog signal.

Additive Primary.

One of the three primary colours which add together (overlap and mix together adding to one another) starting from darkness to form the visible colour spectrum; the three additive primaries are red, green and blue.

Additive Synthesis.

A synthesis method that builds complex waveforms by combining sine waves whose frequencies and amplitudes are independently variable.

Address Track.

A control/timing track on the edge of videotape which contains control data for quick and accurate location of program material

ADSL.

Asynchronous digital subscriber line. A permanently on, broadband connection to the internet which is using the phone line.

ADSR.

Attack, Decay, Sustain and Release are the four stages of an envelope that describe the shape of a sound over time. Attack represents the time the sound takes to rise from an initial value of zero to its maximum level. Decay is the time for the initial falling off to the sustain level. Sustain is the time during which it remains at this level. Release is the time it takes to move from the sustain to its final level. Release typically begins when a note is let up. In most sound generators, the time and the value reached are programmable.

Adjacent Channel Interference.

Wavy lines or two TV images simultaneously appear on the TV screen. A problem appears when you're viewing a weak station while another strong station, one channel number higher or lower, is broadcast nearby or from the same direction as the weak station.

ADR.

Automatic Dialog Replacement. Also known as "looping." A process of re-recording dialog in the studio in synchronization with the picture.

ADSL.

Asymmetric Digital Subscriber Line, a DSL that sends data quickly downstream (to you) but upstream slowly, allocating the digital resources of the twisted pair efficiently for many download-heavy applications.

Advanced Vertical

Special synchronizing signal sent out by a TBC to a VCP to lock the VCP's video playback to the house (TV system's) sync. Makes the VCP play almost in synchronization with the studio cameras.

AES/EBU.

Term for a XLR connector used with digital audio components to transfer low-level signals in a balanced configuration.

AFC time constant.

An internal circuit design on a TV set which determines how much it jitters and flagwaves when playing tapes.

AFM.

Audio Frequency Modulation, a technique used in VHS, SVHS, 8mm and Hi 8 VCRs to record/play hi fi sound, invisibly imbedded in the picture.

After Touch.

A measurement of the force applied by a performer to the key on a controller after it has been depressed. Either polyphonic, which measures the pressure on each individual key, or monophonic, reflecting the total pressure on all keys.

AGC or automatic gain control.

Automatically adjusts the brightness and contrast of a camera's picture.

AGP

Accelerated Graphics Port. An extremely fast expansion slot and bue designed for high performane graphics cards.

AIFF.

The standard file format for storing audio information on an Apple Macintosh computer.

Album.

Round, typically black wax disc about 12 inches in diameter onto which audio signals are recorded in grooves for later retrieval by a phonograph.

ALC. Automatic Level Control.

Circuitry used to automatically adjust the audio recording level to compensate for variations in input volume. Some equipment includes level controls which can switch from automatic to manual control.

Alias.

Stair-steppiness of rounded images or letters rendered by computers and character generators.

Aliasing.

1. An undesirable distortion component that can arise in any digitally encoded information (sound or picture).
2. Undesirable video display effects caused by too much high frequency video information.
   Examples:
   
   1. Temporal aliasing - e.g., rotating wagon wheel spokes apparently reversing direction.
   
   
   2. Raster scan aliasing - e.g., twinkling or strobing effects on sharp horizontal lines
   
   
   3. Stair-stepping - Stepped or jagged edges of angled lines, e.g., at the slanted edges of letters.
   
   
   4. Are created when sampling frequencies greater than one-half the sampling rate.

Algorithm.

A set of instructions supplied to a computer for the purpose of solving a problem.

All Notes.

Off A three byte MIDI channel message that instructs the receiving device to terminate all notes currently sounding.

Alpha channel.

A signal used in video graphics to cut a hole in an image, a hole that gets filled with another image (usully text).

Alternate Channel Selectivity.

Radio tuner specification referring to the ability to ignore or reject information from a radio frequency near that of the one actually tuned in and desired.

AM (Amplitude Modulation).

• Means of transmitting information by modulating (changing some component of an electromagnetic carrier wave such as the frequency, amplitude, phase, etc. to carry another signal) a pure waveform in which the frequency does not change but the amplitude or maximum distance of the wave's peaks and troughs from its centerline changes.


• Amplitude modulation is a process used for some radio (AM broadcast) and television video transmission. A low frequency (program) signal modulates (changes) the amplitude of a high frequency RF carrier signal (causing it to deviate from its nominal base amplitude). The original program signal is recovered (demodulated) at the receiver. This system is extensively used in broadcast radio transmission because it is less prone to signal interference and retains most of the original signal quality. In video, FM is used in order to record high quality signals on videotape.

AM Rejection.

Radio tuner specification referring to how well a tuner is able to ignore changes in a FM (frequency modulation) signal's amplitude caused by noise and signal anomalies due to interference.

Ambience.

The subjective quality of a space; the feel of the space achieved through a mixture of all elements and characteristics affecting the space.

Ambient Light.

General, nondirectional, room light.

Ambiance or ambient lighting.

Light that partially fills in shadows, mimicking the light that scatters from everything in the real world. Without ambiance lighting, shadows could get too dark

Ambient colour.

The shaded colour of an object showing darker colour where light doesn't hit.

Ambient noise.

The total sound in a given are which is peculiar to that space (room tone).

Ambience Synthesis.

Using surround sound technology and various matrixed or digital music or film modes to create the feel or ambience associated with a space other than the one in which the sounds are being heard.

Amp or ampere.

A measure of the volume of electrical current. Institutional circuits are usually rated for 20A (amps).

Amplifier.

Electronic component that accepts a low-level signal and recreates the signal with more power; this term is most often used in audio/video to describe an audio component which takes in line-level audio signals through interconnect cables and outputs a high-powered replica of the input in order to drive speakers and create sound.

Amplitude.

The height of the wave from its highest point or peak to its zero level in any given sample or at any point along the line of the wave; the power of a sound wave expressed by the height of the sound wave in a given instance.

The strength of an electronic signal as measure by its waveform height.

Amplitude is the dynamic range of the sound wave measured from the trough to the peak of the wave or vice versa. (Loudness is a perceived measurement in dbA or acoustic decibels while amplitude refers to the size or how high the sound wave is (peak to through) and volume refers to the amount of sound moved through vibration).

Amplitude Distortion.

The nonlinear relation of input and output induced harmonics which is a function of voltage fluctuations or power consumption. (Acoustics)

Analog.

1. An electrical signal that continuously varies in strength as related to some form of input.


2. A method of representing data using continuously varying electrical voltages. Analog video whether transmitted over cables, read from videotapes or broadcast, is subject to degradation due to noise, distortion and other electronic phenomena. Normal signal levels should be within 0.7-1 volt.


3. Analog refers to a non-digital continuous waveform signal, which may contain an infinite number of points along a frequency range.


4. A signal that varies continuously as opposed to a digital signal made of discrete levels. A device that works with analog signals.


5. Something that varies in infinite gradations. A light dimmer is analog. Analog circuits suffer noise and distortion.

Analog Monitor.

A video monitor which accepts analog signals. Several types of inputs are accepted by analog monitors: composite video, RGB & sync, Y/C, YUV and any combination of these formats. The signals transmitted to an analog monitor are usually between 0 and 1 V and use 75 ohm coaxial cables.

Analog non-linear editor.

NLE that doesn't digitize your tapes and prepare a final edit from the hard drives, but creates an edit decision list from the timeline on your computer screen. The list later drives the VCPs and VCRs to make the edits.

Analog-to-Digital Converter.

Electronic equipment used to change or convert an analog (waveform style) signal into a digital signal (made up of 1s and 0s).
A circuit that samples an analog signal and expresses the information as digital data.

Analog Recording.

A means of recording audio or video whereby the recorded signal is a physical representation of the waveform of the original signal.

Analog Synthesis.

A method of sound synthesis that relies on predefined waveforms to create sounds that vary over time. The amplitude, frequency and harmonic content of these waveforms can be manipulated to produce a vast number of different results.

Analog VTR.

Video recorder that records the continuously varying video signal onto the tape (as opposed to digital).

Anamorphic.

• Process where a "wide" video image (typically in a 16-by-9 widescreen format) is compressed or squeezed horizontally to fit a more narrow video display standard but expands to full size when played over a wide video display.


• An optical system having different magnifications in the horizontal and vertical dimensions of the image.

Anechoic Chamber.

A specially designed room in which there are no reverberations of sound waves.

Anechoic Frequency Response.

The frequency response of a speaker in an anechoic chamber with no room interactions with the sound.

Animation.

Technique or result of creating a series of still images and then playing them quickly in sequence to create motion.

Antenna.

Metal rod or length or wire which sends or receives electromagnetic waves.

Anti-Aliasing:

• Filtering of erroneous frequencies that are created during the analog to digital conversion process.


• The process of electronically reducing aliasing, especially letters and genlocked graphic elements.


• The smoothing out of jagged or stair-steppy edges of electronic graphics or generated characters.

Anti-Clipping Circuitry.

Electronic device included in some amplifiers to prevent clipping, the overloading of an amplifier in which normal waveforms are chopped off resulting in severe harmonic distortion and output problems.

Anti - flicker switch or flicker fixer.

Feature on a scan converter that makes fine lines in computer graphics fuzzier so that they don't flicker when displayed as interlaced video.

Antikeystone.

Feature in some projectors that distorts the projected image so that it looks rectangular on the screen, even though the projector is at an angle to the screen.

Aperture.

An adjustable opening in a lens which, like the iris in the human eye, controls the amount of light entering a camera. The size of the aperture is controlled by the iris adjustment and is measured in f-stops. A smaller f-stop number corresponds to a larger opening which passes more light.

Applet.

Program designed to be executed from within another program. Applets cannot be activated from an operating system.

Architecture

Extensions to the operating system which allow media storage and playback to occur.

1. QuickTime (Apple)
2. Windows Media (Microsoft)
3. RealMedia (RealNetworks)

Arpeggiate.

To play the notes of a chord in succession rather than simultaneously.

Artifact

Undesirable elements or defects in a video picture, such as dots crawling along the edge of coloured graphics, or coloured rainbows around shirts with stripes or herringbones.
Referring to compressed video formats, particularly DVD and direct broadcast satellite using MPEG-2 compression, an artifact is a visual anomaly or error created when the compression system is not able to keep up with fast action or complex scenes in a video image.

Attribute (Database)

An attribute is a named column of a relation.

ASCII.

American Standard Code for Information Interchange. A universal, standardized code for text and numbers used by computers and word processors.

ASP

Active Server Pages.

Aspect Ratio.

1. Relationship in a video image between the width of the image and the height of the image expressed in generic terms of units width by height (4:3, 16:9).


2. The ratio between the height and width of the TV picture on the screen. The aspect ratio for a standard TV or monitor is 4 to 3 (4:3). The HDTV video format has an aspect ratio of 16 to 9 (16:9).

Aspherical lens.

Lens formed to a complex shape that provides improved image sharpness, lighter weight, and more accurate colour imagery than simple convex and concave lens groups.

Asynchronous.

Not synchronized. Running independently without external sync circuits holding the device to the same rhythm as the rest of the studio equipment.

AT&T ST.

Type of high-quality glass fiber-optic cable used to transmit digital data between digital audio sources and digital-to-analog converters.

ATAPI.

AT Attachment Packet Interface. A specification for devices (typically CD-ROM drives) that connect to a PC's IDE Interface.

ATM.

Asynchronous Transfer Mode, a method of grouping data into packets and switching them along a route to their destination quickly.

Attack.

The initial stage of an envelope. Refers to the time from the beginning of the sound to its highest or maximum level.

Attenuate.

Small electronic device that reduces the strength of an audio signal.

ATV.

Advanced Television, a name that replaced HDTV as the specifications evolved, eventually being replaced with DTV.

ATX.

A standard that specifies the layout and power supply for motherboards. ATX motherboards are used by almost all new PC's.

Audio.

Something that is heard or having to do with something that is heard; in audio/video having primarily to do with the process of reproducing sounds through a system of electronic components.

The "other half" of any video production consisting of frequencies corresponding to a normally audible sound wave (20 Hz to 20,000 Hz), the "soundtrack" of a videotape.

The sound part of a TV broadcast. Sound, turned into an electrical signal.
Audio-1, audio-2: Names given to the two audio channels on a 3/4U VCR. Audio-2 is often the main channel. Some home VCRs may have two-channel audio or stereo audio.

Audio bandwidth.

The range of audio frequencies which directly influence the fidelity of a sound. The higher the audio bandwidth, the better the sound fidelity. The highest practical frequency which the human ear can normally hear is 20 kHz. An audio amplifier which processes all frequencies equally (flat response to 20 kHz) and a reasonably high signal to noise ratio, will faithfully reproduce the audio soundtracks of a video recording.

Audio dub.

VCR feature allowing replacement of the audio signals on a previously recorded tape without disturbing the video signal. When dubbing is not available via the video recorder, audio dubbing can be performed while recording using an audio mixer.

Audio Editing.

Similar to video editing. Various portions of audio material are combined and recorded onto the videotape in one continuous form. For example, when a sound track is added to a videotape, various sounds such as background music, sound effects and voice narration, may be introduced in order to highlight particular movie scenes.

Audio-follow-video.

During video recording, the video signal is usually accompanied by an audio signal. Sometimes, during video editing, it is often necessary to separate the audio from the video signal. Audio-follow-video mixers allow companying audio to "follow" the video when switching video sources or not.

Audio levels.

Proper audio levels are crucial. If the audio level is too high when recording, overload of the input electronics will cause audio distortion. If audio levels are too low, the signal-to-noise ratio deteriorates. Audio levels are typically indicated either by mechanical VU-meters or electronic LED bar graph meters.

Audio limiter.

Automatic control on a recorder that reduces volume during a recording if the sound becomes too loud. The audio limiter doesn't affect the quiet and medium parts of the recording

Audio Input.

In an audio/video system, the audio input is a connection on an electronic device allowing electronic signals with audio information sent by another component to enter.

Audio meter.

Meter that indicates the loudness of an audio signal. Could also be a string of LEDs that light up like a bar graph.

Audio mixer.

Mixes audio (sound) signals perhaps from several microphones and combines them into one audio signal.

Audio monitor.

Device that allows you to listen to and check on the quality of a sound signal. Also the switch on a VCR that chooses which channel (or both) is fed to your headphones or in some cases to the VCR's audio output.

Audio mixing.

The blending of two or more audio signals to generate a combined signal which is often used for audio dub. During video processing, audio mixing may be used to insert narration or background music.

Audio Patch Cord.

Wire with audio plugs on each end for feeding signals between two audio devices.

Audio Processing.

Deals with sound, including

1. Generation
2. Recording
3. Manipulation
4. Play-back

Audio Selector.

Knob on a VCR that selects whether audio track 1 or 2 or a combination of both will be played back (or recorded upon).

Audio Output.

The connection point from which an audio signal is electronically transferred via a wire from one audio component to another; the origination point of an audio signal as it travels over a wire.

Authoring.

Process of organizing the materials for an interactive disc and putting them into computer language.

Auto Fade.

Control on some cameras which fades the picture to black at the end of a scene or fades up from black at the beginning.

Auto Preview.

Mechanism on a switcher/SEG that automatically displays on your preview monitor any effect not being recorded but ready to be shown once selected.

Automatic Focus

Electronic system in some cameras that senses whether the picture is sharp and electrically focuses the lens to correct blurry pictures.

Automatic Gain Control or AGC.

Electronic circuit that automatically adjusts the loudness of a recording.

Automatic Iris.

Camera circuit which senses the amount of light in a scene and opens or closes the lens iris to adapt to it.

Autoscan or multiscan.

Where a multisync monitor or projector can be switched to a selected sweep frequency to match a computer or TV scan rate, an autoscan or multiscan monitor or projector will "sense" the frequency and automatically lock onto it.

Aux send/return.

An output/input path on mixers that allow a signal to be manipulated by a device outside the mixer.

A/V, or Audio/Video.

A generic term used to describe products and services associated with audio and video.

AV monitor or multimedia monitor.

TV monitor with audio and video inputs to display picture and sound.

Azimuth: Left/right direction, or east/west when tracking satellites.

As related to consumer direct broadcast satellite systems, the azimuth is the direction and angle needed to point the receiving dish to receive signals from the satellite

top