AC Adapter: A circuit which modifies an AC current, usually converting it to a DC current.
A/D Converter: A circuit which converts a signal from analogue to digital form; the opposite of a D/A converter.
Adobe: A software manufacturer based in San Jose, California, and traded on the Nasdaq National Market under the symbol ADBE. Adobe is a leading provider of media productivity software. More info: Adobe Tutorials, Adobe Premiere, Adobe Photoshop, Adobe ImageReady.
AGC: Automatic Gain Control. A circuit which automatically adjusts the input gain of a device, in order to provide a safe and consistent signal level. AGCs can be handy features, but professional applications often require manual gain control for optimum results.
Aliasing: Distortion of an image file or sound recording due to insufficient sampling or poor filtering. Aliased images appear as jagged edges, aliased audio produces a buzz.
Alpha Channel: A special channel in some digital images reserved for transparency information.
AM: Amplitude Modulation. A method of radio transmission which sends information as variations of the amplitude of a carrier wave.
Amperage: The amount of electrical current transferred from one component to another.
Ambient: The environmental conditions, e.g. surrounding light and sound. More info: Ambient Sound, Ambient Light.
Amplifier: A device which increases signal amplitude.
Amplify: To increase amplitude.
Amplitude: The strength or power of a wave signal. The "height" of a wave when viewed as a standard x vs y graph.
Anamorphic Lens: A special type of wide-angle lens which stretches the width of the image but not the height, creating a widescreen aspect ratio.
Analogue: Information stored or transmitted as a continuously variable signal (as opposed to digital, in which the analogue signal is represented as a series of discreet values). Analogue is often technically the more accurate representation of the original signal, but digital systems have numerous advantages which have tended to make them more popular (a classic example is vinyl records versus CDs).
Antenna: A device which radiates and/or receives electromagnetic waves.
Aperture: Literally means "opening". The camera iris; the opening which lets light through the lens. By adjusting the size of the aperture, the amount of incoming light is controlled. The aperture size is measured in f-stops. More info: Video exposure/iris.
ASF: Windows Media file format ending with the extension .asf. Used for delivering streaming video.
Aspect Ratio: The ratio of width to height of an image. Can be expressed as a number, or a relationship between two numbers. For example, the standard television screen ratio is 4:3 (4 units wide by 3 units high) or 1.33 (the width is 1.33 times the height). The new "wide screen" television ratio is 16:9 (1.78), and many new video cameras have the option to record using this format. Theatrical film aspect ratios vary, but the most common is 18.5:10 (1.85).
ASX: Windows Media file format ending with the extension .asx. This is a metafile which works in conjunction with ASF files for delivering streaming video.
Audio: Sound. Specifically, the range of frequencies which are perceptible by the human ear.
Audio Dub: The process of adding audio to a video recording without disturbing the pictures. The original audio may be replaced, or kept and combined with the new audio.
Audio Insert: A feature of some video equipment which allows audio dubbing.
Automatic functions: Functions which are performed by equipment with little or no input from the operator. Auto-functions can be very useful, but tend to have serious limitations. As a general rule, it is desirable to be able to operate audio-visual equipment manually.
Backlight: A light which is positioned behind the subject. It's primary purpose is to make the subject stand out from the background by highlighting the subject's outline.
Backlight Correction (BLC): A feature of some cameras which increases the apparent brightness of the subject when lit from the rear.
Back Focus: The focus between the lens and the camera. Adjusted by a ring at the rear of the lens (the closest ring to the camera body). If the camera appears focused when zoomed in, but becomes out of focus when zoomed wide, the back focus needs adjusting.
Balanced Audio: An audio signal which consists of two "hot" signals plus the shield. The hot signals are inverted relative to each other as they travel along the balanced cable. They are re-inverted when entering an audio device — this has the effect of inverting any unwanted interference, thus eliminating it.
Bandpass Filter: A circuit which filters out all but a certain range of frequencies, ie. it allows a certain band of frequencies to pass.
Bandwidth: A range of frequencies.
Barn Doors: Metal projections attached to the front of a light, which can be positioned in various ways to control the dispersal of the light.
Batch Capture: The process of capturing multiple video clips automatically. A batch command is set up from the capture software which includes in and out points for each clip.
Baud: Unit of signal speed — the number of signal "bits" per second.
Best Boy: On a film set, the assistant to the Gaffer and Key Grip.
Beta (1): A group of video formats developed by Sony Corporation. Beta, Beta SP, Digital Beta and other variations are all professional television formats. Betamax is a failed consumer version, losing to VHS in the 1980's.
Beta (2): A pre-release version of computer software. Often distributed widely without charge, in order to obtain feedback, identify bugs, and attract customers.
Binary: The "base two number system" which computers use to represent data. It uses only two digits: 0 and 1. Binary code represents information as a series of binary digits (bits). In the table below, binary numbers are shown with their decimal equivalents.
Decimal: 0 1 2 3 4 5 6 7 8 9 10
Binary: 0 1 10 11 100 101 110 111 1000 1001 1010
Bit: Binary digit. One piece of binary (digital) information. A description of one of two possible states, e.g. 0 or 1; off or on.
Bitmap: A series of digital image formats, which record colour information for each individual pixel. As a result, the quality is very high, as is the size of the file.
Biscuit: Square/rectangular metal part which screws to the bottom of the camera plate, and allows the plate to attach to the head. The biscuit comes as part of the head's package, whereas the plate comes with the camera. The biscuit is the "interface" between the two, and is designed to attach to any plate, and fit into a corresponding slot on the head. When the head's quick-release mechanism is activated, the biscuit, plate and camera are all released as one.
Black balance: A camera function which gives a reference to true black. When auto-black balance is activated (by a switch, positioned with the white balance switch), the iris is automatically shut, and the camera adjusts itself to absolute black.
Black burst: A composite video signal with no luminance information, but containing everything else present in a normal composite video signal.
Black noise: Usually refers to silence with occasional spikes of audio. Other definitions are also in use but this is the most common.
Blonde: A term used to describe tungsten lights in the 2Kw range.
Blue noise: Random noise similar to white noise, except the power density increases 3 dB per octave as the frequency increases.
Bluetooth: A wireless data transfer system which allows devices to communicate with each other over short distances, e.g. phones, laptops, etc.
Blu-ray: A high-definition DVD format supported by a group of manufacturers led by Sony. More info: The Blu-ray Format, Blu-ray vs HD-DVD.
BNC: A type of video connector common in television production equipment, used to transmit a composite video signal on a 75Ω cable.
Bridge: Another term for A/D converter.
Broadband: A general term to describe an internet connection faster than 56K. Broadband usually means 512K or greater.
Brown noise: Random noise similar to white noise but with more energy at lower frequencies.
Bucket: A solid coloured horizontal bar across the bottom of a colour bar test pattern. The most commonly used bucket colour in PAL patterns is red, referred to as a "bucket of blood".
Burn: The process of recording information to an optical disk (CD or DVD).
Bus: Pathway which a signal passes along. For example, the main output of an audio mixer is referred to as the master bus.
C: A computer programming language, with variations C+ and C++.
Cable Television: A system of television progam delivery via cable networks.
Camcorder: A single unit consisting of a video camera and recording unit.
Candlepower: A measurement of light, generally that which is output from an electric lamp.
Cans: An informal term for headphones.
Capture Card: A type of computer card with video and/or audio inputs which allows the computer to import an analogue signal and convert it to a digital file.
CCD: Charged Coupled Device.
CCU : Camera Control Unit.
CD Compact Disc. Optical storage device, capable of storing around 600-700MB of data.
Channel (1) : On audio mixers, the pathway along which each individual input travels before being mixed into the next stage (usually a sub-group or the master bus). Each channel will typically have an input socket where the source is physically plugged in, followed by a sequence of amplifiers / attenuators, equalisers, auxiliary channels, monitoring and other controls, and finally a slider to adjust the output level of the channel.
Charged Coupled Device: The image sensing device of video and television cameras -- the component which converts light from the lens into an electrical signal. Made up of pixels - the more pixels, the higher the resolution. CCDs are commonly referred to simply as "chips". They replaced previous tube technology in the 1980's. Larger CCDs can naturally accommodate more pixels, and therefore have higher resolutions. Common sizes are 1/3" (pro-sumer level), 1/2" and 2/3" (professional level). Consumer cameras generally have a single CCD which interprets all colours, whereas professional cameras have three CCDs -- one for each primary colour.
Chroma Key: The process of replacing a particular colour in an image with a different image. The most common types of chroma keys are bluescreen and greenscreen.
Chrominance: Chroma, or colour. In composite video signals, the chrominance component is separated from the luminance component, and is carried on a sub-carrier wave.
Cinematographer: AKA Director of Photography, the person on a film production responsible for photography.
Cinematography: The art and science of movie photography, including both shooting technique and film development.
Clear Scan: A video camera function which allows the camera to alter it's scan rate to match that of a computer monitor. This reduces or eliminates the flicker effect of recording computer monitors.
Codec: Short for compressor/decompressor. A tool which is used to reduce the size of a digital file. Can be software, hardware or a combination of both.
Colour Bars: Click here to see an illustration of colour bars A television test pattern, displaying vertical coloured stripes (bars). Used to calibrate vision equipment. There are numerous variations for different applications.
Colour Temperature: A standard of measuring the characteristics of light, measured in units called kelvins.
Common Mode Signal: A signal which appears equally on both wires of a two wire line, usually unwanted noise. Common mode signals are eliminated with balanced audio cable.
Component Video: A type of high-quality video signal which consists of separate signal components. Usually refers to Y/Pb/Pr, which includes one channel for luminance information and two for colour.
Composite Video: A type of video signal in which all components are recorded or transmitted as one signal. Commonly used with RCA and BNC connectors.
Compression (1): A method of reducing the size of a digital file, whilst retaining acceptable quality. This may be desirable in order to save memory space or to speed up access time. In the case of digital video, large files must be processed very quickly, and compression is still essential for playback on consumer-level computers. Professional digital systems can work with uncompressed video. There are many compression techniques in common use, and digital video often uses various combinations of techniques. Compression can be divided into two types: "lossless" and "lossy". As the names imply, lossless techniques retain all of the original information in a more efficient form, whereas lossy techniques discard or approximate some information. With lossy compression, there is an art to finding a compromise between acceptable quality loss, and file size reduction.
Compression (2): Audio compression is a method of "evening out" the dynamic range of a signal. Compression is very useful when a signal is prone to occasional peaks, such as a vocalist who lets out the odd unexpected scream. The compressor will not affect the dynamic range until a certain user-definable level is reached (the "threshold") - at which point the level will be reduced according to a pre-determined ratio. For example, you could set the compressor to a threshold of 0db, and a compression ratio of 3:1. In this case, all signals below 0db will be unaffected, and all signals above 0db will be reduced by 3db to 1 (i.e. for every 1db input over 0db, 1/3db will be output). Other controls include the attack and decay time, as well as input and output levels.
Contrast Ratio: The difference in brightness between the brightest white and the darkest black within an image.
Convergence: The degree to which the electron beams in a colour CRT are aligned as they scan the raster.
CPU: Central Processing Unit., the "brain" of a computer.
Crab: Camera movement across, and parallel to, the scene.
Crossfade: A video and/or audio transition in which one shot/clip gradually fades into the next. AKA mix or dissolve. More info: The crossfade transition
Crossing the Line: A video transition in which the camera crosses an imaginary line drawn through the scene, resulting in a reversal of perspective for the viewer.
Crossover: An electrical network which divides an incoming audio signal into discreet ranges of frequencies, and outputs these ranges separately.
CRT: Cathode Ray Tube.
Cut (1): An instantaneous transition from one shot to the next.
Cut (2): A location director's instruction, calling for the camera and audio operators to cease recording and all action to halt.
D Series Tape Formats: A series of broadcast digital formats, designated D1, D2, etc. Dx is basically a replacement for 1-inch formats. D2 and D3 combine chrominance and luminance information, whereas D1 and D5 store them separately (and are therefore higher quality).
Dailies (1): Daily raw footage shot during the production of a motion picture (AKA rushes or daily rushes).
Dailies (2): Newspapers that are published every day (or 5/6 days per week).
DAT: Digital Audio Tape.
Data Rate: The amount of data which is transferred per second. In a video file, this means the amount of data the file must transfer to be viewed at normal speed. In relation to optical disks, this means the amount of data which can be read or written per second.
DC: Direct Current. The electrical current output by batteries, etc.
Decibel (dB): Logarithmic measurement of signal strength. 1/10 of a Bel.
Deliverables: The final products of the filmmaking process, used to create prints and other material for distribution.
Depth of Field: The zone between the nearest and furthest points at which the camera can obtain a sharp focus.
Depth Perception:The ability to recognize three-dimensional objects and understand their relative positions, orientation, etc.
Device Control: A tool which allows you to control another device. For example, a window within a video editing package from which you can control a video camera.
Differential Amplification: Method of amplifying a signal, in which the output signal is a function of the difference between two input signals.
Digital: A signal which consists of a series of discreet values, as opposed to an analogue signal, which is made up of a continuous information stream.
Digital S : Professional digital tape format, introduced by JVC in the mid-1990s.
Digital Video Editing: Editing using digital video formats and computer software. Also known as non linear editing.
Digital Zoom: A method of zooming which digitally crops and enlarges part of the image. This is not a true zoom and results in loss of quality.
Dissolve: A video transition in which one shot dissolves (fades) into the next. AKA mix or crossfade.
DLP: Digital Light Processing. A television technology that uses a coloured light beam which bounces across an array of hundreds of thousands of hinge-mounted microscopic mirrors attached to a single chip called a "micro mirror device".
Docutainment: From the words documentary and entertainment. A television programme which includes both news and entertainment content, or a blending of both.
Dolly: Any apparatus upon which a camera can be mounted, which can be moved around smoothly.
Dolly Zoom:: A cinematography technique in which the camera moves closer or further from the subject while simultaneously adjusting the zoom angle to keep the subject the same size in the frame.
Downstage: Toward the camera.
Dropout: Loss of part of a recorded video or audio signal, showing up as glitches on playback. Can be caused by damaged record heads, dirty tapes or heads, etc.
Driver: A piece of software which enables a piece of hardware to work with a computer. Usually supplied with the hardware, but can often be downloaded from the vendor's website.
Dry Run: Rehearsal, without recording or transmitting etc.
DTMF: Dual-Tone Multi-Frequency, better known as touch-tone. The standard system of signal tones used in telecommunications.
Dutch Tilt: A camera shot which is deliberately tilted for artistic effect.
DV: Digital Video.
DVCAM: Digital tape format from Sony.
DVCPRO: Professional digital tape format from Panasonic, introduced in the mid-1990s.
DVD: (Digital Video Disc or Digital Versatile Disc). An optical disc format which provides sufficient storage space and access speeds to playback entire movies.
DVD Authoring: The process of taking video footage, adding chapter stops, menus, and encoding the footage into MPEG files ready to be burned.
DVD Burning: Taking the authored DVD files and physically writing them to a disk.
Dynamic Loudspeaker: Loudspeaker which uses conventional cone and dome drive elements.
Dynamic Microphone: A moving coil microphone, which doesn't require power.
Dynamic Range: The difference between the weakest and strongest points of a signal.
Earth Hum: An unwanted noise which has been induced into a video or audio signal by faulty earthing.
Edit: The process of assembling video clips, audio tracks, graphics and other source material into a presentable package.
Edit Decision List (EDL): A list of all in points and out points for an editing task. Can be stored on a removable disc (e.g. floppy disc). This enables an edit to be constructed in one edit suite, then taken to another (better) suite to make the final version.
ENG : Electronic News Gathering. This term was introduced with the evolution of video cameras for shooting news in the field (as opposed to film cameras). It is still widely used to describe mobile news crews.
Exposure : The amount of light which is passed through the iris, and which the CCD or film is exposed to.
Equalisation: The process of adjusting selected ranges of audio frequencies in order to correct or enhance the characteristics of a signal.
Fade: A transition to or from "nothing". In audio, to or from silence. In video, to or from a colour such as black.
Field: In interlaced video, half a video frame. A field comprises every second horizontal line of the frame, making a total of 312.5 lines in PAL and SECAM, 262.5 lines in NTSC.
Film Noir: French for "black film" or "dark film". A term used describe a genre of film popular in America between 1940 and 1960.
Filter: A transparent or translucent optical element which alters the properties of light passing through a lens.
Flanging: In audio work, a type of phase-shifting effect which mixes the original signal with a varying, slightly delayed copy.
Floating Point Color: Available in 32-bit color digital images, floating point space allows colors to be defined as brighter than pure white or darker than pure black. This has advantages in image processing techniques.
Flying Erase Head: In video recorders, an erase head which is mounted on the drum assembly. The erase head wipes any previous recordings as new ones are made. "Normal" erase heads are stationary, and mounted to the side of the head drum. Because of their close proximity to the record heads, flying erase heads provide cleaner edits.
Floor Manager: In television production, the person in charge of the "floor", i.e. the area where the action takes place.
Focal Length: The distance from the centre of the lens to the camera CCD.
Focus: v. The process of adjusting the lens in order to obtain a sharp, clear picture.
adj. The degree to which an image is correctly focused.
FPS: Frames Per Second. The number of video or film frames which are displayed each second.
Frame (1): The edges of a television / video / film image.
Frame (2): To compose a camera shot. More info: Camera framing, Common shot types
Frame (3): One complete video, television or film picture. In video and television, each frame is divided into two interlaced fields. PAL and SECAM systems deliver 25 frames per second, with 625 horizontal scan lines. NTSC delivers 30 fps with 525 lines.
Frame Rate: The number of video or film frames displayed each second (frames per second; fps). PAL frame rate is 25 fps, NTSC is 30 fps, film is 24 fps.
Fresnel: A type of lens with concentric rings which focus the light. Pronounced fra-NELL.
Frequency Response: The sensitivity of a microphone (or other component) to various frequencies, i.e. the amount each frequency is boosted or attenuated.
F-stop: Measurement of aperture. The higher the f-stop number, the smaller the aperture.
F-type : A family of cable connectors, in which the centre (hot) pin is the centre wire of the cable itself.
Gaffer (1): Chief electrician on a film set.
Gaffer (2): Industrial-strength sticky tape, AKA duct tape.
Gain: The volume/amplification level of an audio or video signal.
Gauss: (pronounced "gows", abbreviation "G") Unit of magnetic induction.
Gel: (pronounced "jel") Semi-transparent heat-resistant material which is placed in front of a light source in order to modify it's colour temperature or other characteristics.
Geosynchronous: A satellite orbit in which the satellite remains in a fixed position above the Earth.
Graphic Equalizer: A type of audio equalizer which uses a graphical layout to represent the changes made to various frequencies.
Gray Card: A gray-coloured card which reflects a known, uniform amount of the light which falls upon it. Used as a reference to calibrate light meters and set exposure.
Gray Noise: Random noise, similar to white noise, which has been filtered to make all frequencies appear equally loud to the human ear.
Green Noise: An unofficial term referring to the background ambient noise of the world. Can also mean the mid-frequencies of white noise.
Green Room: A room located near the main stage in a studio or concert venue, where artists and guests wait before their appearance.
Green Screen: A film and video technique in which action is shot against a green screen, which is subsequently removed from the image and replaced with a different background.
Halogen: Any of the four non-metallic elements flourine, chlorine, bromine and iodine.
Head (1): The component which records an electrical signal onto magnetic tape, or reads a signal from tape into an electrical signal.
Head (2): The part which the camera is mounted on, atop a tripod, pedestal or other mounting. Allows the camera to pan and tilt.
Headroom: The amount of space between the top of the subject's head and the top of the picture frame.
Hertz: Unit of frequency. One cycle per second.
HDBaseT: A digital connection used in home entertainment systems, designed to carry video, audio, ethernet, power and control data over a standard Cat5e/6 cable.
HD DVD: A high-definition DVD format supported by a group of manufacturers led by Toshiba.
HDMI: High-Definition Multimedia Interface. A digital connection used in home entertainment systems.
HDTV: High-Definition Television.
Hi8: An analog video format introduced by Sony in 1989.
HMI: Hydrargyrum Medium-Arc Iodide, a type of light which uses an arc lamp instead of an incandescent bulb to produce light.
Hot (1): An image or part of an image which is excessively bright, i.e. overexposed.
Hot (2): The wire in a cable, and the connecting pins, which carry the signal.
Hz: Hertz. Cycles per second.
i.LINK: AKA i.Link or IEEE 1394, Sony's brand name for Firewire. A type of connection used to connect audio/video equipment and computers.
Impedance: A term in electronics which measures the amount of opposition a device has to an AC current (such as an audio signal). Technically speaking, it is the combined effect of capacitance, inductance, and resistance on a signal.
Indeo: A digital video compression format.
Infra-red: Frequencies beyond the red end of the visible spectrum, i.e. frequencies with longer wavelengths than red light. Perceived by humans as heat. Commonly used for remote-control devices.
Infotainment: Television programming which blends information and entertainment.
In-point: The beginning point of an edit.
Interface: The point of contact between a tool and it's operator. A human/computer interface could be a keyboard or a mouse.
Interlace: The method of dividing a video frame into two fields; one made up of the odd-numbered horizontal lines, the other made up of even-numbered lines.
Internet: If you don't know what the Internet is, you're in trouble.
Intranet: A "closed-circuit internet". A local network of computers linked in much the same way as the wider internet.
Iris: The circular opening (aperture) which controls the amount of light passing through to the camera's sensing element or film.
Jack: A type of audio connector originally developed for telephone switchboards, and sometimes called a phone connector. Still in common use for musical and other audio equipment.
Jackfield: AKA Patch-panel. A board which accommodates connections between multiple sources.
Jib: A revolvable camera mounting arm, which can be attached to a dolly or crane.
JPEG: Joint Photographic Experts Group. A standard for still-image compression.
Jump Cut: A video transition in which one shot appears to "jump" to another shot with very similar framing. Usually considered undesirable but can be used for dramatic effect.
Jump the Shark: A colloquial term used mainly in the US, referring to a defining point in a TV or movie series that marks the beginning of a terminal decline in quality and/or popularity. It stems from the Happy Days episode in which the Fonz literally jumps a shark while waterskiing.
Kelvin: A unit of temperature measurement. Colour is measured in kelvins.
Key Frame: In some forms of digital compression, uncompressed frames (key frames) are placed at regular intervals (eg. every 6th frame is uncompressed). Each subsequent frame exists as variations on the keyframe, until a new keyframe is introduced. The further apart the keyframes, the worse the overall picture quality.
Key Grip: Person in sharge of constructing and dismantling film sets and dolly tracks.
LAN : Local Area Network. A network of computers connected via cables or a wireless system.
LANC: A connection developed by Sony, used to link remote-control units, edit decks, etc.
Lens: A transparent structure made of glass or other material, with at least one curved surface, which causes the light rays passing through it to converge or diverge in a controlled fashion.
Letterbox Format: In video and television, the practice of placing black bars at the top and bottom of the frame, in order to simulate a wide-screen format (as if the viewer were looking through the slot in a letterbox).
Light: That section of the electromagnetic spectrum which is visible, ie. perceptable to the human eye. Specifically, white light contains the wavelengths from 400nm (nanometres) to 700nm. Light travels through a vacuum at approximately 300,000 km (186,000 miles) per second. More info: Lighting tutorials
Lighting, Three-Point: A standard lighting technique using three lights: The key, fill and back lights.
Limiter: A device which limits the level of a signal to a specified threshold.
Loudspeaker: A transducer which converts electrical signals into sound waves.
Lower Third: The lower portion of a video frame which contains graphical information such as station ID, name/title key, etc.
M, MII: Professional tape formats from Panasonic. The M format was based on VHS technology, and was introduced at about the same time as Beta (in the mid-1980's). The MII format was introduced a few years later to compete with Beta SP. MII uses a different sized cassette.
MIDI: Musical Instrument Digital Interface. A standard of communication between musical instruments, controllers and computers.
Mid-Shot: A camera framing term, half-way between a wide-shot and a close-up. A mid-shot of a person will show them from about the waist or chest up.
MiniDV: A consumer-level digital video format. More info: The MiniDV Format
Mix (1): A video transition in which one shot gradually fades into the next. AKA crossfade or dissolve.
Mixer: A device which accepts multiple signal inputs (video or audio), processes them, and provides one or more outputs. The outputs are "mixes" of the input sources.
M-JPEG: See Motion-JPEG
Modulate: To "change". A signal can be transmitted via a carrier wave, by modulating the wave to represent the signal.
Monitor: A device used to view a video, graphic or text source, or to listen to an audio source. Video monitors use CRTs (cathode ray tubes), LCDs (liquid crystal displays), and other technologies. Audio monitors generally use cone drivers and horn divers, mounted in speaker cabinets.
Monocular: Related to having vision in only one eye, as opposed to binocular (stereo vision, with two eyes).
ND (Neutral Density) Filter: A filter which reduces the amount of light coming through the camera lens, without affecting it's colour temperature.
Noddies: Shots of the presenter / interviewer nodding, smiling, frowning etc. These can be shot after the interview and inserted during post-production.
Non-Linear: Any method of video editing which doesn't require all shots to be assembled in a linear fashion.
NTSC: National Television Standards Commission. Video/broadcast standard used in the USA, Canada, Japan, Mexico, and other countries. Delivers 525 horizontal lines of resolution at 30 fps (frames per second).
OB: See Outside Broadcast.
Off-Line: Out of action, not currently useable.
Off-Line Edit: A "draft" edit, usually prepared in an off-line edit suite (at a lower cost), then taken to an on-line facility to make the final cut.
On-Line (1): Operational.
On-Line (2): In multi-camera or multi-tape set-ups, the camera or videotape machine which is currently selected by the director. For example, in an outside broadcast, the on-line camera is the camera which is currently live.
On-Line Edit: The final version of an edit, prepared in a professional edit facility.
Optical: Of light/optics.
Optical Image Stabiliser (OIS): A system of stabilizing a camera image by constantly adjusting the optics.
Optical Zoom: A method of zooming which uses a telephoto lens, i.e. the zoom is provided by the optics rather than digital processing. Optical zoom is better than digital zoom.
Optics: Dealing with properties of light. Camera optics: The components which deal with light rays, before they are converted into electrical signals (i.e. the lens, etc).
Oscilloscope: Device which accepts an electrical input, and represents the variations of the input as a display on a CRT screen.
Out-point: The end point of an edit.
Outside Broadcast: A radio or television program which is broadcast from location, rather than from a studio.
PAL: Phase Alternate Line. Video/broadcast standard developed in Germany, and used primarily in Europe and Australasia. Delivers 625 lines at 25 fps (frames per second).
Pan (1): Horizontal camera movement.
Pan (2): The amount which a signal is divided between two pathways. For example, on an audio mixer, an input source can be panned across two stereo channels.
Pan and Scan: A method of converting widescreen film or video to 4x3 aspect ratio in order to be displayed on traditional television sets. The most important area of the frame is selected and the rest discarded.
Pan Pot: Pan Potentiometer. A component which pans a signal across two pathways. Typically a knob or slider. The knob on a domestic stereo which pans between left and right speakers is a pan pot.
Parametric Equalizer: A type of audio equalizer which provides user-adjustable parameters such as frequency and bandwidth. More info: Parametric Equalisers, Sound Equalization.
Patch Panel: AKA jackfield, a panel containing a series of connection points for electronic equipment. This allows equipment to be inter-connected in various configurations.
Pattern Generator: Click here to see a small portable pattern generator. A device capable of outputting various television test patterns. Used to test and calibrate vision equipment.
PCM: Pulse Code Modulation. A digital audio format.
Peak: The highest level of strength of a signal. If the "peak" or "clip" light on an audio mixer is activated, this means the respective bus (channel) is peaking at a dangerous level.
Pedestal (1): A movable mount for studio cameras. More info: Pedestal shot
Pedestal (2): The black level of a video signal.
Pepper Light: A small light, around 200w, used to light small spaces or to highlight certain features.
Persistence of Vision: A widely-accepted but scientifically unfounded theory which states that the human eye (and/or brain) always retains images for a fraction of a second.
Phantom Power: A means of distributing a DC current through audio cables to provide power for microphones and other equipment.
Phasing: In audio work, an effect which utilizes phased wave interaction to create various sweeping sounds.
Pink noise:Random noise, similar to white noise, that contains equal sound pressure level in each octave band.
Pixel: Picture Element.
Podcast: A portmanteau (fusion) of broadcasting and iPod. A system of syndicating multimedia content via the Internet for personal computers and portable devices.
Pot: See Potentiometer.
Potentiometer: Variable resistor. Potentiometers are used to adjust the level of a signal and are typically controlled by a knob or slider.
Power Amplifier: A device which accepts a relatively low level audio signal and boosts it to a level at which it can be output to a loudspeaker.
Power reset: Disconnecting power from a device (usually by turning it off), in order to purge all charges and reset the device to it's default settings.
PPM: Peak Program Meter. An audio level meter.
Pre-Roll: The "lead-in" time at the beginning of a tape edit. When performing an edit, the tapes are rewound a few seconds, then played back before the edit begins. This ensures that the tapes are running at exactly the right speed.
Production: The process of creating a media product, or in some cases, the product itself.
Quantization: The process of converting a continuous range of values into a finite range of discreet values. Used for various applications in digital image and audio production.
Qubit: Short for quantum digit or quantum bit, the basic unit of a quantum computer, equivalent to the binary bit in traditional computers. Can be state 1 or 0 (pronounced ket 1 and ket 0), or a quantum superposition of the two — this allows vastly more possible states than the binary bit.
Quicktime: A digital media format originally developed for the Apple Computer range, but is now also available for other platforms.
RAM: Random Access Memory. A system of computer memory in which data can be retrieved in any order with equal speed.
RCA (1): The Radio Corporation of America, an American broadcast company.
RCA (2): A small non-locking connector. Typically used in home entertainment systems.
Real Time: Anything which occurs without delay. A real-time effects proccessor will add effects instantly, without having to wait to render.
Red Head: A term loosely used to describe general-purpose tungsten lights in the 800w range.
Reflector Board: A specially-designed reflective surface which is used as a light source.
Resolution: The amount of detail in an image or signal. On a computer screen, the resolution is the number of pixels. In an analogue video signal, the resolution is the number of horizontal lines. In digital audio, the resolution is the number of samples per second.
"Colour resolution" refers to the colour depth of an image, ie. how many colours are present.
Reverberation (Reverb): The amount of time it takes an emmitted sound to cease bouncing off objects such as walls. In audio work, adding a reverberation effect gives the sound more body and can make it sound as if it was recorded in a large room, hall, etc.
Reverse Cut: A video transition in which the camera "crosses the line", resulting in a reversal of perspective for the viewer. This is generally undesirable as it causes confusion.
RGB: Red, Green and Blue. The primary colours of video.
Rule of Thirds: A technique in camera framing where the frame is divided into imaginary sections to create reference points.
Rushes: Daily raw footage shot during the production of a motion picture (AKA daily rushes or dailies).
S-Video: A video signal that carries luminance (Y, brightness) and chrominance (C, colour) values as physically separate signals. Also known as Y/C video. Usually uses a small four-pin mini-DIN connector. First became popular during the S-VHS/Hi8 era.
Sample: A near-instantaneous recording of a signal, measured in thousandths of a second. Digital signals are constructed by sampling analogue signals thousands of times per second. Each of these individual samples are strung together to make a close approximation of the original signal.
Saturation: The level of colour in a vision signal or still image. A highly-saturated signal has very strong colours.
Scene: In film, television or stage, all the action/shots which take place at a certain time and location and comprise a segment of the program.
SCART: A type of multi-pin connector used in home entertainment systems.
Scissor Platform: AKA scissor lift, a mechanical work platform which can be raised and lowered. Sometimes used to elevate a camera position.
SECAM: Systeme Electronique Couleur Avec Memoire. Video standard used primarily by France and various Eastern Bloc countries. Provides 625 horizontal lines at 25 frames per second.
SEG: Special Effects Generator. A device used to create special video effects.
Servo: Remote control of camera functions such as zoom and focus, by means of a motor. Servo controls can be mounted an the lens housing, on the tripod/pedestal handles, or on a remote-control unit.
Setup: The black level of a video signal.
Shot: A continuous piece of video or film footage. Everything you get between pressing "record" and "stop".
Signal Processing Device: Any device which takes a signal input, then modifies the signal before outputting it.
SLR: Single Lens Reflex, a popular type of still photography camera that uses a moveable mirror to synchronize the lens and viewfinder images.
SMPTE: (Pronounced "simptee") Society of Motion Picture and Television Engineers. A group which has set various video standards.
Snow: Random patterns of black and white dots on a TV screen or vision monitor. Snow can be caused by an improperly tuned television (or very poor reception), an unrecorded video tape, or dirty VCR heads.
Solder: An alloy of tin and lead that melts at a relatively low temperature. Used for securing electrical connections between components and wires.
Sound Reinforcement: The process of amplifying sound for the benefit of a live audience.
Speaker: See Loudspeaker
Stereo (1): Audio which is split into two channels.
Stereo (2): Duplicate images of the same scene, taken to simulate 3-D human vision.
Tally Light: A small light on a video camera which turns on when recording is in progress. In multi-camera situations; a light on a camera, or in it's viewfinder, which turns on when the camera is switched on-line or live.
TBC: See Time Base Corrector.
Tele: (Prefix) Producing images or other results from a distance.
Telecast: Material broadcast by television.
Telecine: The process (or equipment used in the process) of transferring film to video and/or television.
Telephotographic Lens: Magnifying lens, or combination of lenses.
Teleprompter: Device which scrolls text on a screen, to provide cues for a television/video presenter.
Televise: To transmit by television.
Television: Literally means vision at a distance. The transmission, reception, and reproduction of moving pictures and audio. Refers to both the process in general, and the receiving appliance.
Tele-zoom: Longer zoom, producing greater magnification.
Test Pattern: Pattern of colours, lines and/or shapes designed to assist equipment calibration.
Tilt: Vertical camera movement, i.e. adjusting the framing up and down.
Time Base Error: An error in the technical data of a video signal which causes picture distortion.
Time Base Corrector: A device which adjusts, improves and corrects defects in a video signal. Can be used to synchronise different vision sources before being mixed together, to avoid picture disturbances when cutting from one source to another.
Timecode: An indexing system that assigns a time value to individual frames of a film or video, or sections of an audio file.
Tone (1): An audio test signal. Used to set signal levels, test signal quality, identify signal pathways, etc. More info: Audio Tone
Tone (2): In music, an interval of two semitones.
Tone (3): Quality of a person's voice, e.g. "The newsreader spoke in an authoritative tone".
Tone (4): Description of an attitude, mood, setting, etc. For example, "The tone of the movie was grim", or "The tone of the article was upbeat".
Transcoding: The process of converting one digital format to another, or re-encoding a digital file in order to change one or more parameters.
Transducer: A device which coverts energy from one form into another. For example, a microphone is a transducer which converts acoustical energy into electrical energy.
Transistor: A device used for switching or amplifying.
Transition: The way in which two video shots or audio clips are linked together; for example, instant cut, crossfade, wipe, etc.
Transmitter: A device which converts video, audio and/or data signals into modulated radio frequency signals, and transmits them as radio waves.
Tripod: A three-legged stand for mounting equipment such as a camera, etc.
UER: Union Européenne de Radio-Télévision (www.ebu.ch).
UHF: Ultra High Frequency radio waves.
Ultrasonic: Audio frequencies above the upper limit of human hearing (approx 20,000 kHz).
Unbalanced Audio: An audio signal which consists of one "hot" signal plus the shield. This is common in home entertainment systems, as well as other systems with short audio cables. Unbalanced audio cables are prone to external interference, and are not prefered in professional situations.
UV: Ultra-violet light.
UV Filter: A filter which blocks out a certain percentage of ultra-violet light.
Vacuum Tube: A multi-electrode valve which controls the flow of electrons in a vacuum from electrode to electrode.
VCR: Video Cassette Recorder.
Vector Image: A graphics image which exists as a series of geometric shapes, rather than as a series of values for each pixel. Has the advantage of being resizable without loss of quality.
Vectorscope: Click here to see a combination waveform monitor and vectorscope. A device which graphically displays information about the chroma (colour) part of a vision signal. Used in conjunction with a waveform monitor (in fact, many devices are switchable between waveform and vectorscope modes).
VHF: Very High Frequency. This is a popular television broadcast band. It is lower than UHF (Ultra-High Frequency), and generally has a higher broadcast range.
VHS: Vertical Helical Scan. In the late1970s, VHS became known as Video Home System. VHS won the format war against Betamax, despite being technically inferior.
Video: There are many definitions of video, most of them rather loose. It essentially means any medium which displays moving images electronically (as opposed to mechanical film).
Video8: An analogue video format introduced by Sony in the 1980s. The first compact cassette format for camcorders.
Video Level: The strength of a video signal. Level is measured in volts/millivolts - the standard broadcast vision level is 1V peak-to-peak, of which 700mV comprises the picture information and 300mV comprises the timing and sync information. Related
Viewfinder: A component of video, television and film cameras. Available as EVF (Electronic Viewfinder) or OVF (Optical Viewfinder). An EVF has a small CRT which displays the camera output (or tape output).
Vision: The picture component of a video, television or film program (as opposed to the audio component).
Vision Control Operator: The person responsible for maintaining the technical quality of the vision signal(s). This may involve controlling some camera's functions remotely (such as iris, colour balance, etc.), as well as making adjustments to any vision source's technical characteristics (such as video level, timing, etc.).
Vision Mixer (1): A device which accepts multiple vision source inputs, manipulates them, and provides one or more vision outputs in real time.
Vision Mixer (2): A person who operates a vision mixer as described above. AKA vision switcher.
VITC: (Pronounced "vitsee") Vertical Interval Time Code. A type of timecode used in some video tape formats.
Vocal: Of the human voice.
Volt: Unit of electromotive force. 1 volt, when applied to a 1 ohm conductor, produces a current of 1 ampere.
Voltage: Electromotive force, in volts.
Voltmeter: A device which measures voltage. One of the functions of a multimeter.
VOX (1): Voice operated switch.
VOX (2): Abbreviation for vocals.
Vox Pop: From the latin phrase vox populi, meaning "voice of the people". The vox pop is a technique used in many forms of media, to provide a "snapshot" of public opinion. Random subjects are asked to give their opinion on a particular topic, and these are presented to the viewer/reader as a reflection of popular opinion.
VT: Video Tape. A magnetic storage medium for video.
VTR: Video Tape Recorder. See also: VCR.
VU: Volume Unit, a unit to measure the volume of an audio signal.
Watt: Unit of power; equivalent to one joule per second. 1 watt (W) = 1 volt (V) x 1 amp (A).
Wattage: Amount of electrical power, in watts.
Wave: An oscillation which is propogated from place to place.
Waveform: The shape (form) of a wave, or a representation of this form.
Waveform monitor: Click here to see a combination waveform monitor and vectorscope. An oscilloscope specifically designed to display the waveforms of video signals. Used to monitor signal strength, sync timing, etc.
Wavelength: The distance between any point on a wave and the equivalent point on the next phase.
White balance: A camera function which gives a reference to "true white", in order for the camera to interpret all colours correctly.
White noise: Random noise that contains an equal amount of energy in all frequency bands.
Whizz-pan: A very fast camera pan, usually such that individual frames are severely blurred.
Wide screen: Generally refers to any video aspect ratio greater than 4:3. More info: Aspect ratio, Why go widescreen?
Wideshot (WS): A framing term, meaning a camera shot which shows the whole of the subject. More info: Wide shot, camera shot types
Wipe: A video transition in which parts of one shot are successively replaced by equivalent parts of the next shot.
Wow: Wavering of audio reproduction due to speed fluctuations
XLR: A lockable connector, available with various numbers of pins (the most common being the 3-pin XLR). Often referred to as a "Cannon" after the original manufacturer of XLR connectors.
XML: Extensible Markup Language, a versatile markup language used in computer programming and web development. More info: XML
X-Y micing (X-Y pickup): A technique that uses two directional microphones aimed in an X or Y pattern to capture stereo sound.
XCU: Script designation for extreme close-up shot. AKA ECU.
XLS: Script designation for extra long shot, AKA extreme long shot, extreme wide shot (EWS).
Y: Luminance. The "brightness" of a signal.
Y/C: Luminance/chrominance. A video signal which consists of two signals: The luminance (brightness) and chrominance (colour). S-video connections use a Y/C signal.
Y-Lead: AKA "Split lead". A lead with one connector at one end, and two at the other. For example, a mono audio output could be split (using a y-lead) into two signals, to be plugged into the left and right inputs of another device.
Yagi: A type of highly directional antenna consisting of an array of straight elements in line with a dipole. The formal name is Yagi-Uda array.
YUV: A type of component video consisting of one luminance signal (Y) and two chrominance signals (U and V).
Zebra Stripes: A feature of professional cameras, which places diagonal lines across any over-exposed parts of the picture in the viewfinder. These stripes will not show on the output/recorded picture, they are only there as a guide for the camera operator.
Zone System: A photographic system which divides light into ten tonal steps, from Zone 0 (absolute black) to Zone IX (absolute white). Zone V is medium gray, the same value found on an 18% gray card.
Zoom: Framing movement, in which the focal length of the zoom lens is altered to make the subject appear closer to, or further away from the camera. Note that this effect is similar, but not the same as moving the camera itself closer to or further away from the subject.
Zoom Lens: A lens with a moveable element, which is able to "zoom" between various focal lengths. This has the effect of making the subject appear closer to, or further away from the camera.
Zoom Microphone: A microphone on a video camera which adjusts it's pickup pattern to match the zoom lens, i.e. the mic becomes more directional as the lens zooms in.
Zoom Ratio: A number indicating the zoom range of a lens, arrived at by dividing the shortest focal length into the longest focal length. A 10 to 100 mm zoom has a zoom ratio of 10x. The number is sometimes stated as a ratio, e.g. 10:1.