Home : Glossary : C
C: A computer programming language, with variations C+ and C++. More info: C
Cable Television: A system of television progam delivery via cable networks.
Camcorder: A single unit consisting of a video camera and recording unit. More info: Camcorders
Candlepower: A measurement of light, generally that which is output from an electric lamp.
Cans: An informal term for headphones. More info: 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. More Info: CCU
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. More info: Audio Mixer Channels
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.
Choker: A type of shot composition in video/film/photography that is closer than a standard closeup. A choker is typically framed on the subject's face from above the eyebrows to below the mouth. More Info: Shot types
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. More Info: Chroma Key : Green Screen
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. More Info: Cinematographer
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: A television test pattern, displaying vertical coloured stripes (bars). Used to calibrate vision equipment. There are numerous variations for different applications. More info: Test patterns
Colour Temperature: A standard of measuring the characteristics of light, measured in units called kelvins. More Info: Colour Temperature
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. More info: Balanced audio
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. More info: Component video, Video connectors
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. More info: Composite video, RCA connectors, 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. More info: Audio compression, How to use a compressor
Contrast Ratio: The difference in brightness between the brightest white and the darkest black within an image. More info: Contrast Ratio
Convergence: The degree to which the electron beams in a colour CRT are aligned as they scan the raster. More info: Convergence Test Patterns
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. More info: Crossing the Line
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. More info: The cut transition
Cut (2): A location director's instruction, calling for the camera and audio operators to cease recording and all action to halt.