|Television Production Handbook|
|©1980-2009 Roger Inman & Greg Smith. All rights reserved.|
Make suggestions for additions or changes to the glossary at RogerInman@MovingPicturesTV.com
AC. Alternating Current. Electrical current that changes polarity regularly and continually.
Access Channel. One of the three cable channels designed for use by the public, government, or education.
AGC. Automatic Gain Control.
Ambient sound. Unintelligible background noise found in and generally unique to an audio environment.
Amp. Ampere. Unit of electrical measure equal to one volt sent through a resistance of one ohm. Also one watt divided by one volt.
Amphenol connector. A threaded connector sometimes used for unbalanced microphone lines.
Amplified. Any electronic device used to increase the level or power of signals applied to it.
Anamorphic. In optics, a lens with different magnification properties along two perpendicular axes and film exposed using such a lens. Anamorphic lenses are used to film wide screen motion pictures on normal film stock. A complementary anamorphic lens is used to fill the wide screen when the film is projected.Anamorphic. In digital video, images that are created using non-square pixels. The DV format, for example, uses pixels with a width that is 90% of their height. Using square pixels, standard definition television would be 640 pixels by 480 pixels. Using anamorphic pixels the frame is 720 pixels by 480 pixels, increasing horizontal resolution. The HDV format also uses non-square pixels, but they are one third wider than they are tall. That means that 1440 pixels fill the same width that 1920 square pixels would. The HDV format is 1080 x 1440, not 1080 x 1920.
Aperture. Any electronic device used to increase the level or power of signals applied to it.
Aperture. Opening in camera lens controlling and allowing light to pass through.
ASA. American Standards Association. A unit measuring the sensitivity of photographic emulsions. The higher the ASA number, the more sensitive the emulsion.
ASCAP. American Society of Composers, Authors and Publishers.
Assemble edit. A video editing procedure which records new video, audio, and control track information simultaneously without reference to any signal already on the tape.
ATSC. American Television Standards Committee. Acronym used to identify the standards for digital television and specifically television sets and tuners able to receive digital television broadcasts.
Attack time. The response time of an automatic gain control circuit to rapidly increasing signals.
Attack time. The time the rotating video head actually contacts the videotape and begins to write or read video information.
Automatic Gain Control. Electronic circuit designed to keep signals at an acceptable level by amplifying signals that are too low and attenuating or reducing signals that are too high.
Available light. Light from a natural source or commonly used lamp, as opposed to light added to a scene by using special photographic or television lights.
AWG. American Wire Gauge. A unit of measure of the cross sectional diameter of wire. The higher the number, the thinner the wire. Ordinary lamp wire is 18 AWG.
Back focus. The distance from the rear element of a lens to the image plane.
Background light. Any light used to illuminate the background of a set or scene, but not intended to illuminate the subject.
Backlight. Light striking a subject from the direction opposite to the camera. Generally used to highlight the subject and set it apart from the background.
Balanced line. A cable carrying two equal signals of opposite polarity on separate conductors, both surrounded by a grounded shield.
Bandwidth. The amount of audio or radio spectrum required or used by a signal or waveform.
Barn door. A metal flap or group of metal flaps attached to the front of a lamp housing to prevent light from spilling outside a desired area.
Base light. An even, diffuse, light filling a setting with sufficient light to keep shadows from key or back lights from being too dark.
Base video. A video signal that is not combined with a carrier to place it in the radio frequency spectrum. Normally has an amplitude of one volt peak to peak across an impedance of 75 ohms.
Bayonet mount. A lens mount, or electrical connector which engages by means of interlocking fingers and cams and permits attachment with only a relatively small amount of twisting action.
Beta format. A group of videotape formats similar to U-matic used with half inch color videocassette recorders and players.
Betacam. A component broadcast system using half-inch tape and cases similar to those for the Beta format.
Bidirectional microphone. A microphone designed to pick up sound on two sides of the microphone along the same axis, but reject sound from any other direction.
Bit. A single element of digital information. Eight bits make up one byte.
Bloom. A loss of picture detail and increase in size of bright portions of a video picture seen when too much light is allowed to strike a pickup tube or when the signals controlling a tube allow it to be overdriven.
Blu-ray. Format for high definition video disks, which
are read by a blue laser because it has a higher frequency than the red
lasers used in CD's and DVD's.
BMI. Broadcast Music, Incorporated. A music licensing service.
BNC connector. A connector with a bayonet lock used with coaxial video cable.
Boom microphone. Any microphone, but usually a unidirectional or shotgun microphone, attached to a pole or boom to keep the microphone near an audio source but outside of the field of view.
Broad. A light with a long bulb perpendicular to the direction in which the light is aimed, designed to throw an even light with an indistinct shadow.
Brightness control. A control used to adjust the illumination of viewfinders, monitors, and receivers, but not affecting signal levels from cameras or other picture sources.
Burn. Part of a pickup tubes that has a depletion of charge evidence by a negative image of the picture source causing the depletion. This condition is temporary unless the tube is turned off and allowed to cool before the problem is corrected.
Burst. A gated 3.58 megahertz signal immediately following horizontal sync and used as a reference in controlling the hue, or phase, of color signals.
Byte. One digital "word," made up of eight bits.
Cable. The electrical cords used to interconnect pieces of audio and video equipment.
Cable. A term generally referring to a broadband distribution system using wire rather than over-the-air broadcast.
Camera cap. A cap screwed or mounted onto the front of a camera in place of the lens to protect the camera pickup tube from light or dirt when the lens is not in place.
Cannon.A three-pin connector used with balanced audio lines for line and mic level audio signals. Also known as an XL or XLR connector.
Capacitor. An electrical device which stores energy as an electrostatic charge. Often used as a component in filter circuits.
Capstan. The spindle that actually drives tape across head assemblies.
Capture Card. A computer card, either internal or external, which converts analog audio and video signals to digital formats for computer editing.
Cardioid microphone. A somewhat unidirectional microphone with a heart-shaped pickup pattern.
Carrier. The RF signal which is modulated by a video or audio signal for broadcast transmission.
CATV. Community Antenna Television. Broadband distribution system using coaxial cable rather than over-the-air broadcast.
CCD. Charge-coupled device. In television, the device that senses light coming through the lens and translates it into electrical impulses (replacing the pickup tube).
CCU. Camera control unit.
CD. Compact disk. Laser disk with five inch diameter, which may contain video, audio, or data in digital format.
CD ROM. Compact disk with digital data used with a computer as "read-only memory."
CG. Character Generator.
Character generator. A small computer used to generate titles and other text electronically without the use of a camera.
Characteristic impedance. The apparent resistance to an alternating current shown by a wire or electronic device.
Chroma. The characteristic of a color which refers to its saturation or intensity. Also the color pattern of the television signal.
Chroma key. A key based on the chroma saturation and hue of portions of a picture, rather than on the luminance, or brightness. A specific hue is replaced by one picture source, while the rest of the picture is replaced by another picture source. A chroma key is an external key.
Chrominance. The color portion of the television signal.
C-mount lens. A lens with a standard one-inch threaded mount assembly that is screwed into the camera body, as opposed to a bayonet or "m" mount.
Close-up. A shot emphasizing detailed elements in a scene, as opposed to the more panoramic wide view.
Coaxial cable. A cable having a center conductor surrounded by insulation and a grounded shield.
Codec. The scheme used to compress and later decompress data in a computer file.
Color killer. A circuit designed to detect the presence of burst in a television signal and deactivate the color circuits if the burst signal is low or absent.
Compatible. Meeting all of the electronic requirements for signals and levels necessary to interface devices to achieve desired results.
Compression. The process of reducing the size of computer files without degrading the apparent quality of the contents. The formula for compressing, then decompressing the data in a file is called a codec.
Condenser microphone. A microphone using a power supply (usually a battery) to maintain a charge across two plates which modulate a voltage when the distance between them changes.
Confidence head. A video head separate from the normal record/play head found on some videotape recorders and used to monitor the actual recorded signal on the videotape during recording.
Contrast. The difference in illumination between the brightest and darkest parts of a scene or picture.
Contrast control. A control used to change the amplitude of the video signal in viewfinders receivers, and monitors, but not affecting the output of cameras or other video sources.
Control track. A reference signal recorded on videotape and used to control the path of the video heads across the tape on playback.
Credits. Listings of all those involved in making a program, usually appearing at the end of a television program or film.
Critical focus. The plane in front of a focused lens in which the image will be precisely in focus on the film or pickup tube.
Cume. The total audience size (number of viewers) for a program or series of programs over several showings. Repeat viewers are not counted.
Cut. The instantaneous transition from one picture or audio source to another.
Cutaway. A shot interposed at an edit point to prevent the appearance of a jump cut at the edit point.
Cyclorama. A seamless background, blending into the floor and usually lit from behind. Used to eliminate any background detail from a set.
D1. The first digital standard for video. Video is uncompressed, while audio is PCM, or pulse code modulated. The NTSC video resolution is 720x486. D1 was introduced in 1986 and is little used today.
DA. Distribution Amplifier.
dB. Decibel. A unit used to compare the relative levels of electrical signals on a logarithmic scale. The formula for the calculation is db=10(log(P2/P1)), or db=20(log(E2/E1)).
Demodulation. The process of separating a signal from its carrier frequency.
Depth of field. The range of distances in front of the lens in which objects appear to be in acceptable focus.
Depth of focus. The range of distances from the rear of the lens to the face of the pickup tube in which acceptable focus can be achieved.
Digital. Literally composed of digits, or discreet elements, as opposed to analog, which consists of continuous waves.
Digital Audio. Audio converted from analog continous waves to a digital representation. Quality depends on sampling rate and compression. Typical sampling rates are 44100 KHz for most audio applications and 4800 KHz for video files.
Digital Subscriber Line. A high frequency use of standard telephone lines to transmit broadband data. Speed is dependent on technology, line condition, and distance from the telephone company central office.
Digital Video. Uncompressed digital video consists of an array of 720 pixels horizontally and 480 or 486 (NTSC SD) or 576 (PAL) pixels vertically. Each pixel is represented by three bytes of color information, for a total of 24 bit color.
DIN. A type of multi-pin connector.
DIN. A standard for film sensitivity similar to ASA. Not Direct Current. An electrical current that does not change polarity.
Dissolve. The gradual change from one picture to another, allowing the pictures to be superimposed during the transition.
Distribution amplifier. An amplifier with essentially unity gain used to distribute control and picture signals to equipment in a television system.
Distortion. Any undesirable alteration in an audio or video signal.
DLP. Digital Light Processing involves the use of arrays of microscopic mirrors to create video displays.
Dolly. A wheeled device attached to a tripod to allow smooth movement of a camera.
Dolly. A camera movement toward or away from the subject (dolly forward, dolly back).
DSL. See Digital Subscriber Line.
Dub. To copy by playing back on one machine and recording on another.
Duct tape. A shiny adhesive tape designed for holding metal heating and cooling ducts, but also commonly used as a substitute for gaffers tape, a general purpose tape used in television and film.
DV. A standard definition digital video format using non-square pixels. Each frame is 720x480 pixels with a 4x3 aspect ratio. The format uses 1/4 inch tape and intra-frame compression.
DVCPro. Panasonic digital video tape format. The standard DVCPro cassette (M size) is larger than the MiniDV (S size) cassette. The format is somewhat different from DV and DVCam. DVCPro cannot be played on most DVCam players.
DVCam. A Sony digital videotape standard in which the tape moves 50% faster than in the standard DV or MiniDV format. DVCam players can also play back DV and MiniDV tapes. DVCam uses L and S size cassettes.
DVD. Digital versatile disk or digital video disk. The common medium for video information. DVD-5 recordable disks hold a nominal 4.7 GB of data, of which about 4 GB is available on a disk formatted for set-top DVD players.
DVD+R. A DVD format promoted by Sony which is slightly different from and has slightly less capacity than the DVD-R developed by the DVD Forum. Accepted as a DVD standard in 2008.
DVD-R. The DVD format developed by the DVD Forum.
Dynamic microphone. A microphone which uses a magnet moving in a coil of wire to generate an electrical signal.
Edit. In television, to record from any program source altering the duration or temporal sequence of events using a recorder specifically designed to do this efficiently and cleanly, maintaining continuity of sync and proper timing relationships between signals at edit points.
EIA. Electrical Industries Association.
EIAJ. Electrical Industries Association of Japan. Universal standard for video recording in black and white on half inch reel-to-reel videotape recorders. The standard involves a tape speed of 7 1/2 inches per second with a sixty-minute capacity using a seven inch reel. There is only one audio channel.
Eight-pin. A common rectangular connector generally used between television monitors and videotape recorders combining all of the cable connections necessary for record and playback functions into a single connector.
EFP. Electronic Field Production.
Electret. A type of condenser microphone.
Electronic Field Production. (EFP) Production of a television program or program segment by recording material on location with a single camera and editing this material to make the finished product.
E to E. Electronics to Electronics. Refers to the normal record mode in a videotape recorder in which the recorder output is connected to the recorder input and cannot show the actual signal recorded on tape. Some videotape recorders have special confidence heads which allow direct tape monitoring during recording. Most do not.
Equalization. Changing the relative balance of frequencies in an audio or video signal.
Equalizing Pulses. A series of sync pulses within the horizontal interval which determine the starting point for the first scan line of each field of video.
Establishing shot. A shot used to introduce a scene, including a relatively wide angle of view and showing the relationships between objects, settings, and people in the scene.
Ethernet. A specific kind of local area computer network codified as
Fade. The gradual change from one picture or sound source to another. Usually to or from black (video) or silence (audio).
F connector. A small threaded connector used with coaxial cable in the RF distribution of television signals.
Fidelity. A subjective appraisal of the amount of distortion in the reproduction and transmission of signals.
Field. One scan from the top to the bottom of the television frame, tracing alternate horizontal lines and taking one sixtieth of a second to complete.
Fill light. Light used to fill in shadows left by key light and keep the contrast range of a scene within the capabilities of the recording medium.
Film chain. An equipment grouping including a dedicated camera, super 8mm and 16mm projectors, dual dissolving 35mm slide projectors, and a special rotating mirror assembly (multiplexer) which transmits the images from one of the projectors to the dedicated camera.
Filter. A flat piece of glass or gelatin with no optical properties other than to control the color or intensity of light.
Filter. An electrical device used to reduce the transmission of signals in some frequency ranges and allow transmission of signals in other frequency ranges.
Firewire. Apple Computer's name for the IEEE 1394 interface. Also called i.Link (Sony). Used to transmit digital video and audio between camcorders and computers and other high-speed applications.
Flag. Temporary persistence of a bright spot on the pickup tube as the image causing the spot is moved across the face of the tube.
Flag. The horizontal shift observed at the top of the screen when a timing error occurs due either to skew and tension problems on playback or to slight timing errors at an edit point created in the editing process.
Flag. A metal flap used near a lens to keep lights from shining directly into the lens and causing lens flare.
Flare. An undesired image, or overall haziness of an image caused by undesired reflections of light from surfaces within the lens itself.
Flat. A framed upright panel, usually 4 x 8 feet or larger, used to simulate a wall or wall section in a television set.
Flat response. The reproduction or transmission of a signal with very little deviation from the original amplitude of the signal over its entire frequency range. Deviations in amplitude are expressed in db, plus or minus.
Flood light. Any light throwing a broad, even illumination in a circular pattern with diffused shadows.
Flutter. A form of signal distortion caused by rapid fluctuations in the speed of a tape crossing a head assembly.
Flying erase head. An erase head mounted on the rotating video head drum in advance of the record/playback head.
Focal length. The distance from the optical center of a lens to the focal plane.
Focal plane. The plane perpendicular to the lens axis at which parallel rays striking the lens are converged to a point.
Focus. To cause a sharp image from a lens to be projected onto the focal plane (in the case of a camera) or onto a screen (in the case of a projector). Also to adjust the electron beam converging circuits in a television monitor for maximum sharpness as they strike the surface of the picture tube.
Foot candle. The amount of light produced by a standard candle at a distance of one foot. The most common unit of measure for incident light used in film and television work.
Frame. A complete television picture consisting of two interlaced fields of video. The frame rate for NTSC television is thirty frames per second.
Freeze frame. The continuous repetition of a single frame of video. It is technically not possible for helical videotape recorders to display freeze frames, since they read only one field of video on each pass across the videotape.
Frequency. The rate of repetition of an electrical or audio signal, expressed in Hertz (cycles per second).
Fresnel. A special light-weight lens used in focusing beams of light. Originally used in lighthouses, now also used in high-quality studio and theatrical lights.
f-stop. The size of the aperture in a lens, given in f-numbers. The lower the f-number, the more light passes through the lens. It is the ratio of the lens focal length to the actual diameter of the aperture opening. See T-stop.
Fuse. A device designed to interrupt an electrical circuit in the event of an overload of that circuit.
Gaffer. The crew member principally responsible for transporting, maintaining, and setting up lighting equipment.
Gaffer's tape. A strong adhesive tape used in film and television production.
Gain. Degree of amplification. The difference between the signal level at the input of a device and the level at the output, usually expressed in dB.
Generation. The number of duplication processes by which a videotape is removed from the live source. The original recording is first generation, while a copy of an original recording is second generation, and so on.
Genloc. To reference a signal generator to a signal normally external to and separate from the system controlled by the signal generator. The purpose is to bring a system, such as a studio, into proper timing with an external source, such as a live remote camera, so that special effects as wipes, keys, and dissolves can be done using the external source in combination with internal sources.
Grip. The crew member principally responsible for the transportation, maintenance and mounting of the camera.
Ground. A connection to the chassis or a common return path, or an actual connection to the earth in an electrical device.
Head. The camera without lens or viewfinder.
Head. The uppermost portion of a tripod or pedestal which provides for the ability to pan and tilt the camera.
Head. A small electromagnet with a very small air gap between the poles used to record and play back magnetic pulses on audio or video tape.
Head gap. The space between the poles of a head. Good frequency response is dependent on proper width of the head gap. Dirt or oxide particles clogging a head can cause reduced signal level and distortion of the signal.
Head room. The space between the top of a subject's head and the top of the video frame.
Helical. Like a helix. Specifically, the geometric pattern formed by a rotating video head in relation to videotape moving across the rotating head assembly. Thus, referring to any videotape recorder using a rotating head assembly that reads a complete field of video on each pass across the tape. These include all EIAJ, U-matic, Beta, and VHS formats as well as one-inch SMPTE types A, B, and C.
Hertz. Cycle per second.
Heterodyne. A system used for recording color video signals at a reduced frequency.
HD. High Definition.
HDDVD. A disk format supporting high definition video which was in competition with Blu-ray.
HDTV. The broadcast standard for high definition video.
High Definition. In video, a format consisting of 1280 horizontal pixels by 720 vertical pixels (720p) or 1920 horizontal pixels by 1080 vertical pixels (1080i or 1080p).
High level. Audio signal intended to attain a maximum, or peak, level of zero db, or one volt at six hundred ohms impedance. (0.775 volts rms.)
Hiss. The background noise generated in an audio system which is internally generated by microphones, amplifiers, and tape.
Horizontal hold. An adjustment on viewfinders, monitors, and receivers to make the frequency of the horizontal sweep circuits to the horizontal sync pulse from an incoming signal.
Horizontal sync. That portion of the sync signal that controls the horizontal timing (and therefore horizontal location) of each line of picture.
Hue. Shade of color, determined in television by the phase angle between a color and the color subcarrier or color burst reference signal.
Hum. Unwanted low frequency audio noise caused by improperly shielded or improperly grounded audio cables and circuits.
i-Link. Sony's name for the IEEE 1394 interface. Also called Firewire (Apple). Used to transmit digital video and audio between camcorders and computers and other high-speed applications.
Impedance. The apparent resistance to an alternating current shown by a wire or electronic device.
Impedance matching. The use of a transformer or other device to alter the impedance of a device to equal the impedance of another device. Minimum distortion and loss of signal can be achieved only where the output transmitting a signal, the cable carrying the signal, and the input receiving the signal all have the same impedance.
Incident light. Light striking a subject, as opposed to light reflected by a subject. Usually measured in film and television by light meters calibrated in foot candles.
Insert. A shot or sequence inserted into a television program used to illustrated a subject.
Insert edit. A video or audio edit made with reference to pre-recorded control track so synchronization is maintained and the insert can be ended without visible disruption of the picture.
Interlace. The process of combining the two video fields into frames by writing only even-numbered lines in one field and only odd-numbered lines in the other.
Internal sync. Synchronizing signals generated by a camera, recorder, or other picture source without reference to or need of external synchronizing signals.
IRE. Institute of radio engineers. NOW IEEE. Also a unit of measure of video amplitude. One IRE unit is equal to 1/140 volt, peak to peak. The composite video signal is composed of sync, from -40 to 0 IRE and video, from 0 to 100 IRE. Black is normally set at between 7.5 IRE and 10 IRE.
Jump cut. An edit made without regard to the thirty degree rule, which results in a visual discontinuity as subjects appear to "jump" on screen.
Key. A video special effect in which the level of a video signal is used as a switch which allows selective substitution of picture information from one source with picture information from a different source. Luminance keyers use the amplitude of the monochrome portion of the signal, while chroma keyers use the amplitude of a specific color or hue. Most printed material is inserted into video using luminance keys, while picture information is inserted using chroma keys.
Key light. The primary illumination for a scene, generally giving the impression of a natural light source and throwing the darkest and most defined shadows in a scene.
Keystone. The effect of projecting an image onto a surface that is not perpendicular to the axis of the projecting lens. Parallel lines tend to converge in the direction where the surface is closer to the lens.
Lag. The tendency in some camera pickup
tubes to retain
an image after it is no longer presented to the tube. This effect
is most evident when a relatively bright image is replaced by a
darker field of view and is aggravated when a bright image is
stationary in the field of view for an extended period of time
before it is replaced.
LASER. Light amplification by stimulated emission of radiation. A laser is a device that emits light through a process of stimulated emission. Lasers are used to read optical disks and to write recordable optical disks.
Latent image. The image retained by a pickup tube after the source of that image is removed. If a latent image is present on a pickup tube when a camera is turned off, the image may be permanently fixed on the tube.
Lavalier. A microphone worn on the body and held in place either with a lanyard worn around the neck or a clip fastened to clothing. The frequency response of a lavalier microphone is skewed toward the higher frequencies to compensate for the low frequency sound transmitted directly to the microphone by contact with the body.
LCD. Liquid Crystal Display. An array of liquid crystals that either transmit or block light depending on electrical stimulation. Liquid crystals are used in everything from digital watches to video displays.
Lens hood. Also lens shade. A cone fastened to the front end of a lens to keep incident light from striking the lens elements and causing lens flare.
Limiter. An amplifier designed to limit or compress signals over a desired level, thus reducing the chances of distortion and keeping the range of signal levels within the range that can be recorded. Unlike an automatic gain control, a limiter does not augment or boost low levels.
Line level. In audio, a signal with a peak power of about one milliwatt at an impedance of 600 ohms, or zero dBm. This is equivalent to a voltage of .775 volts rms. Also know as "high level" or "auxiliary level."
Live. Not prerecorded. Occurring at the same instant as it is seen or recorded.
Live card. A card, usually about 11 x 14, used in television to display text or graphics to a camera.
Live on tape. Unedited. Recorded exactly as occurring with no compression of time or alteration of any sequence of events.
Long shot. A shot including a relatively wide view of an overall scene, often used as an establishing shot.
Low level. Microphone level. An audio signal with a maximum level of about minus fifty dB, relative to line level, or 2.45 millivolts at 600 ohms impedance.
Lux. The amount of light produced by a standard candle at a distance of one meter.
Master. A control uniformly governing the outputs of a number of other controls.
Master. Sometimes in editing, the source, or playback, machine.
Master. The finished copy of a program from which copies are made for distribution.
Matching transformer. A transformer used to alter the impedance of a signal source to match the input impedance of another device. A common use of matching transformers is to change the characteristic impedance of a 75 ohm coaxial antenna cable to 300 ohms to match the antenna input of a television set.
Medium shot. (MS). A shot showing a single subject, rather than an overall scene, but not in detail. For example, a shot of a person including the body from the waist to slightly above the top of the head.
Mic mouse. A soft foam pad or holder for a microphone which is placed on a stage or studio floor. The mic mouse holds the microphone very near the floor without allowing it to touch. The purpose is to eliminate the effect of sound waves bouncing off the floor and interfering with sound waves transmitted directly to the microphone.
MiniDV. S size videocassette using the DV digital video format.,
Mixer. An electronic device for combining the outputs of several sound sources, with separate control over the volume or quality of each.
Modulation. The process of varying the instantaneous amplitude, frequency, or phase of a carrier signal in response to the waveform of an information-bearing signal.
MPEG. Motion Picture Experts Group. Formed in 1988 to formulate compression techniques for audio and video.
MPEG 1 Layer 3 (MP3). a "lossy" compression format for audio
MPEG 2. A collection of compression standards that include the compression standard for video and audio used in DVD's and Blu-ray disks as well as television satellite and cable transmissions. MPEG 2 is a "lossy" system that shows compression artifacts at low bit rates. Typical bit rates for acceptable video are from three to seven mbps (thousand bits per second).
MPEG 4. A collection of compression standards that include audio and video compression used primarily for internet transmission.
Multiplexer. A device which uses a movable mirror to select images from one of several optical sources for transmission to the dedicated camera in a film chain.
Neutral Density Filter. A filter having no effect on color and no optical effect on the lens to which it is attached, but which reduces the overall amount of light reaching the lens. A one power filter reduces transmission by half, or by one f-number. A two power filter reduces transmission by two f-numbers.
Noise. Any unwanted signal interfering with the clarity and intelligibility of desired signals. The background of static inherent in any recording or amplifying device, generally forty to sixty db below the peak output level of the device.
Nose room. The space between the nose of a subject's head in profile and the edge of the video frame the subject is facing.
NTSC. National Television Systems Committee. Referring to any standard for signals devised by that body, such as NTSC color bars or NTSC sync. The television system used in the United States, Canada, Japan, Central America, and a number of other countries. The NTSC system has 525 interlaced horizontal lines and 30 frames per second. Look for countries using NTSC.
Nuvicon. A type of video pickup tube used in inexpensive color television cameras.
Octave. A doubling of frequency. Almost all audio devices have a sound frequency range of from four to ten octaves. A piano, with 88 keys, has a range of seven and a third octaves. A video signal has a range of almost twenty octaves.
Omnidirectional microphone. A microphone which picks up sound equally well from all directions.
Optical Viewfinder. A camera viewfinder which has no electronics and therefore cannot reflect the actual picture being transmitted from the camera. Optical viewfinders for inexpensive television cameras are rangefinder viewfinders which are separate from the camera lens system and show a picture slightly different from that seen by the camera. The difference is most troublesome for subjects close to the camera where the angle of difference, or parallax, is greatest.
Original. Usually first generation audio or videotape from which a master is made.
One-hundred eighty degree rule. A rule of visual continuity which states that when dealing with two or more subjects, shots may only be cut together if they are taken from the same side of a line drawn through the subjects. Used to maintain proper direction on the screen.
PAL. Phase Alternating Line. The television system used in western Europe, China, and most of the rest of the world. The PAL system has 625 interlaced lines and 25 frames per second. Look for countries using PAL.
Pan. A camera movement in which the camera is rotated in the horizontal axis. The proper commands are "pan right" and "pan left."
Parabola. A parabolic dish used to reflect sound waves, concentrating them on a microphone, allowing sound to be picked up from greater distances than with even a normal unidirectional or shotgun microphone.
Parallax. The difference in view caused by looking at a scene from two slightly different locations.
Patch bay. Patch panel. A control panel where all the video and audio lines used in a studio are brought together and terminated in connectors allowing any combination of lines to be wired together as desired by patching in short lengths of cable.
Patch cord. A short cable with connectors used to interconnect lines in a patch panel. Any audio or video cable used for temporary connections.
Peak to peak. Literally, encompassing the entire waveform from the most negative part to the most positive. One of two ways to measure signal amplitude, the other being rms (root mean square). Peak to peak measurements are usually more meaningful in video, while rms is more meaningful in audio.
Pedestal. A camera support generally restricted to studio use having a single elevator column mounted on a tricycle base.
Pedestal. Also called setup. The black level in a television picture, 7.5 to 10 IRE units above sync. Per cent modulation. The amount of amplitude of a signal in terms of the maximum amplitude that signal can be allowed to achieve.
Phase. The difference, expressed in degrees, in the instantaneous amplitude of two signals of the same frequency.
Phase. The difference, expressed in degrees, between two signals. In color television, the angle between the burst reference signal and any color or hue.
Phone jack. An audio connector generally used with unbalanced lines and intercom systems. Phone jacks may have a single conductor with ground (unbalanced lines) or two conductors. with shield (intercom systems and stereo headphones).
Photoflood. Any of a number of lamps designed for still photography that throw an even, diffuse light. They may be designed to fit into a dish reflector or have internal reflectors. Since they are ordinary tungsten bulbs, they tend to lose output power and change color temperature with age, making them unsuitable for color television.
Pickup tube. A light-sensitive electron tube which is scanned by an electron beam to convert an image focused on the face of the tube into an electronic signal.
Pixel. The smallest indivisible area of a video display that can be addressed.
Plasma. A plasma display is made up of an array of gas chambers in which the gas is electrically turned into plasma which then exites phosphors to emit colored light. The first monochrome plasma display was invented at the University of Illinois at Urbana-Champaign in 1964.
Plumbicon. A pickup tube used in almost all tube-type broadcast color cameras.
Pop. Microphone distortion caused by speaking certain consonants (especially "p") into a microphone placed too close to the mouth.
Portapak. A brand name for a battery-operated portable video camera and recorder combination.
Pot. Potentiometer. A variable resistor used to control the level of a signal.
Preamp. An amplifier used to increase signal levels prior to additional processing.
Presence. The ambient sound found in and unique to a recording location.
Proc amp. Processing amplifier. Separates the video signal into sync and picture components to allow limited adjustment of pedestal, gain, and some other aspects of the picture and recombination with internally generated sync signals.
Profile. Side view, especially of a person.
Proximity effect. An overemphasis of low-frequency tones caused by speaking too close to a unidirectional microphone.
Quad. Broadcast videotape recorder having four rotating video heads, each of which reads only 17 horizontal lines of picture per pass over the tape. Quad recorders use two-inch videotape.
Quartz-halogen. The light of choice in color television, designed to maintain correct color temperature and uniform output throughout its life. Provides much higher output than conventional tungsten light of the same power consumption and has a life up to one hundred times that of common tungsten photographic lights. These lamps are sensitive to shock and handling and should never be touched with bare hands.
Radio Frequency. (RF) That part of the frequency spectrum in which it is possible to radiate (transmit) electromagnetic waves. Any part of the broadcast band, including radio and television.
Radio mic. Transmitter mic or wireless mic. A microphone connected to a small radio transmitter, used in situations where cables would be cumbersome or impossible to use. FCC regulations are stringent in the use of transmitter microphones.
Rating. The percentage of the total potential television homes tuned to a specific program. Because the rating is based on total television homes, including those that are not watching any television, the totaling one sixtieth of a second to complete.
RCA pin plug. A small connector used with unbalanced single conductor shielded audio cables to interconnect home entertainment audio products. Also used as high level inputs and outputs on some video recorders and audio mixers. Also called a phone plug.
Receiver. Any device capable of demodulating an RF signal, such as a radio, tuner, or television set.
Recorder. Any device that converts an electronic signal to a magnetic pattern in the oxide coating of a magnetic tape.
Recorder. In editing, the videotape recorder or machine on which the edited tape is compiled.
Reel-to-reel. Any audio or videotape format which uses tape packaged on open reels which must be threaded manually, rather than enclosed in a cassette or cartridge.
Reflected light. Light reaching the camera after being reflected by a subject. Measured in candles per square foot.
Reflector flood. A sealed floodlight with a self-contained reflector.
Reflector spot. A sealed spotlight with a self-contained reflector.
Release time. The response time of an automatic gain control circuit to rapidly decreasing signal levels.
Remote. A production at a location other than a television studio using a special effects generator and other equipment associated with multiple-camera studio facilities.
Resolution. The degree to which fine detail can be recorded or displayed. In film, measured in pairs of light and dark lines per millimeter. In television, measured in lines per scan. Thus, the horizontal resolution of a television camera would be measured by the number of discernible vertical lines that could be displayed across the width of the screen.
RF. Radio frequency.
RF modulator. A device used to convert a signal to a form similar to that transmitted by an over-the-air broadcast so the output can be used by standard receivers.
RF splitter. A passive device used to distribute radio frequency signals to two or more receivers.
Riser. A platform on which talent sit or stand, used to raise the talent to a level more suited to coverage by the television camera.
rms. Root mean square. A measure of the effective level of an audio signal or alternating current.
Roll-off. The gradual reduction of frequencies above or below a certain point. Filters which roll off the bass frequencies are often included in unidirectional microphones to compensate for proximity effect.
ROM. Read only memory. Computer memory that can be read, but cannot be overwritten by the host computer.
Rover. A brand name for a battery-operated portable video camera and recorder combination.
rpm. Revolutions per minute.
Safe area. In television graphics or film shot for television, the area which is almost certain to be displayed on any television set. About 80% of the scanned area.
Saticon. A television pickup tube used mostly in industrial television and electronic news gathering.
Scanned area. In television graphics, the area on a slide or live card which is to be scanned by the television camera. This area is about 25% larger than the safe area.
Scrim. A wire mesh used to reduce and soften the light from a light.
SECAM. Sequential Color with Memory. The color television system developed in France using 25 frames per second and 625 horizontal lines. Look for countries using SECAM.
SEG. Special Effects Generator. The device in television used to switch between and combine various picture sources. Also called a switcher.
Sensitivity. The ability of a device, such as a camera or microphone, to sense intelligible information and convert it into a usable electronic signal.
Servo. An electronic circuit used to control the speed of a motor which drives a videotape recorder head assembly drum, which must be controlled with great precision.
Share. The percentage of the total television sets in use that are tuned to a specific program.
Shield. The outer metal portion of a shielded or coaxial cable, normally grounded, to protect conductors from interference.
Shock mount. A support for a microphone which used rubber of foam supports to isolate the mic from vibrations which can appear as low frequency rumble in the audio.
Shotgun microphone. A unidirectional microphone with a narrow pickup pattern.
Sibilance. An undesired hissing sound resulting from over emphasis of high-frequency sound in the reproduction of "s" and "z" sounds in speech. Reduced by equalization or use of a windscreen.
Signal Generator. A device used to generate electronic test signals and, in television, the drive and synchronizing signals used to control and time components in a television system.
Signal to noise ratio. The difference in amplitude between unintelligible noise and the maximum signal output of a device.
Skew. In television, the tendency of a picture to hook at the top of the television screen and the control found on some videotape recorders which adjusts tape tension in order to correct this picture problem.
Slave. In some editing systems, the record machine, or the machine on which the edited tape is compiled.
Slow motion. Playback of a film or videotape at a speed slower than the speed at which it was recorded. This is impossible to do in all but a few specialized videotape recorders without sacrificing picture stability.
SMPTE. Society of Motion Picture and Television Engineers. An organization devoted to the standardization of equipment and practices.
SMPTE leader. The leader with the eight second count-down commonly used in film.
SMPTE Type A, B, or C. The standards for one inch videotape recorders. Type C is the preferred standard for broadcast one inch videotape.
Source. Any piece of equipment which transmits information to another piece of equipment. Usually referring to devices attached to the input ports of audio mixing consoles, special effects generators, or recorders.
Special Effects Generator or SEG. The device in television used to switch between and combine various picture sources.
Splitter. A passive device used to distribute RF signals. Spotlight. A light having a narrow beam that casts well- defined shadows.
Streaming. In digital transmissions, the use or display of digital information as it is being transmitted and received, as distinct from downloading for later use. Applies to both audio and video.
Subcarrier. The 3.58 megahertz signal used in generating and controlling the hue of NTSC color television signals.
Superimposition. The adding or mixing of two video signals to produce and image with two or more pictures visible simultaneously. Used when a keyer is not available to add graphics to video. Sometimes used to refer to a key.
SVGA. A computer graphics standard specified by the Video Electronics Standards Association. It has come to define a display that is 800 pixels wide and 600 pixels high.
Switcher. Also special effects generator or SEG. The device in television used to switch between and combine various picture sources.
Sync. Any of the signals used to generate and control a television picture, but, specifically, the portion of the composite video signal from zero to minus forty IRE units consisting of vertical and horizontal timing pulses and equalizing signals to maintain the proper relationship of the two fields of video making up each frame.
Sync defeat. A switch on videotape recorders that use the composite video signal at the video input to control the internal timing of the recorder which interrupts that control function, allowing the recorder to control timing functions without reference to the incoming video signal.
Synthesizer. A device used to generate video signals without a camera, used in the production of graphics.
Take. The instantaneous transition from one picture source to another. A cut.
Target Voltage. The voltage applied to the pickup tube which determines the sensitivity of the tube to light.
TBC. Time base corrector.
Telephoto lens. Any lens with a focal length significantly greater than the standard focal length for the format in which it is to be used. The standard length for 35mm still cameras and one inch television cameras is 50mm.
Thirty-degree rule. A principle of visual continuity which states that the relative angle of view of any two similarly framed shots of the same subject which are to be cut together should vary by at least thirty degrees.
Tilt. A camera movement in which the camera is rotated in the vertical axis. The commands are "tilt up" and "tilt down."
Time base corrector. A highly specialized device with the primary function of making the unstable video output of a videotape recorder conform to the rigid timing of a signal generator, allowing videotape to be used as a picture source in combination with other sources driven by the signal generator.
Titles. Graphic information appearing at the beginning of a program, generally including the title, author, producer, writer, director, and major personalities.
Tracking control. The control used to maintain alignment of the video head with the tracks of video information on a tape.
Tracking head. The magnetic head that writes and reads a sixty hertz pulse on videotape. During playback this pulse is used to maintain proper alignment of the video heads with the tracks of video information on a tape.
Truck. The horizontal movement of the entire camera body, as in "truck left" or "truck right." This movement changes the relationship between camera, subject, and background, while panning the camera left or right does not.T-stop. Similar to an f-stop, this is a number which indicates the effective aperture opening of a lens after compensation is made for the amount of light lost due to internal absorption and reflection. The T-number is always larger than the corresponding f-number.
Tuner. The demodulator section of a radio, television set, or videotape recorder.
Universal Serial Bus. High speed serial connection between digital devices which includes the ability to power devices through the bus.
USB. Universal Serial Bus.
UHF. Ultra High Frequency. Radio frequencies from 300 to 3,000 megahertz.
UHF. A television broadcast band consisting of channels 14 through 83.
UHF connector. A threaded video connector used with coaxial cable.
U-matic. The standard format for 3/4 inch videocassette recorders. This format has a maximum record/play time of one hour and two discrete audio channels.
Unbalanced line. A cable with a single signal-carrying conductor and a grounded shield.
Vectorscope. A special type of oscilloscope designed to display the saturation and hue of chroma signals in a polar pattern. This device is essential in the evaluation of color signals when aligning color picture sources or matching and timing color sources in a television system.
Vertical hold. A control on television monitors, viewfinders, and receivers used to control the frequency of the vertical oscillator and allow the vertical sweep circuits to lock to the vertical sync component of an incoming video signal.
Vertical interval. The period of time between the last line of a field and the first line of the next field.
Vertical interval switching. Switching based on circuits that delay switching from one picture source to another until the picture source being switched to is between fields, or in the vertical interval.
Vertical interval editing. Use of a videotape recorder which is capable of recording and erasing video field by field (has a "flying" erase head) and employs vertical interval switching at the edit point.
VGA. A computer graphics standard introduced by IBM in 1987 describing the VGA connector and a display that is 640 pixels wide and 480 pixels high.
VHF. Very high frequency. Radio frequencies from 30 to 300 megahertz.
VHF. The television broadcast band having television channels 2 through 13.
VHS. A half inch videocassette format using the "M" wrap tape path. Not compatible with the BETA format.
Video. The picture portion of a television signal, sometimes referred to as "composite video" when both picture and sync signals are present.
Videocassette. A container holding both the feed and take-up reels which is inserted into a videotape recorder and threaded automatically.
Vidicon. A type of television pickup tube common in inexpensive cameras and still used to some extent in broadcast cameras.
Volt. The standard unit for measuring the difference of potential between two points in an electronic circuit.
VTR. Videotape recorder.
VU. Volume unit. Unit of measure of complex waveforms such as audio signals.
Watt. Unit of electrical power equal to one volt across a resistance of one ohm, or one volt at a current of one ampere.
Waveform monitor. A specialized oscilloscope designed to display the video waveform with great stability and high resolution. Essential in determining and setting correct levels for the luminance (monochrome) and sync portions of the composite video signal and useful in evaluating critical timing relationships.
Wide angle. Any lens with a focal length significantly less than the standard length for the format in which it is used. For 35mm still cameras and one inch television cameras, the standard length is 50mm.
Wide Shot (WS). A picture showing a subject in the context of the surroundings to establish the relationship between the subject and the surroundings.
Wind screen. A thin soft foam cover for microphones which reduces the noise made by wind striking the microphone.
Wipe. The transition between television picture sources in which each picture source is displayed on only a portion of the screen, that portion being determined by an electronically generated pattern which can be sized and positioned using a special effects generator.
Wow. The slow fluctuation in speed of a transport mechanism which results in low frequency instability and distortion in playback of an audio or video tape.
XL. Also XLR or cannon. A three-pin audio connector used with balanced lines in microphone and line level audio applications.
Zoom. To change the focal length of a zoom lens.
Zoom lens. A lens with a variable focal length.
Zoom ratio. The ratio of the longest focal length to the shortest focal length of a zoom lens.