EDITOR’S NOTE: We have tried to make this comprehensive and accurate. Please submit any corrections or additions by email to the address below in the footer.
A/A ROLL EDITING
Editing from a single source VCR using a freeze frame as a transition from the source VCR to itself (source “A” to “A”).
A/B ROLL EDITING
Editing from two source VCRs to a third recording VCR. A switcher or mixer is used to provide effects such as dissolves.
ADO (Ampex Digital Optics)
Trade name for digital effects system manufactured by Ampex.
AGC (Automatic Gain Control)
A circuit that automatically adjusts audio or video input levels.
Undesirable video display effects caused by excessive high frequency video information. Three examples are: Jaggies or Stair-stepping – Stepped or jagged edges of angled lines, especially at the slanted edges of letters. Raster scan aliasing – e.g., twinkling or strobing effects on sharp horizontal lines Temporal aliasing – e.g., rotating wagon wheel spokes apparently reversing direction.
An electrical signal using continuously varying electrical voltages. Analog video that is copied or edited several generations suffers from generation loss and is subject to degradation due to noise and distortion.
An 8-bit, gray-scale representation of an image used to create a mask for keying images.
Simple animation consisting of art work designed to be used as a video tape storyboard. Most commonly used for test commercials.
The process of electronically reducing aliasing, especially letters and genlocked graphic elements.
AM (Amplitude Modulation)
Amplitude modulation is a process used for some radio (AM broadcast) and television video transmission. A low frequency (program) signal modulates (changes) the amplitude of a high frequency RF carrier signal (causing it to deviate from its nominal base amplitude). The original program signal is recovered (demodulated) at the receiver. This system is extensively used in broadcast radio transmission because it is less prone to signal interference and retains most of the original signal quality. See Frequency Modulation.
The video computer that created the desktop video revolution.
An adjustable opening in a lens which, like the iris in the human eye, controls the amount of light entering a camera. The size of the aperture is controlled by the iris adjustment and is measured in f-stops. A smaller f-stop number corresponds to a larger opening which passes more light. F-stop examples are F2, F2.8, F4, F5.6, F8, F11. F-stops are logarithmic. Each stop admits 100% more light than the previous one.
Ratio of picture height to picture width in video and TV systems. The standard is 3:4.
An edit wherein all existing signals on a tape, if any, are replaced with new signals. Assembly edits cannot be used for editing because since they erase the control track portion of the video tape. (See also Insert Edit)
Process of assembling an edited video tape on a computerized editing system using an edit decision list.
Cutaway shots which are used to cover the visual part of an interview or narration. The term is often used in TV news.
The most common broadcast quality video format. Also Betacam SP, the enhanced version.
The obsolete home video format. Lost the format battle to VHS even though it was slightly superior. The cassette size, however, went on to become BETACAM.
A composite color video signal comprised of sync, color burst and black video. Used to synchronize (genlock) other video sources to the same sync and color information. Black burst generators are used in editing systems “lock” the entire facility to a common signal (“house sync” or “house black”).
Voltage in a video signal which corresponds to black.
Also known as the pedestal, it is the voltage level produced at the end of each horizontal picture line which separates the portion of the video signal containing the picture information from the portion containing the synchronizing information. This voltage makes the electron beam “invisible” as it moves to draw the next visible line.
BLANKING INTERVAL (Horizontal & Vertical)
The horizontal blanking interval is the time between the end of one scan line and the beginning of the next. The vertical blanking interval is the time between the end of one video field and the beginning of the next. Blanking occurs when a monitor’s electron beam is positioned to start a new line or a new field. The blanking interval is used to instantly reduce the beam’s amplitude so that the return trace is invisible. The screen goes blank for a fraction of second. (See VERTICAL INTERVAL SWITCHING)
A special effects procedure in which a subject is photographed in front of a uniformly illuminated blue or green background. A new background image can be electronically substituted for the blue or green during the shoot or in postproduction through the use of chroma key to convert analog video to digital form.
A type of professional connector used on some VCRs, cameras and video equipment providing twist-lock capability.
An overhead pole device used to position a microphone close to the actors, but out of the shot. A FISHPOLE is the portable version.
Music or music libraries in which a one-time fee enables the buyer to legally use the music in many productions without paying additional licensing or “needle drop” fees.
Charged Coupled Device. An integrated circuit which captures video images. It has largely replaced tubes in modern video cameras.
CCTV (Closed Circuit TV)
A video system used in commercial internal installations for security, medical and educational.
C.G. (Character Generator)
An electronic typewriter that creates titles for video.
Acronym for cable TV, derived from the older term, community antenna television.
The color information in a video signal, consisting of hue (phase angle) and saturation (amplitude) of the color subcarrier signal.
A device used to correct problems related to the chroma of the video signal, as well as color balance and color noise.
Noise which manifests itself in a video picture as colored snow.
The process of overlaying one video signal over another by replacing a range of colors with the second signal. Typically, the first (foreground) picture is photographed with a person or object against a special, single-color background (the key-color). The second picture is inserted in place of the key-color. The most common example is in broadcast weather segments where pictures of weather maps are inserted “behind” the talent.
CHROMINANCE & CHROMINANCE LEVEL
The color portion of a video signal separate from the luminance component, representing the saturation and tint at a particular point of the image. Black, gray and white have no chrominance, but any colored signal has both chrominance and luminance. The higher the chrominance level, the stronger the color (e.g., a strong signal produces red, and a weak signal, pink). Color saturation level can be changed using a proc amp.
Electronically matting or inserting an image from one camera into the picture produced by another. Also called “keying.” The subject to be inserted is shot against a solid primary color background. Signals from the two sources are merged through a special effects generator.
The color portion of a video signal.
The electronic process of cutting off the peaks of either the white or black excursions of a video signal to limit the signal. Sometimes, clipping is performed prior to modulation, and sometimes to limit the signal, so it does not exceed the limits of the composite video signal (7.5 and 100 IRE units).
A standard cable consisting of a central inner conductor and a cylindrical outer conductor. Used for many video connections, especially the cable TV wire that comes into your home.
Compressor/decompressor. Any technology for compressing and decompressing data. Codecs can be implemented in both software and hardware. Some examples of codecs are: Cinepak, MPEG, and QuickTime to convert analog video to digital form.
A standard video test pattern which includes samples of primary and secondary colors. Used to conform the colors in video monitors and other equipment.
The portion of a color video signal which contains a short sample of the color subcarrier used to add color to a signal. It is used as a color synchronization signal to establish a reference for the color information following it and is used by a color monitor to decode the color portion of a video signal. The color burst acts as both amplitude and phase reference for color hue and intensity. The color oscillator of a color television receiver is phase locked to the color burst.
A process in which the coloring in a television image is altered or corrected by electronic means. (See CHROMA CORRECTOR)
A device which divides a video signal into its basic color components. In TV and video, color decoding is used to derive signals required by a video monitor from the composite or Y/C signals.
The phase of the chroma signal as compared to the color burst, is one of the factors that determines a video signal’s color balance.
A method for measuring the overall color of a light source,
measured in degrees Kelvin (deg.K). Higher numbers indicate bluer light, lower numbers indicate a warmer light. The color temperature of the lighting must match the color temperature of the camera. In video this is accomplished by setting the white balance of the camera. Sunny Daylight is approximately 5500 deg.K. Overcast daylight is higher. Fluorescent Lights are approx. 4100 deg.K. Indoor incandescent lights are 2800 deg.K and professional Movie Lights are 3200 Deg. K
The carrier frequency (3.58 MHz in NTSC and 4.43 MHz in PAL) on
which the color information is impressed. Color TV sets use special circuits which decode the color component for accurate display.
A software language for linking computers, VCRs or edit
controllers to allow bi-directional “conversation” between the units.
Video signal in which luminance and synch information are
recorded separately from the color information. Formats such as Betacam, SVHS and Hi-8 use component signals to achieve maximum quality. Component video comes in several flavors: RGB (red, green, blue), YUV (luminance, sync, and red/blue) and Y/C (luminance and chrominance). Y/C is also called S-Video used in the S-VHS and Hi-8 formats.
A video signal in which the luminance and chrominance elements
have been combined in formats such as VHS.
A signal consisting of horizontal sync pulses, vertical sync
pulses and equalizing pulses only.
The process of electronically processing video signals so that it requires less storage on a computer hard drive. A 5:1 compression requires more storage space, but yields better quality than a 10:1 compression. See Main Menu Desktop Video Handbook Part 1.
The degree to which luminance values contain very dark and very light values. A high-contrast picture has more black and white values with fewer values in between. A low contrast picture has more middle tones without very dark or very light areas.
Sony’s editing control protocol, also called LANC (Local Application Control), which allows two-way communication between a camcorder or VCR and an edit controller.
Panasonic 5-pin edit control protocol. Similar to Control-L, but not compatible.
Sony transport control protocol which duplicates a consumer VCR’s infra-red remote transport control. Unlike Control-L, Control-S does not allow the controller to read tape counter information.
Type of video editing that controls the in and out points of edits by counting pulses on a control track portion of the videotape. The pulses are counted by the edit controller to perform fairly accurate editing. Edit controllers which read time code make more accurate edits.
Online editing to create the final edit master. The offline edit master is used as a guide.
Controlling the elements in a shot to insure that edits will flow smoothly and produce a coherent motion picture story without jarring the viewer.
Text that moves horizontally across the screen.
The audio equivalent of the video picture dissolve. The first sound track gradually fades out while the second sound track simultaneously replaces it.
The interference between two audio or two video signals. In audio crosstalk this signal leakage may occur between the left and right channels. It can be caused by poor grounding connections or improperly shielded cables. In video, crosstalk between channels can be luminance/sync crosstalk or chroma crosstalk. Video crosstalk can cause ghost images from one source appear over the other.
A card with the actor’s lines written on it to enable the actor to read or remember his lines.
A shot of something outside the frame which can be used to hide an edit, e.g. during a testimonial.
A background where all corners and intersections are rounded.
Professional digital video formats. The D1 system uses component video. The D2 and D3 systems use composite video. There is no D4 format. Digital formats do not suffer from the generation loss inherent in analog formats.
Digital Video Effects. A shot can bend, twist and fold into various shapes. Before the advent of the VIDEO TOASTER, this was an expensive post-production special effect. Also, the trade name for a video system manufactured by NEC.
D.V.I. (Digital Video Interface)
Multimedia standard for computer generated text and graphics which cab be transferred to video.
Director of Photography
DAT (Digital Audio Tape)
An audio recording and playback format developed by Sony, with a signal quality capability surpassing that of the CD.
A logarithmic unit which expresses the ratio between two amounts of electric or acoustic signal power. Used for measuring the strength of audio and video signals.
To separate a composite video signal into its component elements.
When an electronic signal travels through electronic circuitry or long cable runs, delay problems may occur. This causes a displaced image. Special circuits are used to correct the delay.
An electronic circuit which separates the audio and video signals from the RF carrier frequency.
DEPTH OF FIELD
The range of objects in front of a camera lens which are in focus. Smaller f-stops provide greater depth of field, i.e., more of the scene, near to far, will be in focus.
A system whereby a variable analog signal is broken down and encoded into discrete binary bits of ones and zeros. These numbers represent a mathematical model of the original signal. When copied, they do not degrade as an analog signal does. An analog-to-digital (A/D) converter chip takes samples of the signal at a fixed time interval known as sampling frequency. This digital stream is can be recorded onto magnetic media. Upon playback, a digital-to-analog (D/A) converter chip reads the binary data and reconstructs the original analog signal.
Theoretically, this process should eliminate generation loss since every copy is an exact duplicate of the original. In reality, digital systems are not perfect and can introduce their own problems in maintaining the original signal. Digital signals are virtually immune to noise, distortion, crosstalk, and other quality problems.
DIN (Deutsche Industrie Norme)
An international connector standard. DIN connectors carry both audio and video signals and are common on equipment in Europe.
A video or film transition where one shot gradually fades out while a second shot fades in.
A device which splits and amplifies an audio and/or video source tape or signal to several audio/video outputs. Used to duplicate one videotape to any number of VCRs with minimal loss of signal strength.
A compression/expansion (companding) noise reduction system developed by Ray Dolby, widely used in consumer, professional and broadcast audio applications. Signal-to-noise ratio improvement is accomplished by processing a signal before recording and reverse-processing the signal upon playback.
A camera platform on wheels. To dolly is to smoothly bring the camera closer or farther from the subject.
Electronically superimposing text or graphics over a scene (luminance key) or of placing one video image into another (chroma key). The Downstream Key signal must be genlocked to the other signals.
A defect on the videotape which causes a brief flash of a
horizontal black line on the screen. Commonly found at the beginning and end of tapes. The quality of videotape is graded by the number of dropouts and priced accordingly.
A type of SMPTE time code designed to exactly match the real time of common clocks. To accomplish this, two frames of time code are dropped every minute, on the minute, except every tenth minute. This corrects for the fact that video frames occur at a rate of 29.97 per second, rather than an exact 30 frames per second (see Non-Drop Frame). This time code system is used in television to insure that broadcast times coincide with real time.
Duplicate copy of a videotape. Also called a dupe.
The timing specification standard for NTSC broadcast video equipment.
The process of combining analog or digital video signals, e.g., red, green and blue, into a composite signal.
A circuit that combines the primary red, green and blue signals into a composite video signal.
Extreme close-up shot.
E.D.L. (Edit Decision List)
A complete list of time code numbers for each shot and sound used in the offline edit master. These time code numbers are used to create the final online edit master.
A wide shot showing much of the location.