|A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Select the first letter of the word to jump to appropriate section
of the glossary.
- A -
Abbreviation for automatic frequency control,
a circuit built into some
- Active Video Lines
All video lines not occurring in the horizontal and vertical blacking intervals.
VCRs and TVs to automatically lock onto an incoming channel.
and VHS HiFi VCRs. The audio is laid on the
tape by audio
Audio frequency modulation is the type of audio recording used on
heads located on the video head assembly.
Abbreviation for automatic gain control. On a TV or VCR, AGC is a
circuit that automatically adjusts the incoming signal
to the proper
levels for display or recording. On a video camera, AGC is a circuit
that automatically adjusts the sensitivity of the pickup tube to render
the most pleasing image.
Alarm Activated VCR
After pressing 'record'', a normal VCR takes
about 20 seconds before
it starts recording usable pictures. With and alarm activated recorder
it can be set so that the tape is ready to start recording in about one
second. The signal to begin recording can be from an alarm or any
The light gathering area of a lens, controlled by the iris.
The ratio of the vertical to the horizontal image size. This is usually 3:4.
This refers to signal loss in a transmission system
Audio S/N Ratio
Signal-To-Noise Ratio is the ratio of pure audio signal versus noise.
A lens that adjusts automatically to allow the right
amount of light to
fall on the imaging device. There is a tiny motor and amplifier built in
which receives a control signal from the camera to maintain a
constant one volt peak to peak
(1.0 Vp-p) video level.
- B -
A mechanical adjustment in a camera that moves the
- Back Focus
relative to the lens to compensate for different focal lengths of lenses.
This is important when a zoom lens is fitted.
A video signal is converted to a balanced signal to enable it to be transmitted along a 'twisted pair' cable. Used in situations where the cabling
distance is too great.
The range of signal frequencies that a piece of audio
or video equipment
can encode or decode; the difference between the limiting frequencies
of a continuous frequency band. Video uses higher frequency that
audio, thus requires a wider bandwidth.
BetaCam & BetaCam SP
BetaCam was first introduced in 1982. It is currently
geared for broadcast use, although there have been some less expensive models destined
more for industrial use. Pictures you will get using a BetaCam system (or other component
format) will generally be markedly superior to those you would get using any of the
preceding formats. Colors in particular come out looking much more vibrant and objects
appear three-dimensional. The superiority of BetaCam shots comes partly from the technical
aspects of the tape format but also in large part because of the use of superior optics
and other camcorder and VTR components (and generally better operators!).
The difference between BetaCam and BetaCam SP, introduced in 1986, is in the tape. Betacam
SP uses a metal tape and is an improvement over BetaCam.
BetaCam cassettes are large. Ninety minute cassettes measures 5.5 by 10 inches (14 by 25
cm). Typically BetaCam field units (camcorders or dockable decks) handle only smaller
cassettes with shorter lengths of tape (30 minutes and less). These smaller cassettes are
4 by 6 inches (10 by 16 cm) in size.
Betamax tapes were a format originally introduced by
Sony in the 80's. It was thought to be a better format at the time. However, the Beta vs
VHS wars took place and VHS was the victor. There are still a few Beta fans out there
though and you can still get a Betamax machine if you look around.
Picture distortion caused by a high video level. Blooming results when the
image sensor of the video camera picks up a very bright subject or an area
with high illumination.
A component of a television signal that carries color information.
In color video, the characteristics that makes pictures appear to be most
intense, created by luminosity; also the quality of being filled with light.
- C -
A new generation of lenses designed for 2/3",
1/2" and 1/3" cameras incorporating CS-mounts. The distance from the flange
surface to the focal point is 12.5mm. CS-mount lenses cannot be used on cameras with
C-mount configuration. These lenses are smaller and cheaper than the C-mount equivalents.
The standard screw mounting for 2/3" and 1" camera lenses. The distance
from the flange surface to the focal point is 17.526mm. A C-Mount lens can
- be used on a camera with a CS-Mount by adding adapter ring to reduce
- distance to 12.5mm.
An abbreviated term for Community Antenna Television, now generally
regarded as "cable TV".
Charged-Couple Device used in some video cameras instead of an image
pickup tube. Light-sensitive microprocessor that converts an image into an
electrical flow. CCDs are not prone to image smear or lag and make light
weight cameras possible.
Committee Consulat International Radiotelegraphique. This is a standards
committee of the International Telecommunications Union, who have made
the technical recommendation for European 625 line standard for video signals.
Short for chrominance. Chroma is the color component of the video signal.
An effect of distortion where the peaks of driven signals are chopped off.
Clipping usually occurs in the amplifier when it is turned up too high, but it
can occur in maladjusted circuits in a VCR or TV set.
The signal, at approximately 3.57MHz in the video
bandwidth, that stores the instantaneous intensity and hue of the color for a particular
spot in the TV image.
An electric filtering system designed to pass a certain set of frequencies but
A picture signal combined with synchronization and (possibly) color
information. Usually called baseband video, or just video.
Also referred to as LANC, this is a control protocol found on 8mm and some
VHS decks that provides computer control of unit operation. Units are
connected through a special cable.
A linear track, consisting of 30- or 60-Hz pulses, placed on the bottom of
videotape that aids in the proper playback of the video signal.
Three colors-red, blue, and green-are used in
television to produce all colors.
These separate scanning beams (one for each color) must strike their targeted phosphors
(screen's internal coating) with precise accuracy. If the beams are out of alignment, then
the image and colors appear muddied.
A signal from one stereo channel that bleeds into the other. Also, a signal
from a video track on a tape bleeding into the signal on the adjacent track.
Cathode Ray Tube. The main part of a normal monitor or television.
AKA the screen.
- D -
- Decibel (dB)
A unit of power measurement. A 6 dB rise in signal strength represents a
100-percent increase (or doubling) in power.
To remove the carrier signal and leave only baseband audio and video.
Depth of Field
The are in which all objects picked-up by the camera lens appear in focus.
Depth of field depends on subject-to-camera distance, focal length of the
lens, and f-stop.
The DIGITAL 8 format is far superior to
HI-8 or 8MM. Sony was the first to introduce this format and has done a great job. It is
backwardly compatible, meaning that the new Digital8 camcorders and VCR's will also play
your 8MM and HI-8 tapes. You do not have to buy special tapes to record in Digital8. A
regular 8MM or HI-8 tape will record up to 60 minutes of digital video and audio. Because
of the design, using regular tapes is not a problem, but it uses twice as much tape. A 2
hour HI-8 or 8MM tape will record 60 minutes when done in the Digital mode. For more
information on Digital8, Click Here.
An analogue signal that has been converted to a digital
form so that it can be processed with less error.
- Digital Signal
Dynamic Noise Reduction.
- E -
Electronic Industry Association. An industry lobbying group; it collects
statistics and establishes testing standards for many types of home electronics.
Electronics Industry Association of Japan. The Japanese equivalent of the EIA.
- F -
The distance between the secondary principal point in
the lens and the plane of the imaging device. The longer the focal length, the narrower is
the angle of view.
The standard connector used with coaxial cable and the RF inputs/outputs
of most video equipment.
One-half of a video field, comprising the odd or even scan lines. There are
60 fields in one second of video.
Bending at the top of a picture played back by a VCR.
- Focal Length
(Ft-c) Lumens per square foot; the measurement of the intensity of light on
One complete video picture, comprising both odd and even fields. There
are 30 video frames per second.
An electronic method of capturing and storing a
single frame of video. All slow scan transmitters include a frame store that holds the
picture at the moment of alarm, while the control is being dialed up. When the link is
confirmed, the picture is transmitted
- G -
The level of amplification of a signal.
Alignment of the sync generators of one or several sources to main sync
source. Used in multi source camera shoots or editing.
- H -
- Helical Scan
The technical name for the way the video heads in a VCR record and play
back picture information. Also used to record and play back stereo HiFi audio.
HI-8 camcorders record their signal at about 400
lines of resolution, slightly less than Mini DV, but substantially higher than 8mm or
regular VHS formats. Most often, HI-8 camcorders record sound in hi-fi stereo. Slight
quality loss is suffered when copying or editing from HI-8, but a better than average
image is maintained. Tapes from HI-8 camcorders generally must be played using the camera
as the source, which means the user often must connect cables to their television or VCR.
HI-8 tapes can be bought in 30, 60, and 120-minute lengths.
The number of vertical black and white lines that can
be defined, as measured along a horizontal line.
- I -
Each television frame (30 per second) or individual
picture is comprised of two fields (A and B). These two fields seem to appear at once on
the TV screen, but each field is scanned separately in the picture or image-creation
process. Each field contains 260 lines of picture information. How well these lines are
interlaced determines the resolution of the resulting picture.
Abbreviation for infrared.
- Image Enhancer
Electronic device that smoothes out irregularities in a video signal to
improve picture definition.
The degrees of resistance that an alternating electrical current (ac)
encounters when passing through a circuit, device, or wire. The
amount of impedance is expressed in ohms.
- Infrared Light
The wavelength of light produced above the visible part of the spectrum.
The internal generation of sync pulses in a camera using a crystal controlled
oscillator. This is needed on non-mains powered cameras.
Adjustable lens opening that regulates amount of light entering the camera.
- J -
- K -
- L -
A camera in which the power is supplied along the same
coaxial cable that carries the video signal.
Loop Frame Store
- Line Locked
The sync pulses of cameras are locked to the AC mains frequency.
- Line Powered
The principal is that a series of video frames is
compressed and stored in a continuous loop. This records a certain number of frames and
then records over them again until an alarm signal is received. When this happens it
carries on recording for a dozen frames or so and then stops. This means that frames
before and after the incident are recorded. This eliminates the boring searching through
hours of video tape and concentrates on the period of activity.
The term used to denote the brightness or black-and-white picture of a video image.
A measurement of illumination. The metric equivalent of footcandle.
- M -
Some zoom lenses include this feature, which
allows you to get as close as one or two inches to your subject. This is a great feature
for video taping small objects such as coins, stamps, or insects.
Lens capable of close-up focusing.
Introduced in 1986, MII is Panasonic's answer to
Betacam SP. All MII tape is metal. The 90 minute cassette at 4 by 8 inches (11 by 19 cm)
is considerably smaller than the 90 minute Betacam SP cassette. However the dockable decks
take only a small 20 minute cassette (3.6 by 5 inches - 9 by 13 cm). Technically, MII is
equal to or superior to Betacam SP. Panasonic MII field equipment includes several small
dockable decks usable with a variety of camera heads and some excellent portable decks.
Be aware if you get into MII that at some point repairs may become an issue and that few
duplicating facilities or clients are likely to have MII. Therefore you will probably have
to copy your MII programs to another format at some stage.
Mini DV tapes are the smallest of the video formats.
They take and maintain crystal clear images because of the nature of a digital format.
Editing enthusiasts benefit from Mini DV as well, since copying between two units is done
with no quality loss. That means edited or copied video looks and sounds every bit as good
as the original footage. Mini DV tapes are available in 30, 60 and 63 minute
lengths. You can also have Mini DV tapes transferred to VHS. For more information on
Mini DV, Click Here.
An electronic system that can accept a number of camera
inputs and record
them virtually simultaneously. They can also provide multi screen
with four, nine, sixteen etc. cameras on the screen
at once. Mulitplexors can be used to transmit multiple pictures down a single video line
whether it is a coaxial cable, microwave, infrared link etc. This requires a multiplexor
at each end of the line.
A way in which one signal modifies or controls another signal for such
purposes as enabling it to carry information. Often used to describe radio
frequency (RF) transmission. FM is a frequency modulation; AM is
A video display. A monitor is like a TV except it lacks the ability to tune in
channels. A monitor may or may not have a sound amplifier and speaker.
Black and White.
- N -
National Television Standards Committee. A
group of businesses and
- Noise Bars
White streaks in a picture, usually caused when video heads trace parts
of the tape that have no recorded signal, also known as guard bands.
engineers originally created to decide on early standards for color and black-
and-white televisions in the U.S.. The NTSC system is also used in Japan.
Other television standards around the world include PAL (most of Europe) and SECAM
(France, parts of Africa and Russia).
- O -
A technique used in consumer display products that
extends the deflection of a CRT's electron beam beyond the physical boundaries of the
screen to ensure that Images will always fill the display area. See also underscanning
- P -
A device that can be remotely controlled to provide
both vertical and horizontal movement for a camera, with zoom.
Phase Alternate by line is the 625-line color video system currently used in
most of Western Europe, England, Australia, and South Africa.
- Pan Tilt Zoom (PTZ)
Abbreviation for pulse code modulation, a way of digitally recording an audio
signal. Used in most 8mm decks and in some high-end VHS and S-VHS decks.
Peak to Peak
The measurement of any signal from the lowest value to
the highest. In a composite or full video signal, this should be 1 Volt.
A function contained within a telemetry system that, on
receipt of a signal, causes a particular camera to pan, tilt and zoom to a predetermined
field of view. Most systems can accommodate up to sixteen preset positions for each
camera. This is an especially useful feature on larger systems with alarmed areas.
- Q -
Display where 4 cameras are viewed on the same screen,
each camera image occupying a quarter of the display area. Other 'multi-screen' modes are
possible such as 9, 16 and 25 way. The splits do not always have to be equal and other
configurations can be possible.
- Quad Screen
- R -
Refers to the top speed of a video recorder; governed
by the monitor - pictures are available as fast as the video can accept them.
- Real Time Recording
A video switcher which is connected to the camera
cables and which contains the switching electronics. This unit may be remotely located and
connected to a desk top controller by a single cable for each monitor.
This is the amount of color in the image of a white
target after a color camera has been white balanced. The less color, the better the
The clarity or sharpness of the picture. Resolution is most often stated in
the number of total lines that make up an image or in MHz.
- S -
A term usually used for a device that can combine the
views from two cameras on a single screen. Normally the camera syncs need to be locked
The strength or amount of a certain color present in a television picture;
saturation is expressed as the purity of the color.
- Scene Illumination
The density of light falling on the area to be viewed. For best results the ratio
- of the lightest to the darkest areas should not be more that a factor
- Screen Splitter
Signal-to-Noise ratio is the amount of desired signal as compared to
undesired signal. In video Tape, noise appears as "snow," audio noise is
the tape hiss heard upon playback. A way of measuring how good a
picture or a sound will be.e The higher the ratio between the desired type of
signal and the unwanted noise, the better the results.
S-VHS or Super VHS
A VHS format that enables recording and playback of very high resolution
video. The format uses a 4 pin din cable to carry the separated signals,
chrominance and luminance, versus the composite type that combines
the signal over one wire.
Type of video signal used in the Hi8 and SVHS videotape
transmits luminance and colour portions separately, using multiple
wires, thus avoiding the colour encoding process and its inevitable loss of picture
A simplified SEG that selects and mixes video signals from two or more sources.
Short for synchronization, a broad term to indicate the proper order of
electrical signals to generate and display sound and picture from a videotape.
- T -
The system by which a signal is transmitted to a remote
location in order to control CCTV equipment e.g. to control pan and tilt and zoom
functions, switch on lights, move to preset positions etc. The controller at the operating
position is the transmitter and there is a receiver at the remote location. The signal can
be transmitted along a simple 'twisted pair' cable or along the same coaxial cable that
carries the video signal.
Television & Film History
A history of Film & Television can be found Here.
A resistor (usually 75 ohms) attached to the end of a cable or to an input
or output on a piece of video equipment. The resistor restores proper system
A test pattern is used to check out video
systems, cameras and control equipment. Several examples can be found Here.
Time Lapse VCR
A type of video recorder that can be set to
record continuously over long periods. This can be anything from three hours to 480 hours,
achieved by the tape moving in steps and recording one frame at a time. This means that if
set to record over long periods much information can be lost. On receipt of an alarm
signal these machines can be automatically switched to
real time mode.
U-Matic also known as 3/4" video tape. The format
was introduced in 1971 but it is still used by some videographers who have been using the
format for a long time. It can produce good quality video and 3/4" decks are still
commonly available in duplicating houses. However, there is little reason for somebody to
persue this format given the technical advantages of some of the other more recent
formats. UMatic has been used by professionals the world round and found mostly in
studios. The format is slowly being replaced with digital equipment such as DV and Mini
A technique generally used by some TV and video systems
as a way of ensuring that the complete image is always visible within a display area; the
opposite of overscanning.
Abbreviation for video home system, a
VCR format pioneered by JVC. VHS/C and full size VHS record at a slightly lower
resolution than 8MM. Their appeal, or course, is the convenience of easy playback. The
large VHS camcorders are almost a thing of the past at this point. There are still a few
models available, but their substantial size and weight make them a difficult sell against
smaller camcorders. VHS/C compact models, on the other hand, remain a popular choice,
offering many of the same key features as 8MM camcorders, at an equally affordable price.
- VHS & VHS/C
A method of detecting movement in the view of the
camera by the electronic analysis of the change in picture contrast.
- Video Motion Detector
Volume Unit is measured by sound-level meter. VU meters
marked from -20 to +5 Vus. O Represents the loudest level before
Assures the correct balance of red, green, and blue.
- White Balance
colors are used to create all other colors in television, white balancing a
camera enables you to bring the colors in line for the existing lighting
conditions. Also refers to a camera control that accurately sets light levels
on a white surface.
The wide-angle position of a lens enables the lens to
capture a wider area
of view. Be careful when video taping people with a wide-angle lens at close
- Y/C Video
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