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B Frames 
Bi-directional predictive frames used in the MPEG-2 signal. These are composed by assessing the difference between the previous and the next frames in a television picture sequence. As they contain only predictive information, they do not make up a complete picture and so have the advantage of taking up much less data than the I frames. However, to see that original picture requires a whole sequence of MPEG-2 frames to be decoded.

See also: I frames, P frames, MPEG.
B-Mode Edit
An editing method where the footage is assembled in the order it appears on the source reels. Missing scenes are left as black holes to be filled in by a later reel. Requires fewer reel changes and generally results in a faster edit session.
“Black and White”. Sometimes erroneously used to mean monochrome.
B-Y Axis
The horizontal axis of a vectorscope viewscreen.  B-Y is one of the color difference signals used in NTSC and is obtained by electrically subtracting the luminance (Y) signal from the blue (B) component signal. 
Back Porch 
The portion of the video signal that lies between the rising edge of the horizontal sync pulse and the start of active video (or the end of horizontal blanking).  The color burst signal sits on the back porch. 
1. Finance or support for a film or video project 
2. Anti-halation Backing: A dark coating applied to the back of film to reduce halation. It is removed in processing. 
3. Non-Curl Backing: A transparent coating applied to the opposite side of a film from the emulsion to prevent curling.
Backup Event 
Schedule event, determined in advance, which is available to the operator for transmission when the originally scheduled event cannot be played back due to system failure. 
Backup Source
Device or system providing the signal content for a Backup Event. 
Baird, John Logie
Pioneer of Television  Click Here   This will take you to where you can learn more
A range of frequencies.
A measure of the resolution and information-carrying capacity of a system, typically described as the range of frequencies in which a signal's amplitude will remain constant.  In digital video systems, bandwidth is limited by filters to a maximum of one-half the sampling frequency to avoid artifacts caused by aliasing.  It is also the maximum amount of data a signal can carry.  In addition, the frequency spectrum occupied by a signal. 
In terms of signal frequency, the range between the lowest and the highest frequencies used to transmit a signal from one site to another. Bandwidth is a measure of an analog signal and is measured in cycles per second. Contemporary units are Hertz (one cycle equals one Hertz). (1) In video systems, bandwidth is specified as the highest frequency value because all video systems must transmit frequencies down to 30 Hz or lower. The greater the bandwidth, the more information is carried and the higher the potential resolution of images. In television, bandwidth is usually expressed in MHz. (2) With digital codec specifications, bandwidth is represented by the number of bits of information that can be transmitted per second or bps. High-bandwidth codecs can have bandwidths between 768 Kbps (thousand bits per second) and 45 Mbps (million bits per second). Low-bandwidth codecs range between 56 Kbps and 384 Kbps.
A series of short lines in an optical scan system used to convey information by their varying width and interval. As it applies to an automation system: Data about the contents of a cassette, stored on a cassette label as a series of black vertical lines. The barcode can contain the following data: cassette and program identification; program start position, duration and title. Barcode labels are produced and read using a tape preparation system, and may be used by the system to identify a tape. 
Barcode Reader 
A machine that reads barcode labels. After the barcode is read, the barcode data      is sent to the automation system.
1. Places that serve alcohol and are coincidentally frequented by off duty engineers. 
2. Abbreviation for Color Bars (a test signal).
The transparent, flexible support, commonly cellulose acetate, on which photographic emulsions are coated to make photographic film.
A signaling technique in which the signal is transmitted in its original form and not changed by modulation. Local Area Networks as a whole, fall into two categories: baseband and broadband. Baseband networks are simpler and cheaper; the entire bandwidth of the LAN cable is used to transmit a single digital signal. In broadband networks, the capacity of the cable is divided into channels, which can transmit many simultaneous signals. Broadband networks may transmit a mixture of digital and analog signals, as will be the case in hybrid fiber/coax interactive cable television networks.
Base Memory
User programmable base settings for different film and video formats. Memory settings are scene by scene programmable.
BAT (Bouquet Association Table) 
Batch File or BAT file
A file that contains DOS commands that are executed when the computer or a program first starts up. Batch file names always end with .BAT. 
Baud rate is a measure of the number of times per second a signal in a communications channel varies, or makes a transition between states (states being frequencies, voltage levels, or phase angles). One baud is one such change. Thus, a 300-baud modem's signal changes state 300 times each second, while a 600-baud modem's signal changes state 600 times per second. This does not necessarily mean that a 300-baud and a 600-baud modem transmit 300 and 600 bits per second. The number of bauds a modem transmits per second is directly related to the number of bits that occur each second, but the numbers are not necessarily the same.
“British Broadcasting Corporation”.
Bulletin Board System. A computer that allowed users to dial-up and connect from remote computers and acted as a central meeting place to chat or play games. The Internet has largely replaced the BBS. BBSes were generally run from someone's home PC that had a few phone lines hooked up to it. 
Broadcast Control/Operations Center. The heart of a broadcast facility.  Monitors various downlinks and up-links to satellites. Also where the System Monitor displays the status of the TCS and its associated external systems. 
BCC Channel 
A group of encoders. 
BCD (Binary Coded Decimal) 
A coding system in which each decimal digit from 0 to 9 is represented by four binary (0 or 1) digits. 
BCO (Broadcast Control Operator) 
A measure of voltage, current, or power gain. One bel is defined as a tenfold increase in power. If an amplifier increases a signal's power by 10 times, its power gain is 1 bel or 10 decibels (dB). If power is increased by 100 times, the power gain is 2 bels or 20 decibels. 3 dB is considered a doubling.
Bernoulli Devices
A medium-high-capacity, disk-storage medium used for digital data storage. Bernoulli disks use a floppy piece of magnetic material housed in a rigid cassette. The disks have a storage capacity of about 20 MB and a data-access performance equivalent to hard drives.
Bit error rate.
The second stage a software program goes through before a final is released. Software undergoes rigorous testing until it is ready to be released.
Sony analog component video tape format. A broadcast quality, 1/2 inch tape, cassette based system. Now rare, replaced by Betacam SP and Digital Beta.
Betacam SP
Sony analog component video tape format. A broadcast quality, 1/2 inch tape, cassette based system.
Betacam SX 
Digital video record/playback format using MPEG-2, 4:2:2 Profile @ Main Level video and implemented in the Sony DNW series of hybrid (tape/disk) recorders. 
Bi-Directional Microphone
A microphone that is sensitive to sounds from only two directions.
Bi-Directional Pictures or B-pictures or B-frames 
Pictures that use both future and past pictures as a reference.  This technique is termed bi-directional prediction.  B-pictures provide the most compression.  B-pictures do not propagate coding errors as they are never used as a reference. 
Electrical pulses from the tachometer of a telecine, used to update the film footage encoder for each new frame of film being transferred.
A constant amplitude high frequency signal added to the signal to be recorded and sent to the record head to improve the signal to noise ratio and reduce the distortion of an analogue recording. It helps to achieve a better level of saturation on the tape’s magnetic particles.

Also a voltage added to the grid of a vacuum tube.
Bias Trap
Used to prevent the bias signal or multiples of this signal, called harmonics, from entering the sound path. (See Bias).
See opening billboard and closing billboard. 
Where a cart machine stores a tape, when the tape is not used by one of the cart machine's VTRS.
A base-2 numbering system using the digits 0 and 1 (as opposed to 10 digits [0 - 9] in the decimal system). In computer systems, the binary digits are represented by two different voltages or currents, one corresponding to 0 and the other corresponding to 1. All computer programs are executed in binary form.
Binary representation requires a greater number of digits than the base 10 decimal system more commonly used. For example, the base 10 number 254 is 11111110 in binary. From right to left, the digits represent 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, etc. Each digit is known as a bit. 
The result of a binary multiplication contains the sum of digits of the original numbers. 
This example multiplies two 8-bit numbers to produce a 16-bit result. 
10101111 x 11010100 = 1001000011101100 
(In decimal 175 x 212 = 37,100)
See also: Bit, Byte, Digital.
Binary Coded Decimal 
A coding method for representing a decimal number as two, four-bit bytes. 
Broadband integrated services digital network. See: ISDN. 
Binary digit: the smallest unit of digital information with a value of 0 or 1. The smallest element of a digital word. A group of bits, such as 8-bits or 16-bits, compose a byte. The number of bits in a byte depends upon the processing system being used.  Typical byte sizes are 8, 16, and 32.  (See binary and word).
Bit Bucket
Any device capable of storing digital data-whether it be video, audio or other types of data.
Bit Budget
The total amount of bits available on the media being used. In DVD, the bit budget of a single sided/single layer DVD5 disk is actually 4.7 GB.
“Burned In Time Code”. Time code numbers that are superimposed on the picture, and may viewed on any monitor or TV.
Bit Depth
The number of levels that a pixel might have, such as 256 with an 8-bit depth or 1,024 with a 10-bit depth.
Bit Parallel
Transmission of digital video a byte at a time down a multi-conductor cable where each pair of wires carries a single bit. This standard is covered under SMPTE 125M, EBU 3267-E, and ITU-R BT.656 (CCIR 656).
Bit Rate
The digital equivalent of bandwidth, bit rate is measured in bits per second. The higher the bit rate, the more information that can be carried and the higher the bandwidth.
The rate at which and 8-by-8 array of pel values or DCT coefficients presenting luminance or chrominance information. 
Bit Rate Reduction
See: Compression.
Bit Serial
Transmission of digital video a bit at a time down a single conductor such as coaxial cable. May also be sent through fiber optics. This standard is covered under ITU-R BT.656 (CCIR 656).
Bit Slippage
1. Occurs when word framing is lost in a serial signal so that the relative value of a bit is incorrect. This is generally reset at the next serial signal (TRS-ID for composite and EAV/SAV for component). 2. The erroneous reading of a serial bit stream when the recovered clock phase drifts enough to miss a bit. 3. A phenomenon that occurs in parallel digital data buses when one or more bits get out of time in relation to the rest. The result is erroneous data. Differing cable lengths is the most common cause. 
Bit Stream 
A series of bits transmitted on a line.
As applies to audio, a sound bite.  A sound bite is usually a sentence or other short bit of audio material.  Its most frequent use is in news. 
A representation of images or graphic information that is made up of individual bits of picture information or pixels (picture elements). Bitmaps are computer maps of these bits which can be re-created pixel for pixel when displayed or printed.
Bitmapped Graphics
A form of graphics that is made up of individual bits of picture information or pixels (picture elements). The graphic consists of a computer map of these bits which is re-created pixel for pixel when displayed or printed.
Bits per Pixel
The number of bits used to represent the color value of each pixel in a digitized image.
Bits Per Second
Bits per second can be obtained by dividing the a modem's baud rate by the number of changes in state, or bauds, required to send one bit.
Video signal set to a pre-determined level (7.5 IRE units) so that no picture information appears and the screen is black. Also referred to as pedestal or setup, the level at which this signal is set determines overall picture contrast and quality.
Black Box
A term used to describe a piece of equipment dedicated to one specific function, usually involving a form of digital video (black) magic.
Black Burst 
A composite video signal consisting of composite sync, reference burst and a black video signal (usually with setup), which is 7.5 IRE (53.5 mV) above blanking level.  Black burst is typically used as a reference signal in video systems. 
Black Crushing
Loss of low light (shadow) detail caused by adjusting luminance information below the Black Level.
Black Level
In an NTSC composite signal, 7.5 IRE units is the lowest point in the signal that luminance components are permitted. Luminance information falling below this point is cut off and lost. The "setup level", it is the blackest/darkest part of the video picture (7.5 IRE). "Superblack" is a term used to refer to a 0.0 IRE level. Signal Level corresponding to minimum light output, (the shadow area). 
The part of the video signal that contains no picture information. A Signal applied to prevent unwanted signals from being visible. Such signals would be synchronizing pulses, burst VITC etc.
Blanking Level 
Blanking level (or pedestal) is the level of the video signal at 0 IRE before and after the horizontal sync and during the vertical interval.  Blanking refers to the period of time when the horizontal and vertical retrace take place. 
Blanking Signal
The pulses added to the video signal to indicate that the scanning beam should be shut off for the period of retrace time.
Chemical for removing the metallic silver image from developed color emulsions.
Bleach Bypass/Reduction
During color film processing when bleaching is not carried to completion, it is called reducing or bypass. Some of the silver image remains and less of the color dye is coupled creating a distinctive contrasty faded look.
A term that refers to crisp edges that are not, usually as a result of some overload. Examples include fuzzy titles in film opticals as a result of over exposure, and chroma bleed on videotape recordings caused by the saturation being to high in the source material.
Rectangular area of picture, usually 8 x 8 pixels in size, which are individually subjected to DCT coding as part of a digital picture compression process.
Artifact of compression generally showing momentarily as misplaced rectangular areas of picture with distinct boundaries. This is one of the major defects of digital compression, its visibility generally depending on the amount of compression used, the quality of the original signal, and the quality of the coder. The visible blocks may be 8 x 8 DCT blocks or "misplaced blocks"-16 x 16 pixel macroblocks, due to the failure of motion prediction/estimation in encoder or other motion vector system, such as a standards converter.
Optical Enlargement of an image
Blue Field 
A test signal. 
Bitmap. A proprietary Microsoft Windows image format. This file format cannot be used on a Web page. 


One of the most popular of the coaxial connectors, the BNC was developed in the late 1940's toward the end of WWII. The name BNC stands for Amphenol engineer, Carl Concelman and Bell Labs engineer, Paul Neill who co-invented the BNC connector: ergo the (B)ayonet (N)eill (C)oncelman connector. Bayonet describes the interface coupling mechanism, while Neill and Concelman were the inventors of the N and C connectors.
The BNC is essentially a miniature version of the C connector which is a Bayonet version of the N connector. BNC connectors are available in both 50 and 75 ohm versions, both versions will mate together. The 50 ohm connector, used primarily for RF, is designs operate up to a frequency of 4 GHz. The 75 ohm version is usually used for video applications and cable television. BNC connectors are used in many applications, some of which are flexible networks, instrumentation and computer peripheral interconnections.
The TNC version is a threaded model: the (T)hreaded (N)eill (C)oncelman connector.
Boot Up
To start up. Most computers contain a system operating program that they read out of memory and operate from after power up or restart. The process of reading and running that program is called boot up.
Collection of services marketed as a single entity. 
Bouquet Association Table (BAT) 
Provides information regarding bouquets including the name and a list of services for each bouquet. 
Bits Per Second  The speed, in bits per second, at which binary data passes through a cable or communication channel. 
Any point where playback can be stopped and resumed again on the next frame after a period of time.  Also a space of time in a program where spots, promos and/or PSAs can be inserted. As it applies to an automation system:  An event in a playlist that does nothing more than stop transmission of the list. A break may be used to delimit a pod (group) of compiled material. An event in a playlist that does nothing more than stop transmission of the list. A break may be used to delimit a pod (group) of compiled material.
Break - Break Pattern
Combination of breaks which can be applied to programs of a particular duration, such as 30 minutes or 60 minutes, which air on a particular service, during a particular time period (e.g. every day, Monday-Friday, primetime). 
A momentary image distortion caused by the loss of sync.  Also, intermittent momentary loss of picture or sound.
A slow, rhythmic variation in either signal or scanning amplitude.
Refers to the portion of the video signal which lies between the rising edge of the horizontal sync pulse and the beginning of the color burst signal.  The breezeway is located on the back porch. 
An electronic device which mixes or switches the signals from three or more locations for audio or video teleconferencing.
Bridging Switcher
A video switcher often used in CCTV security applications which contains two video outputs. Normally, one output is dedicated for sequential viewing of the cameras while the other allows manual call-up of any desired camera.
Another term for the luminance signal (Y) that carries information about the amount of light at each pixel in the image. 
1. A response that is the same over a wide range of frequencies. 2. Capable of handling frequencies greater than those required for high-grade voice communications.