B channel: The ISDN circuit-switched bearer channels, capable of transmitting 64kps of digitized information.

B-Roll: Cutaway shots which are used to cover the visual part ofan interview or narration. The term is often used in TV news.

B8ZS: Binary 8-Zero Substitution. Line-code type, used on T1 and E1 circuits, in which a special code is substituted whenever 8 consecutive zeros are sent through the link. This code is then interpreted at the remote end of the connection. This technique guarantees ones density independent of the data stream. Sometimes called bipolar 8-zero substitution.

 

Back Focus: A mechanical adjustment in a camera that moves the imaging device relative to the lens to compensate for different focal lengths of lenses. This is important when a zoom lens is fitted.

 

Back Porch The portion of the video waveform between the end of horizontal sync and the start of active video.

Balanced Signal: 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.

 

Bandpass Filter A circuit that allows only a selected range of frequencies to pass through.

Bandwidth (BW) A term that defines the information carrying capacity of a channel. In analogue systems, it is the difference between the highest frequency that a channel can carry and the lowest, measured in hertz. In digital systems the unit of measure of bandwidth is bits per second. The range of frequencies a circuit will respond to or pass through. It may also be the difference between the highest and lowest frequencies of a signal. 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.

 

Bandwidth-on-demand: The ability to vary the transmission speed in support of various applications, including videoconferencing. In videoconferencing applications, an inverse multiplexor of I-Mux takes a digital signal that comes from a codec and divides it into multiple 56 or 64 kbps channels for transmission across a switched digital network. On the distant end, a compatible I-Mux recombines these channels for the receiving codec, and therefore ensures that even if the data takes different transmission paths, it will be recombined at the receiving end.

 

Baseband: When applied to audio and video, baseband means an audio or video signal that is not modulated onto another carrier (such as RF modulated to channel 3 or 4 for example). In DTV, baseband also may refer to the basic (unmodulated) MPEG stream.

 

BBC: British Broadcasting Corporation.

Bearer mode: The type of coding or compression which the telephone network is permitted to perform on the bit stream carried on the bearer channel. In POTS, the bearer mode will always be 3.1 kHz voice. A data bearer mode implies that the data stream will not be compressed by the network (the connection is clear channel.

 

BetaCam & BetaCam SP: Through the 1990's, the most common broadcast quality video format. Also Betacam SP, the enhanced version.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 shorte lengths of tape (30 minutes and less). These smaller cassettes are 4 by 6 inches (10 by 16 cm) in size.

 

Betamax: Not to be confused with Betacam, 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. The long ago 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.

 

BETAMAX: 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.

 

Binary: A method of coding in which there are only two possible values: 0 and 1 for a given digit. Each binary digit is called a "bit".

 

B-ISDN: Broadband ISDN. The ITU-T is developing the B-ISDN standard, incorporating the existing ISDN switching, signaling, multiplexing and transmission standards into a higher-speed specification that will support the need to move different types of information around the public switched network.

 

Bit rate (Bps): The number of bits of information transmitted over a channel in a given second.

Bit rate allocation signal (BAS): As specified in the ITU-T H.320 series of recommendations, bits in a frame that enable the transmission of code words to describing the capability of a terminal. Used to structure the capacity of the channel or synchronized multiple channels in various ways and commanding a receiver to demultiplex and make use of the constituent signals in such structures. The BAS signal is also used for controls and indications.

 

Bit: Binary Digit. The basic signaling unit in all digital transmission systems used.

BITC: Burned-In Time Code. The timecode information is displayed within a portion of the picture, and may be viewed on any monitor or TV.

 

Black Burst: Black burst is a composite video signal with a totally black picture. It is used to synchronize together video equipment so the video outputs are aligned. Black burst tells the video equipment the vertical sync, horizontal sync, and the chroma burst timing.

 

Black Level: Voltage in a video signal which corresponds to black. This level represents the darkest an image can get, defining what black is for a particular video system. If for some reason the video goes below this level, it is referred to as blacker-than-black. You could say that sync is blacker-than-black.

 

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. (Please check out: VERTICAL INTERVAL SWITCHING)

 

Blanking Level: 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. That level of the video waveform defined by the system to be where blanking occurs. This could be the black level if a pedestal is not used or below the black level if a pedestal is used.

 

Blanking: Applicable to analog TV systems only. An ordinary television signal consists of 30 separate still pictures or frames sent every second. They occur so rapidly; the human eye blurs them together to form an illusion of moving pictures. This is the basis for television and motion picture systems. The blanking interval is that portion of the television signal that occurs after one picture frame is sent and before the next one is transmitted. During this period of time special data signals can be sent which will not be picked up on an ordinary television receiver. On a CRT display, the scan line moves from the left edge to the right edge, jumps back to the left edge, and starts out all over again, on down the screen. When the scan line hits the right side and is about to be brought back to the left side, the video signal is blanked so that you can't "see" the return path of the scan beam from the right to the left-hand edge. To blank the video signal, the video level is brought down to the blanking level, which below the black level if a pedestal is used.

 

Blooming: 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. This is an effect, sometimes caused when video becomes whiter-than-white, in which a line that is supposed to be nice and thin becomes fat and fuzzy on the screen.

 

Blue Screen: Refers to an obsolete technology. 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.

 

B-Mac: A method of transmitting and scrambling colored television signals. In such transmissions MAC (Multiplexed Analogue Component) signals are time-multiplexed with a digital burst containing digitized sound, video synchronizing, authorization, and information. MAC (A, B, C, D2) Subtypes refer to the various methods used to transmit audio and data signals.

 

BNC connector: A type of professional connector used on some VCRs, cameras and video equipment providing twist-lock capability.

Bonding: Method for making several B channels look like one high-rate line by use of an IMUX (inverse multiplexer.)

Boom: An overhead pole device used to position a microphone close to the actors, but out of the shot. A Fishpole is the portable boom.

bps: Bits per second, a unit of measurement of the speed of data transmission and thus of bandwidth.

Breezeway That portion of the video waveform between the trailing edge of horizontal sync and the start of color burst.

BRI: Basic Rate Interface. In ISDN there are two interfaces, the BRI and the PRI or Primary Rate Interface. The BRI offers two circuit-switched B (bearer) channels of 64 kps each and one packet-switched D (delta) channel that is used for exchanging signals with the network.

 

Bridge: In videoconferencing terminology, a bridge connects three or more conference sites so that they can simultaneously communicate. Bridges are often called MCUs (Multiple Conferencing Units). A bridge is also considered a device that interconnects LAN's or LAN segments at the data-link layer of the OSI model to extend the LAN environment physically. They work with frames (as opposed to packets) of data, forwarding them between networks. They learn station addresses and they resolve problems with loops in the topology by participating in the spanning tree algorithm The term bridge can be used in audio conferencing to refer to a device that connects multiple voice calls so that all participants can hear and be heard.

 

Brightness: This refers to how much light is emitted by the display, and is controlled by the intensity of the video level. In color video, the characteristics that makes pictures appear to be mostintense, created by luminosity; also the quality of being filled with light.

 

Broadband: The term applied to networks having bandwidths significantly greater than that found in telephony networks. Broadband systems are capable of carrying a large number of moving images of a vast quantity of data simultaneously. Broadband techniques usually depend on coaxial or optical cable for transmissions. They utilize multiplexing to permit the simultaneous operation of multiple channels or services on a single cable. Frequently division multiplexing or cell relay techniques can both be used in broadband transmission.

 

BS.707 This ITU recommendation specifies the stereo audio specifications (Zweiton and NICAM 728) for the PAL and SECAM video standards.

 

BST-OFDM This is covered under: Bandwidth Segmented Orthogonal Frequency Division Multiplexing.

BT.1119 Defines the widescreen signaling (WSS) information for NTSC and PAL video signals. For (B, D, G, H, I) PAL systems, WSS may be present on line 23, and on lines 22 and 285 for (M) NTSC. Purchase the ITU specification.

 

BT.1124 Defines the ghost cancellation reference (GCR) signal for NTSC and PAL.

BT.1197 Defines the PALplus standard, allowing the transmission of 16:9 programs over normal PAL transmission systems.

 

BT.1302 Defines the transmission of 16:9 BT.601 4:2:2 YCbCr digital video between pro-video equipment. It defines a parallel interface (8-bit or 10-bit, 36 MHz) and a serial interface (360 Mbps).

 

BT.1303 Defines the transmission of 16:9 BT.601 4:4:4:4 YCbCrK and RGBK digital video between pro-video equipment. Two parallel interfaces (8-bit or 10-bit, 36 MHz) or two serial interfaces (360 Mbps) are used.

 

BT.1304 Specifies the checksum for error detection and status for pro-video digital interfaces.

BT.1305 Specifies the digital audio format for ancillary data for pro-video digital interfaces. Also This is covered under: SMPTE 272M.

BT.1358 720 x 480 (59.94 Hz) and 720 x 576 (50 Hz) 4:2:2 YCbCr pro-video progressive standards. Also This is covered under: SMPTE 293M.

 

BT.1362 Pro-video serial interface for the transmission of BT.1358 digital video between equipment. Two 270 Mbps serial interfaces are used.

 

BT.1364 Specifies the ancillary data packet format for pro-video digital interfaces. Also This is covered under: SMPTE 291M.

 

BT.1365 Specifies the 24-bit digital audio format for pro-video HDTV serial interfaces. Also This is covered under: SMPTE 299M.

 

BT.1366 Specifies the transmission of timecode as ancillary data for pro-video digital interfaces. Also This is covered under: SMPTE 266M.

 

BT.1381 Specifies a serial digital interface-based (SDI) transport interface for compressed television signals in networked television production based on BT.656 and BT.1302.

 

BT.470 Specifies the various NTSC, PAL, and SECAM video standards used around the world. SMPTE 170M also specifies the (M) NTSC video standard used in the United States. BT.470 has replaced BT.624.

 

BT.601 720 x 480 (59.94 Hz), 960 x 480 (59.94 Hz), 720 x 576 (50 Hz), and 960 x 576 (50 Hz) 4:2:2 YCbCr pro-video interlaced standards.

 

BT.653 Defines the various teletext standards used around the world. Systems A, B, C, and D for both 525-line and 625-line TV systems are defined.

 

BT.656 Defines a parallel interface (8-bit or 10-bit, 27 MHz) and a serial interface (270 Mbps) for the transmission of 4:3 BT.601 4:2:2 YCbCr digital video between pro-video equipment. Also This is covered under: SMPTE 125M.

 

BT.709 This ITU recommendation specifies the 1920 x 1080 RGB and 4:2:2 YCbCr interlaced and progressive 16:9 digital video standards. Frame refresh rates of 60, 59.94, 50, 30, 29.97, 25, 24, and 23.976 Hz are supported.

 

BT.799 Defines the transmission of 4:3 BT.601 4:4:4:4 YCbCrK and RGBK digital video between pro-video equipment. Two parallel interfaces (8-bit or 10-bit, 27 MHz) or two serial interfaces (270 Mbps) are used.

 

BTSC This EIA TVSB5 standard defines a technique of implementing stereo audio for NTSC video. One FM subcarrier transmits a L+R signal, and an AM subcarrier transmits a L-R signal.

 

Burst Gate This is a signal that tells a video decoder where the color burst is located within the scan line.

Burst: A component of a television signal that carries color information.

Buy Out: 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.

 

B'-Y': The blue-minus-luma signal, also called a color difference signal. When added to the luma (Y') signal, it produces the blue video signal.

 

Byte: Is equal to 8 bits.