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1000/1001
When the NTSC color television system was being developed, the designers wanted to make it compatible with all of the old black and white systems that were already in people’s homes. To do this, they had to make some compromises. The thing that has probably caused the most problems for our industry over the years is that the field rate was changed by 1/1.001 from 60 to 59.94 per second. This was a small enough change that the older TV’s would still receive the new color broadcast and allowed for the new color information to be encoded into the broadcasted signal. This offset gives rise to “niceties” such as drop-frame timecode and audio that also has to run at the right rate. Although having analog origins, it has also been extended into the digital and HD world where 24, 30, and 60 frames/fields per second becomes 23.98, 29.97, and 59.94 to be compatible with existing NTSC formats and workflows.
1080/24P
Refers to an internationally standardized High Definition production format (ITU BT 709) having a digital sampling structure of 1920 (H) x 1080 (V) and operating at 24-frames per second progressively scanned. Often used to loosely describe a system that operates at 23.976P as well.
1080/60i
Refers to a standardized High Definition production format (SMPTE 274M and ITU 709) having a digital sampling structure of 1920 (H) x 1080 (V) and operating in interlaced scan mode at 60 fields per second. Often used to loosely describe a system that operates at 59.94i as well.
1280x720
Refers to a high definition digital sampling structure of 1280 horizontally and 720 vertically. All 1280x720 images are progressively scanned (720P).
16x9
The standardized aspect ratio of HDTV and Widescreen SDTV – having a width of 16 units and a height of 9 units.
Also see Aspect Ratio- Picture, 1.78
16QCIF
Video format used by H.263 with 1408 by 1152 pixels.
1.78
The ratio of the horizontal size of a screen to its vertical size as 1.78 units wide to 1.0 units high. This ratio is the most standardized aspect ratio of HDTV and Widescreen SDTV. Also known as 16x9.
Also see Aspect Ratio- Picture
1.85
The ratio of the horizontal size of a screen to its vertical size as 1.85 units wide to 1.0 units high. This ratio is the most common screen ratio for motion pictures.
Also see Aspect Ratio- Picture
1920x1080
Refers to a digital sampling structure of 1920 horizontally and 1080 vertically. 1920x1080 images can be scanned either interlaced (1080i) or progressively (1080P).
2k
Resolution defined as 2,048 pixels wide by 1,556 high. Also the name of a color enhancement system made by DaVinci Systems (www.davsys.com) that processes Standard Definition, High Definition, and high resolution images.
22:11:11
Defines high definition video signals, where the luminance (Y) is sampled at 74.25 MHz and the color difference samples (R-Y,B-Y) channels are each sampled at 37.125 MHz. Note that it has become commonplace to denote HDTV Y,R-Y,B-Y also as 4:2:2. While technically incorrect, it is popularly used in a great deal of published literature.
22:22:22
Denotes a high definition system where all signals (R,G,B) are sampled at 74.25 MHz. Note that it has become commonplace to denote HDTV RGB also as 4:4:4. While technically incorrect, it is popularly used in a great deal of published literature.
2.35
A highly popular widescreen motion picture film format of 2.35 units wide by 1 unit high.
Also see Aspect Ratio- Picture
23.98 or 23.976
Refers to a video image rate of 23.976 (truncated to 23.98) frames per second – which is deliberately offset from 24 frames so that a simple 3:2 process will produce the standard 59.94 fields per second interlaced video.
Also see 1000/1001, 24P
24P
Terminology for 24 full frames per second digital video progressively captured. In most cases it refers to the HD picture format of 1920x1080, though it is also used with 1280x720 images as well. Often used to loosely describe a capture system that operates at 23.976P as well.
Also see 1000/1001
24PsF
Term used to describe a 24 (or in common usage 23.98) frame progressive video that divides the video in segments of even and odd lines for transmission and storage (and often display). Though transmitted similarly as an interlaced signal, if treated as a progressive signal, does not cause the same harmful artifacts that interlace scanning causes.
Also see PsF Imaging.
29.97P
Terminology for 29.97 full frames per second digital video progressively captured.
30P
Terminology for 30 full frames per second digital video progressively captured. Often used to loosely describe a capture system that operates at 29.97P.
3:2 Pulldown
The process used to convert 24 frame per second film or 24P video into 59.94i video. Technically the 3:2 pulldown process consists of two parts, the “Pulldown”, and the creation of the “3:2” cadence. The pulldown process is the slowing down of the film or video to 23.976 frames per second. The 3:2 cadence is created by taking one frame of the 24 frame source and filling 3 of the 59.94 fields. The next frame of the 24 frame source will only fill 2 of the 59.94 fields, the next frame 3 fields, the next frame 2 fields, etc. This sequence causes 4 of the 24 frame per second acquired material to fit into 5 frames of the destination 59.94i video. The term is loosely used to describe the process of converting 23.98P HD video to 59.94i even though there is only a 3:2 cadence added and not a pulldown performed.
Also see 1000/1001.
3.58 MHz
The approximate frequency of the subcarrier used in NTSC video to carry the color information. The actual frequency is 3.579545 MHz + 10 Hz.
4:1:1
This terminology has come into common usage to describe both high definition and standard definition systems where the ratio between luminance and chrominance samples is 4 to 1 (1 set of color difference samples (R-Y,B-Y) for every 4 luminance samples (Y)). In its original application in standard definition video signals, it represents a system where the luminance (Y) is sampled at 13.5 MHz and the R-Y,B-Y channels are each sampled at 3.75 MHz.
4.43 MHz
The approximate frequency of the subcarrier used in PAL video to carry the color information. The actual frequency is 4.43361875 MHz + 5 Hz.
4:2:2
Defines standard definition video signals, where the luminance (Y) is sampled at 13.5 MHz and the color difference samples (R-Y,B-Y) channels are each sampled at 6.75 MHz. This terminology has come into common usage to describe both high definition and standard definition systems where the ratio between luminance and chrominance samples is 2 to 1 (i.e. 2 sets of color difference samples (R-Y,B-Y) for every 4 luminance samples (Y)).
Also see 22:11:11
4:2:2:4
Same as 4:2:2 but with the addition of a key channel which is sampled four times for every four samples of the luminance channel.
4:4:4
Defines standard definition video signals, where all signals (usually R,G,B but also Y, R-Y,B-Y) are sampled at 13.5 MHz. This terminology has come into common usage to describe both high definition and standard definition systems where sampling is done on the RGB components of a video signal.
Also see 22:22:22
4:4:4:4
Similar to 4:2:2:4 except that for every four luminance samples, the color and key channels are also sampled four times.
48PsF
Term often used incorrectly to describe a 24 frame progressive segmented frame video. In actual terms, 48PsF would describe an image captured progressively at 48 frames per second and transmitted as a segmented frame. Incorrect usage stems from having each segment of a 24PsF frame arrive at twice the captured rate (48 times a second). See PsF Imaging.
4k
Resolution defined as 4,096 pixels wide by 3,112 deep.
5.1
Denotes an audio system that has 5 full range channels (Left, Center, Right, Left-Rear, Right-Rear) and one Low Frequency Effects (LFE) channel.
59.94i
Describes an interlaced video signal where 1/2 of the total lines of the picture are captured and displayed every 1/59.94th of a second. See also Interlaced Imaging, Progressive Imaging and PsF Imaging.
59.94P
Describes a progressive video signal where all lines of the picture are captured and displayed every 1/59.94th of a second. See also Interlaced Imaging, Progressive Imaging and PsF Imaging.
601
ITU-R 601 (formerly CCIR) designates a "raw" digital video format with 704 x 480 pixels. Also called SDI.
60i
Describes a interlaced video signal where 1/2 of the total lines of the picture are captured and displayed every 1/60th of a second. Often used to loosely describe a capture system that operates at 59.94i. See also Interlaced Imaging, Progressive Imaging and PsF Imaging, 1000/1001.
60P
Describes a interlaced video signal where 1/2 of the total lines of the picture are captured and displayed every 1/60th of a second. Often used to loosely describe a capture system that operates at 59.94P. See also Interlaced Imaging, Progressive Imaging and PsF Imaging, 1000/1001.
720/60P
Refers to a High Definition production format (SMPTE 296M) having a digital sampling structure of 1280 (H) x 720 (V) and operating at 60-frames per second progressively scanned. Often used to loosely describe a capture system that operates at 59.94P as well.
8:8:8
Defines standard definition video signals, where all signals (usually R,G,B but also Y, R-Y,B-Y) are sampled at 27 MHz. Also the name of a color enhancement system made by DaVinci Systems (www.davsys.com) that processes standard definition video.
A-B roll
Videotape editing arrangement where scenes on tape are played alternately on VTRs A and B and recorded on VTR C. Typically, the final output recorded on CTR C contains some scenes from VTR A and some scenes from VTR B with transitions (cuts, mixes, wipes, etc.) between the scenes.
A/D, ADC
Analog to Digital Conversion.
AAF
The Advanced Authoring Format – Designed as the next generation EDL, AAF is an industry initiative to create a file interchange standard for the easy sharing of media data and metadata among digital production tools and content creation applications, regardless of platform. It includes EBU/SMPTE metadata and management of pluggable effects and codecs. It allows open connections between equipment where not only video and audio are transferred but also metadata including information on how the content is composed, where it came from, etc. It can fulfil the role of an all-embracing EDL or offer the basis for a media archive that any AAF-enabled system can use.
Absorption loss
In telecommunications, attenuation of the optical signal within the fiber optic transmission medium. Usually specified in terms of dB/km.
AC coupling
A method of coupling one circuit to another through a capacitor or transformer so as to transmit the varying (ac) characteristics of the signal while blocking the static (dc) characteristics. In some GVG distribution amplifiers, when the ac coupling mode is selected, a feedback loop maintains the output signal at an average dc level of 0 volts regardless of APL (average picture level) or dc offset of the incoming signal.
AC/DC coupling
May also be called simply dc coupling Coupling between circuits which accommodates the passing of both ac and dc signals.
Active video
The portion of a video signal that contains picture information.
Acquisition
The gathering of data, whether it be photographic, audio, or for some other purpose.
Adaptive
Able to adjust or react to a video condition or application, as an adaptive circuit. This term usually refers to filter circuits.
ADC
Analog-to-digital converter.
A/D converter
Analog-to-digital converter.
AES
Audio Engineering Society, a worldwide organization. http://www.aes.org.
Also see AES/EBU.
AES/EBU
Colloquial for the two-channel digital audio interface, defined by AES and EBU. Self-clocking transmission of 2 channels with an audio word length of up to 24 bits at a variety of sampling frequencies.
Afterburner
Usually refers to the HD9150 series of products by Evertz (www.evertz.com). The HD9150 “Afterburner” series downconverts HDTV input video to digital and analog standard definition video with and without burnt in timecode/data windows.
AFV
Audio follow video.
AGC
Automatic gain control.
Air
To broadcast a signal.
Aliasing
Defects or distortion in a television picture due to sampling limitations. Defects are commonly seen as jagged edges on diagonal lines and twinkling or brightening (beating) in picture detail.
Alignment
The adjustment of components in a system for optimum performance.
All inputs hostile
Measurement technique, particularly for crosstalk, using worst case conditions (typically, full chroma signal on all inputs other than the one under test).
All ones
A digital signal consisting of data that contains all logical ones. In telecommunications, a test signal consisting of 11111.
Alphanumeric
A display symbol set consisting of the twenty-six letters of the alphabet and the digits 0 through 9.
Alternate mark inversion (AMI)
In telecommunications, an encoding protocol where successive data 1's are transmitted as alternate, equal positive and negative pulses, and data 0's are sent as spaces, each of zero amplitude.
Amp (A)
Ampere. Or A connector manufacturer.
Ampere (A)
Unit of measure of electrical current.
Amplitude
The magnitude of a signal in voltage or current. Frequently expressed in terms of peak, peak-to-peak, or RMS.
Amplitude modulation (AM)
A method of imposing information on a carrier signal, such as a sine wave, by varying its amplitude.
Analog
Describes a continuously variable signal of some sort. Commonly used to describe equipment or methods that do not involve the electronic digitization of a signal into data. Examples are can be found in Audio Recording (Vinyl Records, Cassette tapes), Video Recording (BetacamSP, VHS), and Broadcasting (AM, FM, Conventional TV).
Analog component
Another name for component video, such as RGB or Y, R-Y, B-Y as opposed to digital component video.
Anamorphic
A term used to denote a difference in magnification along mutually perpendicular meridians. Anamorphic systems are basically image-distorting systems. A wide formatted image will be compressed horizontally creating a “squished” looking picture to fit into a narrow medium (film or video). For proper viewing, the image must be expanded back to its original wide format.
Anti-Aliasing
The smoothing and removing of aliasing effects by filtering and other techniques. Edges on character generators and DVEs contain anti-aliasing facilities.
Analog component
Another name for component video, such as RGB or Y, R-Y, B-Y as opposed to digital component video.
Append mode
In video devices capable of creating key frame effects, a mode that permits new key frames to be added to an existing key frame effect to make the effect longer.
Archive
Off-line storage of video/audio onto back-up tapes, floppy disks, optical disks,
ASC
American Society of Cinematographers http://www.theasc.com
ASCII (American Standard Code for Information Interchange)
A standard code used extensively in data transmissions, in which 128 letters, numerals, symbols, and special codes are each represented by a binary number.
ASIC
Application specific integrated circuit. An integrated circuit designed for special rather than general applications.
Aspect Ratio (Picture)
The ratio of screen width to screen height. Can be expressed as Width by Height (Example: 16x9, 4x3) or as calculated ratio (1.33:1, 1.78:1)
Some common aspect ratios:
1.33 (4x3) Standard Television or Academy Standard
1.78 (16x9) HDTV
1.85 Academy Flat
2.35 Cinemascope
Aspect Ratio (Pixel)
The ratio of pixel width to pixel height. Standard NTSC (ITU-R 601) digital video has rectangular pixels. Computers and HDTV have square pixels.
Assemble edit (assemble mode)
An editing mode that replaces all signals on the record tape (video, audio, control, and time code tracks) with new signals.
Assembly language
A symbolic computer language in which a programmer can create prograrms that the computer's assembler program will translate into machine language for controlling the computer. Assembly language is a higher level language one step above machine language.
Asynchronous
Lacking synchronization. In video, a signal is asynchronous when its timing differs from that of the system reference signal. A foreign video signal is asynchronous before it is treated by a local frame synchronizer.
ATR
Audio tape recorder.
Attenuation
The decrease in amplitude of a signal.
Attenuator
A circuit that provides reduction of the amplitude of an electrical signal without introducing appreciable phase or frequency distortion.
Audio sound
An electrical signal that carries sound information.
Audio bridge
In telecommunications, a device that mixes multiple audio inputs and feeds back composite audio to each stations, minus that station's input. Also known as a mix-minus audio system.
Audio crosspoint module
Circuit board containing crosspoints for audio signal switching.
Audio distribution amplifier (audio DA)
A device used to replicate an audio signal, typically providing 6 outputs, each of which is identical to the input signal.
Audio-follow-video (AFV)
An operational mode in which audio and video switchers are tied together so that when the operator selects the video source, the audio simultaneously and automatically switches to the same source.
ATSC
Acronym for Advanced Television System Committee. Formed to establish technical standards for advanced television systems, including high definition television. (HDTV)
Avid DS|HD
A nonlinear production system made by Avid (www.avid.com) for conforming and finishing of projects at multiple non-compressed HDTV and SDTV formats. Includes a complete range of seamlessly integrated picture and audio editing, compositing, paint, animation, character generation and media management tools. Also available as Avid DS|HD Editor (without compositing functionality) and next generation Avid DS|Nitris which includes hardware acceleration.
Backplane
(Rear connector channel, motherboard.) The physical area, usually at the rear of an electronics frame, where modules and cables plug into the system.
Back porch
The portion of a video signal that occurs during blanking from the end of horizontal sync to the beginning of active video. The blanking signal portion which lies between the trailing edge of a horizontal sync pulse and the trailing edge of the corresponding blanking pulse. Color burst is located on the back porch.
Backup supply
A redundant power supply that takes over if the primary power supply fails.
Balanced
A circuit having two sides (conductors) carrying voltages which are symmetrical around a common reference point, typically ground.
Bandwidth
The amount of information that can be transmitted in a given period of time. For video information, a large amount of bandwidth can be generally associated with better quality of the picture. Digital video in particular requires large amounts of bandwidth. Often, compression techniques are used to reduce the bandwidth needs especially for transmission and storage.
Also refers to the spectrum available to each broadcast station. For digital television conversion, each station is allocated 6 MHz of the broadcast spectrum. In this spectrum, one HDTV signal or up to four multicast standard definition digital signals can be broadcast.
BCD
Binary Coded Decimal. A coding system in which each decimal digit from 0 to 9 is represented by four binary digits (0 or 1).
Beta
Informal name for Betacam, a professional color difference videotape recording format that uses the Y, R-Y, and B-Y color difference components. Also the name of a consumer videotape recording format that is completely different from the professional Betacam format.
Betacam
Portable camera/recorder system using 1/2-inch tape originally developed by Sony. The name may also refer just to the recorder or the interconnect format; Betacam uses a version of the Y, R-Y, B-Y color difference signal set. Betacam is a registered trademark of the Sony Corporation.
Betacam SP
A superior performance version of Betacam. SP uses metal particle tape and a wider bandwidth recording system.
Bit
Short for Binary Digit. The smallest piece of binary digital data and is represented by either a 1 or a 0. Often the number of bits is used to describe the attributes of a pixel are used in digital video as a representation of signal quality (i.e. an 8 bit signal can have 256 levels from black to white while a 10 bit signal can have 1024 levels). See Byte, Kilobyte, Megabyte, Gigabyte, Terabyte, Petabyte
BOXX
Short for Boxx Technologies, a manufacturer of high end computer systems for the graphics and production environments. http://www.boxxtech.com
BNC
Bayonet Neill-Concelman. A cable connector used extensively in television named for its inventor.
Bridge
1. A type of network circuit used to match circuits to each other, ensuring minimum transmission impairment.
2. To place one circuit in parallel with another.
Broadband
1. Having an essentially uniform response over a wide range of frequencies.
2. Capable of handling frequencies greater than those required for high-grade voice communications (higher than 3 to 4 kilohertz).
Buffer
1. A circuit or component which isolates one electrical circuit from another.
2. A digital storage device used to compensate for a difference in the rate of flow of information or the time of occurrence of events when transmitting information from onedevice to another.
3. In telecommunications, a protective material used in cabling optical fiber to cover and protect the fiber. The buffer material has no optical function.
Bus
A central conductor for the primary signal path. A signal path to which a number of inputs may be connected for feed to one or more outputs.
Button per source
A control panel which has a separate button for each source. Also called button per function.
Bypass relay
A relay used to bypass the normal electrical route in the event of power, signal, or equipment failure.
Bypass switcher
An audio-follow-video switcher usually associated with a master control switcher. Used to bypass the master control switcher output during emergencies, failures, or off-line maintenance.
Byte
A group of data bits which are processed together. Typically, a byte consists of 8, 16, or 32 bits.
Camera Utility
Crew member as designated by Local 600, IATSE. Assists the Video Controller in the setup of the cameras, pulls cables during rehearsals and takes, assists the camera operator during complex pedestal moves (does not focus), setup and maintenance of quad split monitors, cables and all other camera accessories.
Capture Rate
Used to describe the number of times per second that a picture is taken or captured in an imaging system. In a progressive system the capture rate is equal to the frame rate. In an interlaced system, the capture rate is double the frame rate because at each capture interval, only one field (a half resolution image) is acquired. It takes two fields to make a complete frame. It is standard practice to refer to the capture rate of an image as well as how it is captured when describing it instead of the frame rate (i.e. 60i (60 captures, 30 frames per second), 30P (30 captures, 30 frames per second) and 60P (60 captures, 60 frames per second))
Also see Frame Rate, Interlace Imaging, Progressive Imaging.
Capacitor
A device that stores electrical energy. It allows the apparent flow of alternating current while blocking the flow of direct current. The degree to which it allows ac flow depends on the frequency of the signal and the size of the capacitor. Capacitors are used in filters, delay-line components, couplers, frequency selectors, timing elements, voltage transient suppression, etc.
Cathode ray tube (CRT)
A tube, usually glass, which is narrow at one end and widens at the other to create a surface onto which pictures can be projected. The narrow end contains circuits to generate and focus an electron beam on the luminesc |