An SDTV component digital video coding or interface standard, based upon Rec 601, using 4:2:2 chroma subsampling, having versions for both 480i or 576i scanning The corresponding 19 mm

videotape is denoted D-1.

422P – The 4:2:2 profile of MPEG-2. (Colons are omitted; the P is written in Roman uppercase.)

422P @ ML – 422 profile at Main Level: a subset of the MPEG-2 standard, which supports digital video

storage (DVD, etc.) and transmissions up to 50 Mbps over various mediums. Used heavily in live satellite video distribution, especially where standard definition sports or heavy movement and action are present.

4:2:2p – A 483p 59.94, 4:2:2 progressive-sc an system specified in SMPTE 294M, typically transmitted on

dual SDI links each operating at 270 Mbps.

4:4:4 – Component digital video, typically SDTV, where RGB or YCBCR components are conveyed with

equal data rate (not subsampled as in 4:2:2 and 4:2:0).

480i, 480i29.97 – An interlaced scanning standard used primarily in North America and the Far East, having

525 total lines per frame, approximately 480 picture lines (usually in an image structure of 720X480), and 29.97 frames per second. A raster notation such as 480i29.97 does not specify color coding; color in

480i29.97 systems is conveyed in the studio using RGB, YCBCR, or YPBPR components, and encoded for

transmission using composite NTSC. Also incorrectly called NTSC, which more specifically refers to a color-encoding standard and not a scanning standard.

601 – See Rec. 601.

64-QAM – The third generation of Quadrature Amplitude Modulation techniques. The first was QAM, the

second was 16-QAM.

7.5% setup – See Setup

720p – A progressive scanning standard for HDTV, having an image structure of 1280X720, and any of

several frame rates including 23.976, 24, 29.97, 30, 59.94, or 60 Hz.

8PSK – The third generation in Phase Shift Keying modulation techniques. The first was Binary (BPSK), the

second was Quadrature (QPSK), and 8PSK is the latest to be adopted by many users. 16PSK is only experimental at this point.

8VSB – Vestigial sideband modulation with 8 discrete amplitude levels.

AAC – Advanced audio coding

AC – 1. Alternating current: Historically, an electrical current or voltage that reverses in polarity periodically – that is, whose sign alternates periodically between positive and negative.

2. In modern usage, a signal whose value varies periodically between positive and negative. Distinguished from DC, direct current.

3. In JPEG and MPEG, any or all DCT coefficints in an 8¥8 block apart from the DC coefficient.

AC-3 – Audio Coding algorithm number 3. See Dolby Digital.

are capable of converting 100V to 240V at either 50 or 60 Hz.

Active – Usually referring to a signal element (a sample or a line) defined by a scanning standard to contain part of the picture or its associated blanking transition. Closed captioning, in the United States, for

example, typically lives on active line 21. VITC (Vertical Interval Time Code) usually live on lines 14 and/or 16, but can be set anywhere from lines 4 to 20, all of them considered active lines, despite they do not contain pictures).

ADA – Audio distribution amplifier is used to increase voltage on an audio line, often to send to multiple

sources. One example of an ADA is a Mult Box.

A/D Converter – A circuit which converts a signal from analog to digital.

ADPCM – Adaptive Differential Pulse Code Modulation is a reduced bit rate variant of PCM (Pulse Code

Modulation). It is an algorithm that encodes the difference between an actual audio sample amplitude and a predicted amplitude and adapts the resolution based on recent differential values.

ADT – Audio, Data and Teletext.

AES – Audio Engineering Society

AFC – Automatic frequency control.

AGC – Automatic gain control, a circuit made to automatically adjust the input gain of a signal. AGC is

present in many consumer-level and pro-sumer electronics. Professional products typically demand manual gain control to get the best results.

Aliasing – A type of distortion found in video, and still images as well as audio. The distortion could be due to power bleeding into the signal. It could be due to insufficient sampling. It could be due to poor filtering. Noise in video and still images appear as sparkles, or with jagged edges. Audio typically has a hiss, buzz, or drop-outs.

AM – Amplitude Modulation, a transmission method which sends information as variations in amplitude

of a carrier wave. While there is an AM radio band, Amplitude Modulation can be accomplished at any frequency.

Ambient – The current environmental conditions, for example, ambient temperature, ambient light, or

ambient moisture (often called relative humidity).

Amp or Ampere – The standard unit of measure for electrical strength defined as the amount of current

that would be produced by an elecrotomotive force of one volt acting through a resistance of one ohm. A=Amps or Current, V=Voltage and W=Wattage

A x V = W

Amplifier – A device which increases signal amplitude. A high powered amplifier (HPA) often uses several

amplification methods to achieve a desired power output.

Amplitude – The strength or power of a wave signal. On the wave, increasing amplitude would increase the size or width of the wave.

Analog – (British = Analogue) – Video or audio stored, transmitted or displayed as a continuously variable

signal. Analogue formats technically have a more accurate representation of the original signal. However, digital formats (which use discrete values rather than gracious curves) have advantages such as bandwidth savings, storage savings, and lack of static or better noise filtering.

Anamorphic – A subsidiary format, or its associated lens, in which the horizontal dimension of a

widescreen image is squeezed by some factor with respect to the horizontal dimension of a base format having narrower aspect ratio. In film, the widescreen (anamorphic) image conventionally has 2:4:1 aspect ratio and the squeeze is by a factor of 2. In video, the widescreen (anamorphic) image has 16:9 aspect ratio, and the squeeze is typically by a factor of 4:3. An anamorphic lens stretches the width of the image without stretching the height. The image is often later stretched back to normal on a widescreen display.

Antenna – A device that radiates and/or receives electromagnetic waves.

Aperture – (From the Latin word, Aperire, “to open”) An opening to a camera, telescope, binoculars, or any

device made to catch light. The size of the aperture is measured in f-stops (also called full-stops, f-number, aperture stops, or lens speed). F-stops are a ratio of focal length to the effective aperture diameter.

• A smaller stop (reducing the aperture size) develops a better depth of field in image capturing devices.

Aperture area can be calculated as follows: ∫

Area = π (---)2 _{Where: ∫ = focal length}

2N N = f-stop

Artifacts or Artifacting – The correct term for digital breakup. The British tend to use “Blockiness” and it means the same thing. Large pixel blocks become visible in parts of the screen when there is not enough information (or there is too much in the buffer) to fill in the missing parts of the transmission.

ASI – Asynchronous serial interface: An industry standard electrical interface, standardized by DVB, used

to convey an MPEG-2 transport stream. Also referred to as DVB ASI.

ASIC – A customized chip designed to perform a specific function.

Aspect Ratio – The ratio of the width of an image to its height. This is commonly referred to in television and motion picture standards such as 2.4:1 or 16:9 or 4:3.

ATM – Asynchronous Transfer Mode is a source-independent transport mechanism. It can use variable bit-

rate transmission, which uses fixed length packets (called cells) to transfer user data.

ATSC – Advanced Television Systems Committee: A U.S.-based organization founded in 1983 that

researched, developed, helped to standardize and promote digital SDTV and HDTV broadcasting for the United States. ATSC advocates MPEG-2 video compression and Dolby Digital (AC-3) audio compression, supplemented by ATSC terrestrial broadcasting transmission standards. In late 1996, the FCC adopted the ATSC standard, and it is considered the “digital counterpart” of the original NTSC standard.

Audio – Sound. For broadcast use, only the frequency range which are picked up by the common human

Audio Dub – The process of adding audio to video. Original audio may be replaced, or kept with the additional audio.

Auto Detecting – The capability of a unit to automatically sense and set its configuration to match the operational parameters of an incoming signal.

Auto Ranging – The capability of a power supply unit to accept variable voltage rates.

Auto Sensing – The capability of a power supply unit to detect variable voltage rates.

Auxiliary Channel – (commonly called an “Aux” channel to fit the word on an audio mixer) is an

additional output from the primary program feed output on an audio mixer. Auxiliary channels exist to offer additional channels, a different output level from the program output level, to provide additional signal processing or lack of signal processing from the program output, or to loop back into the main program to create “reverb” in the program channel.

AV - Audio/Video

Back porch – The time interval between the trailing edge of a normal line sync pulse and the left-hand edge

of active video on the associated video line. This interval is often used as a clamp reference.

Backlight (also called a Rim Light) – A light positioned behind, and usually also elevated from, a subject. Its primary purpose is to make the subject stand out from the background (essentially making the subject more 3-dimensional on a 2-dimensional image), by highlighting the subject's outline.

Back Focus – A focus adjustment between the lens and the camera. It is typically adjusted by loosening a

screw on a ring closest to the camera body. If the camera appears to be focused when zoomed in, but becomes out of focus when widened out (called “pushing-in” or “pushing-out”), then it is said that the back focus “is off” and needs adjustment.

Backward compatibility – Refers to hardware or software that is compatible with earlier versions.

Balanced Audio -

Bandwidth – 1. The transmission capacity of an electronic line such as (among others) a communications

network, computer bus, or broadcast link. It is expressed in bits per second, bytes per second or in Hertz (cycles per second). When expressed in Hertz, the frequency may be a greater number than the actual bits per second, because the bandwidth is the difference between the lowest and highest frequencies

transmitted. Higher bandwidth allows faster transmission or higher-volume transmission. New

modulation techniques tend to offer faster transmission or higher-volume transmission in the same amount of bandwidth.

2. The frequency or frequency range where an analog or digital signal's magnitude has fallen 3 dB –