A/D Converter

A circuit which converts a signal from analogue to digital form; the opposite of a D/A converter.

AC Adapter

A circuit which modifies an AC current, usually converting it to a DC current.

Actuality

Picture and/or sound recorded at the time of shooting - rather than library footage or archive.  Often heard referring to music recorded on location (rather than added to the programme later).

Adobe

A software manufacturer based in San Jose, California, and traded on the Nasdaq National Market under the symbol ADBE. Adobe is a leading provider of media productivity software.

AFM

Assistant Floor Manager - in some areas the term AFM is used to describe the person who assists on the studio floor during a programme recording or transmission. The term AFM was used instead of Second AD on drama type programmes but this use has largely died out now.

Aliasing

Distortion of an image file or sound recording due to insufficient sampling or poor filtering. Aliased images appear as jagged edges, aliased audio produces a buzz.

Alpha Channel

A special channel in some digital images reserved for transparency information.

AM: Amplitude Modulation

A method of radio transmission which sends information as variations of the amplitude of a carrier wave.

Ambient

The environmental conditions, e.g. surrounding light and sound.

Amperage

The amount of electrical current transferred from one component to another.

Amplifier

A device which increases signal amplitude.

Amplify

To increase amplitude.

Amplitude

The strength or power of a wave signal. The "height" of a wave when viewed as a standard x vs y graph.

Analogue

An analogue signal is a continuous wave that represents picture and/or sound.  This wave can distort and degrade, particularly with multiple copying.  Using digital systems can remove some of these problems. For example The UKs terrestial channels are analogue and most are simulcast with the equivalent digital channels which can be received by viewers with set-top boxes.

Anamorphic

The dictionary definition of anamorphic is "affected by distorted projection or perspective". The most common use of the word anamorphic is to describe the type of picture necessary for transmission on the digital widescreen services.  This is called "full height anamorphic", it has normal perspective when it is seen filling a widescreen television.

If the same picture is seen on a standard 4x3 television then it appears distorted - the people in the picture are taller and thinner than they should be and the sides seem to be squashed in.

In feature films anamorphic lenses are sometimes used to enable shooting of wide screen formats such as Cinemascope.

Anamorphic Lens

A special type of wide-angle lens which stretches the width of the image but not the height, creating a widescreen aspect ratio.

Answerprint

The first projection print of a new completed film sent for client approval by the laboratory.  After looking at it the director or film editor may ask for corrections.  The final, perfect print is known as the show print.

Antenna

A device which radiates and/or receives electromagnetic waves.

Aperture

Literally means "opening". The camera iris; the opening which lets light through the lens. By adjusting the size of the aperture, the amount of incoming light is controlled. The aperture size is measured in f-stops.

ARC

1. Aspect ratio convertor (pronounced "arc" not A.R.C.), used to convert pictures from one aspect ratio to another, for instance to convert 4:3 archive footage so it can be included in a 16:9 widescreen programme.  Arc is used sometimes as a verb, eg: "these pictures need to be ARCed".

2. Arc is also a type of powerful lamp used in the film industry.

3. Sometimes Arc might also describe the panning movement of a camera on a crane or jib arm.