A/B Roll

The use of alternating scenes, recorded on separate videotape reels (an A roll and a B roll), to perform dissolves, wipes or other types of video transitions. [BAVC]

Access points

A database field or metadata category designed to be searchable and retrievable by an end-user. Also used to denote a place where wireless network access is available. [Getty]

Access storage

Storage conditions at or near room ambient conditions that allow tape collections to be readily accessed for immediate playback. "See also Archival storage" [AMIA]

Acclimatization areas

A room or storage space that allows film, recordings and other material to adjust between ambient conditions [i.e. room temperature] and cold, dry storage, with minimal stress, and without condensation forming. The process may last days or weeks. [MIC]


Jagged edges along the outer edge of objects or text. Anti-aliasing refers to software adjustments that correct this effect. This effect is created by inadequate sampling techniques in computer-produced images. [Projector People]

Ambient light

Any light in the viewing room created by a source other than the projector or screen. [Projector People]

Ambient sound

A representative sample of background audio (such as a refrigerator hum or crowd murmur) particular to a shooting location. Ambient sound is gathered in the course of a production to aid the sound editor in making cuts or filling in spaces between dialog. Also called Room tone. [BAVC]

Ampex DCT (Digital Component Tape)

Compressed, 10-bit digital component format with similar specifications to Digital Betacam but not as popular. Introduced by Ampex in 1993. Cassette sizes and running times same as D-2, 13 micron tape thickness. Many users of this format claim that it has the best quality of the compressed formats. Machines are solidly built with gentle tape handling, and many are still in use ten years after their introduction. [MIC]


A continuously varying electronic signal. Audio and video analog signals stored on tape deteriorate with each copy or generation. In contrast see digital. [BAVC]

Analog recording

A recording in which continuous magnetic signals are written to the tape that are representations of the voltage signals coming from the recording of the video camera or microphone. Analog signals stored on tape deteriorate with each copy or generation; in contrast see digital. [BAVC]

Analog video

A system of recording video images that employs continuously varying waveforms to encode brightness, color and the timing information necessary to reproduce a moving image. [BAVC]


The process in which a continuous analog signal is quantized and converted to a series of binary integers. [BAVC]


Commentary added to a media object, generally providing explanatory information or editorial notes regarding the media file. Annotations are a form of metadata [Getty]


The American National Standards Institute has served in its capacity as administrator and coordinator of the United States private sector voluntary standardization system for 78 years. Founded in 1918 by five engineering societies and three government agencies, the Institute remains a private, nonprofit membership organization supported by a diverse constituency of private and public sector organizations. [ScreenSound Australia]

ANSI Lumens

ANSI stands for American National Standards Institute. It is a standard for measuring light output. Different lamps play a role on light output. Halogen lamps appear dimmer than another metal-halide, even if the two units have the same ANSI lumen rating. Type of LCD technology (active matrix TFT, Poly-Si, passive), type of overall technology (LCD vs. DLP vs. CRT), contrast ratios, among other factors can also affect the end result. [Projector People]

Archival format

A video format that provides reliable playback, without information loss. The format should be a current (as opposed to obsolescent) professional one supported by the industry. At present archival video material is typically stored on magnetic tape however in the near future computer-based storage is likely to become an option for archives. The advantage of uncompressed digital formats over analog formats is that they can be copied without generational loss. For this reason many archives are using digital formats for creating their archival masters. Ideally these formats should be uncompressed, component formats; however, for practical and cost reasons formats employing lossless compression are also used. Suitable archival formats will change as older formats become obsolete and are no longer supported. Ideally, archival master material is transferred onto new stock every 5-7 years and at this point a decision should be made about whether it is necessary to move to a new format as well. An archival format is therefore one that can be migrated onto new stock and new formats without the loss or distortion of information. [BAVC]

Archival storage

Storage conditions specifically designed to extend or maximize the lifetime of stored media. Generally characterized by levels of temperature and relative humidity lower than those in access storage conditions and with minimal fluctuations. Access to archival storage by personnel is limited for security reasons. [AMIA]


An undesirable picture element in a video image, which may naturally occur in the recording process and must be eliminated in order to achieve a high quality image. Most common artifacts are cross-color and cross-luminance. [BAVC]

Aspect Ratio

Aspect ratio refers to the relationship or ratio between the width of the image and the height of the image. There are two standard aspect ratios: 4:3 and 16:9. A standard TV has an aspect ratio of 4:3, which means that the picture is four units wide for every three units of height. HDTV standard is 16:9, which is 16 units of width for every 9 units of height. [EAI]


American Society for Testing and Materials [BAVC]


The sound portion of a program. [BAVC]

Audio mixer

A component that combines more than one sound input for composite output. [BAVC]

Authoring program

Software designed to help a nonprogrammer write source code, typically through a menu-driven or graphical interface. [Variable Media]

Authority/authority file

A file or set of terms extrinsic to records describing objects or documents. A more efficient way of recording information, which need be recorded only once and may then be linked to all appropriate records. [Getty]


A virtual representation of a user on a network, typically in text or graphic form. Avatars are often assumed identities with only an oblique relationship to their real-world counterparts. [Variable Media]


Audio/Video Interleaved file format. [MIC]


Audio/Video A rotation of the tape head away from perpendicular to the direction of tape/head travel. If a head slopes away from the desired angle a loss of signal will occur. [ScreenSound Australia]