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To erase or remove recorded data from a magnetic medium by subjecting the recording to an alternating magnetic field of gradually diminishing strength.
To remove residual magnetism from audio or video heads that could materially degrade the signal or affect the recorded signal on the magnetic medium.

D-1 Format
A digital recording standard in component form used for both studio and post production applications. Its advantages include excellent color keying capabilities and the ability to copy many generations with almost no degradation of the video signal. Its primary disadvantage is that each digital VCR costs over $100,000. Recording time is limited to two sizes of cassette, either 34 minutes or 76 minutes on standard tape. The D-1 format has high performance standards than the D-2 format. topˆ

D-2 Format
A composite digital recording standard used in studio and post production applications. Its basic advantage is that the VCRs are less expensive than those used in the D-1 format. The D-2 format offers up to 208 minutes of recording on a special 19mm (¾ inch) videotape. It also is capable of producing more generations than standard analog composite recording without noticeable degradation and gives very good slow motion performance. The D-2 format is generally used in cases where the higher performance of the D-1 VCR is not needed. It has made inroads in broadcasting in automated playback applications. It seems a likely replacement for the type "C" VTR. topˆ

Drop Frame Time Code
An SMPTE Time Code (TC) option that allows indicated TC to agree with clock time. The color frame rate for color TV is actually 29.97 frames per second, not 30, so that over a 60 minute period a TC reader would count 108 frames (3.6 seconds) short. To correct this situation, at the beginning of each minute frames 0 and 1 are "dropped" so that the frame count starts at 2. This would result in 120 frames added in an hour, 12 more than needed. By negating this correction at the beginning of every 10th minute, time code is forced to agree with clock time.

When the drop frame mode is selected on a Time Code Generator (TCG), a bit is set in the code that tells the reader and editing systems that they are dealing with drop frame TC. Many editors prefer to work with non-drop frame TC to eliminate the confusion caused by the missing frames.

Note that color is always 29.97 frames/second, but that is not necessarily synonymous with drop frame. See Time Code, Non-Drop Frame Time Code. topˆ

A loss of picture information that may appear as a short white flash and include one or more picture scan lines. Dropouts are caused by minute imperfections in the surface of the tape stock or by dust particles attracted to the tape by static electricity. Stock imperfections are not easily corrected, but if a dropout is caused by dust, then re-recording that section of tape will generally eliminate the dropout. topˆ

Dropout Compensator (DOC)
An electronic device in a VCR or VTR that detects the presence of a dropout and replace is with information from the preceding line, thereby covering up the dropout. topˆ

In television, a copy of a videotape. dub is more commonly used than dupe (short for duplicate), which generally applies to film copies.
In film, to mix and compose audio sound tracks from several elements by balancing for levels, proportion, and equalization. topˆ

Edit Decision List (EDL)
A structured compilation of time code information defining each edit in a sequence. The list may or may not be constructed for use in a computerized editing system. If it is, another compatible computer editing system should be able to use the EDL to edit or conform a videotape or audiotape. The EDL consists of pertinent information such as time code edit points, notes, and switcher data. topˆ

Editing System (Video)
A configuration of hardware and software designed to allow a user to build continuity on videotape in a linear or nonlinear fashion. The following items constitute a basic video editing system:

Computer hardware to interface with VCRs or VTRs and a keyboard or keypad for entering data.
Software designed for videotape editing.
Controllers to communicate between the computer and the VCR or VTR.
A basic switcher to switch video sources from one or more play machines to the record VTR or VCR.
A program monitor to view edits and optional source monitors for each playback machine
A floppy or hard disk for storing the operating program and edit decision lists.
An optional printer for paper printouts of edit decision lists (EDLs)
A joystick to control the tape motion (optional). topˆ

Edit List Management
The organizing and processing of time code data that make up an edit ecision list (EDL). When an editor creates an EDL, there may be some unwanted edits, over recordings or edits out of place. Some computer editing systems offer good list management features, allowing the editor to clean the list before using it to build a finished master. Others have limited or no list management capabilities and the editor must rely on commercial software to perform this function. topˆ

Electronic Editing
A method by which pictures and sound recorded on videotape are transferred from one videotape to another by electronic means. In essence, the original material is played back through electronic circuits and is copied to another tape. This new copy is regarded as a second-generation tape. The advantages of this method are:

That the original source material is never altered in any way.
That this same material may be used as source as many times as desired with minimum degradation since the audio and video signals are merely copied electronically from one tape to another.
Today, virtually all videotape editing is done in this matter, as opposed to the physical cutting and joining of the desired portions of tape as in film editing. topˆ

One-half of a NTSC television frame. A field contains 262.5 lines and has duration of 1/60th of a second. The odd numbered scanning lines are known as field 1, the even numbered as field 2. When these fields are combined by interlacing, a 525 line frame results. See Frame, Interlace. topˆ

Flying Spot Scanner
A TV scanning device that scans the film frame in a continuous motion using an electronic shutter rather than the conventional claw intermittent pull-down. The most popular type uses a monochrome kinescope as the light source and the pickup devices are red, green, and blue filtered photocells. This type of telecine device is much easier on film than an intermittent movement projector because it does not jerk the film down each time a frame changes, but rather moves continuously past the scanner so there is less chance of scratching or other film damage. topˆ

A standard unit of video information containing one complete image. The NTSC system standard in the United States and many other countries transmits nominal 30 frames per second. A frame is made up of two television fields, one odd and one even. Each field is made up o 262.5 lines of information. When interlaced the two fields generate a video frame of 525 lines. See Color Frame. In other parts of the world, the PAL and SECAM systems use 25 frames per second, with each frame containing 625 interlaced lines. These systems are not compatible with NTSC or each other. A standards converter maybe used to translate one format to another with some loss of quality.
One motion picture film image. topˆ

Frame Rate
In video and film, the standard number of frames continuously displayed per second of viewing time. TV frame rates were chosen to be one half the power frequency in use by the country of origin. There are three main international television standards;

NTSC system: 30 frames/60 fields per second (29.97 actual for color).
PAL: 25 frames/50 fields per second.
SECAM: 25 frames/50 fields per second.
Motion picture film for TV is projected at the standard sound speed of 24 frames per second in NTSC countries. In PAL and SECAM systems film is run at 25 f/s, the TV frame rate. See the listing of International TV Standards. topˆ

A generic name for a solid state digital video storage device that is capable of storing from 1 to 4 fields for an indefinite period of time. Framestores are used in Frame Synchronizers (FS), Digital video Effects (DVE), and other devices where it is useful to manipulate picture elements (pixels) in time and space. topˆ





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