Glossary

Adaptive Differential Pulse Code Modulation

> > See ADPCM.

ADPCM

> > Adaptive Differential Pulse Code Modulation. An encoding format for storing audio information in a digital format.

algorithm

> > In compression software, a specific formula used to compress or decompress video.

audio

> > The sound for multimedia systems. Audio frequencies range from 15 Hz to 20,000 Hz.

audio stream

> > The frames of audio data.

Audio/Video Interleaved file format

> > See AVI file format.

AVI file format

> > Audio/Video Interleaved file format. A RIFF file specification used with applications that capture, edit, and play back audio/video sequences.

bitmap

> > A representation of characters or graphics by individual pixels arranged in row and column order. Each pixel can be represented by either one bit (for simple black and white) or up to 32 bits (for high-definition color).

brightness

> > The intensity of light. See also luminance.

chrominance

> > Color information whose form depends on the particular application.

colormap

> > The range of colors that can be used for display. It is the same as a palette but colormap is the term used in the X Window System. A colormap is a list of red, green, and blue values. The values are referenced by an index into the list: entry 0 might be pink, entry 1 might be blue, entry 2 might be black, and so forth.

> > X image data does not contain the actual color information but it does contain the index. This is either to reduce the amount of information contained in the image or because a display cannot handle true color. An 8 bits/pixel image can use 256 colors (28) and a 4 bits/pixel image can use 16 colors (24 ). A 24 bits/pixel image is true color and does not use a colormap.

Common Desktop Environment (CDE)

> > The Common Desktop Environment is a major standardization area within the Common Open Software Environment (COSE). The objective of COSE is to standardize various areas of the UNIX environment. These areas include the desktop interface, system management, and a common UNIX API.

compress

> > To reduce, using a variety of computer algorithms and other techniques, the amount of data required to accurately represent a video image or segment, thereby reducing the amount of space required to store it. Most types of compression, such as JPEG, cause some data to be lost. Compare with decompress.

contrast

> > The difference between the highest level and the lowest level of luminance in a picture.

decompress

> > To reverse the procedure conducted by compression software, thereby returning compressed data to its original size and condition. Compare with compress.

device-independent bitmap format

> > See DIB format.

DIB format

> > Device-independent bitmap format. A file format that represents bitmap images in a form that is independent of a specific device. Bitmaps can be represented as 1, 4, and 8 bits/pixel, with a palette containing colors represented in 24 bits. Bitmaps can also be represented as 24 bits without a palette and in run-length encoded format.

frame

> > A single, complete picture in a video or film recording. A frame consists of two interlaced fields of either 525 (NTSC) or 625 lines (PAL and SECAM), running at 30 frames second (NTSC) or 25 frames per second (PAL and SECAM). Movie theater films run at 24 frames per second.

hue

> > The distinctive characteristics of a color that allow it to assigned a position in the spectrum; a particular shade of a color.

Image

> > The computerized representation of a picture or a graphic International Organization for Standardization.

> > See ISO.

ISO

> > International Organization for Standardization. Worldwide organization responsible for establishing and managing various committees and expert groups, including several image-compression standards.

JPEG

> > Joint Photographic Experts Group. A working committee under the auspices of the International Organization for Standardization (ISO) that has defined the universal standard for the compression and decompression of still images for use in systems.

Joint Photographic Experts Group

> > See JPEG.

luminance

> > The measure of the energy that produces the sensation of brightness.

Motion Picture Experts Group

> > See MPEG.

motion video

> > A sequence of images (frames) that are displayed so rapidly that the viewer sees the images as a continuously moving picture.

MPEG

> > Motion Picture Experts Group, a working committee under the auspices of ISO, which has defined standards for the compression of audio and video for use in systems.

Multimedia

> > Pertaining to the delivery of information that combines different content formats, such as motion video, audio, images, graphics, animation, text, and so forth.

National Television Standards Committee

> > See NTSC.

NTSC

> > National Television Standards Committee. A committee of the Electronics Industries Association (EIA) that prepared the standard of specifications for commercial color broadcasting, which was approved by the Federal Communications Commission (FCC) in December 1953. NTSC is the TV standard for the U.S., Japan, and other countries. See also PAL format, SECAM format.

PAL format

> > Phase Alternation Line format. One of the two European video standards. The PAL format uses interlaced scans with 25 frames per second and 625 lines per screen. See also frame, NTSC, SECAM format.

palette

> > The range of colors that can be used for display. See also colormap.

PCM

> > Pulse code modulation. The most common method of encoding an analog signal into a digital bit stream. PCM is a digitization technique, not a universally accepted standard.

Phase Alternation Line format

> > See PAL format.

pixel

> > The shortened form of picture element. A pixel is the minimum raster display element, represented as a point with a specified color or intensity level. One way to measure picture resolution is by the number of pixels used to create images.

pulse code modulation

> > See PCM.

quality

> > The clarity of an image as the result of the amount of compression it undergoes.

resolution

> > The number of pixels per unit of area. A display with a finer grid contains more pixels and thus has a higher resolution capable of reproducing more detail in an image.

Resource Interchange File Format

> > See RIFF.

RGB

> > Red, green, and blue. A type of computer color display output signal comprised of separately controllable red, green, and blue signals.

RIFF

> > Resource Interchange File Format. A platform-independent multimedia specification (published by Microsoft and others in 1990) that allows audio, image, animation, and other multimedia elements to be stored in a common format.

sample

> > In the context of audio, the digital representation of the analog voltage.

saturation

> > The degree of purity of a color, as measured by its freedom of mixture with white; intensity of hue.

SECAM format

> > Sequential Coleur A Memoire (sequential color with memory) format. The French color TV system, also adopted by Russia. The basis of operation is the sequential recording of primary colors in alternate lines. See also NTSC, PAL format.

Sequential Coleur A Memoire

> > See SECAM format.

SMPTE format

> > Society of Motion Picture and Television Engineers format. A video encoding format developed by the Society of Motion Picture and Television Engineers.

Society of Motion Picture and Television Engineers format

> > See SMPTE format.

S-video

> > A higher quality video signal used in Hi8 and S-VHS video cassette recorders and other high end equipment. It transmits luminance and color portions separately using multiple pairs of wires instead of one, thus avoiding the loss of picture quality associated with composite video signals.

Video

> > See motion video.

video capture

> > The input of video data through the input jack of a video capture device, such as the Sound and Motion J300 option module. Video capture is used to input video frames from a video camera, video player, television tuner, or other video capture device.

video playback

> > The output of video data through the output jack of a video playback device, such as the Sound and Motion J300 option module. Video playback is used to output video frames to an external monitor, a VCR, or other video playback device.

Waveform Audio (WAVE) file format

> > See WAVE file format.

WAVE file format

> > Waveform Audio file format. A RIFF file specification used with applications that record and play back waveform audio data.

YUV format

> > mailAn encoding technique in which luminance and chrominance are encoded separately. The YUV format is as follows: Y(1)U(12)Y(2) V(12) where Y specifies the luminance and U and V specify the chrominance.