英文字典中文字典51ZiDian.com

The Collaborative International Dictionary of English v.0.48 (gcide)

Compression \Com*pres"sion\, n. [L. compressio: cf. F.
compression.]
1. The act of compressing, or state of being compressed.
"Compression of thought." --Johnson.
[1913 Webster]

2. (Computers) reduction of the space required for storage
(of binary data) by an algorithm which converts the data
to a smaller number of bits while preserving the
information content. The act of compressing [3].

Note: Compression may be {lossless compression}, in which all
of the information in the original data is preserved,
and the original data may be recovered in form
identical to its original form; or {lossy compression},
in which some of the information in the original data
is lost, and decompression results in a data form
slightly different from the original. {Lossy
compression} is used, for example, to compress audio or
video recordings, and sometimes images, where the
slight differences in the original data and the data
recovered after {lossy compression} may be
imperceptable to the human eye or ear. The {JPEG}
format is produced by a {lossy compression} algorithm.
[PJC]


JPEG \JPEG\ n. [Acronym from Joint Picture Experts Group.]
(Computers)
A standardized format for storing graphic data in binary
computer files, allowing over 16 million different colors. It
allows for lossy compression, i. e. the compression of data
into a form which re-expands into an image close, but not
identical to the original image. Files stored in this format
usually carry the extension jpg or jpeg. Compare {GIF}.
[PJC]