Compression
from
The Collaborative International Dictionary of English v.0.48
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]
from
The Free On-line Dictionary of Computing (8 July 2008)
compression
compaction
uncompression
1. <application> (Or "compaction") The coding of data to save
storage space or transmission time. Although data is already
coded in digital form for computer processing, it can often be
coded more efficiently (using fewer bits). For example,
{run-length encoding} replaces strings of repeated characters
(or other units of data) with a single character and a count.
There are many compression {algorithms} and utilities.
Compressed data must be decompressed before it can be used.
The standard {Unix} compression utilty is called {compress}
though {GNU}'s superior {gzip} has largely replaced it. Other
compression utilties include {pack}, {zip} and {PKZIP}.
When compressing several similar files, it is usually better
to join the files together into an {archive} of some kind
(using {tar} for example) and then compress them, rather than
to join together individually compressed files. This is
because some common compression {algorithms} build up tables
based on the data from their current input which they have
already compressed. They then use this table to compress
subsequent data more efficiently.
See also {TIFF}, {JPEG}, {MPEG}, {Lempel-Ziv Welch},
"{lossy}", "{lossless}".
Compression FAQ
(ftp://rtfm.mit.edu/pub/usenet/news.answers/compression-faq/).
Web Content Compression FAQ
(http://perl.apache.org/docs/tutorials/client/compression/compression.html).
Usenet newsgroups: news:comp.compression,
news:comp.compression.research.
2. <multimedia> Reducing the dynamic range of an audio signal,
making quiet sounds louder and loud sounds quieter. Thus,
when discussing digital audio, the preferred term for reducing
the total amount of data is "compaction". Some advocate this
term in all contexts.
(2004-04-26)
from
Moby Thesaurus II by Grady Ward, 1.0
74 Moby Thesaurus words for "compression":
abbreviation, abridgment, abstract, agglutination, apocope,
astriction, astringency, bottleneck, cervix, circumscription,
clamping, clamping down, clumping, clustering, coarctation,
compactedness, compaction, compressure, concentration, concretion,
condensation, consolidation, conspectus, constriction,
constringency, contraction, contracture, crush, curtailment,
decrease, densification, diminuendo, elision, ellipsis, epitome,
foreshortening, hardening, hourglass, hourglass figure, isthmus,
knitting, narrow place, narrowing, neck, nip, pinch, precis, press,
pressure, puckering, pursing, recap, recapitulation, reduction,
retrenchment, shortening, solidification, squeeze, squeezing,
stranglement, strangulation, striction, stricture, summary,
summation, syncope, synopsis, systole, telescoping, tightening,
truncation, tweak, wasp waist, wrinkling
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