Compression

4 definitions found

From 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]

From WordNet (r) 2.0 [wn]:

  compression
       n 1: an increase in the density of something [syn: {compaction},
            {concretion}, {densification}]
       2: the process or result of becoming smaller or pressed
          together; "the contraction of a gas on cooling" [syn: {condensation},
           {contraction}]
       3: encoding information while reducing the bandwidth or bits
          required [ant: {decompression}]
       4: applying pressure [syn: {compressing}] [ant: {decompression}]

From Moby Thesaurus II by Grady Ward, 1.0 [moby-thes]:

  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
  
  

From The Free On-line Dictionary of Computing (27 SEP 03) [foldoc]:

  compression
       
          1.  (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 {algorithm}s 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/)}.
       
          {Usenet} newsgroups: {news:comp.compression},
          {news:comp.compression.research}.
       
          2.  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.
       
          (2001-01-30)