Kaj je digitalna kompresija?
Ključne besede: digitalna kompresija, zgoščevanje podatkov, računalništvo
URL:[http://www2.arnes.si/~lmarus/suss/arhiv/suss-arhiv-000318.html]
Prosim za odgovor kaj je DIGITALNA KOMPRESIJA.
Ker sprašujete po v našem področju tujem izrazu (verjetno mislite na računalniško rabo te besedne zveze), vam žal kaj dosti ne znamo povedati (smo namreč jezikoslovci). Pogledali smo v nekaj knjig in pobrskali po internetu. V Računalniškem slovarčku Cankarjeve založbe (1993) je za prevod angleške zveze 'digital compression' uporabljena zveza 'zgoščevanje podatkov', ki pa žal v omenjeni knjigici ni razložena. Obiskali smo spletna naslova http://www.techweb.com in http://www.webopedia.com, ki sta nekakšni spletni računalniški enciklopediji (gotovo ne edini). Spodaj navajamo gesli z obeh. Žal nismo nikjer našli slovenske razlage 'digitalne kompresije'. Našli pa smo tale naslov, kjer se nahaja slovar številnih računalniških pojmov: http://www.s-gim.kr.edus.si/projekti/ucenje/Slovar.htm
http://www.webopedia.com:
"Storing data in a format that requires less space than usual. Compressing data is the same as packing data.
Data compression is particularly useful in communications because it enables devices to transmit the same amount of data in fewer bits. There are a variety of data compression techniques, but only a few have been standardized. The CCITT has defined a standard data compression technique for transmitting faxes (Group 3 standard) and a compression standard for data communications through modems (CCITT V.42bis). In addition, there are file compression formats, such as ARC and ZIP.
Data compression is also widely used in backup utilities, spreadsheet applications, and database management systems. Certain types of data, such as bit-mapped graphics, can be compressed to a small fraction of their normal size."
http://www.techweb.com:
"Data compression: Encoding data to take up less storage space. Digital data is compressed by finding repeatable patterns of binary 0s and 1s. The more patterns can be found, the more the data can be compressed. Text can generally be compressed to about 40% of its original size, and graphics files from 20% to 90%. Some files compress very little. It depends entirely on the type of file and compression algorithm used.
There are numerous compression methods in use. Two major technologies are Huffman coding and Lempel-Ziv-Welch (LZW), representing examples of the statistical and dictionary compression methods.
When a compression algorithm is packaged for use for a specific platform and file format, it is called a "codec" (compressor/decompressor). ADPCM, PCM and GSM are examples of codecs for sound, and Indeo, Cinepak and MPEG are examples of codecs for video.
In the DOS/Windows world, PKZIP is the most widely-used compression application. See archive formats, WinZip and coder."