Compression

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See also: Data | Cryptography

On a computer, compression creates or attempts to create an output which is smaller than the original input. A commonly used compression technique is one which tries to eliminate redundancies within the data. Compression saves bandwidth and reduces storage costs. If it wasn't for compression, there would be less file sharing due to uncompressed files being much too large to readily transmit. For instance, raw uncompressed video captures are many gigabytes in size.

Decompression

The process of decompressing a compressed file to its original state (lossless) or to a similar state as its original state (lossy).

Common compression formats

There are several formats of compression for all file types. A few of the most popular:
  • BZIP2 - a more recent, better compresion format gradually gaining use
  • GZIP - an open-source alternative to ZIP format
  • RAR - a higher-quality, commercial, and slower compression format
  • ZIP - almost a universal format in data compression
For media files:

Lossless vs. lossy compression

In graphics and audio "lossless compression" allows for the recreation of the original data in it's entirety and "lossy" drops some data in compression because we can't really tell the difference. This concept remains even if the recreation is only perfect to human senses and not fundamentally exact compared with the original data.

Cryptography

Compression is often used in cryptography both to ease its transmission and improve its scrambling ability by reducing patterns.

Compression Techniques

Audio

Links

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