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compression - technical definition

A means of reducing the amount of data to be transmitted or stored. Compression is possible since there always is some amount of data redundancy or there may be a predictable flow to the data. These characteristics of a set of data or a stream of data allow the use of a sort of mathematical algorithm to represent or describe the original data in fewer bits. A matching decompression process reverses the compression process and restores the data to its original form, or an approximation thereof. Compression serves to improve the efficiency of data transmission and storage, and is especially valuable if bandwidth and memory resources are limited. Data compression techniques can include the following:

See compression in Webster''s New World Hacker Dictionary

The storing of data in a format requiring less space. In communications, data compression is helpful because it enables devices to store or transmit the same amount of data in fewer bits, thus making the transmission of the data faster. Compression falls into two main categories: lossless compression and lossy compression. With lossless compression, the original data can be restored to be an exact replica of the original, whereas with lossy compression, one accepts some quality losses in the compression/decompression steps. Lossy compression is used mainly for audio and video data, for which the loss in data quality is easily overlooked by the human user. Before data is encrypted, it can be compressed using the compression standard gzip and its compression library zlib. Encrypted data can be entirely noncompressed.

compression - technical definition

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