Editing Data compression (section)

{{short description|Compact encoding of digital data}}
{{redirect|Source coding|the term in computer programming|Source code}}
{{Use American English|date=March 2021}}

In [[information theory]], '''data compression''', '''source coding''',<ref name="Wade"/> or '''bit-rate reduction''' is the process of encoding [[information]] using fewer [[bit]]s than the original representation.<ref name="mahdi53"/> Any particular compression is either [[lossy]] or [[lossless]]. Lossless compression reduces bits by identifying and eliminating [[Redundancy (information theory)|statistical redundancy]]. No information is lost in lossless compression. Lossy compression reduces bits by removing unnecessary or less important information.<ref name="PujarKadlaskar"/> Typically, a device that performs data compression is referred to as an encoder, and one that performs the reversal of the process (decompression) as a decoder.

The process of reducing the size of a [[data file]] is often referred to as data compression. In the context of [[data transmission]], it is called source coding: encoding is done at the source of the data before it is stored or transmitted.<ref name="Salomon"/> Source coding should not be confused with [[channel coding]], for error detection and correction or [[line coding]], the means for mapping data onto a signal.

Data Compression algorithms present a [[Space–time tradeoff|space-time complexity trade-off]] between the bytes needed to store or transmit information, and the [[Computational resource]]s needed to perform the encoding and decoding. The design of data compression schemes involves balancing the degree of compression, the amount of distortion introduced (when using [[lossy data compression]]), and the computational resources or time required to compress and decompress the data.<ref name="Tank"/>