Editing Coding theory (section)

===Principle===
[[Entropy (information theory)|Entropy]] of a source is the measure of information. Basically, source codes try to reduce the redundancy present in the source, and represent the source with fewer bits that carry more information.

Data compression which explicitly tries to minimize the average length of messages according to a particular assumed probability model is called [[entropy encoding]].

Various techniques used by source coding schemes try to achieve the limit of entropy of the source. ''C''(''x'') ≥ ''H''(''x''), where ''H''(''x'') is entropy of source (bitrate), and  ''C''(''x'') is the bitrate after compression. In particular, no source coding scheme can be better than the entropy of the source.