View source for Run-length encoding

'''Run-length encoding''' (RLE) is a [[lossless compression]] technique that replaces consecutive repeated symbols with a count-value pair. It is among the simplest compression algorithms, requiring minimal computational resources and no dictionary or probability model.

RLE is optimal for data with long runs of identical symbols — such as black-and-white fax images, simple graphics, and certain binary file formats. For data without such structure, RLE can actually expand the file size, as each non-repeating symbol requires two values (count and symbol) instead of one.

Despite its simplicity, RLE appears as a preprocessing step in many sophisticated compression pipelines. The [[PCX]] image format and early [[BMP]] variants used RLE exclusively. Modern codecs like [[JPEG]] employ RLE after the [[discrete cosine transform]] to compress runs of zero coefficients, demonstrating that even primitive techniques retain utility when matched to the right statistical structure.

[[Category:Technology]]
[[Category:Mathematics]]