Data Compression Explained

Matt Mahoney Copyright (C) 2010, Ocarina Networks. You are permitted to copy and distribute material from this book provided (1) any material you distribute includes this license, (2) the material is not modified, and (3) you do not charge a fee or require any other considerations for copies or for any works that incorporate material from this book. These restrictions do not apply to normal "fair use", defined as cited quotations totaling less than one page. This book may be downloaded without charge from http://mattmahoney.net/dc/dce.html. Last update: Feb. 26, 2010. About this Book This book is for the reader who wants to understand how data compression works, or who wants to write data compression software. Prior programming ability and some math skills will be needed. Specific topics include:  Information theory: entropy and algorithmic complexity, and the relationship to artificial intelligence.  Benchmarks.  Coding: Huffman, arithmetic, asymmetric binary.  Modeling: fixed order, variable order (PPM), context mixing (PAQ). Static vs. dynamic.  Transforms: run length, string matching (LZ77), dictionary (LZW), context sorting (BWT), symbol ranking, predictive filters, E8E9, recompression.  Lossy compression for images (JPEG), video (MPEG), and audio (MP3). This book is intended to be self contained. Sources are linked when appropriate, but you don't need to click on them to understand the material.