Introduction to Data Compression, 4th Edition

Context-Based Compression

6.1 Overview

In this chapter, we present a number of techniques that use minimal prior assumptions about the statistics of the data. Instead they use the context of the data being encoded and the past history of the data to provide more efficient compression. We will look at a number of schemes that are principally used for the compression of text. These schemes use the context in which the data occurs in different ways.

6.2 Introduction

In Chapters 3 and 4, we learned that we get more compression when the message that is being coded has a more skewed set of probabilities. By “skewed” we mean that certain symbols occur with much higher probability than others in the sequence to be encoded. So it makes sense to look for ...