Data Compression


Criteria

Survey Formats

Basics

Compression Methods

Data Formats


Run Length Encoding

General Principle

8 Bit RLE

Uncoded Original Data

Control Characters

RLE for Image Data

Implementations


Glossary

Index


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Uncoded Original Data


A more effective handling of segments without repetitions can be achieved, if the counter indicates the number of unchanged symbols. The most significant bit can serve as flag; 0 identifies a counter for repetitions, a 1 the number of unchanged symbols taken over from the original data.


8 Bit Coding Cheme:



Regarding the counter as byte variable the range of values from 0 to 127 indicates a run (with 1 to 128 repititions) and the range of symbols from 128 to 255 uncoded data (with 1 to 128 symbols).


By this coding scheme the loss can be held within limits. Even if the original data does not contain repetitions, an additional counter have only to be inserted every 128 symbols.


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General Principle of RLE 8 Bit RLE Versions using Control Characters