Data Compression


Criteria

Survey Formats

Basics

Compression Methods

Data Formats


Arithmetic Coding (AC)

Principle of the AC

General Algorithm

Encoding

Decoding

Calculation of Intervals

Division

Shifting of Intervals

Calculation

AC versus Huffman

Data with high Redundancy

Adaptive AC

Implementations


Glossary

Index


Download


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Calculation of the Interval Shifting


After writing a decimal digit to the data stream, the parameters for the endpoints of the current interval has to be adapted in the following manner:


  • Jcurrl = (Jgesl* 10) - (int)(Jgesl* 10)
  • Jcurru = (Jgesl* 10) - (int)(Jgesl* 10)
  • Jcurrs = Jgesu - Jgesl

Example: Shifting by one decimal digit



At the recalculation of the interval parameters they must also provide, that no partial intervals arise in the following with the size 0.


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Shifting of the Intervals Shifting of the Intervals Comparison Arithmetic Coding versus Huffman