Compression Quality

• Neville-Manning and Witten 1997

size

compress

gzip

sequitur

PPMC

bib

111261

3.35

2.51

2.48

2.12

book

768771

3.46

3.35

2.82

2.52

geo

102400

6.08

5.34

4.74

5.01

obj2

246814

4.17

2.63

2.68

2.77

pic

513216

0.97

0.82

0.90

0.98

progc

38611

3.87

2.68

2.83

2.49

Files from the Calgary Corpus

Units in bits per character (8 bits)

compress - based on LZW

gzip - based on LZ77

PPMC - adaptive arithmetic coding with context

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