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December 1994

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1994.12.14 22:00 "JBIG compression", by Kyriakos Georgiou
1994.12.14 23:51 "Re: JBIG compression", by Sam Leffler
1994.12.16 18:00 "Re: JBIG compression", by Fredrik Lundh
1994.12.16 21:02 "Re: JBIG compression", by Kyriakos Georgiou
1994.12.16 21:17 "Re: JBIG compression", by Sam Leffler
1994.12.16 22:04 "Re: JBIG compression", by Rick Richardson
1994.12.16 22:18 "Re: JBIG compression (really G3/G4 decompression)", by Sam Leffler
1994.12.15 09:59 "Further G4 improvement", by Karsten Spang

1994.12.16 21:02 "Re: JBIG compression", by Kyriakos Georgiou

In response to Sam's comments:

>     Also, can the current libtiff G4 decompression implementation be
>     improved ? What sort of improvements can be expected ?
> 
> What's wrong with the current implementation?

The current implementation is fine, but.. I have in my hands a commercial
product (no source) that does decompression in noticable less time.
That suggests that there are faster ways to decompress G4 in software,
alas my question.

>     I don't want to get into algorithmic issues, my question is, is there
>     room for >15% improvement on G4 for the implementation of libtiff ?
> 
> Until you cite specific goals (and architecture for running the
> software) this question is silly.  Try measuring the performance of the
> current algorithm before looking for improvements.

Unless you didn't understand what I am talking about - CCITT Group 4
decompression speed - I find this answer silly.  What does the
architecture have to do with algorithmic improvements ? Perhaps you
should read a computational theory and algorithms book before defining
what silly questions are.

In response to your 2nd comment, why would I be looking for improvements 
if I had not measured the performance of the current algorithm?  If you
remember, few weeks ago I sent some remarks on the new improved G4
decompression running on a pentium.

K.Georgiou