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From: doctor@vlsi.polymtl.ca (doctor zero)
Newsgroups: alt.comp.compression,comp.compression
Subject: Re: Trying to get maximum compression
Message-ID: <1991Mar28.215547.898@vlsi.polymtl.ca>
Date: 28 Mar 91 21:55:47 GMT
References: <1991Mar24.152106.6333@pegasus.com>
Sender: news@vlsi.polymtl.ca (USENET News System)
Organization: Ecole Polytechnique de Montreal
Lines: 32

In article <1991Mar24.152106.6333@pegasus.com> shaw@pegasus.com (Sandy Shaw) writes:
>I am trying to get the maximum compression possible of the following
>32 byte hex file(in ASC): 
>
>f3e9 ec5c 8bec ecdb ece9 ec12 ec3f ecec
>0cbb 8bec 5cdb ecdb 5c9c bbec 8bdb 9cec
>
>The best results I get are using the compact utility(adaptive Huffman). This
>gives 21.88% compression or 7 bytes saved. Does anyone out there have a 
>scheme that can improve on this? 
>
>Sandy Shaw
>shaw@pegasus.com


	one way that *could* increase your compression is making your
data 'more compressible'.  Try xoring your bytes in a daisy chain
way (first byte xor second byte -> first output byte) and then 
compress THAT output.

	this kind of pre-processing is at its best when you are trying
to compress a checkerboard image.  By XORing successive lines, you
ultimately get a white  picture plus something at the last line.

I think so.. correct me if I'm wrong.

			paul
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