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From: jones@pyrite.cs.uiowa.edu (Douglas W. Jones,201H MLH,3193350740,3193382879)
Newsgroups: comp.compression
Subject: Re: Is there better lossless compression than LZW?
Message-ID: <6200@ns-mx.uiowa.edu>
Date: 24 May 91 14:05:57 GMT
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From article <2722@pdxgate.UUCP>, by hal@eecs.cs.pdx.edu (Aaron Harsh):
> 
>   The only lossless compression algorithms I've seen have either been LZW
> or its derivatives (AP, MW and Y-coding) or Huffman encoding.  These seem
> fast, but their compression doesn't seem that remarkable.  Are there any
> other general purpose algorithms that achieve better results, even at the
> expense of speed?

Well, there's always my splay-tree based prefix code (software available
by e-mail request).  See:

   Application of Splay Trees to Data Compression, by Douglas Jones
     Communications of the ACM, Vol 31 No 8 (Aug 1988) pages 996-1006

But by far the best lossless compression is achieved by arithmetic codes,
especially when used with mulitple state source models.  Arithmetic codes
can code individual source characters in fractional bits (something that
a Huffman code can't do), but they are generally slow, and when used with
multiple state source models, they get quite big as well.  See:

   Arithmetic Coding for Data Compression, by Witten et al
     Communications of the ACM, Vol 30 No 6 (June 1987) pages 520-540

I Hope this helps.
				Doug Jones
				jones@cs.uiowa.edu