Newsgroups: comp.compression
Path: utzoo!utgpu!watserv1!watmath!looking!brad
From: brad@looking.on.ca (Brad Templeton)
Subject: Re: Is there better lossless compression than LZW?
Organization: Looking Glass Software Ltd.
Date: Wed, 29 May 91 15:58:53 GMT
Message-ID: <1991May29.155853.13716@looking.on.ca>
References: <2722@pdxgate.UUCP> <1991May28.231022.11197@unislc.uucp>

You suggest that a string look ahead with clever heuristics to add
and delete from the dictionary would give good compression.

How?  If it's a look ahead method, the decompressor can't look ahead and
duplicate the compresor's model.

This means you must insert tokens into the stream, saying "here's
a good dictionary entry."    And then you need the reference to the
entry.  The two together take as much or more room than the backpointer
of LZ compression.

Or do you have some idea that I am missing?

-- 
Brad Templeton, ClariNet Communications Corp. -- Waterloo, Ontario 519/884-7473