Subject: [Simple] Presence dictionary for Sigcomp

From: Adam Roach <[email-masked]>
Date: Thu, 22 Mar 2007 11:29:15 +0100

Just as a minor comment on the actual entries...

 From a practical perspective, just about any compression algorithm that 
accesses entries out of a static dictionary is going to have a 
break-even point around three or four characters -- meaning that any 
dictionary entry this size or shorter would be smaller to encode as 
those characters instead of a reference to a dictionary.

As a consequence, I would argue that all entries in the current 
dictionary that are two or three characters long should be removed: they 
won't really help anyone's compression ratios, and they server to make 
the dictionary larger (which has some obvious disadvantages).

For what it's worth, this reduces the dictionary from 403 entries down 
to 368 entries, and from 3641 bytes to 3480 bytes.

/a

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From: Miguel Garcia <[email-masked]>
Date: Thu, 22 Mar 2007 13:56:50 +0200

Good advice, thanks.

Next version of the draft will follow your suggestion.

/Miguel

-- 
Miguel A. Garcia           tel:+358-50-4804586
Nokia Research Center      Helsinki, Finland