Dzip's purpose is to compress Quake demo files (.dem format) better than any of the general-purpose compression programs (like Zip etc.)
does. Unlike the compression provided by Demtool's various switches
(e.g. -f and -v), dzip's compression is lossless, i.e. no data is thrown away. Dzip also handles pak files. The compression provided by Dzip for .dem files is approximately twice as good as Zip's on average. For all other file types, dzip is generally very close in performace to normal
.zip utilities, sometimes even slightly better.