#92 Optimize zip files

[Matthew]

Since different zip programs tend to use slightly
different compression methods, I find that I can get
better compression ratios by using various different
zip programs (although 7-zip usually provides the
best one:) ), but when I want to get a zip file as small
as I possibly can, I tend to have to zip the files into
different archives using different zip programs,
compare the compressed sizes, then manually add
the files into a new archive with whichever program
zipped them best. Would it be possible for 7-zip to
compare the files automatically, then to create a new
archive with all the best compression ratios? That
would make 7-zip able to always equal or (usually)
outdo other zip programs.

[Igor Pavlov]

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I don't plan it.

[Nobody/Anonymous]

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A simple solution is alrealdy out there. Use 'zipmix', it will
automatically compare the 2 zip file content (same data) and create
an output zip file with the best compression ratio.

Get
"zipmix.exe" from here

Ken Silverman's Utility
Page
http://advsys.net/ken/utils.htm

On the same page
you can get 'kzip.exe', a good alternative free zip compressor which
sometimes can beat 7-zip on compression ratio.

[Stephen Anderson]

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Along the lines of ZipMix, is a slightly more flexible program called ZipMax. It (and a couple other good utilities BJWFlate and DeflOpt) can be downloaded from: http://www.clrmame.com/download.htm

ZipMax is along the same lines as ZipMix except it can run upto 999 different zip compressors and use the best for each file in an archive. Incidentally, they recommend 7z as a good alternate compressor for most zip archives. I haven't used KZip, but the BJWFlate program can beat 7z's zip about 20% of the time.

The neat thing about ZipMax too is that it can pass the final zip through an end stage optimizer. I have mine configured to pipe the final "mixed" zip through DeflOpt (another good utility) which can then optimize a few bytes off the archive by optimizing the huffman tables I think.

[Strobe]

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I think it would be more useful to find any programs that
compress zip files better than 7zip and improve 7zip's
existing deflate method to match. This way 7zip improves and
zipmix and similar programs become redundant (because then -
in theory - 7zip's deflate would beat all other compressors
that also use deflate :-)