App estimates and shows new size and speed (and needed space during rezip) so you can decide which is the best algorithm to use.

It can give a benchmark "preview" of several algorithms on your file, and instructions about their usability and typical benefits.

Allows for rezipping to new file or on the spot replacement.
-- pashute, Dec 16 2014

could work on multimedia files as well, but only for lossless information from the current compression.
-- pashute, Dec 16 2014


[marked-for-deletion] Widely known to exist. Many compression packages automatically select among several different algorithms on a per-file basis in order to provide the best possible compression.
-- ytk, Dec 16 2014


The idea is to take a zip file and make it smaller. The rezip will show you if its possible, and what the various sizes and times will be. You can then decide accordingly.

This is widely known to NOT exist.

If your not sure if your file is with the best lossless compression, you have no way to test it other than extracting (sometimes a time consuming and usually space consuming task) and then trying various zip options.
-- pashute, Dec 29 2014


It could get very computationally expensive to do this in the manner you suggest.

By the way, the only algorithm supported by ZIP is DEFLATE, so while you could gain a little by using a better implementation of DEFLATE (as 7zip does), you can't get very far unless you deviate from the ZIP format.

If you're gonna do that, the simple way (which could be accomplished with a little shell scripting) would be to TAR the contents of the archive, optionally benchmark performance of algorithms (e.g. PPMd, BZIP2, DEFLATE, LZMA), and then compress the TAR archive....or more realistically just use LZMA since it works well enough at an acceptable speed.

Anyways this ground is well-trodden. Have a look at PAQ, I think you'd like the work that went into it.
-- Spacecoyote, Dec 29 2014



random, halfbakery