How to determine compression method of a ZIP/RAR file

Intenex picture Intenex · Aug 1, 2011 · Viewed 27.8k times · Source

I have a few zip and rar files that I'm working with, and I'm trying to analyze the properties of how each file was compressed (compression level, compression algorithm (e.g. deflate, LZMA, BZip2), dictionary size, word size, etc.), and I haven't figured out a way to do this yet.

Is there any way to analyze the files to determine these properties, with software or otherwise?

Cheers and thanks!

Answer

atatko picture atatko · Jul 2, 2012

This is a fairly old question, but I wanted to throw in my two cents anyway since some of the methods above weren't as easy for me to use.

You can also determine this with 7-Zip. After opening the archive there is a column for method of compression:

7zip properties