Some files are compressed using their own compression scheme and some aren't. If I try Max compression on an already compressed file, I'll get 1%-2% better compression at most. The amount of time wasted compressing those files are worthless.

I want 7zip to use the Store or Fast level of compression instead of Max for those already compressed files, while using Max on the uncompressed files. I can do this if I go into the directory and make 2 different 7z files for multiple different kinds of file types stored in that folder. But is there a way to store these differently compressed files inside the same 7zip file? The files that aren't already compressed will be compressed and the ones that are will just be stored.

Has anybody found a way to do that?


You can add to the 7z file with different settings. Eg:

7za a -t7z -m0=lzma -mx=9 -mfb=64 -md=32m -ms=on archive.7z *.txt

7za a -t7z -m0=copy archive.7z *.zip

You won't take advantage of any commonality between the files for compression, but that doesn't sound important in your scenario.

  • I've got a Steam\Games folder that needs to be shrunk, but a lot of those files are heavily compressed. I don't have many files that are common between one another. I think I can reduce DAYS of compression time down to a few hours with this. – Jim Kieger Dec 10 '13 at 1:41

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