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Correct commands and switches for my need

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Bosanek
2008-01-01
2012-12-07
  • Bosanek

    Bosanek - 2008-01-01

    Hello,
    I need to use 7-zip in a batch, where the goal is to squeeze the maximum compression from cetrain material. Time is not an issue at all (I have got all the time which I need).

    This is what I want to do:

    I want to compress the same material several times (alternating settings each time), and then just keep the smallest resultant 7z file.

    These are the options which are stationery (they do not change):

    - format: 7z
    - compression level: Ultra
    - compression method: LZMA
    - solid block size: Non-solid
    - no SFX, no password, no encyption, no volume splitting

    These are the options which will alternate:
    - dictionary size: 16 MB, 24 MB, 32 MB, 48 MB, 64 MB
    - word size: <all sizes>

    Now, I am having difficulties in understanding 7-zip's command syntax, and I want to be sure that parameters which I set are CORRECT. Can anybody help me - write me what my command string should be, and a few examples of these two alternating options.

     
    • Eugene Teo

      Eugene Teo - 2008-01-05

      This is a sample

      "C:\Program Files\7-Zip\7z.exe" a -t7z c:\myzip.7z "C:\mypic.jpg" -mx=9 -ms=off -m0=BCJ2 -m1=LZMA:d=21:fb=64

      -t7z is 7z format
      -mx=9 is compression level: Ultra
      -m1=LZMA:d=21:fb=64 is compression method: LZMA with dictionary size 21 and word size 64.

      Refer to the help supplied with the application for more information. I must admit the help document is a bit difficult to comprehend. It took some 30 minutes to figure the above. But the information is there.

       
    • SeldomGood

      SeldomGood - 2008-01-09

      consider this very old post

      http://sourceforge.net/forum/message.php?msg_id=3988231

      you can use that utility to find the overall best setting for each filetype once and then use them in a multipass archiving script.

       
    • Bosanek

      Bosanek - 2008-01-11

      Thank you both very much, especially to Eugene Theo. Your command example is very good with good description. That is what I needed. Yes, 7-zips documentation is of very poor quality, I agree. My opinions is that its command syntax could be much better too, but now it is probably too late to change it.

      Good bye.

      - Bosanek

       

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