How can they compress this strong?



  • as an example, download this file:
    http://www.colorpilot.com/chm2pdfstore/Chm2PdfPilot.exe

    then extract it where you like.
    then compress it to ANY archive type PowerArchiver offers the opportunity to, at the strongest ratio.

    the compressed file will always be bigger than the original exe.

    how can that be? I might think they’re using an even stronger compression tool!
    what do you think?


  • conexware

    Can you tried 7-ZIP format and Ultra compression with Solid option?



  • @ivan:

    Can you tried 7-ZIP format and Ultra compression with Solid option?

    yes, I did…that’s why I posted…

    the exe file you download is 1.881KB, if you decompress it then 7-zip it (with the options you said…which, anyway, are my standard), you get a 2.068KB-big archive…

    😕



  • [old image removed] (to save space)



  • btw…compressing to a CAB does slightly better…but always 2.037KB vs 1.881KB only



  • @NTFS:

    I can confirm this!

    See attached image…

    confirmed…as your image lets see, the exe is an SFX 7-Zip archive…

    they used 7-Zip…so, how come we can’t compress as strongly using 7Z within PA?



  • Confirmed here as well. They must have tweaked the compression options for 7-zip.


  • conexware

    @By-Tor:

    Confirmed here as well. They must have tweaked the compression options for 7-zip.

    Yes, you can use “stronger” 7zip compression which uses larger dictionary, however in most of the cases it will not lower the compression. PowerArchiver uses 32 MB dictionary with Ultra settings which will take up 400 MB of your RAM, 7zip allows the use of up to 192 MB of memory, taking up to 1.9 GB of RAM…

    I personally tested it with quite few things and never noticed anything but small difference with larger dictionaries than 32 MB…



  • @spwolf:

    I personally tested it with quite few things and never noticed anything but small difference with larger dictionaries than 32 MB…

    This must be one of those cases where the dictionary size does make a difference. That’s why I put the request for more 7-Zip options in the wishlist. 🙂



  • @spwolf:

    Yes, you can use “stronger” 7zip compression which uses larger dictionary, however in most of the cases it will not lower the compression. PowerArchiver uses 32 MB dictionary with Ultra settings which will take up 400 MB of your RAM, 7zip allows the use of up to 192 MB of memory, taking up to 1.9 GB of RAM…

    I personally tested it with quite few things and never noticed anything but small difference with larger dictionaries than 32 MB…

    I think you should let your users decide about the amount of memory to set the dictionary to…as noticed, some times that does make a differencd in files final size.

    I’ve got a testing pc with 4GB of RAM…so I might very well have 1.9GB of those taken for compressing… 😉



  • @manuangi:

    I think you should let your users decide about the amount of memory to set the dictionary to…as noticed, some times that does make a differencd in files final size.

    I’ve got a testing pc with 4GB of RAM…so I might very well have 1.9GB of those taken for compressing… 😉

    I don’t have “4GB of RAM” but I agree with you anyway. 😉

    Thanks!



  • Good, then everyone is agreeable. 🙂


 

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