Compression Tools

Discussion in 'General Off-Topic Chat' started by Devante, Jan 2, 2007.

Jan 2, 2007

Compression Tools by Devante at 5:48 AM (720 Views / 0 Likes) 4 replies

  1. Devante
    OP

    Member Devante Crescent fresh at best.

    Joined:
    Nov 29, 2002
    Messages:
    1,212
    Country:
    United States
    For those who aren't familiar with GoodMerge, it is a tool that will take your ROM set and combine all version of one game into the same 7zip file, thereby compressing the file down to a fraction of what it would be if all version of the ROM were seperate. Usually the size of a single ROM.

    GoodMerge usually uses 7zip, and the resulting file sizes are impressive. For instance:

    0094 - Akumajou Dracula - Aoitsuki no Juujika (J)(WRG).nds
    0105 - Castlevania - Dawn of Sorrow (E)(Legacy).nds
    0121 - Castlevania - Dawn of Sorrow (U)(Legacy).nds

    These three files are 192MB uncompressed. Using default ZIP compression gets them to about 23MB each, so about 69MB compressed.
    However, with whatever settings GoodMerge uses and with 7zip, it combines all three ROMs into a single 7zip file for about 17MB. That's 192MB compressed to 17MB.


    Now for my questions:

    I've been trying to figure out how to get the same results using 7zip without the GoodMerge tool, but I can only get it down to 50MB or so. It's not as simple as "just use the highest compression settings".

    How is it possible to achieve the same results manually? And is it possible to get close with RAR or ZIP?
     
  2. dblank

    Newcomer dblank Advanced Member

    Joined:
    Sep 24, 2006
    Messages:
    50
    Country:
    You want to create a "solid" archive, 7zip and rar can do this, but not zip.
     
  3. Devante
    OP

    Member Devante Crescent fresh at best.

    Joined:
    Nov 29, 2002
    Messages:
    1,212
    Country:
    United States
    I've done that, but I still can't get anywhere close to the 17MB file that GoodMerge created.

    Anyone know what settings GoodMerge passes through to 7zip?
     
  4. dblank

    Newcomer dblank Advanced Member

    Joined:
    Sep 24, 2006
    Messages:
    50
    Country:
    It should be very close if you've really created a solid archive, it just doesn't sound like you have.

    I generally compress with a command line like this:
    7z a -t7z -m0=lzma -mx=9 -mlc=8 -mfb=64 -md=8m -ms=on archive.7z files*

    -ms=on is the important part for this kind of data.
     
  5. catflap

    Newcomer catflap Newbie

    Joined:
    Nov 27, 2006
    Messages:
    6
    Country:
    United Kingdom
    I tried using GoodMerge but I couldnt work out how to get anything to be listed in the rom sets box in the first page. Anyone know what I'm doing wrong?
     

Share This Page