FCEUGX, SNES9X, VBAGX 7z compression

Discussion in 'Wii - Emulation and Homebrew' started by Patryc, Sep 28, 2011.

Sep 28, 2011
  1. Patryc
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    Member Patryc GBAtemp Fan

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    Just wondered if any one knows the best settings for 7z? Best compression settings etc. I have found some of my 7z roms don't open, although they work fine uncompressed. Many Thanks!
     
  2. giantpune

    Member giantpune GBAtemp Addict

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    you probably dont want the "best" 7z settings. the way that 7z works, it is possible to compress a tiny file in a way that it will take a super huge amount of memory to decompress it. since the wii only has a small amount of RAM to begin with, and some of that is used up by the emulator itself and storing the huge list of games that you have and other stuff like this.

    you should use the less aggressive settings when creating the 7z archives. i dont have the program in front of me to read the settings off of it, but i had a similar issue and it was solved by dialing the compression and dictionary settings down a god bit.
     
  3. Patryc
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    Member Patryc GBAtemp Fan

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    Thanks for your help! Will try that.
     
  4. Dogway

    Member Dogway GBAtemp Regular

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    I can make them work, at least on vbagx, but when I click on the game instead of loading, it takes me inside the 7zip, as if it was another folder.
     
  5. Tantric

    Member Tantric GBAtemp Regular

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    Yes...that's how it works. Then you click on the game inside you want to load.
     
  6. Dogway

    Member Dogway GBAtemp Regular

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    It doesn't happen with .zip... Is there a workaround in the way .7z is compressed to avoid that or is it the way it is?
    What is funny is that when I switch to "cover view" (Wiimpathy's mod) then I cannot load the game "Unrecognized file extension!"
     
  7. Cyan

    Global Moderator Cyan GBATemp's lurking knight

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    The interest in using 7zip is that if you are compressing multiple similar files inside the same archive, it will result only in a slightly bigger file than if you compressed only one file.

    If you compress 3 ROMs of the same game with zip, you will have 3 "independently compressed rom".
    Say, the 4MB rom can compress to 50%, you will have 2MB + 2MB + 2MB = 6 MB .zip file.

    With 7z, you will have all the files analyzed before compressing them, if all file match the same data, then it will make 2.3MB + 0Mb + 0MB = 2.3MB 7z.
    Same part of the game (the code, graphics, etc.) are always the same, so there's no use of including it every time in all files, just compress it one time! Then the differences (few text/language) is the why the file is a little bigger than 2MB.

    You see the importance of the 7zip over the classic Zip.
    It's more suited to contain a lot of similar ROM (NTSC-J, NTSC-U, PAL G, PAL F, etc.), you can add a lot of same game in the 7z and it won't be bigger [​IMG]

    So the interest of opening the 7zip instead of launching the game is because the 7z can contain different version of the same game and it will allow you to choose the one you want to launch.
    But you need to decompress all content from all files, you can't just extract only one file quickly as all files are merged together. (it depend on the size of the compression and dictionary. That's why Giantpune said to use a different dictionary size to help decompressing for the wii memory)

    Of course, if you only have 1 game in the 7z, it will open it as if it were a folder instead of launching the game. You can find it an unnecessary step, but it's designed to support multi files.
    If you only have 1 game compressed, then you better use .zip directly.
     
  8. Dogway

    Member Dogway GBAtemp Regular

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    Thanks for the feedback Cyan, is nice to learn this kind of tidbits everyday.

    I see the benefit of compressing very similar files. But in my case I only compress one file per .7z, because even being only one file, it compresses much better than zip, and my 4Gb SD is becoming very limited. The intelligent way would be if in case of using one file, then launch the title, other open as folder, but this probably has to do more on how the 7zip works rather than the emulators.
     
  9. Jacobeian

    Member Jacobeian GBAtemp Advanced Maniac

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    I think the only thing that matters is the "dictionnary size" when compressing with 7zip. Don't ask me what this is exactly but the bigger, the better compression you can achieve.

    However, since the Wii has (very) limited memory, you might want to keep this setting low. The emulator should throw you a "Out of Memory" error message though if it can't uncompress the file.

    Nope, it's the emulator which displays the inner files listing. Since this requires that you know the number of files, it could decide instead to directly load the first file when only one is found. It's just a design choice, could probably be easily changed in a "mod".
     
  10. Patryc
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    Member Patryc GBAtemp Fan

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    Thanks for all the feedback on this topic, helped me to make up my mind between 7z, zip or uncompressed (I choose 7z with "normal settings")
     
  11. krcroft

    Newcomer krcroft Newbie

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    These are the maximum safe settings for Snes9xGx (and the others) on the GameCube:

    7za a -t7z -m0=lzma -mx=9 -mfb=768 -md=384k -ms=off

    Tested w/ Snes9xGx version 4.2.8
     
  12. Patryc
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    Member Patryc GBAtemp Fan

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    VBAGX ----- Does any know if zip or 7z compression is supported for the GAMECUBE CONSOLE? Normal roms load fine but I get message they aren't? Can't see nothing in the read me to say not.
     
  13. Tantric

    Member Tantric GBAtemp Regular

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    They aren't supported.
     
  14. Patryc
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    Member Patryc GBAtemp Fan

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    Thanks for your reply! A great app still.
     

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