ISO "compression" without any actual compression, possible?

Discussion in 'PSP - Hacking & Homebrew' started by Roflord, Mar 26, 2014.

  1. Roflord
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    Roflord Newbie

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    I'm aware that the best way to store games in a digital format is to compress them into a CSO file, as this removes dummy sectors (if any) and further compresses already existing content, however, it is not the best way to actually play them without messing a bit with the game clock speed, so, the question is:

    Is there any way to just remove the dummy sectors without compressing further? I know there are settings to adjust compression level between 1 and 9 but to my general knowledge 1 is still bigger than 0, or is 1 the "not-compressed-at-all" setting?
    I've already used scrubbing tools for Wii ISOs, assuming the logic behind them is the same than what I'm looking for, would these work?
    And what would be the best setting performance-wise for compression should I need to resort to that anyways?

    Now, I would like people to stay on topic here, so I will just answer now some questions people might make:
    --get more storage: not in the right country to buy hardware at fair prices, not the right time to buy hardware, and no budget, bummer
    --just try and see if they work: I want to make sure before trying, I'm bound to eventually trying anyways
    --keep them somewhere else: I could, but wouldn't want to, USB file transfer is too slow for the PSP
    --just use the UMDs: I'm more of an engineer than a librarian
     
  2. cracker

    cracker Nyah!

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    Get UMDGen. You can dummy the update files and save ~50-100M (UMD Properties - Optimize) as well as remove extra languages, etc. and dummy or relink files (modify the file table to point more than one filename to the same place), etc. Be careful to keep a backup because it sometimes breaks games.
     
  3. Roflord
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    Roflord Newbie

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    Will try, thanks for the info
     
  4. NicoBlogs

    NicoBlogs GBAtemp Regular

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    It doesn't worth it in my opinion, stick to ISO and maybe get a bigger memory stick 32gb is plenty of room for enough games, you can get a micro-sd if pro-duo is too expensive definitely better than using cso.
     
  5. cracker

    cracker Nyah!

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    It usually takes 5m at most to rebuild an image and it can save you hundreds of megs per game. You do it once and save the final image so you only have to do it once. No matter what size your media is it is worth it to fit even more things on it.
     
  6. NicoBlogs

    NicoBlogs GBAtemp Regular

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    I prefer to store games as iso and then compress them with winrar, believe it or not most of the time a game on ISO compressed as RAR results in a smaller file than a CSO compressed as RAR.

    Once i have a clean iso i don't like to touch it. CSO has proven problematic: game lags/slow (like star wars), game doesn't save(various), can f**up rythm games, jackass game won't change episodes on cso, etc. i heard way too much people complaining of cso to stay away from it. (Except for bust a move deluxe :S)
    I feel that unless you have a ridiculously small ms stick you should not rely on CSO.

    You are free to use whatever you like though.
     
  7. Psionic Roshambo

    Psionic Roshambo GBAtemp Advanced Maniac

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    I use something called IceTea 1.3

    I forget exactly what it does but I do know it turns PS1 ISO files into eboots for the PSP (but they work on my PSX emulator on the JXD) I think it doesn't do any sort of compression, I think what it does is to get rid of dummy or padding data.
     
  8. NicoBlogs

    NicoBlogs GBAtemp Regular

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    I believe that converts PSX isos to eboots, it doesn't compress PSP games.
     
  9. Kalker3

    Kalker3 GBAtemp Fan

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    Here's a funny story, I once compressed an Sword Art Online ISO into a 7z file, in the end the 7z file had 10 more MBs than the original ISO.
    Another funny story, after compressing and optimizing Dream C Club, the CSO was 700 MB less than the clean ISO.
    This is CSO only BTW, not a compressed into a 7z file CSO.

    CSO is the way to go for me both in the PSP and cellphone.
    I've never experied any major slowdowns with CSOs but I keep my PSP at 333 MHz at all times anyways.
    Then again, there are certain games that are extremely sluggish when CSO'ed. (GTA IIRC.)

    BTW, if you just want to "optimize" the game but keep it in ISO, you can use UMDGen or YACC.
     
  10. Oxybelis

    Oxybelis GBAtemp Fan

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    Compressing CSO with 7z will work worse than deleting update from ISO and compressing it with 7z.