Detect scrubbed games

Discussion in 'Wii - Console and Game Discussions' started by Hendi48, May 9, 2009.

May 9, 2009

Detect scrubbed games by Hendi48 at 4:14 PM (1,944 Views / 0 Likes) 9 replies

  1. Hendi48
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    Newcomer Hendi48 Newbie

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    Hello,

    does somebody know how you can find out, if a Wii game is scrubbed or not? Is there a specific block that always gets scrubbed?

    I know I could just compress the ISO to find that out, but I want to implement a method in my WBFS Manager, which tells me whether a ISO is a 1:1 copy, scrubbed or trimmed.
     
  2. TheBuzzer

    Newcomer TheBuzzer Advanced Member

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    look at the iso size.
     
  3. Hendi48
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    Newcomer Hendi48 Newbie

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    That won't help me...
    Scrubbed ISOs have the same size as normal ones. They're only smaller when they are trimmed.
     
  4. Cyan

    Global Moderator Cyan GBATemp's lurking knight

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    I think you may want to ask Dack directly.
    He is the most aware if a same location exists on all the iso.
     
  5. nIxx

    Member nIxx GBAtemp Maniac

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    So where is the problem.
    Take a normal iso scrube it compare the two iso files and look after differences [​IMG]
     
  6. lll

    Member lll GBAtemp Regular

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    Making knowledge of how to detect scrubbed images available is probably not a very good idea. A known method of detecting a scrubbed ISO is probably not something Nintendo would bother looking into themselves, but it's certainly something they'd implement a check for if it was already widely known how to do it.
     
  7. FAST6191

    Reporter FAST6191 Techromancer

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    Crude way:
    open in in a hex editor and look for long repeating sections (I think they are 00's but do not hold me to that). If it has those it is scrubbed, if it is "random" then it is not scrubbed. Your compression idea would work too: keep it minimal.

    Note the occasional game is published in a "scrubbed" condition (see some of the early discussion on such things).

    As for detection is is considered near impossible and as we more or less completely own the wii's internals it would not be all that hard. There is the two variations on scrubbing though (one leaves the headers intact and the other nukes them, nuking gives a better compression ration but gets an outside possibility of detection).
     
  8. CreX

    Member CreX GBAtemp Regular

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    What does "scrubbed" mean anyway. And when do we have to care about it? [​IMG]
     
  9. FAST6191

    Reporter FAST6191 Techromancer

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    DVDs hold a given amount of data (4.35 gigabytes user space give or take for single layer disc).

    Wii dumping methods dump this entire space.

    Games however need not take the entire disc (most wii games hover around 2 gigabytes).

    In normal discs the unused space in between the data (or at the end of the disc) is not used or is simply long repeating strings.

    In most wii games this junk data is not long repeating strings but long sections of essentially random data. The wii could not care less about the junk data between files (as evidenced by the few games that do not have "random" data as this junk data).

    Random data does not compress so instead of including it scrubbed isos replace this data with long strings of 00's*. This newly tweaked disc will compress very nicely and allow easy storage, easier transfer via slow networks (the internet for instance) and now we have things like the USB loader easier storage on the USB/SD storage device (if I not mistaken the junk data is "lost" but it is "reconstructed" on the fly as there is little more predictable than 00's). As some games have this and the wii has little in the way of checking this is considered very safe to do, as we also own the wii's internals any "bans" or problems could be circumvented relatively easily.

    *while the basic idea behind wii scrubbing is this the original wii scrubber application has extra features that can make things even smaller at the cost of needing the disc to be fakesigned (not a problem for those with a well hacked wii but potentially a problem for those just running a modchip and nothing else who decide to update menus or otherwise render themselves unable to run fakesigned code, if you are running a USB loader, a disc loader or a have a properly hacked wii then you have no worries about this). Such things include removing the update partition, shifting the data to the front of the disc and more elaborate things like multi game isos.
    Of secondary interest here is the "leave the headers intact", while I said detection is hard there is the outside chance of a read into this scrubbed region (nothing has been said or done to give any hint of such a thing and given that we own the wii.....), by leaving the headers intact the wii can be duped even then but it comes at the cost of losing some compression (about 200 megs over the course of a regular disc if memory serves) note leaving the headers or not does not require fakesigning.
    Other note basic scrubbing still needs the key to able to tell game data from junk data.
     
  10. CreX

    Member CreX GBAtemp Regular

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    Nice reply. Seems like a scrubbed Wii disc is about the same as in the Gamecube era, were all the games had junk data. But the word "scrubbed" were never used. I don't remember that well. But I think ppl said "stripped" or "ripped", dunno. [​IMG]

    But then I completly understand "scrubbed", for me it was just a new word for a thing I knew about. [​IMG]
     

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