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Thread: Sub Channel Data

  1. #21
    Experienced User Nikos's Avatar
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    When reading in raw mode, you can't be sure that any data you get is actually correct. Alcohol and CloneCD performs a software check. However, the actual algorithm for performing data integrity checks on raw sectors+subs is beyong my knowledge.
    To contact me privately, pray. I might answer.

  2. #22

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    Sounds like this could be that "Reed-Soloman" algorythm I've heard of. I guess that's not an option then.

    I've just re-read the post about each company using their own driver, this is a good point and could yield differing results. Part of me still wants to hope that the data output should still be the same.

    Well, this is getting tricky now. I guess this is probably why an open source version isnt' really available, no one's willing to donate a red-book to these folk?

    I'm not sure what I do from here on, I have a rough roadmap:

    First I want to yield similar results to Alcohol 120% using readCD. At least the ISO data should be the same. I then want to investigate the various options in Alcohol and see what compatability readCD has (as well as review the mmc standard, with some assistance). There may be some commands not being utilised by readCD.

    If I can find a way of replicating the Alcohol 120% settings (as best as possible) and obtaining similar results, then that should be successful enough. Though I may note be able to record all protection and subchannel data succesfully, there are those people at DT and other places who can emulate the security and hopefully we'll do without.

    Next step is to find out what the recommended Alcohol settings are for various copy protections, and code that into an app. I want the application to first Identify the copy protection and then copy the cd as appropriate. I want the output files to closely mimic alcohol files, so it can be used with DT.

    Timeline? Well, I've got some time off over christmas, I hate letting these things drag out so long. I also realise that my first ambition of an open 1:1 copy program is not as realistic as I hoped it would, I still want something that does a bit more than ISO copying which is meaningful. I might check out some open CD+G rippers as well.

    Anyway, I'm still all talk at the moment. I do look forward to spending some more time on this again shortly.

  3. #23

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    If anyone has reverse engineered Alcohol or blindwrite files (mainly the header files), I'd appreciate picking your brains.
    Since Alcohols MDS\MDF format was a joint development project with DTools, asking a question like this on this forum is a little stupid. Reverse engineering is not legal.
    Last edited by phoenix : 10.12.2005 at 10:55

  4. #24

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    Thanks for your information, I was not aware that reverse engineering files could be illegal. Despite my personal opinions, law is law; I will research this further.

    If you could please direct me to an appropriate location (either government legislation or even a copy of Alcohol 120% license agreement) where it states that reverse engineering file formats is illegal, I would appreciate it as it would expedite my research.

    It's been a while since I've spent time on this project, I want to spend some time reading the MMC specs (since I believe this is used with read-cd).

    I will admit that I'm loosing momentum on this, as I'm discovering more and more which is making this rather cumbersome.

    I will shortly post whatever code snippets I've collected which may help someone else more experienced or anyone else who wishes to continue this. I'll also contact the developers of read-cd and see if they're interested in this.

  5. #25
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    Jito463's Avatar
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    Straight from the Alcohol Software EULA. Relevant portions are highlighted in bold.

    2. PROTECTION OF SOFTWARE.
    You agree to protect the Software and the Documentation from unauthorized copying or use. You acknowledge that the source code for the Software and other trade secrets embodied in the Software have not been, and are not going to be, disclosed to you. Modifications of, additions to, or deletions from the Software (including any deletion or addition of code) are strictly prohibited. Except as specifically permitted in this Agreement, you agree not to, directly or indirectly, (1) use any Confidential Information to create any software or documentation that is similar to any of the Software or Documentation; (2) reverse engineer, disassemble or decompile the Software; (3) encumber, transfer, sublicense, rent, lease, time-share or use the Software in any service bureau arrangement; or (4) copy (except as provided herein), distribute, manufacture, adapt, create derivative works of, translate, localize, or otherwise modify Software or permit any third party to engage in any of the acts proscribed in clauses (1) through (4). You agree not to remove or alter any printed or on-screen copyright, trade secret or other legal notices contained on or in the Software or the Documentation.

  6. #26

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    Thank you, I appreciate the effort to find the reference. I may have misunderstood these statements to refer to execution binaries and libraries. Not generated files.

    This leaves me in an awkward position then. I will check the Clone CD EULA for a similiar statement, though I suspect that it's a standard agreement.

    My next path is to then develop something different then. My aim would be to split raw data from subchannel data into seperate files, but emulation is still a problem. Got to run, but i will put more thought to this later.

    I also now understand how the B52 to ISO project is probably legal, they are not recreating, just reading and then outputting to a new format.

    G

  7. #27
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    That's part of the reason why you don't always see every company support all the different formats out there. For example, Alcohol still does not support Blindwrite 5 images (it can technically be possible to mount them in the virtual drive, but burning them is another matter). It all depends on the original author of the format and how much information they're willing to release about it.

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