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2016 HTPC for Catfisch Cinema

Discussion in 'Home Theater PCs' started by DaveF, Aug 6, 2017.

  1. jcroy

    jcroy Producer

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    (This may sound really silly).

    Today it was VERY tempting to buy a 4Kbluray player on blackfriday.

    I had talk myself down and out of making such a purchase. The one argument I keep on telling myself over and over again, is that I should not be buying any optical disc format which has not been cracked. Currently there is no widely publicly known crack of 4Kbluray.
     
  2. 42 Nov 27, 2017
    Last edited: Nov 27, 2017
    jcroy

    jcroy Producer

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    (Some more thoughts on general algorithms).

    Recently I noticed there was a complaint (on anydvd's forum) that there was a Lionsgate title released last week which allegedly caused anydvd to take 4 hours to process through the dvd. If this allegation is true, then this is highly suggestive that anydvd's general algorithm might be tracing through the machine code in a dvd's *.ifo files, to figure out which parts of the code is essential and which code is garbage filler which is never played (such as phony playlists). Basically something which functions like a virtual machine (or interpreter) which dynamically "executes" the machine code in the *.ifo files. (In the case of bluray, this would be like an interpreter running through the BD+ javascript code to figure out what code is essential and what code is trash).

    One easy way to cause an interpreter to run for hours on end in such a setup, is to fool it into falling into an infinite loop. Basically causing it to chase its own tail. If the interpreter has no easy way of detecting an infinite loop, then it will keep on running until the program crashes or the computer is turned off.

    In contrast, static parsing of the *.ifo files in a non-dynamic manner wouldn't get fooled into running an infinite loop. (Static parsing is basically like reading the code listing printed out on a piece of paper from start to finish, without paying attention to the execution logic).

    I looked through some recent Lionsgate titles I have to see where there might be some possible machine code sections in the *.ifo files, which might possibly cause an infinite loop. It turns out there were indeed a few sections of *.ifo code which potentially could fool a virtual machine into running an infinite loop, which I overlooked previously.

    My guess is Sony/Lionsgate's drm designers guessed how some parts of anydvd's general algorithm functioned through trial and error, and found a situation where it can be fooled into running an infinite loop. Though I would imagine this is a one-time-deal for Lionsgate, since anydvd's developers/engineers would just modify anydvd to avoid being fooled a second time by the same (or similar) infinite loops.


    (More generally).

    A drm construct which fools anydvd/dvdfab into falling into an infinite loop, is basically the equivalent of a precision weapon which turns the program into a WMD against itself. It only works under certain precise conditions, where anydvd/dvdfab can just modify their algorithm to easily bypass such infinite loops completely.

    I don't know if this is a sign of Sony/Lionsgate changing their drm design MO from a multi-headed hydra, to that of a precision guided WMD.
     
  3. DaveF

    DaveF Moderator
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    I don’t suppose you’d want to create your own thread for these topics? This thread on my particular media computer has sort of run off in a new direction.

    You might find more use in having a thread more
    focused on the topics you care about. :)
     
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  4. 44 Nov 27, 2017
    Last edited: Nov 28, 2017
    jcroy

    jcroy Producer

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    If there's more to say about this line of thought, I'll start my own thread. :)

    Though at this point, I suspect there isn't much more to talk about in regard to dvd/bluray drm.

    DRM that is designed to behave like a precision WMD in the service of total destruction (ie. via infinite loops), is just about the absolute end of the line. There isn't much more one can design (or conjecture), that is even more extreme in terms of annoyance and/or destruction.
     
  5. jcroy

    jcroy Producer

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    (More generally).

    Nowadays I don't bother updating the operating system and drivers on my dedicated htpc machines. My current htpc box still has the old factory default win8 which hasn't been updated at all. This machine has never been connected to the internet, and probably never will be. (Wifi, etc ... have all been disabled).

    As long as it works and my hardware isn't changed.

    The only programs I do change frequently, are periodic updates of VLC and madVR. Otherwise, it is relatively unchanged.


    (One day I should update the windows defender definitions).
     
  6. DaveF

    DaveF Moderator
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    Win10 auto updates. It’s not defeatable unless you take the machine offline, to my knowledge.
     
  7. jcroy

    jcroy Producer

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    Win10 auto updates can actually be turned off in a roundabout way.

    In the Administrative Tools part of the Control Panel, there is the Services program. In Services one can turn off "Windows Update" which can disable any auto updates. This is what I do to turn off any auto updates.

    It is a matter of turning windows update back on in services, to enable updates.
     

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