Reading BCA – The Hard Way

If you ever wanted to know what’s stored in a DVD’s BCA, you’ve probably read it out using your favourite device. Here I present you a different approach: reading it out by scanning the area and running “pattern recognition” on the image.

Here is a part of a Wii game that I’ve scanned:

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After filtering and thresholding it looks like this:

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The black and white image is then fed into a tool I wrote that will estimate the midpoint and the major and minor axes of the inner ellipse, detect all the BCA cuts around it, mark them and spit out the timing between the cuts. This timing can then be decoded into the actual data that is stored in the area. Note that the thick cuts are actually two normal ones that my scanner’s resolution didn’t pick up anymore, the tool will detect that too. Here is a part of a generated image (the blue lines are the detected cuts):

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And here is a complete output too:

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