At one time I believed some aspects of coding were attempts at copy protection: coding drivers to ignore some class of error condition at "layer 2" so that an incorrect image could be seen by the reader and the byte stream passed up.

But now, with a hanlons razor in my hand, I now think these may just be unbelievably badly encoded disks, with things like the article notes: overruns of data into audio frames, checksum errors put in by the master.

While I am mildly disappointed that redumper[1] doesn't support low-level reading of DVDs, I have to say I'm super impressed that the README is very clear about what it does, and does not, do.

1: https://github.com/superg/redumper (linked from TFA).