dd is an impractical tool for ripping many copy-protected DVDs as the discs have many bad sectors intentionally put on them that will make the ISO unusable and the ripping process taking a very long time.
I wouldn't expect any luck using dd for ripping copy-protected discs.
Find a rock, ???, report to the press, ???, profit!
This rock looks exactly the same as the one I got at home -- it has the same shape, color, size and is just as aggressive as the rock advertised, yet, my rock doesn't get all the fame.
Outside of a dog, a book is man's best friend. Inside of a dog, it is too dark to read.