A conventional optical disk always spins in one direction, whilst the laser read head moves radially across its surface -following the spiral path on which the recorded micro-depressions have been laid.
This movement is essentially the same for all disks.
Today’s invention is a way to make piracy of digital content much more difficult (albeit with a small increase in production time/cost).
My DVD player would come with the facility to generate a unique, 2-D read head motion program embedded securely within it -a new one for every disk. The spinning would continue as normal.
My machine is networked to the manufacturer and sends them a code from which they derive the required read pattern and use that to imprint my movie’s bits (together with an identifier which allows my machine to use the right internal movement pattern when reading it).
I can thus buy a DVD online which will be printed with exactly the same bit stream as yours…except that my bits will be laid out in a pattern which only my machine can read.
I can make you a copy of my disk, but it won’t play in your machine.