Strange pattern on fast spinning CD

In the following youtube video and timestamp:
http://www.youtube.com/watch?v=zs7x1Hu29Wc&t=6m51s

one can see a cd spinning very quickly, in slow motion, just before it breaks. I’m not sure I understand what I see, much less the underlying principle. The shape of the cd, which looks like a "rotational wave", seems to be spinning much slower than the cd itself! What is happening there?