I think it might be the pixels.

Then you’d get a copy protected disc that wouldn’t play at all in the disc man, but you could copy it to a CD-R and that’d play just fine. To disable the copy protection you just hold shift while the cd tray closes.

If you smoke enough marijuana you can hear all the complicated stuff drummer Jeff Porcaro isn’t playing on the song Africa by Toto.

I can’t remember if it was Matt Parker or Tom Scott who did a thing about this on youtube, and I think the answer was no, they just use whatever method is easiest to get these numbers, and they’re not even using a consistent methodology from one country to the next.