How Does CD Ripper Know

[mrcd]

How Does CD Ripper know I've ripped a CD from my PC? What info does it gather from my PC in order to recognize if I tried to rip the same CD again?

Does every CD have a unique identifier?

[Spoon]

Re: How Does CD Ripper Know

The Table of Contents is the unique identifier. dBpoweramp uses a temporary cache of the results + metadata.