I can say that the one North Korean secret police document is very concerned about CDs coming in from China to NK, because they bring in "Western music, anti revolutionary themes and RELIGIOUS material".
Here's the caption...( I'm copying from the paper)...
"In May, portraits of both Kim Il Sung, left, and Kim Jung Il hung in the People's Ciltural Center in Pyongyang, North Korea, during a North Korean Red Cross conference. I ASugust, only Kim Il SDung's portratit remained."