A few days ago I saw a screenshot of someone in Machinima's MCN (Machinima Heroes Rise) getting a notice about the music library (Audiomicro) ending, and videos made with those tracks possibly being claimed by third parties. I've only been in one MCN and it didn't have an audio library, but this topic is interesting to me and I'm trying to track down information about MCN Audio Libraries to write an article about it without much success. As there are a lot of people on this site who have been in various MCNs, I was hoping someone could give me some information about this; mainly I want to know: what MCNs have Audio Libraries, and what restrictions are on those Audio Libraries (such as, if you can use those tracks when you leave that MCN)? I know there are countless ways to get copyright free music, but people do use Audio Libraries outside of the YouTube Audio Library and NCS, so I feel like a sort of masterpost of MCN's that offer it and their restrictions would be useful for creators. Thanks for your help!