[ainiriand]

Licensing rights, because if you develop an app that makes money out of playing music it is gonna make some people uncomfortable, even if it the music of the owner of the app. There's gonna be C&D letters even if the app proves to be licit.

[opencl]

This makes no sense, there are no licensing rights involved because no music is being provided. It just plays files provided by the user. Are people sending C&D letters to Sandisk for selling MP3 players, or the hundreds of music player apps for Android?

[ainiriand]

Agree, it makes no sense, lets see if the OP can tell us if this happens in the future or not. Maybe I'm just scared.

[opencl]

There are already a huge number of apps out there doing the exact same thing, as far as I am aware zero have been sued/threatened out of existence over this.