What is the difference between an applicationQueuePlayer and an applicationMusicPlayer?

In the Apple documentation, it says

The application queue music player provides more functionality and greater control over the music played than the application music player.

But what control and functionality is that?

According the declaration, the MPMusicPlayerController inheritance it from NSObject,and MPMusicPlayerApplicationController inheritance it from MPMusicPlayerController.

So,it is clearly that,NSObject => MPMusicPlayerController => MPMusicPlayerApplicationController Then,MPMusicPlayerApplicationController have all func of MPMusicPlayerController, the More func is Changing the Queue Contents added, there are two methods offered about it. In general , you just use MPMusicPlayerController can do many things,hope to help you.