Set MPNowPlayingInfoCenter with other background audio playing
This isn't currently possible in iOS. Even just changing your category options to .MixWithOthers causes your nowPlayingInfo to be ignored.
My guess is iOS only considers non-mixing apps for inclusion in MPNowPlayingInfoCenter, because there is uncertainty as to which app would show up in (e.g.) Control Center if there are multiple mixing apps playing at the same time.
I'd very much like it if iOS used a best-effort approach for choosing the "now playing app", something like this:
- If there's a non-mixing app playing, pick that. Else..
- If there's only one mixing app playing, pick that. Else..
- If there are multiple mixing apps playing, just pick one :) Or pick none, I'm fine with either.
If you'd like this behavior as well, I'd encourage you to file a bug with Apple.