Set MPNowPlayingInfoCenter with other background audio playing

I am trying to play a video using MPMoviePlayerController for an iOS app in Swift.

My goal is to be able to play system music with something like apple music, then open my app and have the audio mix in, but I want my app to be able to take control of MPNowPlayingInfoCenter.

How can I use AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayback, withOptions: .MixWithOthers) while still set the MPNowPlayingInfoCenter?

Google Maps mixes in audio while taking setting MPNowPlayingInfoCenter. Below is how I am trying to set the MPNowPlayingInfoCenter:

func setMeta(){
    UIApplication.sharedApplication().beginReceivingRemoteControlEvents()
    self.becomeFirstResponder()
    if let player = PlayWorkoutViewController.player{
        let coverArt = MPMediaItemArtwork(image: UIImage(named: "AlbumArt")!)
        let dict: [String: AnyObject] = [
            MPMediaItemPropertyArtwork: coverArt,
            MPMediaItemPropertyTitle:workout.title,
            MPMediaItemPropertyArtist:"Alex",
            MPMediaItemPropertyAlbumTitle:workout.program.title,
            MPNowPlayingInfoPropertyPlaybackRate: player.currentPlaybackRate,
            MPNowPlayingInfoPropertyElapsedPlaybackTime: player.currentPlaybackTime,
            MPMediaItemPropertyPlaybackDuration: player.playableDuration
        ]
        MPNowPlayingInfoCenter.defaultCenter().nowPlayingInfo = dict
    }
}

The above function works when I am not trying to play outside music with an option (.MixWithOthers) at the same time, but while I am trying to play outside music with the option (.MixWithOthers) the info center does not update.

Edit 1: Just to make things super clear, I already having video playing properly I am trying to play video with other background audio while being able to set MPNowPlayingInfoCenter.

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:

1. If there's a non-mixing app playing, pick that. Else..
2. If there's only one mixing app playing, pick that. Else..
3. 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.