如何在AirPlay中显示曲目的图片？

Question

我正在尝试通过AVPlayer向Airplay播放AAC-64流，但是未显示曲目的图片和名称。我该怎么办？

播放器代码如下。我将数据放在MPNowPlayingInfoCenter中，但没有任何变化。

class Player {
let radio = AVPlayer()
var currentStation:RadioStation?

func playStation(station : RadioStation) {
    self.currentStation = station

    stop()
    let playerItem = AVPlayerItem(url: URL.init(string: station.stationStreamURL)!)
    radio.replaceCurrentItem(with: playerItem)
    radio.play()

    updateLockScreen()
}

func play() {

    let audioSession = AVAudioSession.sharedInstance()
    do {
        try audioSession.setActive(true)
        try audioSession.setCategory(AVAudioSessionCategoryPlayback)
    } catch {}

    self.radio.play()
}

func stop() {
    self.radio.pause()
}

func updateLockScreen() {
    if let track = currentStation?.getCurrentTrack() {
        Alamofire.request(track.artworkURL, method: .get)
            .responseImage{ response in
                debugPrint(response)
                var info : [String: AnyObject] = [MPMediaItemPropertyArtist: track.artist as AnyObject,
                                                  MPMediaItemPropertyTitle: track.title as AnyObject]
                if let image = response.result.value {
                    print("image downloaded: \(image)")
                    info[MPMediaItemPropertyArtwork] = MPMediaItemArtwork(image: image)
                }

                MPNowPlayingInfoCenter.default().nowPlayingInfo = info
        }
    }      
}
}