MPMusicPlayerController systemMusicPlayer play skipToNextItem慢而慢

Question

我正在使用MPMusicPlayerController systemMusicPlayer来播放音乐，但是跳过歌曲后，我注意到了明显的滞后。

以下是我测量到的“滞后”，有时速度更快：

• 1.280796
• 1.210124
• 1.019931
• 1.167739

跳过几首歌后，你听到声音之前的延迟会增加很多。

-(void)viewDidLoad {
    [[MPMusicPlayerController systemMusicPlayer] setQueueWithQuery:[MPMediaQuery songsQuery]]; 
    [[MPMusicPlayerController systemMusicPlayer] prepareToPlay];

    NSNotificationCenter *notificationCenter = [NSNotificationCenter defaultCenter];

    [notificationCenter addObserver:self selector:@selector(handlePlaybackStateChanged:)
                               name:MPMusicPlayerControllerPlaybackStateDidChangeNotification object:nil];


    [notificationCenter addObserver:self
                           selector:@selector(handleNowPlayingItemChanged:)
                               name:MPMusicPlayerControllerNowPlayingItemDidChangeNotification
                             object:[MPMusicPlayerController systemMusicPlayer]];

    [[MPMusicPlayerController systemMusicPlayer] beginGeneratingPlaybackNotifications];

}

-(IBAction)playBtn:(id)sender {                 
    if ([MPMusicPlayerController systemMusicPlayer].playbackState !=        MPMusicPlaybackStatePlaying) {
             [[MPMusicPlayerController systemMusicPlayer] play];
        } else {
            [[MPMusicPlayerController systemMusicPlayer] pause];
        }
}

-(void)skipTrack {

    startTrackChange = [NSDate date];              
    [[MPMusicPlayerController systemMusicPlayer] skipToNextItem];
}


-(void)handleNowPlayingItemChanged:(id)notification {

    NSLog(@"%f",[startTrackChange timeIntervalSinceNow]);
}

Answer 1

这似乎适用于我：

    MPMediaQuery *mediaQuery = [MPMediaQuery songsQuery];

   // filter out cloud items, cloud items cause delays
   [mediaQuery addFilterPredicate:[MPMediaPropertyPredicate
                                predicateWithValue:@NO
                                       forProperty:MPMediaItemPropertyIsCloudItem]];