AVAudioPlayer停止

Question

我正在尝试使用AVAudioPlayer播放mp3文件：

NSString *path = NSString stringWithFormat:@"%@/%@" , 
    [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"];

NSURL* url = [NSURL fileURLWithPath:path];

AVAudioPlayer* player = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:nil];
    [[AVAudioSession sharedInstance] setCategory: AVAudioSessionCategoryPlayback error: nil];


[player play];
NSLog(@"%f/%f", player.currentTime, player.duration);

然而，即使玩家的持续时间为1044.437506，玩家每次都会停在478.558367附近。 为什么玩家会停在赛道中间？