iphone中avplayer获取总时长

想要获得AvPlayer在线歌曲的总时长，搜索了很多地方也没头绪，请高手指教，谢谢。

DLog(@"%d",(int) AvPlayer.duration);
_duration.text = [NSString stringWithFormat:@"%d:%02d", (int)p.duration / 60, (int)p.duration % 60, nil];

获取AvPlayer的时长。

CMTime duration = player.currentItem.asset.duration;
float seconds = CMTimeGetSeconds(duration);
NSLog(@"duration: %.2f", seconds);