［求助］iphone4上视频流播放

我现在想要播放服务器上的视频，给出了视频的路径。然后我使用如下方式加载播放视频，但在iphone4上界面是空白的，无法播放，但是在其它机器上播放却没问题。我想问下，这样的播放方式iphon4上是不是不支持？如果不支持，iphone4上要如何播放视频流呢？请教各位大侠啦！if(temp != AVKeyValueStatusLoaded) {
                //    AVPlayerItem * playerItem = [AVPlayerItem playerItemWithAsset:asset];
                     AVPlayerItem * playerItem = [AVPlayerItem playerItemWithURL:videoURL];
                    [[NSNotificationCenter defaultCenter] addObserver:self.videoView
                                                             selector:@selector(playerItemDidReachEnd:)
                                                                 name:AVPlayerItemDidPlayToEndTimeNotification
                                                               object:playerItem];                    AVPlayer * player = [[AVPlayer alloc] initWithPlayerItem:playerItem];
                    [self.videoView setPlayer:player];
视频流播放iosiPhone4