AVPlayer 截取视频流的当前帧

*在给应用截图是发现系统截图方法不能截取播放器的画面，所以需要手动截取视频当前帧的画面。

本文说明的是AVPlayer的视频流截图方法。

截取视频画面总共分三步

一、声明所需属性

@interface ViewController (){    AVPlayer *_player;    AVPlayerItemVideoOutput *_videoOutPut;    }@end

二、实例化

    //初始化输出流    _videoOutPut = [[AVPlayerItemVideoOutput alloc] init];    //初始化播放地址    AVPlayerItem *item = [AVPlayerItem playerItemWithURL:[NSURL URLWithString:@"视频地址"]];    //添加输出流    [item addOutput:_videoOutPut];    //初始化播放器    _player = [[AVPlayer alloc] initWithPlayerItem:item];    //展示播放器到视图上。。。。

三、获取关键帧画面

-(void)getCurrentImage{    CMTime itemTime = _player.currentItem.currentTime;    CVPixelBufferRef pixelBuffer = [_videoOutPut copyPixelBufferForItemTime:itemTime itemTimeForDisplay:nil];    CIImage *ciImage = [CIImage imageWithCVPixelBuffer:pixelBuffer];    CIContext *temporaryContext = [CIContext contextWithOptions:nil];    CGImageRef videoImage = [temporaryContext                             createCGImage:ciImage                             fromRect:CGRectMake(0, 0,                                                 CVPixelBufferGetWidth(pixelBuffer),                                                 CVPixelBufferGetHeight(pixelBuffer))];        //当前帧的画面    UIImage *currentImage = [UIImage imageWithCGImage:videoImage];    CGImageRelease(videoImage);}