AVPlayer 对MP4等视频格式进行截屏截屏

CMTime currentTime = playerItem.currentTime;

    AVAssetImageGenerator *generator = [AVAssetImageGeneratorassetImageGeneratorWithAsset:urlAsset];

    AVAssetImageGeneratorCompletionHandler handler = ^(CMTime requestedTime,CGImageRef im, CMTime actualTime,AVAssetImageGeneratorResult result,NSError *error){

       

        if (result ==AVAssetImageGeneratorSucceeded) {

            UIImage * thumbImg = [UIImageimageWithCGImage:im];

            [selfsaveImage:thumbImg];

            dispatch_async(dispatch_get_main_queue(), ^{

                _imageView.image = thumbImg;

            });

        }

    };

    [generator generateCGImagesAsynchronouslyForTimes:[NSArrayarrayWithObject:[NSValuevalueWithCMTime:currentTime]]completionHandler:handler];