如何以编程方式捕捉播放视频的截图？

Question

我想用xcode捕捉一个播放视频的截图。我如何以编程的方式完成它？我在苹果文档中找到了一个截图方法，如下所示。如果我只想拍摄一个视图的截图，这个方法很好。但是，它不能处理播放的视频。

- (UIImage*)screenshot 
{
    // Create a graphics context with the target size
    // On iOS 4 and later, use UIGraphicsBeginImageContextWithOptions to take the scale into consideration
    // On iOS prior to 4, fall back to use UIGraphicsBeginImageContext
    CGSize imageSize = [[UIScreen mainScreen] bounds].size;
    if (NULL != UIGraphicsBeginImageContextWithOptions)
        UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0);
    else
        UIGraphicsBeginImageContext(imageSize);

    CGContextRef context = UIGraphicsGetCurrentContext();

    // Iterate over every window from back to front
    for (UIWindow *window in [[UIApplication sharedApplication] windows]) 
    {
        if (![window respondsToSelector:@selector(screen)] || [window screen] == [UIScreen mainScreen])
        {
            // -renderInContext: renders in the coordinate space of the layer,
            // so we must first apply the layer's geometry to the graphics context
            CGContextSaveGState(context);
            // Center the context around the window's anchor point
            CGContextTranslateCTM(context, [window center].x, [window center].y);
            // Apply the window's transform about the anchor point
            CGContextConcatCTM(context, [window transform]);
            // Offset by the portion of the bounds left of and above the anchor point
            CGContextTranslateCTM(context,
                                  -[window bounds].size.width * [[window layer] anchorPoint].x,
                                  -[window bounds].size.height * [[window layer] anchorPoint].y);

            // Render the layer hierarchy to the current context
            [[window layer] renderInContext:context];

            // Restore the context
            CGContextRestoreGState(context);
        }
    }

    // Retrieve the screenshot image
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    return image;
}

我需要捕捉一个播放视频的截图。有什么想法吗？

Answer 1

希望这段代码能帮上忙

捕捉播放视频的截图

- (void)setupVideoPlayerView
{
videoPlayerVC = [[AVPlayerViewController alloc] init];
videoPlayerVC.view.frame = self.videoPlayerView.bounds;
videoPlayerVC.videoGravity = AVLayerVideoGravityResizeAspectFill
[videoPlayerView addSubview:_videoPlayerVC.view];
[videoPlayerVC setShowsPlaybackControls:NO];
videoPlayerVC.player = [AVPlayer playerWithURL:[NSURL URLWithString:kVideoURL];
[videoPlayerVC.player play];
}

- (UIImage *)snapImageFromRuningVideo
{
AVAsset *assest = [self.videoPlayerVC.player.currentItem asset];
AVAssetImageGenerator *imageGenerator = [AVAssetImageGenerator assetImageGeneratorWithAsset:assest];
CGImageRef imageRef = [imageGenerator copyCGImageAtTime:self.videoPlayerVC.player.currentItem.currentTime actualTime:nil error:nil];
UIImage *screengrab = [UIImage imageWithCGImage:imageRef];
return screengrab;
}

这里，只要创建AVPlayerViewController，如果您想要控制器栏，或只是实例化AVPlayer和绑定的网址的视频和播放。

无论何时，只要您想要在快照按钮上捕获正在运行的视频的快照，就可以调用方法"snapImageFromRuningVideo“，它将返回UIImage对象引用。

AVPlayer内部创建AVPlayerItem和AVAsset对象。现在只使用copyCGImageAtTime:self.videoPlayerVC.player.currentItem.currentTime对象创建AVAssetImageGenerator对象，然后通过调用"CGImageRef imageRef = imageGenerator实际时间:nil error:nil;“，每次复制快照时开始复制图像。

在这里，我们必须在抓取快照的瞬间传递播放器当前的时间。