视频中的AVfoundation模糊背景
视频中的AVfoundation模糊背景
提问于 2016-09-04 13:01:23
在我应用程序中，我将合成渲染大小固定为1280x720。因此，如果要导入任何肖像视频，那么我必须显示模糊的背景与填充和在中心的视频的纵横比框架。如下所示：
https://www.youtube.com/watch?v=yCOrqUA0ws4
我实现了用AVMtableComposition播放这两个视频，但我不知道如何模糊特定的背景音轨。我在我的代码中执行了以下操作：
self.composition = [AVMutableComposition composition];
AVAsset *firstAsset = [AVAsset assetWithURL:[NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"ScreenFlow_Blend" ofType:@"mp4"]]];
[self addAsset:firstAsset toComposition:self.composition withTrackID:1];
[self addAsset:firstAsset toComposition:self.composition withTrackID:2];
// [self addAsset:ThirdAsset toComposition:self.composition withTrackID:3];
AVAssetTrack *backVideoTrack = [firstAsset tracksWithMediaType:AVMediaTypeVideo][0];;
self.videoComposition = [AVMutableVideoComposition videoComposition];
self.videoComposition.renderSize = CGSizeMake(1280, 720);
self.videoComposition.frameDuration = CMTimeMake(1, 30);
AVMutableVideoCompositionInstruction *instruction = [AVMutableVideoCompositionInstruction videoCompositionInstruction];
instruction.timeRange = [backVideoTrack timeRange];
CGFloat scale = 1280/backVideoTrack.naturalSize.width;
CGAffineTransform t = CGAffineTransformMakeScale(scale, scale);
t = CGAffineTransformTranslate(t, 0, -backVideoTrack.naturalSize.height/2 + self.videoComposition.renderSize.height/2);
AVMutableVideoCompositionLayerInstruction *frontLayerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstruction];
frontLayerInstruction.trackID = 1;
[frontLayerInstruction setTransform:t atTime:kCMTimeZero];
CGFloat scaleSmall = 720/backVideoTrack.naturalSize.height;
CGAffineTransform translate = CGAffineTransformMakeTranslation(self.videoComposition.renderSize.width/2 - ((backVideoTrack.naturalSize.width/2)*scaleSmall),0);
CGAffineTransform scaleTransform = CGAffineTransformMakeScale(scaleSmall,scaleSmall);
CGAffineTransform finalTransform = CGAffineTransformConcat(scaleTransform, translate);
CGAffineTransform t1 = CGAffineTransformMakeScale(scaleSmall,scaleSmall);
t1 = CGAffineTransformTranslate(t1,1280, 0);
AVMutableVideoCompositionLayerInstruction *backLayerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstruction];
backLayerInstruction.trackID = 2;
[backLayerInstruction setTransform:finalTransform atTime:kCMTimeZero];
// AVMutableVideoCompositionLayerInstruction *maskLayerInstruction = [AVMutableVideoCompositionLayerInstruction videoCompositionLayerInstruction];
// maskLayerInstruction.trackID = 3;
// [maskLayerInstruction setTransform:t atTime:kCMTimeZero];
instruction.layerInstructions = @[backLayerInstruction,frontLayerInstruction];
self.videoComposition.instructions = @[ instruction ];
AVPlayerItem *playerItem = [AVPlayerItem playerItemWithAsset:self.composition];
playerItem.videoComposition = self.videoComposition;
self.player = [AVPlayer playerWithPlayerItem:playerItem];
AVPlayerLayer *newPlayerLayer = [AVPlayerLayer playerLayerWithPlayer:[self player]];
[newPlayerLayer setFrame:[[[self playerView] layer] bounds]];
// [newPlayerLayer setHidden:YES];
[[[self playerView] layer] addSublayer:newPlayerLayer];
[self setPlayerLayer:newPlayerLayer];使用上面的代码我可以做到这一点：
https://drive.google.com/open?id=0B2jCvCt5fosyOVNOcGZ1MU1laEU
我知道用于过滤组合框架的customVideoCompositor类。我试过了，但是如果我使用customVideoCompositor，那么我在合成层上的转换就会失败。另外，在customVideoCompositor中，我不知道如何过滤特定的曲目id。
如果有人有任何文档、链接或建议，请在这篇文章中继续前进。
回答 2
Stack Overflow用户
发布于 2016-09-15 12:17:46
在添加位于屏幕中心的第二个视频层之前，添加以下代码
UIVisualEffect *blurEffect;
blurEffect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleExtraLight];//Change the effect which you want.
UIVisualEffectView *visualEffectView;
visualEffectView = [[UIVisualEffectView alloc] initWithEffect:blurEffect];
visualEffectView.frame = self.view.bounds;
[self.view addSubview:visualEffectView];在Swift中
let blurEffect = UIBlurEffect(style: UIBlurEffectStyle.Light) //Change the style which suites you
let blurEffectView = UIVisualEffectView(effect: blurEffect)
blurEffectView.frame = view.bounds
blurEffectView.autoresizingMask = [.FlexibleWidth, .FlexibleHeight] // for supporting device rotation
view.addSubview(blurEffectView)Stack Overflow用户
发布于 2016-09-15 12:15:29
一种方法是使用两个不同的AVPlayer和一个a blur overlay view：backgroundLayer -> bluer overlay view -> frontLayer。你只需要确保两个玩家同时开始和停止。
另一种选择是使用1个AVPlayer和一个time observer。在每一帧上提取frontLayer的当前图像，对其进行模糊处理，并在backgroundLayer中显示。模糊功能可以在上面提供的相同链接中找到。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/39313688
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