如何输出CIFilter到相机视图？

我只是从Objective-C开始，我试图创build一个简单的应用程序，它显示相机视图上的模糊效果。 我得到了相机输出与AVFoundation框架一起工作。 现在，我试图挂钩核心图像框架，但不知道如何，苹果文档是我困惑，search指南和教程在线导致没有结果。 先谢谢您的帮助。

#import "ViewController.h" #import <AVFoundation/AVFoundation.h> @interface ViewController () @property (strong ,nonatomic) CIContext *context; @end @implementation ViewController AVCaptureSession *session; AVCaptureStillImageOutput *stillImageOutput; -(CIContext *)context { if(!_context) { _context = [CIContext contextWithOptions:nil]; } return _context; } - (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib. } -(void)viewWillAppear:(BOOL)animated{ session = [[AVCaptureSession alloc] init]; [session setSessionPreset:AVCaptureSessionPresetPhoto]; AVCaptureDevice *inputDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo]; NSError *error; AVCaptureDeviceInput *deviceInput = [AVCaptureDeviceInput deviceInputWithDevice:inputDevice error:&error]; if ([session canAddInput:deviceInput]) { [session addInput:deviceInput]; } AVCaptureVideoPreviewLayer *previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session]; [previewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill]; CALayer *rootLayer = [[self view] layer]; [rootLayer setMasksToBounds:YES]; CGRect frame = self.imageView.frame; [previewLayer setFrame:frame]; [previewLayer.connection setVideoOrientation:AVCaptureVideoOrientationLandscapeRight]; [rootLayer insertSublayer:previewLayer atIndex:0]; stillImageOutput = [[AVCaptureStillImageOutput alloc] init]; NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys:AVVideoCodecJPEG, AVVideoCodecKey, nil]; [stillImageOutput setOutputSettings:outputSettings]; [session addOutput:stillImageOutput]; [session startRunning]; } @end 

Answer 1

这是让你开始的东西。 这是来自以下链接的代码的更新版本。
https://gist.github.com/eladb/9662102

诀窍是使用AVCaptureVideoDataOutputSampleBufferDelegate 。
有了这个委托，你可以使用imageWithCVPixelBuffer从你的相机缓冲区中构build一个CIImage 。

现在虽然我试图找出如何减less滞后。 我会尽快更新。

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更新：延迟现在是最小的，并在一些效果不明显。 不幸的是，模糊是最慢的一个。 你可能想看看vImage 。

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 #import "ViewController.h" #import <CoreImage/CoreImage.h> #import <AVFoundation/AVFoundation.h> @interface ViewController () { } @property (strong, nonatomic) CIContext *coreImageContext; @property (strong, nonatomic) AVCaptureSession *cameraSession; @property (strong, nonatomic) AVCaptureVideoDataOutput *videoOutput; @property (strong, nonatomic) UIView *blurCameraView; @property (strong, nonatomic) CIFilter *filter; @property BOOL cameraOpen; @end @implementation ViewController - (void)viewDidLoad { [super viewDidLoad]; self.blurCameraView = [[UIView alloc]initWithFrame:[[UIScreen mainScreen] bounds]]; [self.view addSubview:self.blurCameraView]; //setup filter self.filter = [CIFilter filterWithName:@"CIGaussianBlur"]; [self.filter setDefaults]; [self.filter setValue:@(3.0f) forKey:@"inputRadius"]; [self setupCamera]; [self openCamera]; // Do any additional setup after loading the view, typically from a nib. } - (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated. } - (void)setupCamera { self.coreImageContext = [CIContext contextWithOptions:@{kCIContextUseSoftwareRenderer : @(YES)}]; // session self.cameraSession = [[AVCaptureSession alloc] init]; [self.cameraSession setSessionPreset:AVCaptureSessionPresetLow]; [self.cameraSession commitConfiguration]; // input AVCaptureDevice *shootingCamera = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo]; AVCaptureDeviceInput *shootingDevice = [AVCaptureDeviceInput deviceInputWithDevice:shootingCamera error:NULL]; if ([self.cameraSession canAddInput:shootingDevice]) { [self.cameraSession addInput:shootingDevice]; } // video output self.videoOutput = [[AVCaptureVideoDataOutput alloc] init]; self.videoOutput.alwaysDiscardsLateVideoFrames = YES; [self.videoOutput setSampleBufferDelegate:self queue:dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0)]; if ([self.cameraSession canAddOutput:self.videoOutput]) { [self.cameraSession addOutput:self.videoOutput]; } if (self.videoOutput.connections.count > 0) { AVCaptureConnection *connection = self.videoOutput.connections[0]; connection.videoOrientation = AVCaptureVideoOrientationPortrait; } self.cameraOpen = NO; } - (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection { // Get a CMSampleBuffer's Core Video image buffer for the media data CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer); // turn buffer into an image we can manipulate CIImage *result = [CIImage imageWithCVPixelBuffer:imageBuffer]; // filter [self.filter setValue:result forKey:@"inputImage"]; // render image CGImageRef blurredImage = [self.coreImageContext createCGImage:self.filter.outputImage fromRect:result.extent]; dispatch_async(dispatch_get_main_queue(), ^{ self.blurCameraView.layer.contents = (__bridge id)blurredImage; CGImageRelease(blurredImage); }); } - (void)openCamera { if (self.cameraOpen) { return; } self.blurCameraView.alpha = 0.0f; [self.cameraSession startRunning]; [self.view layoutIfNeeded]; [UIView animateWithDuration:3.0f animations:^{ self.blurCameraView.alpha = 1.0f; }]; self.cameraOpen = YES; }