ios - 这是OC版实时人脸检测的代码，今天写了一天了，不知道为什么没成功？

我在各种社区寻求帮助最终搞定了，这是全部代码，有些不需要的可以删掉，关键代码还是sampletoimage的方法和capturoutput的方法。

#import "ViewController.h"
#import <AVFoundation/AVFoundation.h>
#import "FaceppLocalDetectorSDK/FaceppLocalDetector.h"
#import "FaceppSDK_ARC/FaceppAPI.h"

@interface ViewController ()<AVCaptureVideoDataOutputSampleBufferDelegate>{
    AVCaptureSession *captureSession;
    AVCaptureDevice *captureDevice;
    AVCaptureVideoPreviewLayer *previewLayer;
    FaceppLocalDetector *detector;
    UIImage *resultImage;
    UIImage *sample;
    BOOL isStart;
    
    UIImageView *screenShot;
    UIButton *photo;
    UIImageView *ok;
    UIImageView *circle;
    UIImageView *person;
    BOOL getSample;
}

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    getSample = NO;
    sample = [[UIImage alloc]init];
    [self initLocalDetector];
    isStart = NO;
    [self isStartTrue];
    
    captureSession = [[AVCaptureSession alloc]init];
    captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    captureSession.sessionPreset = AVCaptureSessionPresetMedium;
    
    NSArray *devices = [[NSArray alloc]init];
    devices = [AVCaptureDevice devices];
    for (AVCaptureDevice *device in devices) {
        if ([device hasMediaType:AVMediaTypeVideo]) {
            if (device.position == AVCaptureDevicePositionFront) {
                captureDevice = device;
                if (captureDevice != nil) {
                    NSLog(@"Capture Device found");
                    [self beginSession];
                }
            }
        }
    }
    [self initUI];
    // Do any additional setup after loading the view, typically from a nib.
}

-(void)initLocalDetector {
    NSDictionary *option = [NSDictionary dictionaryWithObjects:[NSArray arrayWithObjects:[NSNumber numberWithBool:NO],[NSNumber numberWithInt:20],FaceppDetectorAccuracyHigh, nil] forKeys:[NSArray arrayWithObjects:FaceppDetectorTracking,FaceppDetectorMinFaceSize,FaceppDetectorAccuracy, nil]];
    detector = [FaceppLocalDetector detectorOfOptions:option andAPIKey:@"8577edf0b2176bd9964fdfa8c9203659"];
    
}

-(void) isStartTrue {
    isStart = YES;
}

-(void)beginSession {
    AVCaptureDeviceInput *captureDeviceInput = [[AVCaptureDeviceInput alloc]initWithDevice:captureDevice error:nil];
    [captureSession addInput:captureDeviceInput];
    AVCaptureVideoDataOutput *output = [[AVCaptureVideoDataOutput alloc]init];
    dispatch_queue_t cameraQueue;
    cameraQueue = dispatch_queue_create("cameraQueue", DISPATCH_QUEUE_SERIAL);
    [output setSampleBufferDelegate:self queue:cameraQueue];
    NSDictionary *videoSettings = [[NSDictionary alloc] initWithObjectsAndKeys:[NSNumber numberWithUnsignedInt:kCVPixelFormatType_32BGRA],kCVPixelBufferPixelFormatTypeKey, nil];
    output.videoSettings = videoSettings;
    [captureSession addOutput:output];
    previewLayer = [[AVCaptureVideoPreviewLayer alloc]initWithSession:captureSession];
    previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
    previewLayer.frame = self.view.bounds;
    [self.view.layer addSublayer:previewLayer];
    [captureSession startRunning];
    
}

-(void)initUI {
    screenShot = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 110, 177.5)];
    ok = [[UIImageView alloc]initWithFrame:CGRectMake(self.view.bounds.size.width/2 +23, self.view.bounds.size.height-73, 20, 20)];
    person = [[UIImageView alloc]initWithFrame:CGRectMake(-70, self.view.bounds.size.height/2-180, 460, 540)];
    person.image = [UIImage imageNamed:@"redperson"];
    ok.image = [UIImage imageNamed:@"ok"];
    ok.hidden = YES;
    circle = [[UIImageView alloc]initWithFrame:CGRectMake(self.view.bounds.size.width/2 - 40, self.view.bounds.size.height-73, 80, 80)];
    circle.image = [UIImage imageNamed:@"redcircle"];
    photo = [[UIButton alloc]initWithFrame:CGRectMake(self.view.bounds.size.width/2 - 25, self.view.bounds.size.height-55, 50, 45)];
    [photo setBackgroundImage:[UIImage imageNamed:@"redphoto"] forState:UIControlStateNormal];
    [photo addTarget:self action:@selector(takePicture) forControlEvents:UIControlEventTouchUpInside];
    photo.enabled = NO;
    [self.view addSubview:photo];
    [self.view addSubview:ok];
    [self.view bringSubviewToFront:ok];
    [self.view bringSubviewToFront:photo];
    [self.view addSubview:screenShot];
    [self.view addSubview:person];
    [self.view bringSubviewToFront:person];
    [self.view bringSubviewToFront:screenShot];
    [self.view addSubview:circle];
    [self.view bringSubviewToFront:circle];
}


-(void)takePicture{
    
    getSample = YES;
}

-(void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection{

    if (isStart) {
        
        resultImage = [[UIImage alloc] init];


        UIImage *image = [self sampleBufferToImage:sampleBuffer];
        resultImage = [self fixOrientation:image];
        
        FaceppLocalResult *result = [detector detectWithImage:resultImage];
        for (size_t i=0; i<result.faces.count; i++) {
            FaceppLocalFace *face = [result.faces objectAtIndex:i];
//            NSLog(@"=========%@",NSStringFromCGRect(face.bounds));
        }

        if (result.faces.count ==1) {
            if (getSample) {
                sample = resultImage;
                getSample = !getSample;
                
            }
            dispatch_sync(dispatch_get_main_queue(), ^{
                photo.enabled = YES;
                ok.hidden = NO;
                screenShot.image = sample;
                circle.image = [UIImage imageNamed:@"bluecircle"];
                person.image = [UIImage imageNamed:@"blueperson"];
                [photo setBackgroundImage:[UIImage imageNamed:@"bluephoto"] forState:UIControlStateNormal];
            });
            
        }
        else{
            dispatch_sync(dispatch_get_main_queue(), ^{
                photo.enabled = NO;
                ok.hidden = YES;
                circle.image = [UIImage imageNamed:@"redcircle"];
                person.image = [UIImage imageNamed:@"redperson"];
                [photo setBackgroundImage:[UIImage imageNamed:@"redphoto"] forState:UIControlStateNormal];
            });
        }
//
    }
}


-(UIImage *)sampleBufferToImage:(CMSampleBufferRef)sampleBuffer{
    
    CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
    CIImage *ciImage = [CIImage imageWithCVPixelBuffer:imageBuffer];
    CIContext *temporaryContext = [CIContext contextWithOptions:nil];
    CGImageRef videoImage = [temporaryContext createCGImage:ciImage fromRect:CGRectMake(0, 0, CVPixelBufferGetWidth(imageBuffer), CVPixelBufferGetHeight(imageBuffer))];
    UIImage *result = [[UIImage alloc] initWithCGImage:videoImage scale:1.0 orientation:UIImageOrientationLeftMirrored];
    CGImageRelease(videoImage);
    
    return result;
    
}



- (UIImage *)fixOrientation:(UIImage *)aImage {
    
    // No-op if the orientation is already correct
    if (aImage.imageOrientation == UIImageOrientationUp)
        return aImage;
    
    // We need to calculate the proper transformation to make the image upright.
    // We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
    CGAffineTransform transform = CGAffineTransformIdentity;
    
    switch (aImage.imageOrientation) {
        case UIImageOrientationDown:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, aImage.size.width, aImage.size.height);
            transform = CGAffineTransformRotate(transform, M_PI);
            break;
            
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
            transform = CGAffineTransformTranslate(transform, aImage.size.width, 0);
            transform = CGAffineTransformRotate(transform, M_PI_2);
            break;
            
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, 0, aImage.size.height);
            transform = CGAffineTransformRotate(transform, -M_PI_2);
            break;
        default:
            break;
    }
    
    switch (aImage.imageOrientation) {
        case UIImageOrientationUpMirrored:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, aImage.size.width, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
            
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, aImage.size.height, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
        default:
            break;
    }
    
    // Now we draw the underlying CGImage into a new context, applying the transform
    // calculated above.
    CGContextRef ctx = CGBitmapContextCreate(NULL, aImage.size.width, aImage.size.height,
                                             CGImageGetBitsPerComponent(aImage.CGImage), 0,
                                             CGImageGetColorSpace(aImage.CGImage),
                                             CGImageGetBitmapInfo(aImage.CGImage));
    CGContextConcatCTM(ctx, transform);
    switch (aImage.imageOrientation) {
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            // Grr...
            CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.height,aImage.size.width), aImage.CGImage);
            break;
            
        default:
            CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.width,aImage.size.height), aImage.CGImage);
            break;
    }
    
    // And now we just create a new UIImage from the drawing context
    CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
    UIImage *img = [UIImage imageWithCGImage:cgimg];
    CGContextRelease(ctx);
    CGImageRelease(cgimg);
    return img;
}



- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    [captureSession stopRunning];
    // Dispose of any resources that can be recreated.
}

@end