如何用AVFoundation框架实现相机拍照和录制视频

#import "CustomeCameraViewController.h" 
#import  
#import  
 
@interface CustomeCameraViewController () 
 
{ 
 // AVCaptureSession对象来执行输入设备和输出设备之间的数据传递 
 AVCaptureSession *iSession; 
 //当前设备 
 AVCaptureDevice *iDevice; 
 //输入设备 
 AVCaptureDeviceInput *iDeviceInput; 
 //照片输出流 
 AVCaptureStillImageOutput *iStillImageOutput; 
 //预览图层 
 AVCaptureVideoPreviewLayer *iPreviewLayer; 
  
} 

-(void)viewDidLoad { 
 [super viewDidLoad]; 
  
 //点击屏幕对焦 
 UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(focusTap:)]; 
 [self.view addGestureRecognizer:tap]; 
  
  
 iSession = [[AVCaptureSession alloc]init]; 
  
 NSArray *deviceArray = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo]; 
 for (AVCaptureDevice *device in deviceArray) { 
   
  //AVCaptureDevicePositionBack 后置摄像头 
  //AVCaptureDevicePositionFront 前置摄像头 
  if (device.position == AVCaptureDevicePositionBack) { 
   iDevice = device; 
  } 
 } 
  
  
 iSession.sessionPreset = [self getSessionPresetForDevice:iDevice]; 
  
 iDeviceInput = [[AVCaptureDeviceInput alloc]initWithDevice:iDevice error:nil]; 
  
  
 ////输出设置。AVVideoCodecJPEG 输出jpeg格式图片 
 iStillImageOutput = [[AVCaptureStillImageOutput alloc]init]; 
 NSDictionary *outputDic = [NSDictionary dictionaryWithObjectsAndKeys:AVVideoCodecJPEG,AVVideoCodecKey, nil nil]; 
 [iStillImageOutput setOutputSettings:outputDic]; 
  
  
 //更改这个设备设置的时候必须先锁定设备，修改完后再解锁，否则崩溃 
 [iDevice lockForConfiguration:nil]; 
 if ([iDevice isFlashModeSupported:AVCaptureFlashModeOff]) { 
  [iDevice setFlashMode:AVCaptureFlashModeOff]; 
 } 
 if ([iDevice isFocusModeSupported:AVCaptureFocusModeAutoFocus]) { 
  [iDevice setFocusMode:AVCaptureFocusModeAutoFocus]; 
 } 
 if ([iDevice isWhiteBalanceModeSupported:AVCaptureWhiteBalanceModeAutoWhiteBalance]) { 
  [iDevice setWhiteBalanceMode:AVCaptureWhiteBalanceModeAutoWhiteBalance]; 
 } 
 [iDevice unlockForConfiguration]; 
  
 if ([iSession canAddInput:iDeviceInput]) { 
  [iSession addInput:iDeviceInput]; 
 } 
 if ([iSession canAddOutput:iStillImageOutput]) { 
  [iSession addOutput:iStillImageOutput]; 
 } 
 if ([iSession canAddOutput:iVideoOutput]) { 
  [iSession addOutput:iVideoOutput]; 
 } 
  
 //初始化预览图层 
 iPreviewLayer = [[AVCaptureVideoPreviewLayer alloc]initWithSession:iSession]; 
 [iPreviewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill]; 
 iPreviewLayer.frame = CGRectMake(0, 60, [UIScreen mainScreen].bounds.size.width, [UIScreen mainScreen].bounds.size.height-160); 
 [self.iCameraView.layer addSublayer:iPreviewLayer]; 
  
 [iSession startRunning];  
  
}

//拍照 
-(void)takePictures{ 
 AVCaptureConnection *connection = [iStillImageOutput connectionWithMediaType:AVMediaTypeVideo]; 
 if (!connection) { 
  NSLog(@"失败"); 
  return; 
 } 
 //设置焦距 
 [connection setVideoScaleAndCropFactor:1]; 
  
 [iStillImageOutput captureStillImageAsynchronouslyFromConnection:connection completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) { 
  if (imageDataSampleBuffer==NULL) { 
   NSLog(@"NUll"); 
   return ; 
  } 
   
  NSData *data = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer]; 
  UIImage *image = [UIImage imageWithData:data]; 
   
   
 }]; 
}

-(NSString *)getSessionPresetForDevice:(AVCaptureDevice *)device{ 
 if ([device supportsAVCaptureSessionPreset:AVCaptureSessionPreset3840x2160]) { 
  return AVCaptureSessionPreset3840x2160; 
 } else if([device supportsAVCaptureSessionPreset:AVCaptureSessionPreset1920x1080]){ 
  return AVCaptureSessionPreset1920x1080; 
 } else if ([device supportsAVCaptureSessionPreset:AVCaptureSessionPreset1280x720]){ 
  return AVCaptureSessionPreset1280x720; 
 } else if ([device supportsAVCaptureSessionPreset:AVCaptureSessionPreset640x480]){ 
  return AVCaptureSessionPreset640x480; 
 } else if ([device supportsAVCaptureSessionPreset:AVCaptureSessionPreset352x288]){ 
  return AVCaptureSessionPreset352x288; 
 } else if ([device supportsAVCaptureSessionPreset:AVCaptureSessionPresetHigh]){ 
  return AVCaptureSessionPresetHigh; 
 } else if ([device supportsAVCaptureSessionPreset:AVCaptureSessionPresetMedium]){ 
  return AVCaptureSessionPresetMedium; 
 } else{ 
  return AVCaptureSessionPresetLow; 
 } 
}

- (IBAction)iFlashBtn:(id)sender { 
  
 [iDevice lockForConfiguration:nil]; 
 if (iDevice.flashMode == AVCaptureFlashModeOff) { 
  if ([iDevice isFlashModeSupported:AVCaptureFlashModeOn]) { 
   [iDevice setFlashMode:AVCaptureFlashModeOn]; 
    
   [self.iFlashBtn setBackgroundImage:[UIImage imageNamed:@"flashBtn"] forState:UIControlStateNormal]; 
  } 
 } else if (iDevice.flashMode == AVCaptureFlashModeOn){ 
  if ([iDevice isFlashModeSupported:AVCaptureFlashModeOff]) { 
   [iDevice setFlashMode:AVCaptureFlashModeOff]; 
    
    [self.iFlashBtn setBackgroundImage:[UIImage imageNamed:@"flashOffBtn"] forState:UIControlStateNormal]; 
  } 
 } 
 [iDevice unlockForConfiguration]; 
  
}

- (IBAction)iChangeBtn:(id)sender { 
  
  
 NSArray *array = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo]; 
 AVCaptureDevice *newDevice = nil; 
 AVCaptureDeviceInput *newDeviceInput = nil; 
  
 CATransition *animation = [CATransition animation]; 
 animation.duration = 0.5f; 
 animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]; 
 animation.type = @"oglFlip"; 
  
 if (iDevice.position == AVCaptureDevicePositionBack) { 
  animation.subtype = kCATransitionFromLeft; 
  for (AVCaptureDevice *device in array) { 
   if (device.position == AVCaptureDevicePositionFront) { 
    newDevice = device; 
   } 
  } 
 } else if (iDevice.position == AVCaptureDevicePositionFront){ 
  animation.subtype = kCATransitionFromRight; 
  for (AVCaptureDevice *device in array) { 
   if (device.position == AVCaptureDevicePositionBack) { 
    newDevice = device; 
   } 
  } 
 } 
  
 newDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:newDevice error:nil]; 
 [iPreviewLayer addAnimation:animation forKey:nil]; 
 if (newDeviceInput!=nil) { 
  [iSession beginConfiguration]; 
  [iSession removeInput:iDeviceInput]; 
   iSession.sessionPreset = [self getSessionPresetForDevice:newDevice]; 
  if ([iSession canAddInput:newDeviceInput]) { 
   [iSession addInput:newDeviceInput]; 
   iDeviceInput = newDeviceInput; 
   iDevice = newDevice; 
  } else { 
   [iSession addInput:iDeviceInput]; 
  } 
  [iSession commitConfiguration]; 
 } 
  
  
}

//点击屏幕对焦 
-(void)focusTap:(UIGestureRecognizer *)tap{ 
 CGPoint tapPoint = [tap locationInView:self.view]; 
  
  
 float Y = tapPoint.y; 
 if (Y<60 || Y>([UIScreen mainScreen].bounds.size.height-100)) { 
  return; 
 } 
  
 [iDevice lockForConfiguration:nil]; 
 if ([iDevice isFocusModeSupported:AVCaptureFocusModeAutoFocus]) { 
  [iDevice setFocusPointOfInterest:CGPointMake(tapPoint.x/self.view.frame.origin.x, tapPoint.y/self.view.frame.origin.y)]; 
  [iDevice setFocusMode:AVCaptureFocusModeAutoFocus]; 
 } 
 [iDevice unlockForConfiguration]; 
  
 self.iFocusImgView.center = tapPoint; 
 self.iFocusImgView.hidden = NO; 
 [UIView animateWithDuration:0.3 animations:^{ 
  self.iFocusImgView.transform = CGAffineTransformMakeScale(1.25, 1.25); 
 }completion:^(BOOL finished) { 
  [UIView animateWithDuration:0.5 animations:^{ 
   self.iFocusImgView.transform = CGAffineTransformIdentity; 
  } completion:^(BOOL finished) { 
   self.iFocusImgView.hidden = YES; 
  }]; 
 }]; 
}