iOS AVCaptureSession实现视频录制功能

#import "RecordingVideoViewController.h" #import <AVFoundation/AVFoundation.h> #import <AssetsLibrary/AssetsLibrary.h>  @interface RecordingVideoViewController ()<AVCaptureFileOutputRecordingDelegate>  //会话 负责输入和输出设备之间的数据传递 @property (strong,nonatomic) AVCaptureSession  *captureSession; //设备输入 负责从AVCaptureDevice获得输入数据 @property (strong,nonatomic) AVCaptureDeviceInput  *videoCaptureDeviceInput; @property (strong,nonatomic) AVCaptureDeviceInput  *audioCaptureDeviceInput; //视频输出流 @property (strong,nonatomic) AVCaptureMovieFileOutput  *captureMovieFileOutput; //相机拍摄预览图层 @property (strong,nonatomic) AVCaptureVideoPreviewLayer  *captureVideoPreviewLayer;  //自定义UI控件容器 @property (strong,nonatomic) UIView  *viewContainer; //聚焦图标 @property (strong,nonatomic) UIImageView  *focusCursor; //录制时长 @property (strong,nonatomic) UILabel  *timeLabel; //切换前后摄像头 @property (strong,nonatomic) UIButton  *switchCameraBtn; //改变焦距 @property (strong,nonatomic) UIButton  *scaleBtn; //计时器 @property (strong,nonatomic) NSTimer  *timer;   @end  @implementation RecordingVideoViewController {  @private   NSInteger _num;   CGFloat _kCameraScale; }   - (UIView *)viewContainer {   if (!_viewContainer) {     _viewContainer = [[UIView alloc] initWithFrame:[UIScreen mainScreen].bounds];          UIButton *takeButton = [UIButton buttonWithType:UIButtonTypeCustom];     takeButton.backgroundColor = [UIColor redColor];     [takeButton setTitle:@"start" forState:UIControlStateNormal];     [takeButton addTarget:self action:@selector(takeButtonClick:) forControlEvents:UIControlEventTouchUpInside];             _timeLabel = [[UILabel alloc] init];     _timeLabel.textColor = [UIColor redColor];     _timeLabel.textAlignment = NSTextAlignmentCenter;     _timeLabel.font = [UIFont boldSystemFontOfSize:20];     _timeLabel.text = @"00:00";               _switchCameraBtn = [UIButton buttonWithType:UIButtonTypeCustom];     [_switchCameraBtn setTitle:@"switch" forState:UIControlStateNormal];     _switchCameraBtn.backgroundColor = [UIColor redColor];     [_switchCameraBtn addTarget:self action:@selector(switchCameraBtnClick) forControlEvents:UIControlEventTouchUpInside];          _scaleBtn = [UIButton buttonWithType:UIButtonTypeCustom];     [_scaleBtn setTitle:@"1X" forState:UIControlStateNormal];     _scaleBtn.backgroundColor = [UIColor redColor];     [_scaleBtn addTarget:self action:@selector(scaleBtnClick:) forControlEvents:UIControlEventTouchUpInside];          [_viewContainer addSubview:takeButton];     [_viewContainer addSubview:_timeLabel];     [_viewContainer addSubview:_scaleBtn];     [_viewContainer addSubview:_switchCameraBtn];     [takeButton mas_makeConstraints:^(MASConstraintMaker *make) {       make.size.mas_equalTo(CGSizeMake(60, 40));       make.centerX.mas_equalTo(_viewContainer);       make.bottom.mas_equalTo(_viewContainer).offset(-64);     }];     [_timeLabel mas_makeConstraints:^(MASConstraintMaker *make) {       make.centerX.mas_equalTo(_viewContainer);       make.height.mas_equalTo(@30);       make.top.mas_equalTo(_viewContainer);     }];     [_scaleBtn mas_makeConstraints:^(MASConstraintMaker *make) {       make.size.mas_equalTo(CGSizeMake(60, 40));       make.left.mas_equalTo(_viewContainer).offset(10);       make.top.mas_equalTo(_viewContainer);     }];     [_switchCameraBtn mas_makeConstraints:^(MASConstraintMaker *make) {       make.size.mas_equalTo(CGSizeMake(60, 40));       make.top.mas_equalTo(_viewContainer);       make.right.mas_equalTo(_viewContainer).offset(-10);     }];          _focusCursor = [[UIImageView alloc] init];     kBorder(_focusCursor, 1, [UIColor yellowColor]);     _focusCursor.alpha = 0;     [_viewContainer addSubview:self.focusCursor];     [_focusCursor mas_makeConstraints:^(MASConstraintMaker *make) {       make.size.mas_equalTo(CGSizeMake(40, 40));       make.center.mas_equalTo(_viewContainer);     }];    }   return _viewContainer; }  - (void)viewDidLoad {   [super viewDidLoad];      self.title = @"视频录制";   _kCameraScale = 1.0f;   //初始化会话对象   _captureSession = [[AVCaptureSession alloc] init];   if ([_captureSession canSetSessionPreset:AVCaptureSessionPreset1280x720]) {     _captureSession.sessionPreset = AVCaptureSessionPreset1280x720;   }         NSError *error = nil;    //获取视频输入对象   AVCaptureDevice *videoCaptureDevice = [self cameraDeviceWithPosition:(AVCaptureDevicePositionBack)];   if (!videoCaptureDevice) {     NSLog(@"获取后置摄像头失败！");     return;   }   _videoCaptureDeviceInput = [[AVCaptureDeviceInput alloc] initWithDevice:videoCaptureDevice error:&error];   if (error) {     NSLog(@"取得视频设备输入对象时出错");     return;   }         //获取音频输入对象   AVCaptureDevice *audioCatureDevice = [[AVCaptureDevice devicesWithMediaType:AVMediaTypeAudio] firstObject];   _audioCaptureDeviceInput = [[AVCaptureDeviceInput alloc] initWithDevice:audioCatureDevice error:&error];   if (error) {     NSLog(@"取得音频设备输入对象时出错");     return;   }      //初始化设备输出对象   _captureMovieFileOutput = [[AVCaptureMovieFileOutput alloc] init];      //将设备输入添加到会话中   if ([_captureSession canAddInput:_videoCaptureDeviceInput]) {     [_captureSession addInput:_videoCaptureDeviceInput];     [_captureSession addInput:_audioCaptureDeviceInput];          //防抖功能     AVCaptureConnection *captureConnection = [_captureMovieFileOutput connectionWithMediaType:AVMediaTypeAudio];     if ([captureConnection isVideoStabilizationSupported]) {       captureConnection.preferredVideoStabilizationMode = AVCaptureVideoStabilizationModeAuto;     }   }      //将设备输出添加到会话中   if ([_captureSession canAddOutput:_captureMovieFileOutput]) {     [_captureSession addOutput:_captureMovieFileOutput];   }         //创建视频预览图层   _captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:_captureSession];   self.viewContainer.layer.masksToBounds = YES;   _captureVideoPreviewLayer.frame = self.viewContainer.bounds;   _captureVideoPreviewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;   [self.view.layer addSublayer:_captureVideoPreviewLayer];      //显示自定义控件   [self.view addSubview:self.viewContainer];      //添加点按聚焦手势   UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tapScreen:)];   [self.viewContainer addGestureRecognizer:tapGesture];    }  -(void)viewDidAppear:(BOOL)animated{   [super viewDidAppear:animated];   [self.captureSession startRunning]; }  -(void)viewDidDisappear:(BOOL)animated{   [super viewDidDisappear:animated];   [self.captureSession stopRunning];   [self.timer invalidate];   self.timer = nil; }  - (void)viewWillDisappear:(BOOL)animated {   [super viewWillDisappear:animated];   [self.captureVideoPreviewLayer setAffineTransform:CGAffineTransformMakeScale(1, 1)]; }  - (void)didReceiveMemoryWarning {   [super didReceiveMemoryWarning]; }  //开始 + 暂停录制 - (void)takeButtonClick:(UIButton *)sender {   if ([self.captureMovieFileOutput isRecording]) {     [self.captureMovieFileOutput stopRecording];          [self.navigationController popViewControllerAnimated:YES];        } else {     AVCaptureConnection *captureConnection = [self.captureMovieFileOutput connectionWithMediaType:AVMediaTypeVideo];     captureConnection.videoOrientation = [self.captureVideoPreviewLayer connection].videoOrientation;          NSString *filePath = [NSTemporaryDirectory() stringByAppendingPathComponent:@"Movie.mov"];     NSLog(@"%@",filePath);     [self.captureMovieFileOutput startRecordingToOutputFileURL:[NSURL fileURLWithPath:filePath] recordingDelegate:self];               self.switchCameraBtn.hidden = YES;          sender.backgroundColor = [UIColor greenColor];     [sender setTitle:@"stop" forState:UIControlStateNormal];          self.timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(timeAction) userInfo:nil repeats:YES];     [self.timer setFireDate:[NSDate distantPast]];   } }  //切换摄像头 - (void)switchCameraBtnClick {   AVCaptureDevicePosition currentPosition = self.videoCaptureDeviceInput.device.position;   AVCaptureDevicePosition toPosition;   if (currentPosition == AVCaptureDevicePositionUnspecified ||     currentPosition == AVCaptureDevicePositionFront) {     toPosition = AVCaptureDevicePositionBack;   } else {     toPosition = AVCaptureDevicePositionFront;   }      AVCaptureDevice *toCapturDevice = [self cameraDeviceWithPosition:toPosition];   if (!toCapturDevice) {     NSLog(@"获取要切换的设备失败");     return;   }      NSError *error = nil;   AVCaptureDeviceInput *toVideoDeviceInput = [[AVCaptureDeviceInput alloc] initWithDevice:toCapturDevice error:&error];   if (error) {     NSLog(@"获取要切换的设备输入失败");     return;   }      //改变会话配置   [self.captureSession beginConfiguration];      [self.captureSession removeInput:self.videoCaptureDeviceInput];   if ([self.captureSession canAddInput:toVideoDeviceInput]) {     [self.captureSession addInput:toVideoDeviceInput];          self.videoCaptureDeviceInput = toVideoDeviceInput;   }   //提交会话配置   [self.captureSession commitConfiguration]; }   //点按手势 - (void)tapScreen:(UITapGestureRecognizer *)tap {   CGPoint point = [tap locationInView:self.viewContainer];      //将界面point对应到摄像头point   CGPoint cameraPoint = [self.captureVideoPreviewLayer captureDevicePointOfInterestForPoint:point];    //设置聚光动画   self.focusCursor.center = point;   self.focusCursor.transform = CGAffineTransformMakeScale(1.5, 1.5);   self.focusCursor.alpha = 1.0f;   [UIView animateWithDuration:1 animations:^{     self.focusCursor.transform = CGAffineTransformIdentity;   } completion:^(BOOL finished) {     self.focusCursor.alpha = 0.0f;    }];      //设置聚光点坐标   [self focusWithMode:AVCaptureFocusModeAutoFocus exposureMode:AVCaptureExposureModeAutoExpose atPoint:cameraPoint];  }   /**设置聚焦点*/ -(void)focusWithMode:(AVCaptureFocusMode)focusMode exposureMode:(AVCaptureExposureMode)exposureMode atPoint:(CGPoint)point{      AVCaptureDevice *captureDevice= [self.videoCaptureDeviceInput device];   NSError *error = nil;   //设置设备属性必须先解锁 然后加锁   if ([captureDevice lockForConfiguration:&error]) {          if ([captureDevice isFocusModeSupported:focusMode]) {       [captureDevice setFocusMode:focusMode];     }     if ([captureDevice isFocusPointOfInterestSupported]) {       [captureDevice setFocusPointOfInterest:point];     }     //    //曝光     //    if ([captureDevice isExposureModeSupported:exposureMode]) {     //      [captureDevice setExposureMode:exposureMode];     //    }     //    if ([captureDevice isExposurePointOfInterestSupported]) {     //      [captureDevice setExposurePointOfInterest:point];     //    }     //    //闪光灯模式     //    if ([captureDevice isFlashModeSupported:AVCaptureFlashModeAuto]) {     //      [captureDevice setFlashMode:AVCaptureFlashModeAuto];     //    }          //加锁     [captureDevice unlockForConfiguration];        }else{     NSLog(@"设置设备属性过程发生错误，错误信息：%@",error.localizedDescription);   } }    //调整焦距 -(void)scaleBtnClick:(UIButton *)sender {   _kCameraScale += 0.5;   if(_kCameraScale > 3.0) {     _kCameraScale = 1.0;   }   //改变焦距   AVCaptureDevice *videoDevice = self.videoCaptureDeviceInput.device;   NSError *error = nil;   if ([videoDevice lockForConfiguration:&error]) {          [videoDevice setVideoZoomFactor:_kCameraScale];          [videoDevice unlockForConfiguration];          [sender setTitle:[NSString stringWithFormat:@"%lgX",_kCameraScale] forState:UIControlStateNormal];      [CATransaction begin];     [CATransaction setAnimationDuration:0.25];     [self.captureVideoPreviewLayer setAffineTransform:CGAffineTransformMakeScale(_kCameraScale, _kCameraScale)];     [CATransaction commit];        } else {     NSLog(@"修改设备属性失败!")   } }    #pragma mark -------- AVCaptureFileOutputRecordingDelegate ---------- - (void)captureOutput:(AVCaptureFileOutput *)captureOutput didStartRecordingToOutputFileAtURL:(NSURL *)fileURL fromConnections:(NSArray *)connections {   NSLog(@"开始录制"); }  - (void)captureOutput:(AVCaptureFileOutput *)captureOutput didFinishRecordingToOutputFileAtURL:(NSURL *)outputFileURL fromConnections:(NSArray *)connections error:(NSError *)error {   NSLog(@"录制结束");   ALAssetsLibrary *assetsLibrary = [[ALAssetsLibrary alloc] init];   [assetsLibrary writeVideoAtPathToSavedPhotosAlbum:outputFileURL completionBlock:^(NSURL *assetURL, NSError *error) {     if (error) {       NSLog(@"保存视频到相簿过程中发生错误，错误信息：%@",error.localizedDescription);     }   }]; }  //录制计时 - (void)timeAction {   self.timeLabel.text = [NSString stringWithFormat:@"%.2ld:%.2ld",_num/60,_num%60];   _num ++; }   /**取得指定位置的摄像头*/ - (AVCaptureDevice *)cameraDeviceWithPosition:(AVCaptureDevicePosition )position{   NSArray *cameras = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];   for (AVCaptureDevice *camera in cameras) {     if ([camera position] == position) {       return camera;     }   }   return nil; }   @end 

#import "VideoTestViewController.h" #import <AVFoundation/AVFoundation.h> #import <AssetsLibrary/AssetsLibrary.h>  typedef void(^PropertyChangeBlock)(AVCaptureDevice *captureDevice);  @interface VideoTestViewController ()<AVCaptureFileOutputRecordingDelegate>//视频文件输出代理  @property (strong,nonatomic) AVCaptureSession *captureSession;//负责输入和输出设备之间的数据传递 @property (strong,nonatomic) AVCaptureDeviceInput *captureDeviceInput;//负责从AVCaptureDevice获得输入数据 @property (strong,nonatomic) AVCaptureMovieFileOutput *captureMovieFileOutput;//视频输出流 @property (strong,nonatomic) AVCaptureVideoPreviewLayer *captureVideoPreviewLayer;//相机拍摄预览图层  @property (assign,nonatomic) BOOL enableRotation;//是否允许旋转（注意在视频录制过程中禁止屏幕旋转） @property (assign,nonatomic) CGRect *lastBounds;//旋转的前大小 @property (assign,nonatomic) UIBackgroundTaskIdentifier backgroundTaskIdentifier;//后台任务标识 @property (strong,nonatomic) UIView *viewContainer; @property (strong,nonatomic) UIButton *takeButton;//拍照按钮 @property (strong,nonatomic) UIImageView *focusCursor; //聚焦光标   @end  @implementation VideoTestViewController  #pragma mark - 控制器视图方法 - (void)viewDidLoad {   [super viewDidLoad]; }  -(void)viewWillAppear:(BOOL)animated{   [super viewWillAppear:animated];      //初始化会话   _captureSession=[[AVCaptureSession alloc]init];   if ([_captureSession canSetSessionPreset:AVCaptureSessionPreset1280x720]) {//设置分辨率     _captureSession.sessionPreset=AVCaptureSessionPreset1280x720;   }   //获得输入设备   AVCaptureDevice *captureDevice=[self getCameraDeviceWithPosition:AVCaptureDevicePositionBack];//取得后置摄像头   if (!captureDevice) {     NSLog(@"取得后置摄像头时出现问题.");     return;   }   //添加一个音频输入设备   AVCaptureDevice *audioCaptureDevice=[[AVCaptureDevice devicesWithMediaType:AVMediaTypeAudio] firstObject];         NSError *error=nil;   //根据输入设备初始化设备输入对象，用于获得输入数据   _captureDeviceInput=[[AVCaptureDeviceInput alloc]initWithDevice:captureDevice error:&error];   if (error) {     NSLog(@"取得设备输入对象时出错，错误原因：%@",error.localizedDescription);     return;   }   AVCaptureDeviceInput *audioCaptureDeviceInput=[[AVCaptureDeviceInput alloc]initWithDevice:audioCaptureDevice error:&error];   if (error) {     NSLog(@"取得设备输入对象时出错，错误原因：%@",error.localizedDescription);     return;   }   //初始化设备输出对象，用于获得输出数据   _captureMovieFileOutput=[[AVCaptureMovieFileOutput alloc]init];      //将设备输入添加到会话中   if ([_captureSession canAddInput:_captureDeviceInput]) {     [_captureSession addInput:_captureDeviceInput];     [_captureSession addInput:audioCaptureDeviceInput];     AVCaptureConnection *captureConnection=[_captureMovieFileOutput connectionWithMediaType:AVMediaTypeVideo];     if ([captureConnection isVideoStabilizationSupported ]) {       captureConnection.preferredVideoStabilizationMode=AVCaptureVideoStabilizationModeAuto;     }   }      //将设备输出添加到会话中   if ([_captureSession canAddOutput:_captureMovieFileOutput]) {     [_captureSession addOutput:_captureMovieFileOutput];   }      //创建视频预览层，用于实时展示摄像头状态   _captureVideoPreviewLayer=[[AVCaptureVideoPreviewLayer alloc]initWithSession:self.captureSession];      CALayer *layer=self.viewContainer.layer;   layer.masksToBounds=YES;      _captureVideoPreviewLayer.frame=layer.bounds;   _captureVideoPreviewLayer.videoGravity=AVLayerVideoGravityResizeAspectFill;//填充模式   //将视频预览层添加到界面中   //[layer addSublayer:_captureVideoPreviewLayer];   [layer insertSublayer:_captureVideoPreviewLayer below:self.focusCursor.layer];      _enableRotation=YES;   [self addNotificationToCaptureDevice:captureDevice];   [self addGenstureRecognizer]; }  -(void)viewDidAppear:(BOOL)animated{   [super viewDidAppear:animated];   [self.captureSession startRunning]; }  -(void)viewDidDisappear:(BOOL)animated{   [super viewDidDisappear:animated];   [self.captureSession stopRunning]; }  - (void)didReceiveMemoryWarning {   [super didReceiveMemoryWarning]; }  -(BOOL)shouldAutorotate{   return self.enableRotation; }  ////屏幕旋转时调整视频预览图层的方向 //-(void)willTransitionToTraitCollection:(UITraitCollection *)newCollection withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator{ //  [super willTransitionToTraitCollection:newCollection withTransitionCoordinator:coordinator]; ////  NSLog(@"%i,%i",newCollection.verticalSizeClass,newCollection.horizontalSizeClass); //  UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation]; //  NSLog(@"%i",orientation); //  AVCaptureConnection *captureConnection=[self.captureVideoPreviewLayer connection]; //  captureConnection.videoOrientation=orientation; // //} //屏幕旋转时调整视频预览图层的方向 -(void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration{   AVCaptureConnection *captureConnection=[self.captureVideoPreviewLayer connection];   captureConnection.videoOrientation=(AVCaptureVideoOrientation)toInterfaceOrientation; } //旋转后重新设置大小 -(void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation{   _captureVideoPreviewLayer.frame=self.viewContainer.bounds; }  -(void)dealloc{   [self removeNotification]; } #pragma mark - UI方法 #pragma mark 视频录制 - (void)takeButtonClick:(UIButton *)sender {   //根据设备输出获得连接   AVCaptureConnection *captureConnection=[self.captureMovieFileOutput connectionWithMediaType:AVMediaTypeVideo];   //根据连接取得设备输出的数据   if (![self.captureMovieFileOutput isRecording]) {     self.enableRotation=NO;     //如果支持多任务则则开始多任务     if ([[UIDevice currentDevice] isMultitaskingSupported]) {       self.backgroundTaskIdentifier=[[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:nil];     }     //预览图层和视频方向保持一致     captureConnection.videoOrientation=[self.captureVideoPreviewLayer connection].videoOrientation;     NSString *outputFielPath=[NSTemporaryDirectory() stringByAppendingString:@"myMovie.mov"];     NSLog(@"save path is :%@",outputFielPath);     NSURL *fileUrl=[NSURL fileURLWithPath:outputFielPath];     [self.captureMovieFileOutput startRecordingToOutputFileURL:fileUrl recordingDelegate:self];   }   else{     [self.captureMovieFileOutput stopRecording];//停止录制   } } #pragma mark 切换前后摄像头 - (void)toggleButtonClick:(UIButton *)sender {   AVCaptureDevice *currentDevice=[self.captureDeviceInput device];   AVCaptureDevicePosition currentPosition=[currentDevice position];   [self removeNotificationFromCaptureDevice:currentDevice];   AVCaptureDevice *toChangeDevice;   AVCaptureDevicePosition toChangePosition=AVCaptureDevicePositionFront;   if (currentPosition==AVCaptureDevicePositionUnspecified||currentPosition==AVCaptureDevicePositionFront) {     toChangePosition=AVCaptureDevicePositionBack;   }   toChangeDevice=[self getCameraDeviceWithPosition:toChangePosition];   [self addNotificationToCaptureDevice:toChangeDevice];   //获得要调整的设备输入对象   AVCaptureDeviceInput *toChangeDeviceInput=[[AVCaptureDeviceInput alloc]initWithDevice:toChangeDevice error:nil];      //改变会话的配置前一定要先开启配置，配置完成后提交配置改变   [self.captureSession beginConfiguration];   //移除原有输入对象   [self.captureSession removeInput:self.captureDeviceInput];   //添加新的输入对象   if ([self.captureSession canAddInput:toChangeDeviceInput]) {     [self.captureSession addInput:toChangeDeviceInput];     self.captureDeviceInput=toChangeDeviceInput;   }   //提交会话配置   [self.captureSession commitConfiguration];    }  #pragma mark - 视频输出代理 -(void)captureOutput:(AVCaptureFileOutput *)captureOutput didStartRecordingToOutputFileAtURL:(NSURL *)fileURL fromConnections:(NSArray *)connections{   NSLog(@"开始录制..."); } -(void)captureOutput:(AVCaptureFileOutput *)captureOutput didFinishRecordingToOutputFileAtURL:(NSURL *)outputFileURL fromConnections:(NSArray *)connections error:(NSError *)error{   NSLog(@"视频录制完成.");   //视频录入完成之后在后台将视频存储到相簿   self.enableRotation=YES;   UIBackgroundTaskIdentifier lastBackgroundTaskIdentifier=self.backgroundTaskIdentifier;   self.backgroundTaskIdentifier=UIBackgroundTaskInvalid;   ALAssetsLibrary *assetsLibrary=[[ALAssetsLibrary alloc]init];   [assetsLibrary writeVideoAtPathToSavedPhotosAlbum:outputFileURL completionBlock:^(NSURL *assetURL, NSError *error) {     if (error) {       NSLog(@"保存视频到相簿过程中发生错误，错误信息：%@",error.localizedDescription);     }     if (lastBackgroundTaskIdentifier!=UIBackgroundTaskInvalid) {       [[UIApplication sharedApplication] endBackgroundTask:lastBackgroundTaskIdentifier];     }     NSLog(@"成功保存视频到相簿.");   }];    }  #pragma mark - 通知 /**  * 给输入设备添加通知  */ -(void)addNotificationToCaptureDevice:(AVCaptureDevice *)captureDevice{   //注意添加区域改变捕获通知必须首先设置设备允许捕获   [self changeDeviceProperty:^(AVCaptureDevice *captureDevice) {     captureDevice.subjectAreaChangeMonitoringEnabled=YES;   }];   NSNotificationCenter *notificationCenter= [NSNotificationCenter defaultCenter];   //捕获区域发生改变   [notificationCenter addObserver:self selector:@selector(areaChange:) name:AVCaptureDeviceSubjectAreaDidChangeNotification object:captureDevice]; } -(void)removeNotificationFromCaptureDevice:(AVCaptureDevice *)captureDevice{   NSNotificationCenter *notificationCenter= [NSNotificationCenter defaultCenter];   [notificationCenter removeObserver:self name:AVCaptureDeviceSubjectAreaDidChangeNotification object:captureDevice]; } /**  * 移除所有通知  */ -(void)removeNotification{   NSNotificationCenter *notificationCenter= [NSNotificationCenter defaultCenter];   [notificationCenter removeObserver:self]; }  -(void)addNotificationToCaptureSession:(AVCaptureSession *)captureSession{   NSNotificationCenter *notificationCenter= [NSNotificationCenter defaultCenter];   //会话出错   [notificationCenter addObserver:self selector:@selector(sessionRuntimeError:) name:AVCaptureSessionRuntimeErrorNotification object:captureSession]; }  /**  * 设备连接成功  *  * @param notification 通知对象  */ -(void)deviceConnected:(NSNotification *)notification{   NSLog(@"设备已连接..."); } /**  * 设备连接断开  *  * @param notification 通知对象  */ -(void)deviceDisconnected:(NSNotification *)notification{   NSLog(@"设备已断开."); } /**  * 捕获区域改变  *  * @param notification 通知对象  */ -(void)areaChange:(NSNotification *)notification{   NSLog(@"捕获区域改变..."); }  /**  * 会话出错  *  * @param notification 通知对象  */ -(void)sessionRuntimeError:(NSNotification *)notification{   NSLog(@"会话发生错误."); }  #pragma mark - 私有方法  /**  * 取得指定位置的摄像头  *  * @param position 摄像头位置  *  * @return 摄像头设备  */ -(AVCaptureDevice *)getCameraDeviceWithPosition:(AVCaptureDevicePosition )position{   NSArray *cameras= [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];   for (AVCaptureDevice *camera in cameras) {     if ([camera position]==position) {       return camera;     }   }   return nil; }  /**  * 改变设备属性的统一操作方法  *  * @param propertyChange 属性改变操作  */ -(void)changeDeviceProperty:(PropertyChangeBlock)propertyChange{   AVCaptureDevice *captureDevice= [self.captureDeviceInput device];   NSError *error;   //注意改变设备属性前一定要首先调用lockForConfiguration:调用完之后使用unlockForConfiguration方法解锁   if ([captureDevice lockForConfiguration:&error]) {     propertyChange(captureDevice);     [captureDevice unlockForConfiguration];   }else{     NSLog(@"设置设备属性过程发生错误，错误信息：%@",error.localizedDescription);   } }  /**  * 设置闪光灯模式  *  * @param flashMode 闪光灯模式  */ -(void)setFlashMode:(AVCaptureFlashMode )flashMode{   [self changeDeviceProperty:^(AVCaptureDevice *captureDevice) {     if ([captureDevice isFlashModeSupported:flashMode]) {       [captureDevice setFlashMode:flashMode];     }   }]; } /**  * 设置聚焦模式  *  * @param focusMode 聚焦模式  */ -(void)setFocusMode:(AVCaptureFocusMode )focusMode{   [self changeDeviceProperty:^(AVCaptureDevice *captureDevice) {     if ([captureDevice isFocusModeSupported:focusMode]) {       [captureDevice setFocusMode:focusMode];     }   }]; } /**  * 设置曝光模式  *  * @param exposureMode 曝光模式  */ -(void)setExposureMode:(AVCaptureExposureMode)exposureMode{   [self changeDeviceProperty:^(AVCaptureDevice *captureDevice) {     if ([captureDevice isExposureModeSupported:exposureMode]) {       [captureDevice setExposureMode:exposureMode];     }   }]; } /**  * 设置聚焦点  *  * @param point 聚焦点  */ -(void)focusWithMode:(AVCaptureFocusMode)focusMode exposureMode:(AVCaptureExposureMode)exposureMode atPoint:(CGPoint)point{   [self changeDeviceProperty:^(AVCaptureDevice *captureDevice) {     if ([captureDevice isFocusModeSupported:focusMode]) {       [captureDevice setFocusMode:AVCaptureFocusModeAutoFocus];     }     if ([captureDevice isFocusPointOfInterestSupported]) {       [captureDevice setFocusPointOfInterest:point];     }     if ([captureDevice isExposureModeSupported:exposureMode]) {       [captureDevice setExposureMode:AVCaptureExposureModeAutoExpose];     }     if ([captureDevice isExposurePointOfInterestSupported]) {       [captureDevice setExposurePointOfInterest:point];     }   }]; }  /**  * 添加点按手势，点按时聚焦  */ -(void)addGenstureRecognizer{   UITapGestureRecognizer *tapGesture=[[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(tapScreen:)];   [self.viewContainer addGestureRecognizer:tapGesture]; } -(void)tapScreen:(UITapGestureRecognizer *)tapGesture{   CGPoint point= [tapGesture locationInView:self.viewContainer];   //将UI坐标转化为摄像头坐标   CGPoint cameraPoint= [self.captureVideoPreviewLayer captureDevicePointOfInterestForPoint:point];   [self setFocusCursorWithPoint:point];   [self focusWithMode:AVCaptureFocusModeAutoFocus exposureMode:AVCaptureExposureModeAutoExpose atPoint:cameraPoint]; }  /**  * 设置聚焦光标位置  *  * @param point 光标位置  */ -(void)setFocusCursorWithPoint:(CGPoint)point{   self.focusCursor.center=point;   self.focusCursor.transform=CGAffineTransformMakeScale(1.5, 1.5);   self.focusCursor.alpha=1.0;   [UIView animateWithDuration:1.0 animations:^{     self.focusCursor.transform=CGAffineTransformIdentity;   } completion:^(BOOL finished) {     self.focusCursor.alpha=0;   }]; } @end