使用AVCaptureSession實現視頻錄製功能

#import "RecordingVideoViewController.h"
#import <AVFoundation/AVFoundation.h>
#import <AssetsLibrary/AssetsLibrary.h>

@interface RecordingVideoViewController ()<AVCaptureFileOutputRecordingDelegate>

//會話 負責輸入和輸出設備之間的數據傳遞
@property (strong,nonatomic) AVCaptureSession    *captureSession;
//設備輸入 負責從AVCaptureDevice獲得輸入數據
@property (strong,nonatomic) AVCaptureDeviceInput    *videoCaptureDeviceInput;
@property (strong,nonatomic) AVCaptureDeviceInput    *audioCaptureDeviceInput;
//視頻輸出流
@property (strong,nonatomic) AVCaptureMovieFileOutput    *captureMovieFileOutput;
//相機拍攝預覽圖層
@property (strong,nonatomic) AVCaptureVideoPreviewLayer    *captureVideoPreviewLayer;

//自定義UI控件容器
@property (strong,nonatomic) UIView    *viewContainer;
//聚焦圖標
@property (strong,nonatomic) UIImageView    *focusCursor;
//錄製時長
@property (strong,nonatomic) UILabel    *timeLabel;
//切換前後攝像頭
@property (strong,nonatomic) UIButton    *switchCameraBtn;
//改變焦距
@property (strong,nonatomic) UIButton    *scaleBtn;
//計時器
@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 = @"視頻錄製";
    _kCameraScale = 1.0f;
    //初始化會話對象
    _captureSession = [[AVCaptureSession alloc] init];
    if ([_captureSession canSetSessionPreset:AVCaptureSessionPreset1280x720]) {
        _captureSession.sessionPreset = AVCaptureSessionPreset1280x720;
    }
    
    
    NSError *error = nil;

    //獲取視頻輸入對象
    AVCaptureDevice *videoCaptureDevice = [self cameraDeviceWithPosition:(AVCaptureDevicePositionBack)];
    if (!videoCaptureDevice) {
        NSLog(@"獲取後置攝像頭失敗！");
        return;
    }
    _videoCaptureDeviceInput = [[AVCaptureDeviceInput alloc] initWithDevice:videoCaptureDevice error:&error];
    if (error) {
        NSLog(@"取得視頻設備輸入對象時出錯");
        return;
    }
    
    
    //獲取音頻輸入對象
    AVCaptureDevice *audioCatureDevice = [[AVCaptureDevice devicesWithMediaType:AVMediaTypeAudio] firstObject];
    _audioCaptureDeviceInput = [[AVCaptureDeviceInput alloc] initWithDevice:audioCatureDevice error:&error];
    if (error) {
        NSLog(@"取得音頻設備輸入對象時出錯");
        return;
    }
    
    //初始化設備輸出對象
    _captureMovieFileOutput = [[AVCaptureMovieFileOutput alloc] init];
    
    //將設備輸入添加到會話中
    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;
        }
    }
    
    //將設備輸出添加到會話中
    if ([_captureSession canAddOutput:_captureMovieFileOutput]) {
        [_captureSession addOutput:_captureMovieFileOutput];
    }
    
    
    //創建視頻預覽圖層
    _captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:_captureSession];
    self.viewContainer.layer.masksToBounds = YES;
    _captureVideoPreviewLayer.frame = self.viewContainer.bounds;
    _captureVideoPreviewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
    [self.view.layer addSublayer:_captureVideoPreviewLayer];
    
    //顯示自定義控件
    [self.view addSubview:self.viewContainer];
    
    //添加點按聚焦手勢
    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];
}

//開始 + 暫停錄製
- (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]];
    }
}

//切換攝像頭
- (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(@"獲取要切換的設備失敗");
        return;
    }
    
    NSError *error = nil;
    AVCaptureDeviceInput *toVideoDeviceInput = [[AVCaptureDeviceInput alloc] initWithDevice:toCapturDevice error:&error];
    if (error) {
        NSLog(@"獲取要切換的設備輸入失敗");
        return;
    }
    
    //改變會話配置
    [self.captureSession beginConfiguration];
    
    [self.captureSession removeInput:self.videoCaptureDeviceInput];
    if ([self.captureSession canAddInput:toVideoDeviceInput]) {
        [self.captureSession addInput:toVideoDeviceInput];
        
        self.videoCaptureDeviceInput = toVideoDeviceInput;
    }
    //提交會話配置
    [self.captureSession commitConfiguration];
}


//點按手勢
- (void)tapScreen:(UITapGestureRecognizer *)tap {
    CGPoint point = [tap locationInView:self.viewContainer];
    
    //將界面point對應到攝像頭point
    CGPoint cameraPoint = [self.captureVideoPreviewLayer captureDevicePointOfInterestForPoint:point];

    //設置聚光動畫
    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;

    }];
    
    //設置聚光點座標
    [self focusWithMode:AVCaptureFocusModeAutoFocus exposureMode:AVCaptureExposureModeAutoExpose atPoint:cameraPoint];

}


/**設置聚焦點*/
-(void)focusWithMode:(AVCaptureFocusMode)focusMode exposureMode:(AVCaptureExposureMode)exposureMode atPoint:(CGPoint)point{
    
    AVCaptureDevice *captureDevice= [self.videoCaptureDeviceInput device];
    NSError *error = nil;
    //設置設備屬性必須先解鎖 然後加鎖
    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];
        //        }
        //        //閃光燈模式
        //        if ([captureDevice isFlashModeSupported:AVCaptureFlashModeAuto]) {
        //            [captureDevice setFlashMode:AVCaptureFlashModeAuto];
        //        }
        
        //加鎖
        [captureDevice unlockForConfiguration];
        
    }else{
        NSLog(@"設置設備屬性過程發生錯誤，錯誤信息：%@",error.localizedDescription);
    }
}



//調整焦距
-(void)scaleBtnClick:(UIButton *)sender
{
    _kCameraScale += 0.5;
    if(_kCameraScale > 3.0) {
        _kCameraScale = 1.0;
    }
    //改變焦距
    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(@"修改設備屬性失敗!")
    }
}



#pragma mark --------  AVCaptureFileOutputRecordingDelegate  ----------
- (void)captureOutput:(AVCaptureFileOutput *)captureOutput didStartRecordingToOutputFileAtURL:(NSURL *)fileURL fromConnections:(NSArray *)connections {
    NSLog(@"開始錄製");
}

- (void)captureOutput:(AVCaptureFileOutput *)captureOutput didFinishRecordingToOutputFileAtURL:(NSURL *)outputFileURL fromConnections:(NSArray *)connections error:(NSError *)error {
    NSLog(@"錄製結束");
    ALAssetsLibrary *assetsLibrary = [[ALAssetsLibrary alloc] init];
    [assetsLibrary writeVideoAtPathToSavedPhotosAlbum:outputFileURL completionBlock:^(NSURL *assetURL, NSError *error) {
        if (error) {
            NSLog(@"保存視頻到相簿過程中發生錯誤，錯誤信息：%@",error.localizedDescription);
        }
    }];
}

//錄製計時
- (void)timeAction {
    self.timeLabel.text = [NSString stringWithFormat:@"%.2ld:%.2ld",_num/60,_num%60];
    _num ++;
}


/**取得指定位置的攝像頭*/
- (AVCaptureDevice *)cameraDeviceWithPosition:(AVCaptureDevicePosition )position{
    NSArray *cameras = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
    for (AVCaptureDevice *camera in cameras) {
        if ([camera position] == position) {
            return camera;
        }
    }
    return nil;
}



@end

 

參考代碼：-------------------------分割線--------------------------

 

 

#import "VideoTestViewController.h"
#import <AVFoundation/AVFoundation.h>
#import <AssetsLibrary/AssetsLibrary.h>

typedef void(^PropertyChangeBlock)(AVCaptureDevice *captureDevice);

@interface VideoTestViewController ()<AVCaptureFileOutputRecordingDelegate>//視頻文件輸出代理

@property (strong,nonatomic) AVCaptureSession *captureSession;//負責輸入和輸出設備之間的數據傳遞
@property (strong,nonatomic) AVCaptureDeviceInput *captureDeviceInput;//負責從AVCaptureDevice獲得輸入數據
@property (strong,nonatomic) AVCaptureMovieFileOutput *captureMovieFileOutput;//視頻輸出流
@property (strong,nonatomic) AVCaptureVideoPreviewLayer *captureVideoPreviewLayer;//相機拍攝預覽圖層

@property (assign,nonatomic) BOOL enableRotation;//是否允許旋轉（注意在視頻錄製過程中禁止屏幕旋轉）
@property (assign,nonatomic) CGRect *lastBounds;//旋轉的前大小
@property (assign,nonatomic) UIBackgroundTaskIdentifier backgroundTaskIdentifier;//後臺任務標識
@property (strong,nonatomic) UIView *viewContainer;
@property (strong,nonatomic) UIButton *takeButton;//拍照按鈕
@property (strong,nonatomic) UIImageView *focusCursor; //聚焦光標


@end

@implementation VideoTestViewController

#pragma mark - 控制器視圖方法
- (void)viewDidLoad {
    [super viewDidLoad];
}

-(void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];
    
    //初始化會話
    _captureSession=[[AVCaptureSession alloc]init];
    if ([_captureSession canSetSessionPreset:AVCaptureSessionPreset1280x720]) {//設置分辨率
        _captureSession.sessionPreset=AVCaptureSessionPreset1280x720;
    }
    //獲得輸入設備
    AVCaptureDevice *captureDevice=[self getCameraDeviceWithPosition:AVCaptureDevicePositionBack];//取得後置攝像頭
    if (!captureDevice) {
        NSLog(@"取得後置攝像頭時出現問題.");
        return;
    }
    //添加一個音頻輸入設備
    AVCaptureDevice *audioCaptureDevice=[[AVCaptureDevice devicesWithMediaType:AVMediaTypeAudio] firstObject];
    
    
    NSError *error=nil;
    //根據輸入設備初始化設備輸入對象，用於獲得輸入數據
    _captureDeviceInput=[[AVCaptureDeviceInput alloc]initWithDevice:captureDevice error:&error];
    if (error) {
        NSLog(@"取得設備輸入對象時出錯，錯誤原因：%@",error.localizedDescription);
        return;
    }
    AVCaptureDeviceInput *audioCaptureDeviceInput=[[AVCaptureDeviceInput alloc]initWithDevice:audioCaptureDevice error:&error];
    if (error) {
        NSLog(@"取得設備輸入對象時出錯，錯誤原因：%@",error.localizedDescription);
        return;
    }
    //初始化設備輸出對象，用於獲得輸出數據
    _captureMovieFileOutput=[[AVCaptureMovieFileOutput alloc]init];
    
    //將設備輸入添加到會話中
    if ([_captureSession canAddInput:_captureDeviceInput]) {
        [_captureSession addInput:_captureDeviceInput];
        [_captureSession addInput:audioCaptureDeviceInput];
        AVCaptureConnection *captureConnection=[_captureMovieFileOutput connectionWithMediaType:AVMediaTypeVideo];
        if ([captureConnection isVideoStabilizationSupported ]) {
            captureConnection.preferredVideoStabilizationMode=AVCaptureVideoStabilizationModeAuto;
        }
    }
    
    //將設備輸出添加到會話中
    if ([_captureSession canAddOutput:_captureMovieFileOutput]) {
        [_captureSession addOutput:_captureMovieFileOutput];
    }
    
    //創建視頻預覽層，用於實時展示攝像頭狀態
    _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
    //將視頻預覽層添加到界面中
    //[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;
}

////屏幕旋轉時調整視頻預覽圖層的方向
//-(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;
//
//}
//屏幕旋轉時調整視頻預覽圖層的方向
-(void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration{
    AVCaptureConnection *captureConnection=[self.captureVideoPreviewLayer connection];
    captureConnection.videoOrientation=(AVCaptureVideoOrientation)toInterfaceOrientation;
}
//旋轉後重新設置大小
-(void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation{
    _captureVideoPreviewLayer.frame=self.viewContainer.bounds;
}

-(void)dealloc{
    [self removeNotification];
}
#pragma mark - UI方法
#pragma mark 視頻錄製
- (void)takeButtonClick:(UIButton *)sender {
    //根據設備輸出獲得連接
    AVCaptureConnection *captureConnection=[self.captureMovieFileOutput connectionWithMediaType:AVMediaTypeVideo];
    //根據連接取得設備輸出的數據
    if (![self.captureMovieFileOutput isRecording]) {
        self.enableRotation=NO;
        //如果支持多任務則則開始多任務
        if ([[UIDevice currentDevice] isMultitaskingSupported]) {
            self.backgroundTaskIdentifier=[[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:nil];
        }
        //預覽圖層和視頻方向保持一致
        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];//停止錄製
    }
}
#pragma mark 切換前後攝像頭
- (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];
    //獲得要調整的設備輸入對象
    AVCaptureDeviceInput *toChangeDeviceInput=[[AVCaptureDeviceInput alloc]initWithDevice:toChangeDevice error:nil];
    
    //改變會話的配置前一定要先開啓配置，配置完成後提交配置改變
    [self.captureSession beginConfiguration];
    //移除原有輸入對象
    [self.captureSession removeInput:self.captureDeviceInput];
    //添加新的輸入對象
    if ([self.captureSession canAddInput:toChangeDeviceInput]) {
        [self.captureSession addInput:toChangeDeviceInput];
        self.captureDeviceInput=toChangeDeviceInput;
    }
    //提交會話配置
    [self.captureSession commitConfiguration];
    
}

#pragma mark - 視頻輸出代理
-(void)captureOutput:(AVCaptureFileOutput *)captureOutput didStartRecordingToOutputFileAtURL:(NSURL *)fileURL fromConnections:(NSArray *)connections{
    NSLog(@"開始錄製...");
}
-(void)captureOutput:(AVCaptureFileOutput *)captureOutput didFinishRecordingToOutputFileAtURL:(NSURL *)outputFileURL fromConnections:(NSArray *)connections error:(NSError *)error{
    NSLog(@"視頻錄製完成.");
    //視頻錄入完成之後在後臺將視頻存儲到相簿
    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(@"保存視頻到相簿過程中發生錯誤，錯誤信息：%@",error.localizedDescription);
        }
        if (lastBackgroundTaskIdentifier!=UIBackgroundTaskInvalid) {
            [[UIApplication sharedApplication] endBackgroundTask:lastBackgroundTaskIdentifier];
        }
        NSLog(@"成功保存視頻到相簿.");
    }];
    
}

#pragma mark - 通知
/**
 *  給輸入設備添加通知
 */
-(void)addNotificationToCaptureDevice:(AVCaptureDevice *)captureDevice{
    //注意添加區域改變捕獲通知必須首先設置設備允許捕獲
    [self changeDeviceProperty:^(AVCaptureDevice *captureDevice) {
        captureDevice.subjectAreaChangeMonitoringEnabled=YES;
    }];
    NSNotificationCenter *notificationCenter= [NSNotificationCenter defaultCenter];
    //捕獲區域發生改變
    [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];
    //會話出錯
    [notificationCenter addObserver:self selector:@selector(sessionRuntimeError:) name:AVCaptureSessionRuntimeErrorNotification object:captureSession];
}

/**
 *  設備連接成功
 *
 *  @param notification 通知對象
 */
-(void)deviceConnected:(NSNotification *)notification{
    NSLog(@"設備已連接...");
}
/**
 *  設備連接斷開
 *
 *  @param notification 通知對象
 */
-(void)deviceDisconnected:(NSNotification *)notification{
    NSLog(@"設備已斷開.");
}
/**
 *  捕獲區域改變
 *
 *  @param notification 通知對象
 */
-(void)areaChange:(NSNotification *)notification{
    NSLog(@"捕獲區域改變...");
}

/**
 *  會話出錯
 *
 *  @param notification 通知對象
 */
-(void)sessionRuntimeError:(NSNotification *)notification{
    NSLog(@"會話發生錯誤.");
}

#pragma mark - 私有方法

/**
 *  取得指定位置的攝像頭
 *
 *  @param position 攝像頭位置
 *
 *  @return 攝像頭設備
 */
-(AVCaptureDevice *)getCameraDeviceWithPosition:(AVCaptureDevicePosition )position{
    NSArray *cameras= [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
    for (AVCaptureDevice *camera in cameras) {
        if ([camera position]==position) {
            return camera;
        }
    }
    return nil;
}

/**
 *  改變設備屬性的統一操作方法
 *
 *  @param propertyChange 屬性改變操作
 */
-(void)changeDeviceProperty:(PropertyChangeBlock)propertyChange{
    AVCaptureDevice *captureDevice= [self.captureDeviceInput device];
    NSError *error;
    //注意改變設備屬性前一定要首先調用lockForConfiguration:調用完之後使用unlockForConfiguration方法解鎖
    if ([captureDevice lockForConfiguration:&error]) {
        propertyChange(captureDevice);
        [captureDevice unlockForConfiguration];
    }else{
        NSLog(@"設置設備屬性過程發生錯誤，錯誤信息：%@",error.localizedDescription);
    }
}

/**
 *  設置閃光燈模式
 *
 *  @param flashMode 閃光燈模式
 */
-(void)setFlashMode:(AVCaptureFlashMode )flashMode{
    [self changeDeviceProperty:^(AVCaptureDevice *captureDevice) {
        if ([captureDevice isFlashModeSupported:flashMode]) {
            [captureDevice setFlashMode:flashMode];
        }
    }];
}
/**
 *  設置聚焦模式
 *
 *  @param focusMode 聚焦模式
 */
-(void)setFocusMode:(AVCaptureFocusMode )focusMode{
    [self changeDeviceProperty:^(AVCaptureDevice *captureDevice) {
        if ([captureDevice isFocusModeSupported:focusMode]) {
            [captureDevice setFocusMode:focusMode];
        }
    }];
}
/**
 *  設置曝光模式
 *
 *  @param exposureMode 曝光模式
 */
-(void)setExposureMode:(AVCaptureExposureMode)exposureMode{
    [self changeDeviceProperty:^(AVCaptureDevice *captureDevice) {
        if ([captureDevice isExposureModeSupported:exposureMode]) {
            [captureDevice setExposureMode:exposureMode];
        }
    }];
}
/**
 *  設置聚焦點
 *
 *  @param point 聚焦點
 */
-(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];
        }
    }];
}

/**
 *  添加點按手勢，點按時聚焦
 */
-(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];
    //將UI座標轉化爲攝像頭座標
    CGPoint cameraPoint= [self.captureVideoPreviewLayer captureDevicePointOfInterestForPoint:point];
    [self setFocusCursorWithPoint:point];
    [self focusWithMode:AVCaptureFocusModeAutoFocus exposureMode:AVCaptureExposureModeAutoExpose atPoint:cameraPoint];
}

/**
 *  設置聚焦光標位置
 *
 *  @param point 光標位置
 */
-(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