获取音视频输入

// 捕获音视频
- (void)setupCaputureVideo
{
    // 1.创建捕获会话,必须要强引用，否则会被释放
    /*
     协调输入与输出之间传输数据，
     系统作用：可以操作硬件设备
     工作原理：让app与系统之间产生一个捕捉会话，相当于app和硬件设备之间有联系，我们只需要把硬件输入对象和输出对象添加到绘画中，会话就会自动把硬件输入对象和输出产生连接，这样硬件输入和输出设备就能传输音视频数据。
     现实生活场景：租客（输入钱）中介（会话）房东（输出房）中介会房租客和房东之间产生联系，
     */
    AVCaptureSession *captureSession = [[AVCaptureSession alloc] init];
    _captureSession = captureSession;
    
    // 2.获取AVCaptureDevicel 录像设备（摄像头）录音设备（麦克风）注意不具备输入数据功能，只是用来调节硬件设备的配置
    // 2.1 获取摄像头设备，默认是后置摄像头
    AVCaptureDevice *videoDevice = [self getVideoDevice:AVCaptureDevicePositionFront];
    // 2.2 获取声音设备
    AVCaptureDevice *audioDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio];
    
    // 3 根据音频/视频硬件设备（AVCaptureDevice）创建音频/视频硬件输入数据对象(AVCaptureDeviceInput)，专门管理数据输入。
    // 3.1 创建对应视频设备输入对象
    AVCaptureDeviceInput *videoDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:nil];
    _currentVideoDeviceInput = videoDeviceInput;
    // 3.2 创建对应音频设备输入对象
    AVCaptureDeviceInput *audioDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:audioDevice error:nil];
    
    // 4.添加到会话中
    // 注意“最好要判断是否能添加输入，会话不能添加空的
    // 4.1 添加视频
    if ([captureSession canAddInput:videoDeviceInput]) {
        [captureSession addInput:videoDeviceInput];
    }
    // 4.2 添加音频
    if ([captureSession canAddInput:audioDeviceInput]) {
        [captureSession addInput:audioDeviceInput];
    }
    
    // 5.获取视频数据输出设备，并设置样品缓存代理就可以通过它拿到采集到的视频数据
    AVCaptureVideoDataOutput *videoOutput = [[AVCaptureVideoDataOutput alloc] init];
    // 5.1 设置代理，捕获视频样品数据
    // 注意：队列必须是串行队列，才能获取到数据，而且不能为空
    dispatch_queue_t videoQueue = dispatch_queue_create("Video Capture Queue", DISPATCH_QUEUE_SERIAL);
    [videoOutput setSampleBufferDelegate:self queue:videoQueue];
    if ([captureSession canAddOutput:videoOutput]) {
        [captureSession addOutput:videoOutput];
    }
    
    // 6.获取音频数据输出设备，并设置样品缓存代理就可以通过它拿到采集到的音频数据
    AVCaptureAudioDataOutput *audioOutput = [[AVCaptureAudioDataOutput alloc] init];
    // 6.1 设置代理，捕获视频样品数据
    // 注意：队列必须是串行队列，才能获取到数据，而且不能为空
    dispatch_queue_t audioQueue = dispatch_queue_create("Audio Capture Queue", DISPATCH_QUEUE_SERIAL);
    [audioOutput setSampleBufferDelegate:self queue:audioQueue];
    if ([captureSession canAddOutput:audioOutput]) {
        [captureSession addOutput:audioOutput];
    }
    
    /*
     将数据输入对象AVCaptureDeviceInput，数据输出对象AVCaptureOutput添加到媒体会话管理对象AVCaptureSession中，就会自动让音频输入与输出和视频输入与输出产生连接。
     */
    
    // 9.获取视频输入与输出连接，用于分辨音视频数据
    _videoConnection = [videoOutput connectionWithMediaType:AVMediaTypeVideo];
    
    // 10.添加视频预览图层
    AVCaptureVideoPreviewLayer *previedLayer = [AVCaptureVideoPreviewLayer layerWithSession:captureSession];
    previedLayer.frame = [UIScreen mainScreen].bounds;
    [self.view.layer insertSublayer:previedLayer atIndex:0];
    _previedLayer = previedLayer;
    
    // 11.启动会话，只有开启才会开始输入到输出数据流传输
    [captureSession startRunning];
}

// 指定摄像头方向获取摄像头
- (AVCaptureDevice *)getVideoDevice:(AVCaptureDevicePosition)position
{
    NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
    for (AVCaptureDevice *device in devices) {
        if (device.position == position) {
            return device;
        }
    }
    return nil;
}

//  1.切换摄像头
- (IBAction)changeVideoPosition:(UIButton *)sender {
    
    CATransition *animation = [CATransition animation];
    animation.duration = .5f;
    animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
    animation.type = @"cube";
    
    //  1.获取当前视频设备输入对象
    AVCaptureDevicePosition curPosition = _currentVideoDeviceInput.device.position;
    
    //  2.获取需要改变的的方向，判断当前视频设备是前置还是后置
    AVCaptureDevicePosition togglePosition = curPosition == AVCaptureDevicePositionBack ? AVCaptureDevicePositionFront : AVCaptureDevicePositionBack;
    
    //  3.获取改变的摄像头设备
    AVCaptureDevice *toggleDevice = [self getVideoDevice:togglePosition];
    
    //  4.获取改变的摄像头的输入设备
    AVCaptureDeviceInput *toggleDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:toggleDevice error:nil];
    
    //  5.移除之前摄像头的输入设备
    [_captureSession removeInput:_currentVideoDeviceInput];
    
    //  6.添加新的摄像头输入设备
    [_captureSession addInput:toggleDeviceInput];
    
    //  7.记录当前摄像头输入设备
    _currentVideoDeviceInput = toggleDeviceInput;
    
    //  添加动画
    [_previedLayer addAnimation:animation forKey:nil];
}

//  2.聚焦光标
//  点击屏幕，出现聚焦视图
-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    //  获取点击的位置
    UITouch *touch = [touches anyObject];
    CGPoint point = [touch locationInView:self.view];
    NSLog(@"%f---%f",point.x,point.y);
    //  把当前位置转换为摄像头点上的位置
    CGPoint cameraPoint = [_previedLayer captureDevicePointOfInterestForPoint:point];
    
    //  设置聚焦点光标的位置
    [self setFocusCursorWithPoint:point];
    
    //  设置聚焦
    // 设置聚焦
    [self focusWithMode:AVCaptureFocusModeAutoFocus exposureMode:AVCaptureExposureModeAutoExpose atPoint:cameraPoint];
}

/**
 *  设置聚焦
 */
-(void)focusWithMode:(AVCaptureFocusMode)focusMode exposureMode:(AVCaptureExposureMode)exposureMode atPoint:(CGPoint)point{
    
    AVCaptureDevice *captureDevice = _currentVideoDeviceInput.device;
    // 锁定配置
    [captureDevice lockForConfiguration:nil];
    
    // 设置聚焦
    if ([captureDevice isFocusModeSupported:AVCaptureFocusModeAutoFocus]) {
        [captureDevice setFocusMode:AVCaptureFocusModeAutoFocus];
    }
    if ([captureDevice isFocusPointOfInterestSupported]) {
        [captureDevice setFocusPointOfInterest:point];
    }
    
    // 设置曝光
    if ([captureDevice isExposureModeSupported:AVCaptureExposureModeAutoExpose]) {
        [captureDevice setExposureMode:AVCaptureExposureModeAutoExpose];
    }
    if ([captureDevice isExposurePointOfInterestSupported]) {
        [captureDevice setExposurePointOfInterest:point];
    }
    
    // 解锁配置
    [captureDevice unlockForConfiguration];
}


/**
 *  设置聚焦光标位置
 *
 *  @param point 光标位置
 */
-(void)setFocusCursorWithPoint:(CGPoint)point{
    self.testView.center=point;
    self.testView.transform=CGAffineTransformMakeScale(1.5, 1.5);
    self.testView.alpha=1.0;
    [UIView animateWithDuration:1.0 animations:^{
        self.testView.transform=CGAffineTransformIdentity;
    } completion:^(BOOL finished) {
        self.testView.alpha=0;
    }];
}



#pragma mark - AVCaptureVideoDataOutputSampleBufferDelegate
// 获取输入设备数据，有可能是音频有可能是视频
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
{
    if (_videoConnection == connection) {
        NSLog(@"采集到视频数据");
    } else {
        NSLog(@"采集到音频数据");
    }
}