【如何快速的开发一个完整的iOS直播app】(采集篇)

// 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
    AVCaptureSession *captureSession = [[AVCaptureSession alloc] init];
    _captureSession = captureSession;

    // 2.获取摄像头设备，默认是后置摄像头
    AVCaptureDevice *videoDevice = [self getVideoDevice:AVCaptureDevicePositionFront];

    // 3.获取声音设备
    AVCaptureDevice *audioDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio];

    // 4.创建对应视频设备输入对象
    AVCaptureDeviceInput *videoDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:nil];
    _currentVideoDeviceInput = videoDeviceInput;

    // 5.创建对应音频设备输入对象
    AVCaptureDeviceInput *audioDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:audioDevice error:nil];

    // 6.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
    // 6.1 添加视频
    if ([captureSession canAddInput:videoDeviceInput]) {
        [captureSession addInput:videoDeviceInput];
    }
    // 6.2 添加音频
    if ([captureSession canAddInput:audioDeviceInput]) {
        [captureSession addInput:audioDeviceInput];
    }

    // 7.获取视频数据输出设备
    AVCaptureVideoDataOutput *videoOutput = [[AVCaptureVideoDataOutput alloc] init];
    // 7.1 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];
    }

    // 8.获取音频数据输出设备
    AVCaptureAudioDataOutput *audioOutput = [[AVCaptureAudioDataOutput alloc] init];
    // 8.2 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];
    }

    // 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
    [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;
}

#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");
    }
}

// 切换摄像头
- (IBAction)toggleCapture:(id)sender {

    // 获取当前设备方向
    AVCaptureDevicePosition curPosition = _currentVideoDeviceInput.device.position;

    // 获取需要改变的方向
    AVCaptureDevicePosition togglePosition = curPosition == AVCaptureDevicePositionFront?AVCaptureDevicePositionBack:AVCaptureDevicePositionFront;

    // 获取改变的摄像头设备
    AVCaptureDevice *toggleDevice = [self getVideoDevice:togglePosition];

    // 获取改变的摄像头输入设备
    AVCaptureDeviceInput *toggleDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:toggleDevice error:nil];

    // 移除之前摄像头输入设备
    [_captureSession removeInput:_currentVideoDeviceInput];

    // 添加新的摄像头输入设备
    [_captureSession addInput:toggleDeviceInput];

    // 记录当前摄像头输入设备
    _currentVideoDeviceInput = toggleDeviceInput;

}

// 点击屏幕，出现聚焦视图
- (void)touchesBegan:(NSSet< UITouch *> *)touches withEvent:(UIEvent *)event
{
    // 获取点击位置
    UITouch *touch = [touches anyObject];
    CGPoint point = [touch locationInView:self.view];

    // 把当前位置转换为摄像头点上的位置
    CGPoint cameraPoint = [_previedLayer captureDevicePointOfInterestForPoint:point];

    // 设置聚焦点光标位置
    [self setFocusCursorWithPoint:point];

    // 设置聚焦
    [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.focusCursorImageView.center=point;
    self.focusCursorImageView.transform=CGAffineTransformMakeScale(1.5, 1.5);
    self.focusCursorImageView.alpha=1.0;
    [UIView animateWithDuration:1.0 animations:^{
        self.focusCursorImageView.transform=CGAffineTransformIdentity;
    } completion:^(BOOL finished) {
        self.focusCursorImageView.alpha=0;

    }];
}

/**
 *  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];
}

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