Question

我正在尝试同时从iOS设备上的两台摄像机拍照。我也想在屏幕上预览两台摄像机。我使用这段代码：

- (void)prepareCameraView:(UIView *)window
{
    NSArray *captureDevices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];

    {
        AVCaptureSession *session = [[AVCaptureSession alloc] init];
        session.sessionPreset = AVCaptureSessionPresetMedium;

        CALayer *viewLayer = window.layer;
        NSLog(@"viewLayer = %@", viewLayer);

        AVCaptureVideoPreviewLayer *captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
        captureVideoPreviewLayer.frame = CGRectMake(0.0f, 0.0f, window.bounds.size.width/2.0f, window.bounds.size.height);
        [window.layer addSublayer:captureVideoPreviewLayer];

        NSError *error = nil;
        AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:[captureDevices objectAtIndex:0] error:&error];
        if (!input)
        {
            NSLog(@"ERROR : trying to open camera : %@", error);
        }

        [session addInput:input];

        [session startRunning];
    }

    {
        AVCaptureSession *session = [[AVCaptureSession alloc] init];
        session.sessionPreset = AVCaptureSessionPresetMedium;

        CALayer *viewLayer = window.layer;
        NSLog(@"viewLayer = %@", viewLayer);

        AVCaptureVideoPreviewLayer *captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session];
        captureVideoPreviewLayer.frame = CGRectMake(window.bounds.size.width/2.0f, 0.0f, window.bounds.size.width/2.0f, window.bounds.size.height);
        [window.layer addSublayer:captureVideoPreviewLayer];

        NSError *error = nil;
        AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:[captureDevices objectAtIndex:1] error:&error];
        if (!input)
        {
            NSLog(@"ERROR : trying to open camera : %@", error);
        }

        [session addInput:input];

        [session startRunning];
    }

}

但是，当应用程序启动前置摄像头的会话时，后置摄像头的会话将停止并留下静止图像。

有没有办法实时显示两台摄像机的输出？

由于

Answer 1

不，不是。使用AVCaptureSession时，一次只能使用一个摄像机输入。

不允许同时使用多个AVCaptureInput。所以一旦一个会话开始，另一个会议就会停止。

你最好的选择是创建两个会话，从第一个开始，一报告一帧，停止并开始第二个。然后停止第二个并开始第一个，继续这样做。这将有效，但您收到的输入会有明显的延迟。

iOS上的双AVCaptureSession输出

1 个答案: