GPT答：

7i24.cn

The code you provided seems to be incorrect. It looks like you are trying to use the `open` function of the `cap` object from the `grabImage` namespace, but there is no mention of such namespace or object in your code.

If you are trying to open a new video source using OpenCV's VideoCapture class, here is an example of how it can be done:

```cpp
#include <opencv2/opencv.hpp>

int main() {
    cv::VideoCapture cap;
    std::string new_source = "path_to_video_file.mp4";

    // Open the video source
    cap.open(new_source);

    if (!cap.isOpened()) {
        std::cout << "Error opening video file" << std::endl;
        return -1;
    }

    // Rest of your code...

    return 0;
}
```

Make sure to replace `"path_to_video_file.mp4"` with the actual path or URL of your video source.