在OpenCV中将视频序列与另一个视频交互播放

对于每一帧,您需要在视频帧内复制一个包含所需内容的图像。步骤如下:

1. 定义覆盖框架的大小
2. 定义显示覆盖框架的位置

3. 对于每个帧

   1. 用一些内容填充覆盖框架
   2. 将覆盖帧复制到原始帧中定义的位置。

这个小片段将在相机提要的右下角显示一个随机噪声叠加窗口:

#include <opencv2/opencv.hpp>
using namespace cv;
using namespace std;


int main()
{
    // Video capture frame
    Mat3b frame;
    // Overlay frame
    Mat3b overlayFrame(100, 200);

    // Init VideoCapture
    VideoCapture cap(0);

    // check if we succeeded
    if (!cap.isOpened()) {
        cerr << "ERROR! Unable to open camera\n";
        return -1;
    }

    // Get video size
    int w = cap.get(CAP_PROP_FRAME_WIDTH);
    int h = cap.get(CAP_PROP_FRAME_HEIGHT);

    // Define where the show the overlay frame 
    Rect roi(w - overlayFrame.cols, h - overlayFrame.rows, overlayFrame.cols, overlayFrame.rows);

    //--- GRAB AND WRITE LOOP
    cout << "Start grabbing" << endl
        << "Press any key to terminate" << endl;
    for (;;)
    {
        // wait for a new frame from camera and store it into 'frame'
        cap.read(frame);

        // Fill overlayFrame with something meaningful (here random noise)
        randu(overlayFrame, Scalar(0, 0, 0), Scalar(256, 256, 256));

        // Overlay
        overlayFrame.copyTo(frame(roi));

        // check if we succeeded
        if (frame.empty()) {
            cerr << "ERROR! blank frame grabbed\n";
            break;
        }
        // show live and wait for a key with timeout long enough to show images
        imshow("Live", frame);
        if (waitKey(5) >= 0)
            break;
    }
    // the camera will be deinitialized automatically in VideoCapture destructor
    return 0;
}