C++ VideoWriter::write方法代码示例

void Tracker2D::writeToVideo(cv::VideoWriter & writer)
{

	cv::Mat dispImage;
	drawTrackers(dispImage);
	writer.write(dispImage);
}

	void operator()(const cv::Mat& image,bool record)
	{
		// no image no fun
		if (image.empty()) return;

		int cF = currentFrame ? 1 : 0;
		int pF = currentFrame ? 0 : 1;

		// resize the image
		cv::resize(image,frames[cF],cv::Size(image.cols*scale,image.rows*scale),0,0,cv::INTER_LINEAR);

		std::cout << "Current: " << cF << " Previous: " << pF << std::endl;
		std::cout << "Image " << image.size() << " c:" << image.channels() << " > " << frames[cF].size() << std::endl;

		if (record && !output.isOpened())
		{
			// fourcc
			int fourCC = FourCC<'X','V','I','D'>::value;
			// set framerate to 1fps - easier to check in a standard video player
			if (output.open("flow.avi",fourCC,25,frames[cF].size(),false))
				{
					std::cout << "capture file opened" << std::endl;
				}		
		}

		// make a copy for the initial frame
		if (frames[pF].empty())
			frames[cF].copyTo(frames[pF]);

		if (!flow.empty())
			flow = cv::Mat::zeros(flow.size(),flow.type());

		// calculate dense optical flow
		cv::calcOpticalFlowFarneback(frames[pF],frames[cF],flow,.5,2,8,3,7,1.5,0);

		// we can't draw into the frame!
		cv::Mat outImg = frames[cF].clone();

		drawOptFlowMap(flow,outImg,8,cv::Scalar::all(255));

		cv::imshow("Flow",outImg);

		// flip the buffers
		currentFrame = !currentFrame;
		
		// record the frame
		if (record && output.isOpened())
			output.write(outImg);
		
	}

//.........这里部分代码省略.........
  findContours(src, contours, CV_RETR_CCOMP, CV_CHAIN_APPROX_NONE);
  //printf("Num contours: %lu\n", contours.size());

  std::vector<double> contour_area, contour_arclength;
  contour_area.resize(contours.size());
  contour_arclength.resize(contours.size());
  std::vector<unsigned int> circle_index;
  for(unsigned int idx = 0; idx < contours.size(); idx++)
  {
    if(contours[idx].size() > 25)
    {
      cv::Mat contour(contours[idx]);
      contour_area[idx] = contourArea(contour);
      if(contour_area[idx] > 50)
      {
        contour_arclength[idx] = arcLength(contour,true);
        float q = 4*M_PI*contour_area[idx] /
            (contour_arclength[idx]*contour_arclength[idx]);
        if(q > 0.8f)
        {
          circle_index.push_back(idx);
          //printf("isoperimetric quotient: %f\n", q);
          //Scalar color( rand()&255, rand()&255, rand()&255 );
          //drawContours(contours_dark, contours, idx, color, 1, 8);
        }
      }
    }
  }
  std::list<Circle> circles;
  for(unsigned int i = 0; i < circle_index.size(); i++)
  {
    Circle c;
    cv::Moments moment = moments(contours[circle_index[i]]);
    float inv_m00 = 1./moment.m00;
    c.center = cv::Point2f(moment.m10*inv_m00, moment.m01*inv_m00);
    c.radius = (sqrtf(contour_area[circle_index[i]]/M_PI) + contour_arclength[circle_index[i]]/(2*M_PI))/2.0f;
    circles.push_back(c);
  }

  // Get the circles with centers close to each other
  std::vector<std::list<Circle> > filtered_circles;
  std::list<Circle>::iterator it = circles.begin();
  unsigned int max_length = 0;
  while(it != circles.end())
  {
    std::list<Circle> c;
    c.push_back(*it);

    cv::Point c1 = it->center;

    std::list<Circle>::iterator it2 = it;
    it2++;
    while(it2 != circles.end())
    {
      cv::Point c2 = it2->center;
      std::list<Circle>::iterator it3 = it2;
      it2++;
      if(hypotf(c2.x - c1.x, c2.y - c1.y) < 10)
      {
        c.push_back(*it3);
        circles.erase(it3);
      }
    }
    unsigned int length_c = c.size();
    if(length_c > 1 && length_c > max_length)
    {
      max_length = length_c;
      filtered_circles.push_back(c);
    }

    it2 = it;
    it++;
    circles.erase(it2);
  }

  if(filtered_circles.size() > 0)
  {
    Circle target_circle;
    target_circle.radius = std::numeric_limits<float>::max();

    for(it = filtered_circles.back().begin(); it != filtered_circles.back().end(); it++)
    {
      //printf("circle: c: %f, %f, r: %f\n", it->center.x, it->center.y, it->radius);
      if(it->radius < target_circle.radius)
      {
        target_circle.radius = it->radius;
        target_circle.center = it->center;
      }
    }
    circle(color_src, cv::Point(target_circle.center.x, target_circle.center.y), target_circle.radius, cv::Scalar(0,0,255), 2);
    printf("target: c: %f, %f, r: %f\n", target_circle.center.x, target_circle.center.y, target_circle.radius);

  }
#if defined(CAPTURE_VIDEO)
  static cv::VideoWriter video_writer("output.mp4", CV_FOURCC('M','J','P','G'), 20, cv::Size(width, height));
  video_writer.write(color_src);
#endif
  imshow("Target", color_src);
  cv::waitKey(1);
}