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• OpenCV's VideoCapture::open Video Source Dialog

  13 novembre 2015, par swtdrgn

  In my current project, when I call VideoCapture::open(camera device index) and the camera is in used by another program, it shows a Video Source dialog and returns true when I select a device that is already in use.

  However, in my [previous] experiment project, when I called VideoCapture::open(camera device index), it doesn’t show this dialog.

  I want to know what is causing the Video Source dialog to show and the program to behave differently from the experimental project.

  This is the source code to the experiment project :

  int main (int argc, char *argv[])
  
  {
  
  
  
      //vars
  
      time_duration td, td1;
  
      ptime nextFrameTimestamp, currentFrameTimestamp, initialLoopTimestamp, finalLoopTimestamp;
  
      int delayFound = 0;
  
      int totalDelay= 0;
  
  
  
      // initialize capture on default source
  
      VideoCapture capture;
  
      std::cout << "capture.open(0): " << capture.open(0) << std::endl;
  
      std::cout << "NOOO" << std::endl;
  
      namedWindow("video", 1);
  
  
  
      // set framerate to record and capture at
  
      int framerate = 15;
  
  
  
      // Get the properties from the camera
  
      double width = capture.get(CV_CAP_PROP_FRAME_WIDTH);
  
      double height = capture.get(CV_CAP_PROP_FRAME_HEIGHT);
  
  
  
      // print camera frame size
  
      //cout << "Camera properties\n";
  
      //cout << "width = " << width << endl <<"height = "<< height << endl;
  
  
  
      // Create a matrix to keep the retrieved frame
  
      Mat frame;
  
  
  
      // Create the video writer
  
      VideoWriter video("capture.avi",0, framerate, cvSize((int)width,(int)height) );
  
  
  
      // initialize initial timestamps
  
      nextFrameTimestamp = microsec_clock::local_time();
  
      currentFrameTimestamp = nextFrameTimestamp;
  
      td = (currentFrameTimestamp - nextFrameTimestamp);
  
  
  
      // start thread to begin capture and populate Mat frame
  
      boost::thread captureThread(captureFunc, &frame, &capture);
  
      // loop infinitely
  
      for(bool q=true;q;)
  
      {
  
          if(frame.empty()){continue;}
  
          //if(cvWaitKey( 5 ) == 'q'){ q=false; }
  
          // wait for X microseconds until 1second/framerate time has passed after previous frame write
  
          while(td.total_microseconds() < 1000000/framerate){
  
              //determine current elapsed time
  
              currentFrameTimestamp = microsec_clock::local_time();
  
              td = (currentFrameTimestamp - nextFrameTimestamp);
  
              if(cvWaitKey( 5 ) == 'q'){
  
                  std::cout << "B" << std::endl;
  
                  q=false;
  
                  boost::posix_time::time_duration timeout = boost::posix_time::milliseconds(0);
  
                  captureThread.timed_join(timeout);
  
                  break;
  
              }
  
          }
  
  
  
          // determine time at start of write
  
          initialLoopTimestamp = microsec_clock::local_time();
  
  
  
          // Save frame to video
  
          video << frame;
  
          imshow("video", frame);
  
  
  
          //write previous and current frame timestamp to console
  
          cout << nextFrameTimestamp << " " << currentFrameTimestamp << " ";
  
  
  
          // add 1second/framerate time for next loop pause
  
          nextFrameTimestamp = nextFrameTimestamp + microsec(1000000/framerate);
  
  
  
          // reset time_duration so while loop engages
  
          td = (currentFrameTimestamp - nextFrameTimestamp);
  
  
  
          //determine and print out delay in ms, should be less than 1000/FPS
  
          //occasionally, if delay is larger than said value, correction will occur
  
          //if delay is consistently larger than said value, then CPU is not powerful
  
          // enough to capture/decompress/record/compress that fast.
  
          finalLoopTimestamp = microsec_clock::local_time();
  
          td1 = (finalLoopTimestamp - initialLoopTimestamp);
  
          delayFound = td1.total_milliseconds();
  
          cout << delayFound << endl;
  
  
  
          //output will be in following format
  
          //[TIMESTAMP OF PREVIOUS FRAME] [TIMESTAMP OF NEW FRAME] [TIME DELAY OF WRITING]
  
          if(!q || cvWaitKey( 5 ) == 'q'){
  
              std::cout << "C" << std::endl;
  
              q=false;
  
              boost::posix_time::time_duration timeout = boost::posix_time::milliseconds(0);
  
              captureThread.timed_join(timeout);
  
              break;
  
          }
  
      }
  
  
  
      // Exit
  
      return 0;
  
  }

  

• cannot open http://[wowza-ip-address]:8086/streammanager

  26 août 2017, par mahdi gh

  I’m following this guide for publishing mpegts to wowza server. but when I try to navigate to http://[wowza-ip-address]:8086/streammanager it redirects to http://[wowza-ip-address]:8086/enginemanager

  What should I do ?
  here is the link for guide page : How to publish and play a live stream (MPEG-TS based encoder)

• Windows FFMPEG : Open Icecast Stream and output Metadata / "icy_metadata_packet" continuously

  6 octobre 2017, par Henry

  I managed to open a mp3 stream and save it to 6-second-files continuously.

  What I can’t find is a way to save the song titles to a file or output them.

  I came across "icy_metadata_packet" which should do exactly what I need but it is not well-documented as it seems. Can I use that option in the command line as an option or do I need a script of some sort to put this value somewhere ?
  If so, what’s the easiest way/language for a script like this ? (maybe a .bat file ?)

  Thanks in advance for your help !