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• Capture from multiple streams concurrently, best way to do it and how to reduce CPU usage

  19 juin 2019, par DRONE_6969

  I am currently in the process of writing an application that will capture a lot of RTSP streams(in my case its 12) and display it on the QT widget. The problem arouses when I am going beyond around 6-7 streams, the CPU usage spikes and there is visible stutter.

  The reason why I think that it is not QT draw function is because I have done some checking to measure how much time it takes to draw an incoming image from camera and just sample images I had, it is always a lot less than 33 milliseconds(even if there are 12 widgets being updated).

  I also just ran opencv capture method without drawing and got pretty much the same CPU consumption as if I was drawing the frames (lost like 10% CPU at most and GPU usage went to zero).

  IMPORTANT : I am using RTSP stream which is a h264 stream.

  IF IT MATTERS MY SPECS :

  Intel Core i7-6700 @ 3.40GHZ(8 CPUS)
  Memory : 16gb
  GPU : Intel HD Graphics 530

  (Also I ran my code on a computer with dedicated Graphics card, it did eliminate some stutter but CPU usage is still pretty high)

  I am currently using OPENCV 4.1.0 with GSTREAMER enabled and built, I also have the OPENCV-WORLD version, there is no difference in performance.

  I have created a special class called Camera that holds its frame size constraints and various control functions as well stream function. The stream function is being ran on a separate thread, whenever stream() function is done with current frame it sends ready Mat via onNewFrame event I created which converts to QPixmap and updates widget’s lastImage variable. This way I can update image in a more thread safe way.

  I have tried to manipulate those VideoCapture.set() values, but it didn’t really help.

  This is my stream function (Ignore the bool return, it doesn’t do anything it is a remnant from couple of minutes ago when I was trying to use std::async) :

  bool Camera::stream() {
  
      /* This function is meant to run on a separate thread and fill up the buffer independantly of
  
      main stream thread */
  
      //cv::setNumThreads(100);
  
      /* Rules for these slightly changed! */
  
      Mat pre;  // Grab initial undoctored frame
  
      //pre = Mat::zeros(size, CV_8UC1);
  
      Mat frame; // Final modified frame
  
      frame = Mat::zeros(size, CV_8UC1);
  
      if (!pre.isContinuous()) pre = pre.clone();
  
  
  
      ipCam.open(streamUrl, CAP_FFMPEG);
  
  
  
  
  
      while (ipCam.isOpened() && capture) {
  
          // If camera is opened wel need to capture and process the frame
  
          try {
  
              auto start = std::chrono::system_clock::now();
  
  
  
              ipCam >> pre;
  
  
  
              if (pre.empty()) {
  
                  /* Check for blank frame, return error if there is a blank frame*/
  
                  cerr << id << ": ERROR! blank frame grabbed\n";
  
                  for (FrameListener* i : clients) {
  
                      i->onNotification(1); // Notify clients about this shit
  
                  }
  
                  break;
  
              }
  
  
  
              else {
  
                  // Only continue if frame not empty
  
  
  
                  if (pre.cols != size.width && pre.rows != size.height) {
  
                      resize(pre, frame, size);
  
                      pre.release();
  
                  }
  
                  else {
  
                      frame = pre;
  
                  }
  
  
  
                  dPacket* pack = new dPacket{id,&frame};
  
                  for (auto i : clients) {
  
                      i->onPNewFrame(pack);
  
                  }
  
                  frame.release();
  
                  delete pack;
  
              }
  
          }
  
  
  
          catch (int e) {
  
              cout << endl << "-----Exception during capture process! CODE " << e << endl;
  
          }
  
          // End camera manipulations
  
      }
  
  
  
      cout << "Camera timed out, or connection is closed..." << endl;
  
      if (tryResetConnection) {
  
          cout << "Reconnection flag is set, retrying after 3 seconds..." << endl;
  
          for (FrameListener* i : clients) {
  
              i->onNotification(-1); // Notify clients about this shit
  
          }
  
          this_thread::sleep_for(chrono::milliseconds(3000));
  
          stream();
  
      }
  
  
  
      return true;
  
  }

  This is my onPNewFrame function. The conversion is still being done on camera’s thread because it was called within stream() and therefore is within that scope(and I also checked) :

  void GLWidget::onPNewFrame(dPacket* inPack) {
  
      lastFlag = 0;
  
  
  
      if (bufferEnabled) {
  
          buffer.push(QPixmap::fromImage(toQImageFromPMat(inPack->frame)));
  
      }
  
      else {
  
          if (playing) {
  
              /* Only process if this widget is playing */
  
              frameProcessing = true;
  
              lastImage.convertFromImage(toQImageFromPMat(inPack->frame));
  
              frameProcessing = false;
  
          }
  
      }
  
  
  
      if (lastFlag != -1 && !lastImage.isNull()) {
  
          connecting = false;
  
      }
  
      else {
  
          connecting = true;
  
      }
  
  }

  This is my Mat to QImage :

  QImage GLWidget::toQImageFromPMat(cv::Mat* mat) {
  
  
  
  
  
  
  
      return QImage(mat->data, mat->cols, mat->rows, QImage::Format_RGB888).rgbSwapped();

  NOTE : not converting does not result in CPU boost (at least not a significant one).

  Minimal verifiable example

  This program is large. I am going to paste GLWidget.cpp and GLWidget.h as well as Camera.h and Camera.cpp. You can put GLWidget into anything just as long as you spawn more than 6 of it. Camera relies on the CamUtils, but it is possible to just paste url in videocapture

  I also supplied CamUtils, just in case

  Camera.h :

  #pragma once
  
  #include <iostream>
  
  #include <vector>
  
  #include <fstream>
  
  #include <map>
  
  #include <string>
  
  #include <sstream>
  
  #include <algorithm>
  
  #include "FrameListener.h"
  
  #include 
  
  #include <thread>
  
  #include "CamUtils.h"
  
  #include <ctime>
  
  #include "dPacket.h"
  
  
  
  using namespace std;
  
  using namespace cv;
  
  
  
  class Camera
  
  {
  
  
  
      /*
  
          CLEANED UP!
  
          Camera now is only responsible for streaming and echoing captured frames.
  
          Frames are now wrapped into dPacket struct.
  
      */
  
  
  
  
  
  private:
  
      string id;
  
      vector clients;
  
      VideoCapture ipCam;
  
      string streamUrl;
  
      Size size;
  
      bool tryResetConnection = false;
  
  
  
      //TODO: Remove these as they are not going to be used going on:
  
      bool isPlaying = true;
  
      bool capture = true;
  
  
  
      //SECRET FEATURES:
  
      bool detect = false;
  
  
  
  
  
  public:
  
      Camera(string url, int width = 480, int height = 240, bool detect_=false);
  
      bool stream();
  
      void setReconnectable(bool newReconStatus);
  
      void addListener(FrameListener* client);
  
      vector<bool> getState();    // Returns current state: vector[0] stream state; vector[1] stream state; TODO: Remove this as this is no longer should control behaviour
  
      void killStream();
  
      bool getReconnectable();
  
  };
  
  
  
  </bool></ctime></thread></algorithm></sstream></string></map></fstream></vector></iostream>

  Camera.cpp

  #include "Camera.h"
  
  
  
  
  
  Camera::Camera(string url, int width, int height, bool detect_) // Default 240p
  
  {
  
      streamUrl = url; // Prepare url
  
      size = Size(width, height);
  
      detect = detect_;
  
  
  
  }
  
  
  
  void Camera::addListener(FrameListener* client) {
  
      clients.push_back(client);
  
  }
  
  
  
  
  
  /*
  
                  TEST CAMERAS(Paste into cameras.dViewer):
  
                  {"id":"96a73796-c129-46fc-9c01-40acd8ed7122","ip":"176.57.73.231","password":"null","username":"null"},
  
                  {"id":"96a73796-c129-46fc-9c01-40acd8ed7122","ip":"176.57.73.231","password":"null","username":"null"},
  
                  {"id":"96a73796-c129-46fc-9c01-40acd8ed7144","ip":"172.20.101.13","password":"admin","username":"root"}
  
                  {"id":"96a73796-c129-46fc-9c01-40acd8ed7144","ip":"172.20.101.13","password":"admin","username":"root"}
  
  
  
  */
  
  
  
  
  
  
  
  bool Camera::stream() {
  
      /* This function is meant to run on a separate thread and fill up the buffer independantly of
  
      main stream thread */
  
      //cv::setNumThreads(100);
  
      /* Rules for these slightly changed! */
  
      Mat pre;  // Grab initial undoctored frame
  
      //pre = Mat::zeros(size, CV_8UC1);
  
      Mat frame; // Final modified frame
  
      frame = Mat::zeros(size, CV_8UC1);
  
      if (!pre.isContinuous()) pre = pre.clone();
  
  
  
      ipCam.open(streamUrl, CAP_FFMPEG);
  
  
  
      while (ipCam.isOpened() && capture) {
  
          // If camera is opened wel need to capture and process the frame
  
          try {
  
              auto start = std::chrono::system_clock::now();
  
  
  
              ipCam >> pre;
  
  
  
              if (pre.empty()) {
  
                  /* Check for blank frame, return error if there is a blank frame*/
  
                  cerr << id << ": ERROR! blank frame grabbed\n";
  
                  for (FrameListener* i : clients) {
  
                      i->onNotification(1); // Notify clients about this shit
  
                  }
  
                  break;
  
              }
  
  
  
              else {
  
                  // Only continue if frame not empty
  
  
  
                  if (pre.cols != size.width && pre.rows != size.height) {
  
                      resize(pre, frame, size);
  
                      pre.release();
  
                  }
  
                  else {
  
                      frame = pre;
  
                  }
  
  
  
                  auto end = std::chrono::system_clock::now();
  
                  std::time_t ts = std::chrono::system_clock::to_time_t(end);
  
                  dPacket* pack = new dPacket{ id,&frame};
  
                  for (auto i : clients) {
  
                      i->onPNewFrame(pack);
  
                  }
  
                  frame.release();
  
                  delete pack;
  
              }
  
          }
  
  
  
          catch (int e) {
  
              cout << endl << "-----Exception during capture process! CODE " << e << endl;
  
          }
  
          // End camera manipulations
  
      }
  
  
  
      cout << "Camera timed out, or connection is closed..." << endl;
  
      if (tryResetConnection) {
  
          cout << "Reconnection flag is set, retrying after 3 seconds..." << endl;
  
          for (FrameListener* i : clients) {
  
              i->onNotification(-1); // Notify clients about this shit
  
          }
  
          this_thread::sleep_for(chrono::milliseconds(3000));
  
          stream();
  
      }
  
  
  
      return true;
  
  }
  
  
  
  
  
  void Camera::killStream(){
  
      tryResetConnection = false;
  
      capture = false;
  
      ipCam.release();
  
  }
  
  
  
  void Camera::setReconnectable(bool reconFlag) {
  
      tryResetConnection = reconFlag;
  
  }
  
  
  
  bool Camera::getReconnectable() {
  
      return tryResetConnection;
  
  }
  
  
  
  vector<bool> Camera::getState() {
  
      vector<bool> states;
  
      states.push_back(isPlaying);
  
      states.push_back(ipCam.isOpened());
  
      return states;
  
  }
  
  
  
  
  
  
  
  </bool></bool>

  GLWidget.h :

  #ifndef GLWIDGET_H
  
  #define GLWIDGET_H
  
  
  
  #include <qopenglwidget>
  
  #include <qmouseevent>
  
  #include "FrameListener.h"
  
  #include "Camera.h"
  
  #include "FrameListener.h"
  
  #include 
  
  #include "Camera.h"
  
  #include "CamUtils.h"
  
  #include 
  
  #include "dPacket.h"
  
  #include <chrono>
  
  #include <ctime>
  
  #include 
  
  #include "FullScreenVideo.h"
  
  #include <qmovie>
  
  #include "helper.h"
  
  #include <iostream>
  
  #include <qpainter>
  
  #include <qtimer>
  
  
  
  class Helper;
  
  
  
  class GLWidget : public QOpenGLWidget, public FrameListener
  
  {
  
      Q_OBJECT
  
  
  
  public:
  
      GLWidget(std::string camId, CamUtils *cUtils, int width, int height, bool denyFullScreen_ = false, bool detectFlag_=false, QWidget* parent = nullptr);
  
      void killStream();
  
      ~GLWidget();
  
  
  
  public slots:
  
      void animate();
  
      void setBufferEnabled(bool setState);
  
      void setCameraRetryConnection(bool setState);
  
      void GLUpdate();            // Call to update the widget
  
      void onRightClickMenu(const QPoint&amp; point);
  
  
  
  protected:
  
      void paintEvent(QPaintEvent* event) override;
  
      void onPNewFrame(dPacket* frame);
  
      void onNotification(int alert_code);
  
  
  
  
  
  private:
  
      // Objects and resourses
  
      Helper* helper;
  
      Camera* cam;
  
      CamUtils* camUtils;
  
      QTimer* timer; // Keep track of update
  
      QPixmap lastImage;
  
      QMovie* connMov;
  
      QMovie* test;
  
  
  
      QPixmap logo;
  
  
  
      // Control fields
  
      int width;
  
      int height;
  
      int camUtilsAddr;
  
      int elapsed;
  
      std::thread* camThread;
  
      std::string camId;
  
      bool denyFullScreen = false;
  
      bool playing = true;
  
      bool streaming = true;
  
      bool debug = false;
  
      bool connecting = true;
  
      int lastFlag = 0;
  
  
  
  
  
      // Debug fields
  
      std::chrono::high_resolution_clock::time_point lastFrameAt;
  
      std::chrono::high_resolution_clock::time_point now;
  
      std::chrono::duration<double> painTime; // time took to draw last frame
  
  
  
      //Buffer stuff
  
      std::queue<qpixmap> buffer;
  
      bool bufferEnabled = false;
  
      bool initialBuffer = false;
  
      bool buffering = true;
  
      bool frameProcessing = false;
  
  
  
  
  
  
  
      //Functions
  
      QImage toQImageFromPMat(cv::Mat* inFrame);
  
      void mousePressEvent(QMouseEvent* event) override;
  
      void drawImageGLLatest(QPainter* painter, QPaintEvent* event, int elapsed);
  
      void drawOnPaused(QPainter* painter, QPaintEvent* event, int elapsed);
  
      void drawOnStatus(int statusFlag, QPainter* painter, QPaintEvent* event, int elapsed);
  
  };
  
  
  
  #endif
  
  
  
  </qpixmap></double></qtimer></qpainter></iostream></qmovie></ctime></chrono></qmouseevent></qopenglwidget>

  GLWidget.cpp :

  #include "glwidget.h"
  
  #include <future>
  
  
  
  
  
  FullScreenVideo* fullScreen;
  
  
  
  GLWidget::GLWidget(std::string camId_, CamUtils* cUtils, int width_, int height_,  bool denyFullScreen_, bool detectFlag_, QWidget* parent)
  
      : QOpenGLWidget(parent), helper(helper)
  
  {
  
      cout &lt;&lt; "Player for CAMERA " &lt;&lt; camId_ &lt;&lt; endl;
  
  
  
      /* Underlying properties */
  
      camUtils = cUtils;
  
      cout &lt;&lt; "GLWidget Incoming CamUtils addr " &lt;&lt; camUtils &lt;&lt; endl;
  
      cout &lt;&lt; "GLWidget Set CamUtils addr " &lt;&lt; camUtils &lt;&lt; endl;
  
      camId = camId_;
  
      elapsed = 0;
  
      width = width_ + 5;
  
      height = height_ + 5;
  
      helper = new Helper();
  
      setFixedSize(width, height);
  
      denyFullScreen = denyFullScreen_;
  
  
  
      /* Camera capture thread */
  
      cam = new Camera(camUtils->getCameraStreamURL(camId), width_, height_, detectFlag_);
  
      cam->addListener(this);
  
  
  
      /* Sync states */
  
      vector<bool> initState = cam->getState();
  
      playing = initState[0];
  
      streaming = initState[1];
  
      cout &lt;&lt; "Initial states: " &lt;&lt; playing &lt;&lt; " " &lt;&lt; streaming &lt;&lt; endl;
  
      camThread = new std::thread(&amp;Camera::stream, cam);
  
      cout &lt;&lt; "================================================" &lt;&lt; endl;
  
  
  
      // Right click set up
  
      setContextMenuPolicy(Qt::CustomContextMenu);
  
  
  
  
  
      /* Loading gif */
  
      connMov = new QMovie("establishingConnection.gif");
  
      connMov->start();
  
      QString url = R"(RLC-logo.png)";
  
      logo = QPixmap(url);
  
      QTimer* timer = new QTimer(this);
  
      connect(timer, SIGNAL(timeout()), this, SLOT(GLUpdate()));
  
      timer->start(1000/30);
  
      playing = true;
  
  
  
  }
  
  
  
  /* SYSTEM */
  
  void GLWidget::animate()
  
  {
  
      elapsed = (elapsed + qobject_cast(sender())->interval()) % 1000;
  
      std::cout &lt;&lt; elapsed &lt;&lt; "\n";
  
  }
  
  
  
  
  
  void GLWidget::GLUpdate() {
  
      /* Process descisions before update call */
  
      if (bufferEnabled) {
  
          /* Process buffer before update */
  
          now = chrono::high_resolution_clock::now();
  
          std::chrono::duration timeSinceLastUpdate = now - lastFrameAt;
  
          if (timeSinceLastUpdate.count() > 25) {
  
              if (buffer.size() > 1 &amp;&amp; playing) {
  
                  lastImage.swap(buffer.front());
  
                  buffer.pop();
  
                  lastFrameAt = chrono::high_resolution_clock::now();
  
              }
  
          }
  
          //update(); // Update
  
      }
  
      else {
  
          /* No buffer */
  
      }
  
      repaint();
  
  }
  
  
  
  
  
  /* EVENTS */
  
  void GLWidget::onRightClickMenu(const QPoint&amp; point) {
  
      cout &lt;&lt; "Right click request got" &lt;&lt; endl;
  
  
  
      QPoint globPos = this->mapToGlobal(point);
  
      QMenu myMenu;
  
  
  
      if (!denyFullScreen) {
  
          myMenu.addAction("Open Full Screen");
  
      }
  
      myMenu.addAction("Toggle Debug Info");
  
  
  
  
  
      QAction* selected = myMenu.exec(globPos);
  
  
  
      if (selected) {
  
          string optiontxt = selected->text().toStdString();
  
  
  
          if (optiontxt == "Open Full Screen") {
  
              cout &lt;&lt; "Chose to open full screen of " &lt;&lt; camId &lt;&lt; endl;
  
              fullScreen = new FullScreenVideo(bufferEnabled, this);
  
              fullScreen->setUpView(camUtils, camId);
  
              fullScreen->show();
  
              playing = false;
  
          }
  
  
  
          if (optiontxt == "Toggle Debug Info") {
  
              cout &lt;&lt; "Chose to toggle debug of " &lt;&lt; camId &lt;&lt; endl;
  
              debug = !debug;
  
          }
  
      }
  
      else {
  
          cout &lt;&lt; "Chose nothing!" &lt;&lt; endl;
  
      }
  
  
  
  
  
  }
  
  
  
  
  
  
  
  void GLWidget::onPNewFrame(dPacket* inPack) {
  
      lastFlag = 0;
  
  
  
      if (bufferEnabled) {
  
          buffer.push(QPixmap::fromImage(toQImageFromPMat(inPack->frame)));
  
      }
  
      else {
  
          if (playing) {
  
              /* Only process if this widget is playing */
  
              frameProcessing = true;
  
              lastImage.convertFromImage(toQImageFromPMat(inPack->frame));
  
              frameProcessing = false;
  
          }
  
      }
  
  
  
      if (lastFlag != -1 &amp;&amp; !lastImage.isNull()) {
  
          connecting = false;
  
      }
  
      else {
  
          connecting = true;
  
      }
  
  }
  
  
  
  
  
  void GLWidget::onNotification(int alert) {
  
      lastFlag = alert;   
  
  }
  
  
  
  
  
  /* Paint events*/
  
  
  
  
  
  void GLWidget::paintEvent(QPaintEvent* event)
  
  {
  
      QPainter painter(this);
  
  
  
          if (lastFlag != 0 || connecting) {
  
              drawOnStatus(lastFlag, &amp;painter, event, elapsed);
  
          }
  
          else {
  
  
  
              /* Actual frame drawing */
  
              if (playing) {
  
                  if (!frameProcessing) {
  
                      drawImageGLLatest(&amp;painter, event, elapsed);
  
                  }
  
              }
  
              else {
  
                  drawOnPaused(&amp;painter, event, elapsed);
  
              }
  
          }
  
      painter.end();
  
  
  
  }
  
  
  
  
  
  /* DRAWING STUFF */
  
  
  
  void GLWidget::drawOnStatus(int statusFlag, QPainter* bgPaint, QPaintEvent* event, int elapsed) {
  
  
  
      QString str;
  
      QFont font("times", 15);
  
      bgPaint->eraseRect(QRect(0, 0, width, height));
  
      if (!lastImage.isNull()) {
  
          bgPaint->drawPixmap(QRect(0, 0, width, height), lastImage);
  
      }
  
      /* Test background painting */
  
      if (connecting) {
  
          string k = "Connecting to " + camUtils->getIp(camId);
  
          str.append(k.c_str());
  
      }
  
      else {
  
          switch (statusFlag) {
  
          case 1:
  
              str = "Blank frame received...";
  
              break;
  
  
  
          case -1:
  
              if (cam->getReconnectable()) {
  
                  str = "Connection lost, will try to reconnect.";
  
                  bgPaint->setOpacity(0.3);
  
              }
  
              else {
  
                  str = "Connection lost...";
  
                  bgPaint->setOpacity(0.3);
  
              }
  
  
  
              break;
  
          }
  
      }
  
  
  
      bgPaint->drawPixmap(QRect(0, 0, width, height), QPixmap::fromImage(connMov->currentImage()));
  
      bgPaint->setPen(Qt::red);
  
      bgPaint->setFont(font);
  
      QFontMetrics fm(font);
  
      const QRect kek(0, 0, fm.width(str), fm.height());
  
      QRect bound;
  
      bgPaint->setOpacity(1);
  
      bgPaint->drawText(bgPaint->viewport().width()/2 - kek.width()/2, bgPaint->viewport().height()/2 - kek.height(), str);
  
  
  
      bgPaint->drawPixmap(bgPaint->viewport().width() / 2 - logo.width()/2, height - logo.width() - 15, logo);
  
  
  
  }
  
  
  
  
  
  
  
  void GLWidget::drawOnPaused(QPainter* painter, QPaintEvent* event, int elapsed) {
  
      painter->eraseRect(0, 0, width, height);
  
      QFont font = painter->font();
  
      font.setPointSize(18);
  
      painter->setPen(Qt::red);
  
      QFontMetrics fm(font);
  
      QString str("Paused");
  
      painter->drawPixmap(QRect(0, 0, width, height),lastImage);
  
      painter->drawText(QPoint(painter->viewport().width() - fm.width(str), 50), str);
  
  
  
      if (debug) {
  
          QFont font = painter->font();
  
          font.setPointSize(25);
  
          painter->setPen(Qt::red);
  
          string camMess = "CAMID: " + camId;
  
          QString mess(camMess.c_str());
  
          string camIp = "IP: " + camUtils->getIp(camId);
  
          QString ipMess(camIp.c_str());
  
          QString bufferSize("Buffer size: " + QString::number(buffer.size()));
  
          QString lastFrameText("Last frame draw time: " + QString::number(painTime.count()) + "s");
  
          painter->drawText(QPoint(10, 50), mess);
  
          painter->drawText(QPoint(10, 60), ipMess);
  
          QString bufferState;
  
          if (bufferEnabled) {
  
              bufferState = QString("Experimental BUFFER is enabled!");
  
              QString currentBufferSize("Current buffer load: " + QString::number(buffer.size()));
  
              painter->drawText(QPoint(10, 80), currentBufferSize);
  
          }
  
          else {
  
              bufferState = QString("Experimental BUFFER is disabled!");
  
          }
  
          painter->drawText(QPoint(10, 70), bufferState);
  
          painter->drawText(QPoint(10, height - 25), lastFrameText);
  
      }
  
  }
  
  
  
  
  
  void GLWidget::drawImageGLLatest(QPainter* painter, QPaintEvent* event, int elapsed) {
  
      auto start = chrono::high_resolution_clock::now();
  
      painter->drawPixmap(QRect(0, 0, width, height), lastImage);
  
      if (debug) {
  
          QFont font = painter->font();
  
          font.setPointSize(25);
  
          painter->setPen(Qt::red);
  
          string camMess = "CAMID: " + camId;
  
          QString mess(camMess.c_str());
  
          string camIp = "IP: " + camUtils->getIp(camId);
  
          QString ipMess(camIp.c_str());
  
          QString bufferSize("Buffer size: " + QString::number(buffer.size()));
  
          QString lastFrameText("Last frame draw time: " + QString::number(painTime.count()) + "s");
  
          painter->drawText(QPoint(10, 50), mess);
  
          painter->drawText(QPoint(10, 60), ipMess);
  
          QString bufferState;
  
          if(bufferEnabled){
  
              bufferState = QString("Experimental BUFFER is enabled!");
  
              QString currentBufferSize("Current buffer load: " + QString::number(buffer.size()));
  
              painter->drawText(QPoint(10,80), currentBufferSize);
  
          }
  
          else {
  
              bufferState = QString("Experimental BUFFER is disabled!");
  
              QString currentBufferSize("Current buffer load: " + QString::number(buffer.size()));
  
              painter->drawText(QPoint(10, 80), currentBufferSize);
  
          }
  
          painter->drawText(QPoint(10, 70), bufferState);
  
          painter->drawText(QPoint(10, height - 25), lastFrameText);
  
  
  
      }
  
      auto end = chrono::high_resolution_clock::now();
  
      painTime = end - start;
  
  }
  
  
  
  
  
  
  
  /* END DRAWING STUFF */
  
  
  
  
  
  
  
  /* UI EVENTS */
  
  
  
  void GLWidget::mousePressEvent(QMouseEvent* e) {
  
  
  
      if (e->button() == Qt::LeftButton) {
  
          if (fullScreen == nullptr || !fullScreen->isVisible()) { // Do not unpause if window is opened
  
              playing = !playing;
  
          }
  
      }
  
  
  
      if (e->button() == Qt::RightButton) {
  
          onRightClickMenu(e->pos());
  
      }
  
  }
  
  
  
  
  
  
  
  /* Utilities */
  
  QImage GLWidget::toQImageFromPMat(cv::Mat* mat) {
  
  
  
  
  
  
  
      return QImage(mat->data, mat->cols, mat->rows, QImage::Format_RGB888).rgbSwapped();
  
  
  
  
  
  
  
  }
  
  
  
  /* State control */
  
  
  
  void GLWidget::killStream() {
  
      cam->killStream();
  
      camThread->join();
  
  }
  
  
  
  void GLWidget::setBufferEnabled(bool newBufferState) {
  
      cout &lt;&lt; "Player: " &lt;&lt; camId &lt;&lt; ", buffer state updated: " &lt;&lt; newBufferState &lt;&lt; endl;
  
      bufferEnabled = newBufferState;
  
      buffer.empty();
  
  }
  
  
  
  void GLWidget::setCameraRetryConnection(bool newState) {
  
      cam->setReconnectable(newState);
  
  }
  
  
  
  /* Destruction */
  
  GLWidget::~GLWidget() {
  
      cam->killStream();
  
      camThread->join();
  
  }
  
  </bool></future>

  CamUtils.h :

  #pragma once
  
  #include <iostream>
  
  #include <vector>
  
  #include <fstream>
  
  #include <map>
  
  #include <string>
  
  #include <sstream>
  
  #include <algorithm>
  
  #include <nlohmann></nlohmann>json.hpp>
  
  
  
  using namespace std;
  
  using json = nlohmann::json;
  
  
  
  class CamUtils
  
  {
  
  private:
  
  
  
      string camDb = "cameras.dViewer";
  
      map> cameraList; // Legacy
  
      json cameras;
  
      ofstream dbFile;
  
      bool dbExists(); // Always hard coded
  
  
  
      /* Old IMPLEMENTATION */
  
      void writeLineToDb_(const string&amp; content, bool append = false);
  
      void loadCameras_();
  
  
  
      /* JSON based */
  
      void loadCameras();
  
  
  
  public:
  
      CamUtils();
  
      string generateRandomString(size_t length);
  
      string getCameraStreamURL(string cameraId) const;
  
      string saveCamera(string ip, string username, string pass); // Return generated id
  
      vector<string> listAllCameraIds();
  
      string getIp(string cameraId);
  
  };
  
  
  
  
  
  </string></algorithm></sstream></string></map></fstream></vector></iostream>

  CamUtils.cpp :

  #include "CamUtils.h"
  
  #pragma comment(lib, "rpcrt4.lib")  // UuidCreate - Minimum supported OS Win 2000
  
  #include 
  
  #include <iostream>
  
  
  
  CamUtils::CamUtils()
  
  {
  
      if (!dbExists()) {
  
          ofstream dbFile;
  
          dbFile.open(camDb);
  
          cameras["cameras"] = json::array();
  
          dbFile &lt;&lt; cameras &lt;&lt; std::endl;
  
          dbFile.close();
  
  
  
      }
  
      else {
  
          loadCameras();
  
      }
  
  }
  
  
  
  
  
  
  
  
  
  vector<string> CamUtils::listAllCameraIds() {
  
      vector<string> ids;
  
      cout &lt;&lt; "IN LIST " &lt;&lt; endl;
  
      for (auto&amp; cam : cameras["cameras"]) {
  
          ids.push_back(cam["id"].get<string>());
  
          //cout &lt;&lt; cam["id"].get<string>() &lt;&lt; std::endl;
  
      }
  
      return ids;
  
  }
  
  
  
  string CamUtils::getIp(string id) {
  
      vector<string> camDetails = cameraList[id];
  
      string ip = "NO IP WILL DISPLAYED UNTIL I FIGURE OUT A BUG";
  
      for (auto&amp; cam : cameras["cameras"]) {
  
          if (id == cam["id"]) {
  
              ip = cam["ip"].get<string>();
  
          }
  
      }
  
  
  
      return ip;
  
  }
  
  
  
  string CamUtils::getCameraStreamURL(string id) const {
  
      string url = "err"; // err is the default, it will be overwritten in case id is found, dont forget to check for it
  
  
  
      for (auto&amp; cam : cameras["cameras"]) {
  
          if (id == cam["id"]) {
  
              if (cam["username"].get<string>() == "null") {
  
                  url = "rtsp://" + cam["ip"].get<string>() + ":554/axis-media/media.amp?tcp";
  
              }
  
              else {
  
                  url = "rtsp://" + cam["username"].get<string>() + ":" + cam["password"].get<string>() + "@" + cam["ip"].get<string>() + ":554/axis-media/media.amp?streamprofile=720_30";
  
              }
  
          }
  
      }
  
  
  
      return url;  // Dont forget to check for err when using this shit
  
  }
  
  
  
  
  
  string CamUtils::saveCamera(string ip, string username, string password) {
  
      UUID uid;
  
      UuidCreate(&amp;uid);
  
      char* str;
  
      UuidToStringA(&amp;uid, (RPC_CSTR*)&amp;str);
  
      string id = str;
  
      cout &lt;&lt; "GEN: " &lt;&lt; id &lt;&lt; endl;
  
      json cam = json({}); //Create emtpy object
  
      cam["id"] = id;
  
      cam["ip"] = ip;
  
      cam["username"] = username;
  
      cam["password"] = password;
  
      cameras["cameras"].push_back(cam);
  
      std::ofstream out(camDb);
  
      out &lt;&lt; cameras &lt;&lt; std::endl;
  
      cout &lt;&lt; cameras["cameras"] &lt;&lt; endl;
  
  
  
      cout &lt;&lt; "Saved camera as " &lt;&lt; id &lt;&lt; endl;
  
      return id;
  
  }
  
  
  
  
  
  bool CamUtils::dbExists() {
  
      ifstream dbFile(camDb);
  
      return (bool)dbFile;
  
  }
  
  
  
  
  
  
  
  
  
  
  
  void CamUtils::loadCameras() {
  
      cout &lt;&lt; "Load call" &lt;&lt; endl;
  
      ifstream dbFile(camDb);
  
      string line;
  
      string wholeFile;
  
  
  
      while (std::getline(dbFile, line)) {
  
          cout &lt;&lt; line &lt;&lt; endl;
  
          wholeFile += line;
  
      }
  
      try {
  
          cameras = json::parse(wholeFile);
  
          //cout &lt;&lt; cameras["cameras"] &lt;&lt; endl;
  
  
  
      }
  
      catch (exception e) {
  
          cout &lt;&lt; e.what() &lt;&lt; endl;
  
      }
  
      dbFile.close();
  
  }
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  /*
  
      LEGACY CODE, TO BE REMOVED!
  
  
  
  */
  
  
  
  
  
  
  
  void CamUtils::loadCameras_() {
  
      /* 
  
          LEGACY CODE:
  
          This used to be the way to load cameras, but I moved on to JSON based configuration so this is no longer needed and will be removed soon
  
      */
  
  
  
      ifstream dbFile(camDb);
  
      string line;
  
      while (std::getline(dbFile, line)) {
  
          /*
  
              This function load camera data to the map:
  
              The order MUST be the following: 0:ID, 1:IP, 2:USERNAME, 3:PASSWORD.
  
              Always delimited with | no spaces between!
  
          */
  
          if (!line.empty()) {
  
              stringstream ss(line);
  
              string item;
  
              vector<string> splitString;
  
  
  
              while (std::getline(ss, item, '|')) {
  
                  splitString.push_back(item);
  
              }
  
              if (splitString.size() > 0) {
  
                  /* Dont even parse if the program didnt split right*/
  
                  //cout &lt;&lt; "Split string: " &lt;&lt; splitString.size() &lt;&lt; "\n";
  
                  for (int i = 0; i &lt; (splitString.size()); i++) cameraList[splitString[0]].push_back(splitString[i]);
  
              }
  
          }
  
      }
  
  }
  
  
  
  
  
  
  
  void CamUtils::writeLineToDb_(const string &amp; content, bool append) {
  
      ofstream dbFile;
  
      cout &lt;&lt; "Creating?";
  
      if (append) {
  
          dbFile.open(camDb, ios_base::app);
  
      }
  
      else {
  
          dbFile.open(camDb);
  
      }
  
  
  
      dbFile &lt;&lt; content.c_str() &lt;&lt; "\r\n";
  
      dbFile.flush();
  
  }
  
  
  
  /* JSON Reworx */
  
  
  
  
  
  
  
  
  
  string CamUtils::generateRandomString(size_t length)
  
  {
  
      const char* charmap = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  
      const size_t charmapLength = strlen(charmap);
  
      auto generator = [&amp;]() { return charmap[rand() % charmapLength]; };
  
      string result;
  
      result.reserve(length);
  
      generate_n(back_inserter(result), length, generator);
  
      return result;
  
  }
  
  </string></string></string></string></string></string></string></string></string></string></string></string></iostream>

  End of example

  How would I go about decreasing CPU usage when dealing with large amount of streams ?

• Today we celebrate Data Privacy Day 2019

  28 janvier 2019, par Jake Thornton — Privacy
  Today we celebrate Data Privacy Day 2019 !!!

  What is Data Privacy Day ?

  Wikipedia tells us that : The purpose of Data Privacy Day is to raise awareness and promote privacy and data protection best practices.

  Our personal data is our online identity. When you think what personal data means – our phone records, credit card transactions, GPS position, IP addresses, browsing history and so much more. All so valuable and personal to us as human beings.

  That’s why we cannot take our personal data online for granted. We have a right to know which websites collect our data and how it’s then used, something that’s often not visible or easily recognisable when browsing.

  What Data Privacy Day means to Matomo

  Every year the team at Matomo uses this day as a chance to reflect on how far the Matomo (formerly Piwik) project has come. But then also reflect how far we still have to go in spreading the message that our data and personal information online matters.

  2018 saw the introduction of the EU General Data Protection Regulation (GDPR) to protect people’s data online. As a team, Matomo was at the forefront of this development in the analytics space and have since built a GDPR Manager to ensure our users can be fully compliant with the GDPR.

  With every new release of Matomo, we are ensuring that security continues to be at the highest standard and we will continue to be committed to our bug bounty program. Our most recent release of Matomo 3.8.0 alone added a Two Factor Authentication (2FA) feature and a password brute force prevention.

  What next for Matomo and data privacy ?

  As always, security is a top priority for every new release of Matomo and continues to only get better and better. We have a duty to spread our message further that the protection of personal data matters and today is a vital reminder of that. We are, and forever will be, the #1 open-source (and free to use) web analytics platform in the world that fully respects user privacy and gives our users 100% data ownership.

  In 2018 we changed our name, we updated our logo and website, and advanced our platform to compete with the most powerful web analytics tools in the world, all so we can spread our message further and continue our mission.

  Come with us on this exciting journey. Now is the time to take back control of your data and let’s continue creating a safer web for everyone.

  Please help us spread this message.

• Connecting to RTSP stream via FFMpeg - 'could not find codec parameters for stream 0'

  14 novembre 2013, par user2992545

  I'm a beginner in the FFMpeg world, so please excuse me my overall level of knowledge and any mistakes.

  What I have here is a DVR, made by ITX Security. I have an SDK for it and currently I'm trying to connect to its RTSP using FFMPEG. I've been partially succesfull (i think), the best what I got was :

  `(...)bin>ffplay -user-agent "ITX Security" rtsp://ADMIN:1234@192.168.2.130:5554/live/
  
  
  
  [rtsp @ 02a242e0] UDP timeout, retrying with TCPB sq=0B f=0/0
  
  [rtsp @ 02a242e0] method PAUSE failed: 501 Not Implemented
  
  [rtsp @ 02a242e0] Could not find codec parameters for stream 0 (Video: h264):unspecified size Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  rtsp://ADMIN:1234@192.168.2.130:5554/live/: could not find codec parameters
  
  
  
  nan:  0.000 fd=0 aq=    0KB vq=    0KB sq=    0B f=0/0`

  Is it really indicating that it has trouble in playing the stream (because it lacks a proper codec ?) - or am I just not getting the point ?

  I've captured traffic between my computer and the DVR in question, and something is happening (at least that's what Wireshark says).

  https://www.dropbox.com/s/j65lige244kg8jt/rtsp_ffmpeg.pcap

  What am I doing wrong ?

  Regards.