Simplified videobuffer usage by copying all the buffer data -- reduces chances of memory issues across threads.

src/video/videobuffer.cpp

@@ -149,10 +149,6 @@ void imageCollectionThread(void* arg)
 // it returns so that the video capture can be recreated.
 void getALPRImages(cv::VideoCapture cap, VideoDispatcher* dispatcher)
 {
-  cv::Mat frame1;
-  cv::Mat frame2;
-  cv::Mat* receiveframe;
-  bool receiveframeisframe1 = true;
 
   while (dispatcher->active)
   {
@@ -162,11 +158,10 @@ void getALPRImages(cv::VideoCapture cap, VideoDispatcher* dispatcher)
       bool hasImage = false;
       try
       {
-	if (receiveframeisframe1)  receiveframe = &frame1;
-	else receiveframe = &frame2;
-	hasImage = cap.read(*receiveframe);
+        cv::Mat frame;
+	hasImage = cap.read(frame);
 		  // Double check the image to make sure it's valid.
-	if (!(*receiveframe).data || (*receiveframe).empty())
+	if (!frame.data || frame.empty())
 	{
 	  std::stringstream ss;
 	  ss << "Stream " << dispatcher->mjpeg_url << " received invalid frame";
@@ -175,10 +170,9 @@ void getALPRImages(cv::VideoCapture cap, VideoDispatcher* dispatcher)
 	}
 	
 	dispatcher->mMutex.lock();
-	dispatcher->setLatestFrame(receiveframe);
+	dispatcher->setLatestFrame(frame);
 	dispatcher->mMutex.unlock();
-	receiveframeisframe1 = !receiveframeisframe1;
-	  }
+      }
       catch (const std::runtime_error& error)
       {
 	// Error occured while trying to gather image.  Retry, don't exit.

src/video/videobuffer.h

@@ -31,10 +31,10 @@ class VideoDispatcher
       tthread::lock_guard<tthread::mutex> guard(mMutex);
       
       if (latestFrameNumber == lastFrameRead)
-	return -1;
+        return -1;
       
-      frame->create(latestFrame->size(), latestFrame->type());
-      latestFrame->copyTo(*frame);
+      frame->create(latestFrame.size(), latestFrame.type());
+      latestFrame.copyTo(*frame);
       
       this->lastFrameRead = this->latestFrameNumber;
       
@@ -45,11 +45,10 @@ class VideoDispatcher
       return this->lastFrameRead;
     }
     
-    void setLatestFrame(cv::Mat* frame)
+    void setLatestFrame(cv::Mat frame)
     {      
-      //tthread::lock_guard<tthread::mutex> guard(mMutex);
-      this->latestFrame = frame;
-      this->latestRegionsOfInterest = calculateRegionsOfInterest(frame);
+      frame.copyTo(this->latestFrame);
+      this->latestRegionsOfInterest = calculateRegionsOfInterest(&this->latestFrame);
       
       this->latestFrameNumber++;
     }
@@ -83,7 +82,7 @@ class VideoDispatcher
     tthread::mutex mMutex;
     
   private:
-    cv::Mat* latestFrame;
+    cv::Mat latestFrame;
     std::vector<cv::Rect> latestRegionsOfInterest;
 };