Dear forum,
I am using this method to change from IplImage captured by OpenCV library to a QImage to use QPainter class on and paint on it another QImage, now the problem is that I am using the method in a while loop which eats up my memory (over 1GB in mere seconds) and I can't find a way around it.
Qt Code: 
  1. QImage MainWindow::IplImage2QImage(IplImage *iplImg)
  2. {
  3.     this->h = iplImg->height;
  4.     this->w = iplImg->width;
  5.     this->channels = iplImg->nChannels;
  6.     this->qimg = new QImage(w, h, QImage::Format_ARGB32);
  7.     this->data = iplImg->imageData;
  8.  
  9.     for (int y = 0; y < h; y++, data += iplImg->widthStep)
  10.     {
  11.     for (int x = 0; x < w; x++)
  12.     {
  13.     char r, g, b, a = 0;
  14.     if (channels == 1)
  15.     {
  16.     r = data[x * channels];
  17.     g = data[x * channels];
  18.     b = data[x * channels];
  19.     }
  20.     else if (channels == 3 || channels == 4)
  21.     {
  22.     r = data[x * channels + 2];
  23.     g = data[x * channels + 1];
  24.     b = data[x * channels];
  25.     }
  26.  
  27.     if (channels == 4)
  28.     {
  29.     a = data[x * channels + 3];
  30.     qimg->setPixel(x, y, qRgba(r, g, b, a));
  31.     }
  32.     else
  33.     {
  34.     qimg->setPixel(x, y, qRgb(r, g, b));
  35.     }
  36.     }
  37.     }
  38.     return *qimg;
  39. }
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now that's the method itself and the while loop for looping on frames is the following
Qt Code: 
  1. while(i<numFrames){
  2.     if(i<(SelectedFrame+numofFrames)){
  3.         cvGrabFrame(capture);
  4.         img2=cvRetrieveFrame(capture);
  5.         qimage=this->IplImage2QImage(img2);
  6.         QPainter p(&qimage);
  7.         p.drawImage(xcoordinate, ycoordinate, input , 0,0,-1,-1,Qt::AutoColor);
  8.         img3=this->qtToCv(&(qimage));
  9.         cvWriteFrame(writer,img3);
  10.         i++;
  11.         img2=0;
  12.         img3=0;
  13.         p.end();
  14.         qimage=QImage();
  15.     }
  16.     else {
  17.       cvGrabFrame(capture);
  18.       img2=cvRetrieveFrame(capture);
  19.       cvWriteFrame(writer,img2);
  20.       i++;
  21.       img2=0;
  22.     }
  23.     ui->progressBar_2->setValue(i);
  24.     }
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now I know that the problem is with the method because I commented everything else and only the calling of the method caused the memory overload. All I need is for another method (or a change in this method) to ensure that not too much memory is used while applying it.
Thanks a lot and best regards,
p3l