Flicker Problem

I figured out how to get my overlay to work on my DirectShow video. I just made a QPixmap of size 5x5 and put this on a QLabel of size 5x5 which I draw on top of the QAxWidget displaying my video. This works great instead of trying to create a transparent pixmap/label but I get a lot of flicker when I click on the video to draw the point. In my GUI building function I set these variables up like this:

Code:

mpOverlay = new QPixmap( 5, 5 );
   mpOverlay->fill( Qt::red );
 
   mpOverlayLabel = new QLabel( mpVideoPlayer );
   mpOverlayLabel->setGeometry( QRect( 0, 0, 5, 5 ) );
   mpOverlayLabel->hide( );
   mpOverlayLabel->setPixmap( *mpOverlay );

Then whenever I click on the screen I do this:

Code:

if( event->type() == QEvent::MouseButtonRelease )
      { 
         AzElPoint point;
         QMouseEvent *mouseEvent = static_cast<QMouseEvent *>(event);
 
         point.frameNumber = getCurrentFrame( );
         point.xPos = mouseEvent->x( );
         point.yPos = mouseEvent->y( ); 
 
         if( mouseEvent->button() == Qt::LeftButton )
         {
            // If left button, place mark on overlay to indicate position
            // and store position in array at the current frame index
            for( int i = 0 ; i < azElPoints.size( ) ; i++ )
            {
               if( azElPoints[i].frameNumber == getCurrentFrame( ) )
               {
                  azElPoints.removeAt( i );
                  erasePoint = true;
               }
            }
            azElPoints.push_back( point );
            printf( "x=%d, y=%d\n", point.xPos, point.yPos );
            update( );
            return true;
         }
      }

And my paint event handler just calls repaintWindow( ) which looks like this:

Code:

void VideoViewerWindow::repaintWindow( )
{
   long lWidth, lHeight; 
   HRESULT hr = pWindowlessControl->GetNativeVideoSize( &lWidth, &lHeight, NULL, NULL ); 
   RECT rcSrc, rcDest; 
   // Set the source rectangle.
   SetRect( &rcSrc, 0, 0, lWidth, lHeight ); 
 
   // Get the window client area.
   GetClientRect( (HWND) mpVideoPlayer->winId( ), &rcDest ); 
   // Set the destination rectangle.
   SetRect(&rcDest, 1, 1, 558, 349); 
 
   // Set the video position.
   hr = pWindowlessControl->SetVideoPosition( &rcSrc, &rcDest ); 
 
   PAINTSTRUCT ps; 
   HDC hdc; 
   RECT rcClient;
   GetClientRect( (HWND) mpVideoPlayer->winId( ), &rcClient ); 
   hdc = BeginPaint( (HWND) mpVideoPlayer->winId( ), &ps ); 
   if( pWindowlessControl != NULL ) 
   { 
      // Find the region where the application can paint by subtracting 
      // the video destination rectangle from the client area.
      // (Assume that g_rcDest was calculated previously.)
      HRGN rgnClient = CreateRectRgnIndirect( &rcClient ); 
      HRGN rgnVideo  = CreateRectRgnIndirect( &rcDest );  
      CombineRgn( rgnClient, rgnClient, rgnVideo, RGN_DIFF );  
 
      // Paint on window.
      HBRUSH hbr = GetSysColorBrush( COLOR_BTNFACE ); 
      FillRgn( hdc, rgnClient, hbr ); 
 
      // Clean up.
      DeleteObject( hbr ); 
      DeleteObject( rgnClient ); 
      DeleteObject( rgnVideo ); 
 
      // Request the VMR to paint the video and draw the point chosen by the user.
      int i;
      for( i = 0 ; i < azElPoints.size( ) ; i++ )
      {
         if( azElPoints[i].frameNumber == getCurrentFrame( ) )
         {
            mpOverlayLabel->move( azElPoints[i].xPos - 2, azElPoints[i].yPos - 2 );
            mpOverlayLabel->show( );
            break;
         }
      }
      if( i == azElPoints.size( ) ) 
      {
         mpOverlayLabel->hide( );
      }
      HRESULT hr = pWindowlessControl->RepaintVideo( (HWND) mpVideoPlayer->winId( ), hdc );  
   }  
}

You can see what I am doing is just showing/hiding the QLabel and then redrawing the video (ie. the QAxWidget) which in turns redraws the QLabel since it is a child of the QAxWidget. But when I click the screen, I want the dot (QPixmap/QLabel) to appear without causing the entire screen to flicker. Sometimes the screen flickers and sometimes it does not. And when it does flicker, sometimes the flicker lasts almost a half of a second - which is very noticeable. So any ideas on how to improve my function(s) to prevent this from flickering would be great! Thanks!