Screenshot for video files

Question

I am trying to create screenshots of a powerpoint presentation using mij application. This is not the biggest issue. I have managed to do so with the following code

    Bitmap memoryImage = new Bitmap(rc.Width, rc.Height,
                    PixelFormat.Format32bppArgb);

    using (Graphics memoryGrahics =
            Graphics.FromImage(memoryImage))
    {
        memoryGrahics.CopyFromScreen(rc.X, rc.Y,
            0, 0, rc.Size, CopyPixelOperation.SourceCopy);
    }
    return new Bitmap(memoryImage, 800, 600);

But, when a video file is being played it only shows a black square. It seems like the media is played on a different layer en thus not captured.

How can i create a screenshot with an image of the video? I searched alot about directx or windowsapicodepack but i don't exactly know if it is the right way to do this