Draw polygons on moving cars in video

I am trying to find a way to display a video of a car moving down the street and draw a polygon around the car as it  moves.   I would like to use HTML+TIME, but am open to any solutions.   I have the location of where the polygon should be drawn in the video, but I cannot figure out how to do this.  I believe I need to show  the first frame of the video and draw the polygon around the car for this frame in one sequence.   Then I need to show the next frame of the video and draw the polygon around the car on this frame as the next sequence.   Since the car is moving the polygon will not be in the same location in each frame.  Can anyone suggest a way to this?