I'm not sure if Star sports is broadcasting SD match at 4:3 or 16:9 format. If they are broadcasting at 16:9 format then check your TV settings.
But, if they are broadcasting at 4:3 format then you'll not see any country flags. For that you need to subscribe to HD channels.
Difference in quality and aspect ratio. Not all but many SD cuts off both sides to provide 4:3 aspect ratio picture. Some provides 16:9 picture like MTV beats SD and some channels show full 16:9 picture but with black bars on SD TV.