I was watching Match Of the Day (a soccer highlights show for those not from the UK) and I've found they use this software Piero to annotate the football matches.
When annotating video of moving players I find that the graphics can be quite clunky and perhaps a bit too obtrusive. You can't see clearly the ball when some graphics are applied for example.
As I take an interest in video editing myself, my question is what would be the best design principles to annotate sports videos, especially while they are moving?