Rough sort of thumbnail sketchy-thing based on the timings observed from the reference footage.
From this, I put together a quick first draft laid out roughly according to the timing and spacing on the diagram. It needs a lot of tweaking but I think the basic principle is there.
It's pretty basic keyframing stuff so far with some minor tweaks to the fcurves to slightly alter the timings. Nothing major so far - no squash and stretch or rotation at all. This will all come later, once I'm happy with the timing and spacing and so forth.
Some things I've noticed straight off the bat - the ball doesn't look like it bounces quite high enough to me, especially on the second bounce. It appears to be a really cheap tennis ball - one that's heavy, comes in a 3-pack from Poundland. I'm going to increase the height of the successive bounces a bit, and I think it ought to hang in the air a bit longer at the top of each bounce, too. It seems as if it hits an invisible ceiling at the top of each bounce, coming to quite a sudden halt - I don't think I've given it enough time to slow into the peak of its bounce so I'll probably space out the keys a little more.
It kind of looks like it loses energy and power too quickly and too suddenly, so I might even look at adding maybe just one more bounce in there towards the end, just to make it a little more gradual. Part of the problem might also be the fact that it bounces in a perfectly straight line, up and down in a very mechanical fashion, which looks pretty unnatural. I'll probably space it out and have it bounce across the screen just a little bit.