I'll start with the flat. Your seat looks very nice, you are not slumping or hunched over. Also, gorgeous horse! What breed is he?? I only notice some minor things about your form. Your fingers should be closed around the reins. Closed hands will give you more control and you can send clearer signals to your horse... right now you are holding the reins with your fingertips! I would also like to see you lift your hands a bit and have them in front of the saddle instead of resting on it. I always carry my hands a few inches in front of the pommel and floating slightly above the neck:
It looks like your heels could be down a bit more, but it's hard to tell from that angle. Overall you look pretty good, just fix your hands and maybe shorten your reins a bit and you're good to go!
Okay, onto the jumping. I like how you are looking up and ahead and you are giving a nice release so your horse has plenty of room to jump. I only notice one thing... you are pinching slightly with your knees and your legs look like they are swinging back a bit, although it's hard to tell without a side angle. It looks like your stirrups may be a tad long. Other than that you look great!
Hope this helped. =)
PS sorry the pics turned out big, I meant to make them smaller!!
***I wrote this before I saw the video so this is just a critique of the 2 pics***