As Derek said (he's been paying attention!), your start and 1st pull are whacky - get the bar over the base of your toes and your arms approx. vertical in the start. Off the floor, keep your chest up - don't let your hips rise more than a couple inches more than your shoulders. Right now, you're basically driving your knees back into almost full extension before the bar moves at all, making your first pull a stiff-legged deadlift. Actually looking again, the position you initially set is pretty good - but as you get ready to go, you rock forward. Just maintain that initial set position and pull from there, sweeping everything back to get the weight toward your heels as the bar leaves the platform.
That hip-leading shifts your weight forward on the feet as you rise, which makes the bar start swinging forward, which pulls you forward even more. You end up chasing after the bar instead of pulling it back into your hips as you should.
Relax your arms - allow the weight of the bar to stretch them straight rather than tensing them up, which will often result in early arm bend like you're getting (and which also encourages the bar to swing forward during the 3rd pull as it does). When you turn your elbows out during the pull, make sure to keep your shoulder position neutral rather than rounding forward.
Also as Derek said, don't let your hands slide in as you pull under - keep them a few inches wider than your shoulders.
Really sit those hips in when you receiev - let the knees come forward and sit your ass on your heels to keep your torso upright and drive the elbows up to help you out of the bottom. You're stopping short of full depth, which just makes your life harder because it's a tougher position to maintain and you're losing some of the potenial drive from the bounce out of the bottom. Make sure to lead with the chest/elbows as you recover, not the hips.