Starting from the beginning, try making your walkout shorter. That's a lot of distance you cover which is really not necessary. Clear the j-hooks and you're cheering. Just think in terms of energy used: a big walkout like that is taking more out of you than a shorter one. Also, your steps are big. Again, that just makes your life harder. Take as small a step as possible, use as little energy as possible in the walkout. Concentrate on getting and staying nice and tight especially in the upper back as you unrack and walk out. It'll make a HUGE difference. A good 'drill' is to walk out a squat against bands. The tension and instability teach you very, very quickly to get and stay tight unracking and walking out. Anywhere between 15-60 lbs of tension per band when the bar is racked should be fine, but only put around 60% on the bar to start with.
Your squat itself really isn't too bad at all. There were only two issues I saw, which are linked: your hips shoot up early as you come up, and your torso pitches forward. Fix one and the chances are you fix the other.
The first step I would suggest is working on your overall tightness. Like for the walkout, get really tight from your neck to your toes. That'll make you stable. For me, the simplest way to do that is (from top to bottom):
- pull the bar down into your shoulders (try to bend it) and pull your elbows under the bar. Even if they don't get under the bar, pulling them forward while pulling the bar down will make your upper back nice and tight.
- drive your head back into the bar. This is a newer one for me but works a treat. Thanks Reed, he of the 700 lbs squat who gave my that tip.
- squeeze your glutes. You'll immediatelly feel your hips come forward and sit right under the bar. Nice and stable, and your lower back will thank you.
- breathe into your lower back and hold your air. The tension will become very, very apparent. With a belt even more so. Squeeze down on that air.
Hold ALL those points. Drop your butt down and push your knees out. Keep as tight as you can while doing this. The main thing that'll keep you tight once you start moving is pulling the bar into your back, pulling your elbows under it and driving your head into the bar (again, Reed's sage advice to me. It works) while squeezing down on your air. Hit depth and come up head/chest first, pushing your knees out the whole time, and only once you're well and truly out of the hole (in something like a half squat) drive your hips forward.