It looks like the bar is too high on your back (based on the movement of the bar as you squat), but even if you fix that, you need to keep your chest tighter.
Think "show off my pecs" before you descend.
You should take a rear view video to see if your feet and knees are in the right position. It's hard to see from this angle, but I'd guess you're not driving your knees out enough. As a result, your knees are not inline with your feet.