Not quite full extension. This seems to cause the bar to be too far away, shifting you forward just a little in the catch.
Flare your knees out. Didn't look like you were doing this.
Get proper weightlifting shoes, increase flexibility, and make sure to set your back tight in an arch. Also, your set position often shifts forward (perhaps too much) just before the pull. Find where you're going to pull from and try to avoid losing that position when you start.