Hate to say it but I do see some arm pull. Play the video in slow motion if you can, or pause it just as the bar passes your knees. Your elbows begin to bend as you begin your jump when you still have a good back angle and haven't fully extended yet. As you jump, a lot of your power is taken away as your arms straighten back out. You want all that power to go directly to the bar. 1st and 2nd reps show it most, 3rd is a bit better.
Try to focus on keeping them straight all the way through the jump, then quickly move into the catch. As an analogy, imagine you want to pull a kettle bell up with a chain. You lift it off the ground slowly, then as you get ready to pull hard you let it down a bit and slack the chain. As you pull hard the chain snaps tight again against your pull and you lose power. You want the chain (your arms) tight the whole time as you jerk it up. If you try to lift with your biceps at all, they will lose and the bar will stretch your arms out again.
Would a SSC or more experienced user agree with this analogy?