Nothing super obvious there. Your knees do appear to flash in for a moment right around the bottom, but I cannot say whether that's the cause of the pain - I've seen much more knee cave not causing any pain. It's very dependent on the individual, but it couldn't hurt to keep your knees out better.
It also looks like the bar might be just slightly too low on your back, and your wrists are flexed back instead of neutral. Also, keep your feet on the ground.