Throughout your heelside carve, there is a gradual deterioration of your body alignment with your board. This is evidenced by your front hand swinging across the board near the end of the carve. Ideally you want your upper body and lower body to remain aligned with your binding angles at all times. There is no need for all this swiveling at the waist.
Try this drill to help break this habit - touch your back hand to your front boot cuff on a heelside carve and reach to the inside of the turn with your front hand. Hold that position for the whole carve. Then on toeside touch your front hand to your front boot cuff. This will have you twisted more forward than your binding angles, which is not really the way you want to ride normally, but it should cause a lightbulb to light up in your head!
Also I think maybe the comments about knee bend are caused by the camera angle, lighting, and the black pants. I think you may be bending your knees enough.