It's very difficult to get a good understanding of your mechanics for the following reasons:
1. The frame rate is too low, probably 15 fps or less. 30 fps is the minimum useful frame rate for pitching.
2. The front view is too far away
3. You need a clip from the open (3rd base) side.
That being said, what I do see is that you are getting very little hip rotation. It is stunted, or held back by your back leg action. The back leg flies out to your right as you throw. This is probably due to a couple of things. Firstly, you have very little forward centre of gravity motion. You tend to stop this motion early and lean to your left. At release, your chest is well behind your support leg. It really needs to be further forward (approximately over the front foot). Also at release, your back knee is tucked in beside (almost) your front knee. This indicates a lack of contribution of the back leg to rotation of the back hip. Your back hip finally comes around AFTER the ball is long gone.
1. Use your back leg to fuel the rotation of the back hip around the front one. Just as you are about to turn the front foot over to land, rotate/spin the back knee/leg/foot, driving the back hip. This, along with the action of the core, will help your hips rotate into landing. DON'T pull that back knee forward as was the recommendation by some in the past and still is now. Just think about it. How can it help with hip rotation when it does that?
Once that front foot has landed, the shoulders rotate with the chest thrusting forward. This results in an arching of the spine. Then, as the lower arm is to come forward to release, the torso then flexes forward, assisting with the acceleration of the arm.
The back knee should be fully rotated, because of the full hip rotation, and should NOT be pointing out to the side, as is the case now. It should be oriented such that it points downward.
Send me a PM with your email address and I'll send you some video clips of Clemens, Nolan Ryan, Kevin Brown, etc. to illustrate what I'm saying.