Take this for what it's worth because I'm no real expert. It looks to me like your slide foot ends up too far to the right instead of ending up under your chin and body centered. The ball is therefore released too far from your ankle, losing leverage. It looks like your arm is having to clear your left leg and that puts your whole arm too far out, thus your elbow is not inside. The position of your body going into the release makes it impossible for your elbow to stay inside. Pause your video with your ball right at the height of your back swing. Your arm looks good; it's lined up with your head nicely, but look where your slide foot appears to be heading. Does it look possible that the ball is ever going to end up close to your ankle?
Have you ever tried spotting at the foul line? You can focus on the point you want your slide foot to be or you can focus on a point you want to set the ball down that is close to your ankle. You can also focus on the spot where you want the ball to first touch the lane.
Watch this for comparison: http://www.youtube.com/watch?v=3WQeNFHTasI
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