While your 'choice' (which he counted to in an unshuffled deck) is filling the screen you can actually see him manipulating the deck behind it. My guess is he's flipping it over, with one card reversed on the back so the deck still looks face down. When your 'choice' goes back in the deck he's all set up. Putting his hands behind his back is so he can flip the reversed end-card back - so as not to give himself away when he spreads the deck. Even if it really is your free choice, the trick works.
Puts the chosen card close to the camera, so you can't see him turning the deck but leaving top card face down. Try better lad. U can see his had working the deck in the back ground
