It seems that the rumors were true: iPhone X owners can use their phone to map emojis from their facial expressions in real time. They need only select their chosen emoji from a fairly extensive list and the Animoji app will map your eye, mouth and cheek expressions to your animated counterpart. Yes, even the poo emoji.
Once you've selected an animoji, the depth-cameras will map the image of, say, a cute panda or unicorn on your face. Then you can record clips of you speaking that'll directly animate onto the character you've chosen.