[lionleaf]

That is really cool! They are using a realistic 3D model of the persons face and eye-tracking in the VR headset to make a good guess at their facial expression, effectively reconstructing the face that's hidden by the headset.

Not something you can easily do as a consumer yet, but for high quality mixed reality production this seems like a great boon.

For an explanation of mixed reality videos are made I recommend this: https://www.youtube.com/watch?v=8T7ux3DXP_w