Watch my lips

Why lease expensive video conferencing links when you can transmit a still
mugshot on a normal line and then superimpose moving lips and eyes on it? In WO
98/58351, British Telecom proposes taking digital photos of each participant
from several angles, and transmitting them at a low data rate. The system uses
this to build a 3D computer model of the head, which is displayed when the
subject talks. Real-time eye and lip movements are coded as a low rate signal
which is also sent down the line—so the subject appears to talk. BT says
the effect can be very convincing.