Ask a question about the shooting technique. I am watching you in the Korean drama Stars. The time in the play stopped and the hostess did not move. It's really motionless. This is a computer.

The technology of overlapping two mirror images has existed for a long time, that is, recording the actions of characters and then putting them in a pre-recorded background. In this background, you look at many people, maybe a few or a dozen people are real, and others are background props. There are many movies that use this technique now, and there are also shadows of this technique in mobile phone photography, such as Nokia 1020 passerby removal and motion trajectory map.