The Input Problem Nobody Talks About

Most of the conversation around AI video generation focuses on the output — how realistic the motion looks, whether fingers melt, if the lips sync. Almost nobody talks about the input. But when a video has to reconstruct two distinct identities at once , the quality of your two source photos matters more than any prompt you could write.

This is the engineering reality behind the "scream-and-swap" dance videos currently flooding short-form feeds: one face screams into the camera in close-up while a second subject dances behind, then they swap. It's a single 21-second, portrait, 720p clip, generated from exactly two photos — or one photo of two people. No prompt.…