[JaRail]

Gemini man is a better example of where this is heading.

https://www.youtube.com/watch?v=k5y4kxhZIBA

A DF has a pretty specific meaning if you are diving into the technical aspects. It's an approach that has a lot of specific limitations that put a practical ceiling on how good it can be. For example, it's a 2D system that won't capture lighting differences with good accuracy. The limitations become more apparent as resolution increases.

Newer systems use source material to generate 3D facial models. The face in the target video is also 'motion captured.' The target video's lighting is estimated and a resulting face image is rendered and composited into the target. That's a lot closer to the pipeline of movies such as Gemini man.

So while DF isn't a technique used in movies, machine learning is heavily involved. It's built into model generation, motion capture, animation, etc. Artists will start with captured/generated assets and hand-tweak them to get the desired result.