How I built CastRemix: swap the lead character in any short video with AI

I've been building CastRemix, a tool for AI video character swaps.

What it does: you upload a short reference video (2–30s) plus a photo of your character, and it generates a new take where your character becomes the lead.

How to get a good first result

1. Pick a short clip with one performer, clear movement and a steady camera.
2. Use a clear character photo with a similar pose and framing.
3. Check the credit quote before generating, then review identity, motion, hands and scene consistency.

Limits worth knowing: identity, motion, camera and background can drift during generation, and exact face replacement or lip sync isn't guaranteed, so start with one short test.

Try it at https://www.castremix.com — feedback welcome in the comments!