A safety gate inside a face-swap tool or how the NSFW check is wired into the pipeline

A face-swap tool can be pointed at the wrong content. That is not a hypothetical, it is the first thing some users try. So before the swap runs, there is a check: a small classifier looks at the target frame, and if it sees explicit content, the swap is skipped. The original frame goes through untouched. This is a walkthrough of that check in an open-source repo, down to the labels and the number that decides. It is short code. The interesting part is where it sits in the pipeline and what it…