People predicted that Photoshop was the end of truth, that journalism could no longer be trusted, that photographic evidence at criminal trials would be inadmissible.

None of that actually happened because people learned to be skeptical, and to care about who took the photo, the chain of custody, and the controls to prevent digital alteration.

Maybe we need something similar but more rigorous for video. The camera itself could encode a PKI signature in every frame of the original. If subsequent edits preserve frames as is, then the viewer could determine how many frames were cut or duplicated.

If subsequent edits crop, recolor or otherwise alter the frames, that editor could encode its own digital signature so the viewer could judge how much to trust their edits.