It's way more feasible to simply require social media sites to do the verification and display something like a blue check on verified videos.
This is actually a really good idea. Sure there will still be deepfakes out there, but at least a deepfake that claims to be from a trusted source can be removed relatively easily.
Theoretically a social media site could boost content that was verified over content that isn't, but that would require social media sites to not be bad actors, which I don't have a lot of hope in.