What we can have is attestation and reputation, then provenance.
It starts with a container format that allows signatures of both the entire video with audio, audio only, and video only, along with reasonable segments (three seconds?) of each of these.
Excerpts of any of these can be transcluded into another such container. The editor can transform it in any way, the resulting display doesn't have to match the particulars of the excerpt (captioning, noise filtering, color correction) but the excerpt is itself included, or at least the signature.
It would be useful for some people to have cameras which do this at the moment of recording, along with GPS, cell location data, and so on, to get really bulletproof documentary footage.
I don't want that built into my phone, necessarily. As a container format and ffmpeg style tool, this would support anonymous attestation which can be demonstrated by the keyholder at any future time. As a built-in subpoena-able feature of my phone or mirrorless camera? Hmm, probably don't want that. If it snitches proactively, not a chance in hell.