To the people complaining that what you see is no longer believable: there is a way out: signatures. It is time to start pressuring public people to digitally sign whatever they say.
I don't understand the complain. It's a movie: what you saw never was believable.
It's trickery by design. Everything you see as been spliced together from multiple takes, purposefully framed, lighted and colorized. It's all fake but in a way so culturally ingrained that people don't even notice the deceit anymore. You think this continuous action you are watching?
although you are right about video 'evidence', editing, cuts, and carefully muted dialog can alter things to the point of being the opposite of what was being filmed - an unprovoked attack can become self-defense or vice-versa, etc. Again, deep-fakery is just another tool in that unsavory toolbox, not anything paradigm shifting.
Plenty of videos are candid or shot and released by a 3rd party.
This could work for press releases and such, but not for videos with headlines like "CEO CAUGHT KICKING A BABY IN THE FACE" or "UNDERCOVER INVESTIGATION: PRESIDENT ADMITS ALIENS ARE REAL".
Image formats could be updated with an 'original' layer so that if the news site wanted to crop or edit the content, the original would still be avaliable for comparison.
Given all of the hardware design going into high speed hashing on asic, shouldn't be that hard to find a component to do the work.
I know there are cameras that digitally sign the data. However, you hardly ever get to see raw footage. It is always edited.