Convincing fake video and audio is coming soon - it isn't a major problem yet, but it will be more challenging to determine if recorded evidence can actually be relied on.
Some sort of service that signs and proves the authenticity of videos I think is a an idea that was until recently probably bad, but has now became good.
It'd be similar to what digicert does for websites. You could then work with browsers to show verification for trusted videos.
In an age with surveillance everywhere and when video and audio are so important in litigation I would make a tamper-proof camera that would sign every video/audio it produces. Tricky part would be to keep the signing key away from bad hands.
I don't think that is even possible.
You might want to succeed with amateur efforts, but I would guess there will be a point where it is impossible to tell if a video is fake or not.
Company would be responsible for effectively verifying identity - similar to how this is done for websites.