If AI and deep fakes can listen to a video or audio of a person and then are able to successfully reproduce such person, what does this entail for trials?

It used to be that recording audio or video would give strong information which often would weigh more than witnesses, but soon enough perfect forgery could enter the courtroom just as it’s doing in social media (where you’re not sworn to tell the truth, though the consequences are real)

I know fake information is a problem everywhere, but I started wondering what will happen when it creeps in testimonies.

How will we defend ourselves, while still using real videos or audios as proof? Or are we just doomed?