“The in-court testimony would have to wait until trial, but the identification of the video custodian and authentication would happen pre-trial.”
Do you actually think LE and DAs even care whether they have “solid forensic evidence” or not before arresting you? Not anymore, “looks like him” is enough and they arrest you and say “let the courts figure it out”. You are guilty before you prove your innocence, they are not going to do any work to make sure you are not guilty before they arrest you. It doesn’t work that way anymore. You being innocent is the very last thing they care about because there is no longer any accountability for wrongful arrests. “False Arrest” is now a completely obsolete concept. No skin off their nose if they were wrong...
If the video evidence is forged, the person submitting it gets both prosecuted and sued, and that will happen pretty early on. That is likely to limit how often this actually happens. And neither cops nor the DA generally want to waste their time with bogus evidence either.
I'm not saying this to minimize the harm to the accused when it does happen. It obviously has to be illegal to do that, and I'd fully support additional laws to increase punishments for anyone who forgets video or audio to falsely implicate someone else.
What else do you suggest should be done?