“Also, to submit as evidence any video, a specific person must have personal knowledge of how that video was recorded, and testify to the authenticity of that video.”
Not until you end up in court. And you are still arrested for suspicion before any evidence is even addressed.
Just being arrested “as a suspect” is a serious problem. Society deems you are automatically guilty when you are arrested whether you are or not. And because Law Enforcement reports arrests with real names in the public spaces now your honesty and integrity has been challenged by both authorities and society. This arrest and public ridicule has cost many their jobs, their friends, and their families many times. I have seen it happen countless times.
Nothing should be allowed that can cause an innocent law abiding person to be arrested period. You can lose everything dear to you even if you are never convicted. Too late... Your life will never be the same just because of one wrongful arrest. And you never get it back...
The in-court testimony would have to wait until trial, but the identification of the video custodian and authentication would happen pre-trial.