| The burden is on whichever side is attempting to introduce a piece of evidence. From the federal rules of evidence: > (a) In General. To satisfy the requirement of authenticating or identifying an item of evidence, the proponent must produce evidence sufficient to support a finding that the item is what the proponent claims it is. https://www.rulesofevidence.org/article-ix/rule-901/ Specific to recordings > An original writing, recording, or photograph is required in order to prove its content unless these rules or a federal statute provides otherwise. https://www.rulesofevidence.org/article-x/rule-1002/ Unfortunately, the rules of evidence are pretty vague about what is actually required to prove that a video is admitable as evidence; but the burden to do so is absolutely on the party introducing it. |
At that point the reliability of the evidence may of course be called into question, as with any evidence or witness. The question mark would be whether it was convincing.