Let me reprhase that then.

Tell the LEO the dog attacked you. Since "attack" is not limited to physical contact, but also includes the threat of physical contact, it isn't a lie. Since you cannot say for sure what the dog's true intent was, you cannot discount that the threat was there, whether perceived or real. His mere presence and the possibility that you felt threatened by him are satisfactory legal criteria.

Now, whether you actually felt threatened by the dog or not really doesn't matter anymore. In your mind, you may not have been threatened, but that doesn't diminish the propensity that a threat existed, whether you perceived it or not. So telling the officer the dog attacked you may not be physically accurate, but nonetheless legally appropriate. The issue of video is then moot, so long as the presence of the dog in your proximity, uncontrolled, is evidentiary. In your mind an attack may not have actually occured, but the possibility that one may have without you being aware of it precludes your assumption or predisposition, and so the more responsible act as a citizen is to assume an attack did occur, or was likely to have occured and necessary legal intervention on the part of the LEO is warranted.

There, how's that for lawyering it up?