I'm surprised they didn't just take the camera or at the very least delete the video.
If they tried you could say something to them like "Do you think that's the only camera I have recording you?"
Best reply: “Thank you officer. You do realize that I have direct, real-time upload to my CLOUD account, right?”
Perhaps (as clueless as many of them reveal themselves to be) they are catching on to the growing likelihood that the video had been backed up in realtime on the internet.
Damage or seize property and then it turns out to not be a he said she said thing after all. Don’t think they can claim entrapment on a stop they made.
Or just tell them it's streaming live to the interwebs, and any action they take against the camera will itself be recorded.
If they tried you could say something to them like “Do you think that’s the only camera I have recording you?”
I wouldn’t advise that, they would just rip the car apart to find any other devices. You say that to them in court, after you have submitted the surviving recordings into evidence :)