If I were in a similar position, I wouldn’t merely use the video to stop my traffic ticket. I’d use the video as evidence to sue the cop for fraud, “tampering with a government record,” official oppression or some such and to sue the police department for employing a liar. I’ll bet the city would easily settle out of court for $25,000 to $50,000.
Two things I dislike about the dashcam:
1) it’s obvious and easily seen; I’d like a model that’s more stealthy and less obvious; and
2) it apparently runs only while the car is running. If the cop orders to turn off your engine, your video stops. I’d want a dashcam that could be turned on to run even after the car was turned off.