Not quite true. This wouldn't be wiretapping. There would have to be a reasonable expectation of privacy in communication.
That said, just cooperate. Cops are people too, and most are decent to you if you are decent to them.
Video recording is actually covered in wiretapping laws, and if you're in your car that's technically private property where those laws apply. Whether you have to inform them or not varies by state, but the law applies to cops pulling you over for now. That may change though, since recording police incidents has started to become more common.
I agree on cooperation though. Much easier to just talk to the guy for 10 minutes and end up having a decent conversation than cause a lot of trouble.