On the grounds of the first amendment, there should be no laws or statutes forbidding the recording of police in the performance of their duties. Recording is a form of free speech in the same sense as if I were to blog about a police encounter - only with video I am proving that I am telling the truth with a digital record.
Wiretapping statutes do not apply. With the officer seeing the recording device, he or she is being made aware they are on tape. A videographer could give warning that they are recording, but if an officer is doing his or her job within the law, they really shouldn't fear being recorded.
After all, when you're pulled over, they're sure as he'll recording you for their "protection" - a citizen should be extended that same courtesy to do so, as our law already allows it.
Not positive but I think it is a law that if you are recoding someone in general it must be stated first. People should only get put on record if they are aware of it and know what is happening. I do not think anyone should be excluded from getting recorded though.