I think if you watch my videos of recording public servants and people, you will get the idea that you can legally video and audio record anyone. Just remember to state that you are audio recording.
Here is the law on Audio recording (There is no law against video recording, beside for some sex under age and others). ORS-165.540:
165.540 Obtaining contents of communications. (1) Except as otherwise provided in ORS 133.724 or 133.726 or subsections (2) to (7) of this section, a person may not:
(c) Obtain or attempt to obtain the whole or any part of a conversation by means of any device, contrivance, machine or apparatus, whether electrical, mechanical, manual or otherwise, if not all participants in the conversation are specifically informed that their conversation is being obtained.