What if they just sit and talk? What is the description of this? What if only part of the communication is relevant? What if it's not relevant at all because they reacted to atmospheric changes? Or electromagnetic signals, that can't be observed on video? Or smell? Or sound outside of human hearing frequency? What if the decision based on communication is deferred? etc etc

As I mentioned before, only the most obvious examples of behaviors and context can be translated into anything meaningful.