Well, just being exposed to informational stimulus on video is not a guarantee that viewers will pay attention to the stimuli.
Watching someone talk for more than a minute when the only thing that is moving is the speakers mouth is NOT going to maintain the interest of the viewer. In fact, we as web users have become very savvy about what videos we are willing to automatically view, whereas in the past video was novel and we were willing to watch this new communication tool. Not anymore.
So the lesson here is to not waste your money on something just because you think you need a video. Go to the experts and let them share with you what works and what is not going to work.