What should I do while my professor is showing a video?

I have two classes where the lectures just have a video on for the whole class. One is an hour and a half and the other is three hours long. I feel extremely useless watching videos in class when I can watch them at home on .5x speed. I feel like it’s extremely inefficient to just sit there and watch videos. So what should I do while watching the video? Should I just sit there and watch the video? Should I do powers notes that my professor also has or should I do something else?<br><br>Edit: It’s not just the whole time but a big chunk of the class .