Active Learning
Learning should be more than listening, or watching. At very least it should be both of those things together.
You can actively translate what you learn though, into something which is both easy to understand and involves you in understanding.
As you listen and watch you can also think and translate what you see and hear into something called a concept map. You could do this instead of taking notes as long as you are good at creating concept maps. If you become good at creating concept maps there will be no need for more formal notes and you will have to think hard about the topic as you create the map.
But there are better ways to learn.
Learning should involve you in doing something. Even if you are learning something rather theoretical, you should still do something in order to learn.
I can’t make a universe in order to understand it!
This is an example map I created for a simple radio receiver but you could do better. Start at the radio receiver box and see what you can learn from the map.
A concept map has nodes and links. Nodes are names of objects or items from the concept. Links, which have a direction, explain the relationship between two objects.
That's all you need to know really but there is more help available.
You can get some software to help you to create concept maps here. You could also use a pencil and paper if you like.