What are you screaming?

I like this. It's a jazz pianist giving a talk to some students. He discusses some really important ideas about playing music. The basic one is that "all music is played by ear" and that what we must work on is how well we hear. We should develop the vividness of what we hear inside. 

When you imagine a phrase, how vivid is the articulation or the color of the sound, or the direction of the line, etc.? If you are screaming it inside, to the point that it must come out, you are ready to play it.