I am looking for the title of a movie, telling the story about a father and son that don't interact too well. It turns out that the boys father is not his real father. One of the peculiarities that I can still remember and that might help is that the father always asks the boy to play some piano, but he never wants to. The viewer gets the idea that the boy can't really play that well, until the end scene where he gets to play for the whole school and in fact can play. Another detail is that the boy make real curious drawings that no one seems to understand, but turn out to be his own way of writing music.

Who remembers the title of this movie? Thanks in advance!