P.1 Submarine Music Analysis

The genre of the music of this clip is classical.
You can hear the instruments such as a violin,piano,strings,orchestra and a flute.

The tempo is calm yet up beat at the same tie which creates emotion. Its like our main character Oliver Tate composed it himself. It reflects his emotions such as happiness.

The purpose of this music during that clip is that its a montage and you can hear the voice over of him telling the story of his life, his diary. The music on the background fills up the empty space behind the dialogue and makes it more interesting to the viewer as it can get a bit boring, but the lively music helps keep the viewer engaged. 
It's kind of like his thinking music, which can relate to the audience as i personally have a thinking song i put on.
This song is magical kind of like an imaginary world for out main character which links to the narrative as he is quite a different guy compare to the rest.
Also the fact that classical musical is played on the background shows that  his different too as you wouldn't imagine a 15 year old listening to that genre of music.