Saving Private Ryan
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Finally when his hearing is no longer impaired is when the audience get the full idea of the scene, due to all of the diegetic sounds which can be heard, such as dialogue and sound effects such as gun shots, screams and bombs going off which gives us the initial idea of the setting of the set and the sound creates both the mood and atmosphere.
500 Days of Summer
In the clip for 500 Days of Summer, we see our main protagonist strolling down the street with an obvious happy expression and the non- diegetic music matches this emotion of the character; therefore giving this idea of emotional realism in this scene. The sound being heard in the scene is non-diegetic and therefore only the audience can hear it, the song that can be heard in the scene isn't actually being heard by the characters, but almost like a song that is being played in the characters head to reflect his emotions.