As a music composer, you write original music, such as scores for film or TV shows, compositions for bands or orchestras to perform, or for a solo artist. Your duties are to conceptualize and score all the parts of a song, including melodies and harmonies, rhythm, and structure, and write the music for however many instruments or voices you decide to use for a given song or arrangement. If you work in entertainment, you work closely with directors, often after the film has been shot. Your responsibilities are to analyze the visual elements, structure, and story and develop music to complement it.