Harmony refers to the "vertical" sounds of pitches in music, which implies pitches that are performed or sung with each other concurrently to create a chord. Generally, this means the notes are played concurrently, Though harmony might also be implied by a melody that outlines a harmonic structure (i.e., by http://cunori.edu.gt/campus/app/upload/users/8/8923/my_files/differences-in-mp3-and-mp4-video-and-music-formats.html