Sibelius ( is the name of the first computer-aided music software that actually fooled anyone into thinking that expanded output from a midi file was music being played in real time by real musicians. This hoodwinking of the human senses is achieved by introducing a measured quantity or randomness into the various components making up a note in midi: start-time, sustain, pitch, vibrato, etc. This in fact is exactly what humans do, though not deliberately. Sibelius company's motto is "Sibelius would have used Sibelius."