Automatic transcription of solo audio into music notation

Creating sheet music can be an arduous task for instrumentalists and vocalists who improvise. This problem can be solved by using a pitch detector that produces a MIDI data file. MIDI data is a good solution because it can be easily transformed into music notation by standard programs such as Logic Pro X or Finale. The authors have developed an open source C/UNIX-based program that automatically transforms a monophonic sound file into a playable MIDI file. Pitch (F0) detection is accomplished using a short-time autocorrelation algorithm. Successive F0’s that correspond to the same MIDI note number are combined to form notes. The minimum duration of each note is determined by the autocorrelation window size, which in our case is set to 0.03 s. To achieve a more accurate notation result, the program employs duration and RMS amplitude thresholds to exclude spurious notes from the MIDI data.