How to split midi file based on notes pitch using python?

Question

How can I split midi files based on their pitch using python? I tried the music21 library, but I don't really know how this works...

Answer 1

Try this code:

import pretty_midi
import copy

pitch_cutoff = 65

mid = pretty_midi.PrettyMIDI('my_file.mid')
low_notes = copy.deepcopy(mid)
high_notes = copy.deepcopy(mid)

for instrument in low_notes.instruments:
    for note in instrument.notes:
        if note.pitch > pitch_cutoff:
            note.velocity = 0

for instrument in high_notes.instruments:
    for note in instrument.notes:
        if note.pitch < pitch_cutoff:
            note.velocity = 0

low_notes.write("low_notes.mid")
high_notes.write("high_notes.mid")

it uses the pretty_midi module to split a midi file into two different files. The file called "high_notes.mid" will only have notes above what you set the pitch_cutoff variable to, and "low_notes.mid" will only have notes below that. Just change "my_file.mid" to whatever the name of your file is and try it out. Let me know if you have any questions.