midascii.py

#!/usr/bin/env python3
# midascii.py - Listen to ASCII strings as MIDI notes
# Nicolas Seriot - 2024-05-14
# https://gist.github.com/nst/bccc3dc2d2318cf637e65e1a03c1c9f7
# Minimal midi file thanks to @corkami
# https://github.com/corkami/pics/blob/master/binary/midi.png

def ascii_to_midi(s, filename):

    header = list(b'MThd') + [0,0,0,6,0,1,0,1,0,60] # ticks per quarter note
        
    notes = []
    for c in s:
        print(c, ord(c))
        notes += [0,  0x90, ord(c), 127, # note on
                  30, 0x90, ord(c), 0]   # note off

    prog_change = [0, 0xC0, 0x22] # Electric Picked Bass

    end_of_track = [0, 0xFF, 0x2F, 0]

    length = len(prog_change) + len(notes) + len(end_of_track)
        
    track = list(b'MTrk') + [0, 0, length >> 8, length & 0xFF]
        
    midi = header + track + prog_change + notes + end_of_track
    
    with open(filename, "wb") as f:
        bytes = bytearray(midi)
        f.write(bytes)

if __name__ == "__main__":

    # https://seriot.ch/midi/pi.mid
    import math
    s = str(math.pi)
    
    #s = "01234"
    
    #s = "Nicolas Seriot http://seriot.ch"

    ascii_to_midi(s, "x.mid")