convert_leisureland.py

# convert samples from http://leisureland.us/mellotron.htm
# unzip one of the zip files into a folder
# copy this file into that folder
# run
# python3 convert_leisureland.py
# a new folder "mx.samples" will have the converted samples for mx.samples
import os
import re
import mimetypes
import itertools as it
from pathlib import Path
from shutil import copyfile

MIDI_A4 = 69  # MIDI Pitch number
FREQ_A4 = 440.0  # Hz
SEMITONE_RATIO = 2.0 ** (1.0 / 12.0)  # Ascending


def is_audio(path):
    try:
        if "audio" in mimetypes.guess_type(path)[0]:
            return True
        else:
            return False
    except TypeError:
        # path is not a file
        return False


def str2midi(note_string):
    """
    Given a note string name (e.g. "Bb4"), returns its MIDI pitch number.
    """
    if note_string == "?":
        return nan
    data = note_string.strip().lower()
    name2delta = {"c": -9, "d": -7, "e": -5, "f": -4, "g": -2, "a": 0, "b": 2}
    accident2delta = {"b": -1, "#": 1, "x": 2}
    accidents = list(it.takewhile(lambda el: el in accident2delta, data[1:]))
    octave_delta = int(data[len(accidents) + 1 :]) - 4
    return (
        MIDI_A4
        + name2delta[data[0]]
        + sum(accident2delta[ac] for ac in accidents)  # Name
        + 12 * octave_delta  # Accident  # Octave
    )


folder_in = "."
folder_out = "mx.samples"

audio_files = [x for x in list(Path(folder_in).rglob("*")) if is_audio(x)]

try:
    os.mkdir(folder_out)
except:
    pass

for _, file in enumerate(audio_files):
    # get the filename only
    filename = os.path.basename(file)
    # remove the extension
    filename = os.path.splitext(filename)[0]

    match = re.search(r"[a-g]{1}[#b]?[0-9]{1}", filename, flags=re.IGNORECASE)
    if match is None:
        print("could not find note name in {}".format(filename))
        pass
    midival = str2midi(match.group(0))

    variation = 1
    dynamic = 1
    dynamics = 1
    variation = 1
    release = 0
    new_name = "{}.{}.{}.{}.{}.wav".format(
        midival, dynamic, dynamics, variation, release
    )
    new_path = os.path.join(folder_out, new_name)
    try:
        copyfile(file, new_path)
        print(f"{file} -> {new_path}")
    except:
        print(f"{file} -> {new_path} failed")