#!/usr/bin/env python # -*- coding: utf-8 -*- # # drumseq.py # # MIDI Drum sequencer prototype, by Michiel Overtoom, motoom@xs4all.nl # """Play drum pattern from file to MIDI out.""" from __future__ import print_function import argparse import sys import threading from random import gauss from time import sleep, time as timenow import rtmidi from rtmidi.midiutil import open_midioutput from rtmidi.midiconstants import (ALL_SOUND_OFF, BANK_SELECT_LSB, BANK_SELECT_MSB, CHANNEL_VOLUME, CONTROL_CHANGE, NOTE_ON, PROGRAM_CHANGE) FUNKYDRUMMER = """ # 1...|...|...|... 36 x.x.......x..x.. Bassdrum 38 ....x..m.m.mx..m Snare 42 xxxxx.x.xxxxx.xx Closed Hi-hat 46 .....x.x.....x.. Open Hi-hat """ class Sequencer(threading.Thread): """MIDI output and scheduling thread.""" def __init__(self, midiout, pattern, bpm, channel=9, volume=127): super(Sequencer, self).__init__() self.midiout = midiout self.bpm = max(20, min(bpm, 400)) self.interval = 15. / self.bpm self.pattern = pattern self.channel = channel self.volume = volume self.start() def run(self): self.done = False self.callcount = 0 self.activate_drumkit(self.pattern.kit) cc = CONTROL_CHANGE | self.channel self.midiout.send_message([cc, CHANNEL_VOLUME, self.volume & 0x7F]) # give MIDI instrument some time to activate drumkit sleep(0.3) self.started = timenow() while not self.done: self.worker() self.callcount += 1 # Compensate for drift: # calculate the time when the worker should be called again. nexttime = self.started + self.callcount * self.interval timetowait = max(0, nexttime - timenow()) if timetowait: sleep(timetowait) else: print("Oops!") self.midiout.send_message([cc, ALL_SOUND_OFF, 0]) def worker(self): """Variable time worker function. i.e., output notes, emtpy queues, etc. """ self.pattern.playstep(self.midiout, self.channel) def activate_drumkit(self, kit): if isinstance(kit, (list, tuple)): msb, lsb, pc = kit elif kit is not None: msb = lsb = None pc = kit cc = CONTROL_CHANGE | self.channel if msb is not None: self.midiout.send_message([cc, BANK_SELECT_MSB, msb & 0x7F]) if lsb is not None: self.midiout.send_message([cc, BANK_SELECT_LSB, lsb & 0x7F]) if kit is not None and pc is not None: self.midiout.send_message([PROGRAM_CHANGE | self.channel, pc & 0x7F]) class Drumpattern(object): """Container and iterator for a multi-track step sequence.""" velocities = { "-": None, # continue note ".": 0, # off "+": 10, # ghost "s": 60, # soft "m": 100, # medium "x": 120, # hard } def __init__(self, pattern, kit=0, humanize=0): self.instruments = [] self.kit = kit self.humanize = humanize pattern = (line.strip() for line in pattern.splitlines()) pattern = (line for line in pattern if line and line[0] != '#') for line in pattern: parts = line.split(" ", 2) if len(parts) == 3: patch, strokes, description = parts patch = int(patch) self.instruments.append((patch, strokes)) self.steps = len(strokes) self.step = 0 self._notes = {} def reset(self): self.step = 0 def playstep(self, midiout, channel=9): for note, strokes in self.instruments: char = strokes[self.step] velocity = self.velocities.get(char) if velocity is not None: if self._notes.get(note): midiout.send_message([NOTE_ON | channel, note, 0]) self._notes[note] = 0 if velocity > 0: if self.humanize: velocity += int(round(gauss(0, velocity * self.humanize))) midiout.send_message([NOTE_ON | channel, note, max(1, velocity)]) self._notes[note] = velocity self.step += 1 if self.step >= self.steps: self.step = 0 def main(args=None): ap = argparse.ArgumentParser(description=__doc__.splitlines()[0]) aadd = ap.add_argument aadd('-b', '--bpm', type=float, default=100, help="Beats per minute (BPM) (default: %(default)s)") aadd('-c', '--channel', type=int, default=10, metavar='CH', help="MIDI channel (default: %(default)s)") aadd('-p', '--port', help="MIDI output port number (default: ask)") aadd('-k', '--kit', type=int, metavar='KIT', help="Drum kit MIDI program number (default: none)") aadd('--bank-msb', type=int, metavar='MSB', help="MIDI bank select MSB (CC#00) number (default: none)") aadd('--bank-lsb', type=int, metavar='MSB', help="MIDI bank select LSB (CC#32) number (default: none)") aadd('-H', '--humanize', type=float, default=0.0, metavar='VAL', help="Random velocity variation (float, default: 0, try ~0.03)") aadd('pattern', nargs='?', type=argparse.FileType(), help="Drum pattern file (default: use built-in pattern)") args = ap.parse_args(args if args is not None else sys.argv[1:]) if args.pattern: pattern = args.pattern.read() else: pattern = FUNKYDRUMMER kit = (args.bank_msb, args.bank_lsb, args.kit) pattern = Drumpattern(pattern, kit=kit, humanize=args.humanize) try: midiout, port_name = open_midioutput( args.port, api=rtmidi.API_UNIX_JACK, client_name="drumseq", port_name="MIDI Out") except (EOFError, KeyboardInterrupt): return seq = Sequencer(midiout, pattern, args.bpm, args.channel - 1) print("Playing drum loop at %.1f BPM, press Control-C to quit." % seq.bpm) try: while True: sleep(1) except KeyboardInterrupt: print('') finally: seq.done = True # And kill it. seq.join() del midiout print("Done") if __name__ == "__main__": sys.exit(main(sys.argv[1:]) or 0)