main.py

import logging
import sys
import time
from binascii import a2b_base64 as b64
from collections import deque

from broadlink import discover as bl_discover  # https://github.com/mjg59/python-broadlink
from rtmidi import midiutil  # https://github.com/SpotlightKid/python-rtmidi
from rtmidi.midiconstants import (TIMING_CLOCK, SONG_CONTINUE, SONG_START, SONG_STOP)

log = logging.getLogger('midiin_callback')
logging.basicConfig(level=logging.INFO)


class MIDIClockReceiver:
	pkt_ptrn = 'JgBQAAABJJIUERQSExITEhMSExITEhMSEzcTNxM3EzcTNxM3EzgSNxM3FBEUERQ2FBEUEhMSExITEhM3EzcTEhM3EzcTNxQ2Ew=='
	pkt_30_pc = 'JgBQAAABIZQSFBEUERQSExITExIUERQRFDYUNhQ2FDYUNhQ2FDYUNhQSExITNRU3ExITEhMSExITNxQ2FBEUERQ2FDYUNhQ2FA=='
	pkt_60_pc = 'JgBYAAABJJIUEhMSExITEhMSExITEhQRFDYUNhQ2FDYUNhQ2FDYUNhQ3ExITNxMSExITEhMSExIUERQ2FBEUNhQ2FDYUNhQ2FA=='
	pkt_100_pc = 'JgBQAAABJJIUERQRFBEUERQSExITEhMSEzcTNxM3EzcUNhQ2FDYUNhQRFDYUNhQ3ExITEhMSExITNxMSExITEhQ2FDYUNhQ2FA=='

	def __init__(self, bpm=None, device=None):
		self.device = device
		self.cycle = [self.pkt_100_pc, self.pkt_60_pc, self.pkt_30_pc]  # , pkt_chg_ptrn]
		self.cycle_ctr = 0
		self.bpm = bpm if bpm is not None else 120.0
		self.sync = False
		self.running = True
		self._samples = deque()
		self._last_clock = None
		self.clock_ctr = 0

	def on_beat(self):
		self.device.send_data(b64(self.pkt_ptrn))

	def __call__(self, event, data=None):
		msg, _ = event
		if msg[0] == TIMING_CLOCK:
			now = time.time()
			if self._last_clock is not None:
				self._samples.append(now - self._last_clock)
			self._last_clock = now
			self.clock_ctr += 1
			if self.clock_ctr >= 23:
				self.on_beat()
				self.clock_ctr = 0
			if len(self._samples) > 24:
				self._samples.popleft()
			if len(self._samples) >= 2:
				self.bpm = 2.5 / (sum(self._samples) / len(self._samples))
				self.sync = True
		elif msg[0] in (SONG_CONTINUE, SONG_START):
			self.running = True
			print("START/CONTINUE received.")
		elif msg[0] == SONG_STOP:
			self.running = False
			print("STOP received.")


def main(args=None):
	print("INFO:broadlink:Locating infrared transmitter. This may take a few attempts.")
	devices = []
	while len(devices) < 1:
		print("INFO:broadlink:Running discovery with 10s timeout.")
		devices = bl_discover(timeout=10)
	print("INFO:broadlink:Transmitter found. Authenticating.")
	devices[0].auth()
	print("INFO:broadlink:Ready to transmit.")

	clock = MIDIClockReceiver(bpm=None, device=devices[0])

	try:
		m_in, port_name = midiutil.open_midiinput(args[0] if args else 0)
	except (EOFError, KeyboardInterrupt):
		return 1

	m_in.set_callback(clock)
	# Important: enable reception of MIDI Clock messages (status 0xF8)
	m_in.ignore_types(timing=False)

	try:
		print("Waiting for clock sync...")
		while True:
			time.sleep(1)

			if clock.running:
				if clock.sync:
					print("%.2f bpm" % clock.bpm)
				else:
					print("%.2f bpm (no sync)" % clock.bpm)

	except KeyboardInterrupt:
		pass
	finally:
		m_in.close_port()
		del m_in


if __name__ == '__main__':

	sys.exit(main(sys.argv[1:]) or 0)