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Decode received MIDI RPN messages
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import time | |
from collections import defaultdict | |
import rtmidi | |
from rtmidi.midiconstants import * | |
from rtmidi.midiutil import open_midiinput | |
class RPNDecoder: | |
def __init__(self, channel=1): | |
self.channel = (channel - 1) & 0xF | |
self.rpn = 0 | |
self.values = defaultdict(int) | |
self.last_changed = None | |
def __call__(self, event, data=None): | |
msg, deltatime = event | |
# event type = upper four bits of first byte | |
if msg[0] == (CONTROL_CHANGE | self.channel): | |
cc, value = msg[1], msg[2] | |
if cc == RPN_LSB: | |
self.rpn = (self.rpn >> 7) * 128 + value | |
elif cc == RPN_MSB: | |
self.rpn = value * 128 + (self.rpn & 0x7F) | |
elif cc == DATA_INCREMENT: | |
self.set_rpn(self.rpn, min(2 ** 14, self.values[self.rpn] + 1)) | |
elif cc == DATA_DECREMENT: | |
self.set_rpn(self.rpn, max(0, self.values[self.rpn] - 1)) | |
elif cc == DATA_ENTRY_LSB: | |
self.set_rpn(self.rpn, (self.values[self.rpn] >> 7) * 128 + value) | |
elif cc == DATA_ENTRY_MSB: | |
self.set_rpn(self.rpn, value * 128 + (self.values[self.rpn] & 0x7F)) | |
def set_rpn(self, rpn, value): | |
self.values[rpn] = value | |
self.last_changed = rpn | |
decoder = RPNDecoder() | |
m_in, port_name = open_midiinput() | |
m_in.set_callback(decoder) | |
while True: | |
rpn = decoder.last_changed | |
if rpn: | |
print("RPN %i: %i" % (rpn, decoder.values[rpn])) | |
decoder.last_changed = None | |
time.sleep(0.1) |
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Latest version: https://github.com/SpotlightKid/python-rtmidi/blob/master/examples/advanced/recvrpn.py