Show basic tempo and time/key signature information of a standard MIDI file using miditk-smf

smfinfo.py

import sys

from miditk.smf.reader import MidiFileReader
from miditk.smf.sequence import MidiSequence, ObjectMidiEventHandler


# This defines callbacks called while parsing the MIDI sequence
# We only need to overwrite the event handlers we want to handle specially
class MySequenceHandler(ObjectMidiEventHandler):
    def __init__(self, instance=None, debug=False):
        super().__init__(instance, debug)
        instance.tempo_map = []
        instance.time_signature_map = []
        instance.key_signature_map = []

    def tempo(self, value):
        """Handle tempo change events."""
        bpm = 60000000.0 / value
        ms_per_quarter = value / 1000.0
        self._instance.tempo_map.append((self.current_time, (bpm, ms_per_quarter)))

    def time_signature(self, nn, dd, cc, bb):
        """Handle time signature change events."""
        self._instance.time_signature_map.append((self.current_time, (nn, dd**2)))

    def key_signature(self, sf, mi):
        """Handle key signature change events."""
        self._instance.key_signature_map.append((self.current_time, (sf, mi)))


def main():
    filename = sys.argv[1]
    seq = MidiSequence()
    reader = MidiFileReader(filename, MySequenceHandler(seq, debug=True))
    reader.read()

    print(seq)

    print("PPQN:", seq.tick_division)

    print("Tempo changes:")
    for time, tempo in seq.tempo_map:
        print(time, tempo)

    print("Time signature changes:")
    for time, tempsig in seq.time_signature_map:
        print(time, tempsig)

    print("Key signature changes:")
    for time, keysig in seq.key_signature_map:
        print(time, keysig)


if __name__ == '__main__':
    sys.exit(main() or 0)