60 lines
1.3 KiB
Python
60 lines
1.3 KiB
Python
import math
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notes = ['C', 'C#', 'D', 'D#', 'E', 'F', 'F#', 'G', 'G#', 'A', 'A#', 'B']
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base_c = 24
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def midi_to_midi_str(midi):
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"""
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:param int midi: MIDI int value (e.g. 69)
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:return: MIDI string (e.g. A4)
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:rtype: str
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"""
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global notes, base_c
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assert 24 <= midi <= 127
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i = (midi - base_c) % len(notes)
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octave = int((midi - base_c) / 12) + 1
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return '{note}{octave}'.format(note=notes[i], octave=octave)
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def freq_to_midi(freq):
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"""
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:param float freq: Frequency (e.g. 440.0)
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:return: MIDI int value (e.g. 69)
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:rtype: int
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"""
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return int(math.log2(freq / 440.0) * 12) + 69
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def freq_to_midi_str(freq):
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"""
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:param float freq: Frequency (e.g. 440.0)
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:return: MIDI string (e.g. A4)
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:rtype: str
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"""
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return midi_to_midi_str(freq_to_midi(freq))
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def midi_to_freq(midi):
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"""
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:param int midi: MIDI note (e.g. 69)
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:return: Frequency in Hz (e.g. 440.0)
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:rtype: float
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"""
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return 440.0 * math.pow(2.0, (midi - 69) / 12)
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def midi_str_to_midi(midi_str):
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"""
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:param str midi_str: MIDI string (e.g. A4)
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:return: MIDI int value (e.g. 69)
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:rtype: int
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"""
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global notes, base_c
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note = notes.index(midi_str[0].upper())
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octave = int(midi_str[1])
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assert 1 <= octave <= 9
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return 12 + note + 12*octave
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