1 # -*- coding: utf-8 -*-
2 """ utilities to convert midi note number to and from note names """
4 __all__ = ['note2midi', 'midi2note', 'freq2note']
7 py3 = sys.version_info[0] == 3
12 str_instances = (str, unicode)
13 int_instances = (int, long)
16 " convert note name to midi note number, e.g. [C-1, G9] -> [0, 127] "
17 _valid_notenames = {'C': 0, 'D': 2, 'E': 4, 'F': 5, 'G': 7, 'A': 9, 'B': 11}
19 u'𝄫': -2, # double flat
20 u'♭': -1, 'b': -1, '\u266d': -1, # simple flat
21 u'♮': 0, '\u266e': 0, None: 0, # natural
22 '#': +1, u'♯': +1, '\u266f': +1, # sharp
23 u'𝄪': +2, # double sharp
25 _valid_octaves = range(-1, 10)
26 if not isinstance(note, str_instances):
27 raise TypeError("a string is required, got %s (%s)" % (note, str(type(note))))
28 if len(note) not in range(2, 5):
29 raise ValueError("string of 2 to 4 characters expected, got %d (%s)" \
31 notename, modifier, octave = [None]*3
34 notename, modifier, octave_sign, octave = note
35 octave = octave_sign + octave
37 notename, modifier, octave = note
39 octave = modifier + octave
42 notename, octave = note
44 notename = notename.upper()
47 if notename not in _valid_notenames:
48 raise ValueError("%s is not a valid note name" % notename)
49 if modifier not in _valid_modifiers:
50 raise ValueError("%s is not a valid modifier" % modifier)
51 if octave not in _valid_octaves:
52 raise ValueError("%s is not a valid octave" % octave)
54 midi = 12 + octave * 12 + _valid_notenames[notename] + _valid_modifiers[modifier]
56 raise ValueError("%s is outside of the range C-2 to G8" % note)
60 " convert midi note number to note name, e.g. [0, 127] -> [C-1, G9] "
61 if not isinstance(midi, int_instances):
62 raise TypeError("an integer is required, got %s" % midi)
63 if midi not in range(0, 128):
64 raise ValueError("an integer between 0 and 127 is excepted, got %d" % midi)
65 _valid_notenames = ['C', 'C#', 'D', 'D#', 'E', 'F', 'F#', 'G', 'G#', 'A', 'A#', 'B']
66 return _valid_notenames[midi % 12] + str(int(midi / 12) - 1)
69 " convert frequency in Hz to nearest note name, e.g. [0, 22050.] -> [C-1, G9] "
70 from aubio import freqtomidi
71 return midi2note(int(freqtomidi(freq)))