1 # -*- coding: utf-8 -*-
2 """ utilities to convert midi note number to and from note names """
4 __all__ = ['note2midi', 'midi2note', 'freq2note']
7 from ._aubio import freqtomidi, miditofreq
9 py3 = sys.version_info[0] == 3
14 str_instances = (str, unicode)
15 int_instances = (int, long)
18 " convert note name to midi note number, e.g. [C-1, G9] -> [0, 127] "
19 _valid_notenames = {'C': 0, 'D': 2, 'E': 4, 'F': 5, 'G': 7, 'A': 9, 'B': 11}
21 u'𝄫': -2, # double flat
22 u'♭': -1, 'b': -1, '\u266d': -1, # simple flat
23 u'♮': 0, '\u266e': 0, None: 0, # natural
24 '#': +1, u'♯': +1, '\u266f': +1, # sharp
25 u'𝄪': +2, # double sharp
27 _valid_octaves = range(-1, 10)
28 if not isinstance(note, str_instances):
29 msg = "a string is required, got {:s} ({:s})"
30 raise TypeError(msg.format(str(type(note)), repr(note)))
31 if len(note) not in range(2, 5):
32 msg = "string of 2 to 4 characters expected, got {:d} ({:s})"
33 raise ValueError(msg.format(len(note), note))
34 notename, modifier, octave = [None]*3
37 notename, modifier, octave_sign, octave = note
38 octave = octave_sign + octave
40 notename, modifier, octave = note
42 octave = modifier + octave
45 notename, octave = note
47 notename = notename.upper()
50 if notename not in _valid_notenames:
51 raise ValueError("%s is not a valid note name" % notename)
52 if modifier not in _valid_modifiers:
53 raise ValueError("%s is not a valid modifier" % modifier)
54 if octave not in _valid_octaves:
55 raise ValueError("%s is not a valid octave" % octave)
57 midi = 12 + octave * 12 + _valid_notenames[notename] \
58 + _valid_modifiers[modifier]
60 raise ValueError("%s is outside of the range C-2 to G8" % note)
64 " convert midi note number to note name, e.g. [0, 127] -> [C-1, G9] "
65 if not isinstance(midi, int_instances):
66 raise TypeError("an integer is required, got %s" % midi)
67 if midi not in range(0, 128):
68 msg = "an integer between 0 and 127 is excepted, got {:d}"
69 raise ValueError(msg.format(midi))
70 _valid_notenames = ['C', 'C#', 'D', 'D#', 'E', 'F', 'F#', 'G', 'G#',
72 return _valid_notenames[midi % 12] + str(int(midi / 12) - 1)
75 " convert frequency in Hz to nearest note name, e.g. [0, 22050.] -> [C-1, G9] "
76 nearest_note = int(freqtomidi(freq) + .5)
77 return midi2note(nearest_note)
80 """Convert note name to corresponding frequency, in Hz.
89 freq : float [0, 23000[
94 >>> aubio.note2freq('A4')
96 >>> aubio.note2freq('A3')
99 midi = note2midi(note)
100 return miditofreq(midi)