[7d89e61] | 1 | # -*- coding: utf-8 -*- |
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[1827c498] | 2 | """ utilities to convert midi note number to and from note names """ |
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[33102ab] | 3 | |
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[744190f] | 4 | __all__ = ['note2midi', 'midi2note', 'freq2note'] |
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| 5 | |
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[e76842e] | 6 | import sys |
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[6f944b5] | 7 | from ._aubio import freqtomidi, miditofreq |
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[1f07bdd] | 8 | |
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[1827c498] | 9 | py3 = sys.version_info[0] == 3 |
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| 10 | if py3: |
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[016813e] | 11 | str_instances = str |
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| 12 | int_instances = int |
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[e76842e] | 13 | else: |
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[016813e] | 14 | str_instances = (str, unicode) |
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| 15 | int_instances = (int, long) |
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[e76842e] | 16 | |
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[33102ab] | 17 | def note2midi(note): |
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[f552e9e] | 18 | " convert note name to midi note number, e.g. [C-1, G9] -> [0, 127] " |
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[33102ab] | 19 | _valid_notenames = {'C': 0, 'D': 2, 'E': 4, 'F': 5, 'G': 7, 'A': 9, 'B': 11} |
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[3aad0b1] | 20 | _valid_modifiers = { |
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| 21 | u'𝄫': -2, # double flat |
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| 22 | u'♭': -1, 'b': -1, '\u266d': -1, # simple flat |
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| 23 | u'♮': 0, '\u266e': 0, None: 0, # natural |
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| 24 | '#': +1, u'♯': +1, '\u266f': +1, # sharp |
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| 25 | u'𝄪': +2, # double sharp |
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| 26 | } |
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[7d89e61] | 27 | _valid_octaves = range(-1, 10) |
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[016813e] | 28 | if not isinstance(note, str_instances): |
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[40136171] | 29 | msg = "a string is required, got {:s} ({:s})" |
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| 30 | raise TypeError(msg.format(str(type(note)), repr(note))) |
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[1827c498] | 31 | if len(note) not in range(2, 5): |
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[40136171] | 32 | msg = "string of 2 to 4 characters expected, got {:d} ({:s})" |
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| 33 | raise ValueError(msg.format(len(note), note)) |
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[33102ab] | 34 | notename, modifier, octave = [None]*3 |
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| 35 | |
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| 36 | if len(note) == 4: |
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| 37 | notename, modifier, octave_sign, octave = note |
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| 38 | octave = octave_sign + octave |
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| 39 | elif len(note) == 3: |
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| 40 | notename, modifier, octave = note |
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| 41 | if modifier == '-': |
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| 42 | octave = modifier + octave |
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| 43 | modifier = None |
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| 44 | else: |
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| 45 | notename, octave = note |
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| 46 | |
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| 47 | notename = notename.upper() |
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| 48 | octave = int(octave) |
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| 49 | |
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| 50 | if notename not in _valid_notenames: |
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[b8ed85e] | 51 | raise ValueError("%s is not a valid note name" % notename) |
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[33102ab] | 52 | if modifier not in _valid_modifiers: |
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[b8ed85e] | 53 | raise ValueError("%s is not a valid modifier" % modifier) |
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[33102ab] | 54 | if octave not in _valid_octaves: |
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[b8ed85e] | 55 | raise ValueError("%s is not a valid octave" % octave) |
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[33102ab] | 56 | |
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[40136171] | 57 | midi = 12 + octave * 12 + _valid_notenames[notename] \ |
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| 58 | + _valid_modifiers[modifier] |
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[33102ab] | 59 | if midi > 127: |
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[b8ed85e] | 60 | raise ValueError("%s is outside of the range C-2 to G8" % note) |
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[33102ab] | 61 | return midi |
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[9ead7a9] | 62 | |
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| 63 | def midi2note(midi): |
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| 64 | " convert midi note number to note name, e.g. [0, 127] -> [C-1, G9] " |
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[016813e] | 65 | if not isinstance(midi, int_instances): |
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[b8ed85e] | 66 | raise TypeError("an integer is required, got %s" % midi) |
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[1827c498] | 67 | if midi not in range(0, 128): |
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[40136171] | 68 | msg = "an integer between 0 and 127 is excepted, got {:d}" |
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| 69 | raise ValueError(msg.format(midi)) |
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| 70 | _valid_notenames = ['C', 'C#', 'D', 'D#', 'E', 'F', 'F#', 'G', 'G#', |
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| 71 | 'A', 'A#', 'B'] |
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[1827c498] | 72 | return _valid_notenames[midi % 12] + str(int(midi / 12) - 1) |
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[3cc1491] | 73 | |
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| 74 | def freq2note(freq): |
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[1827c498] | 75 | " convert frequency in Hz to nearest note name, e.g. [0, 22050.] -> [C-1, G9] " |
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[44582b0] | 76 | nearest_note = int(freqtomidi(freq) + .5) |
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| 77 | return midi2note(nearest_note) |
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[6f944b5] | 78 | |
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| 79 | def note2freq(note): |
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| 80 | """Convert note name to corresponding frequency, in Hz. |
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| 81 | |
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| 82 | Parameters |
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| 83 | ---------- |
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| 84 | note : str |
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| 85 | input note name |
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| 86 | |
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| 87 | Returns |
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| 88 | ------- |
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| 89 | freq : float [0, 23000[ |
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| 90 | frequency, in Hz |
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| 91 | |
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| 92 | Example |
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| 93 | ------- |
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| 94 | >>> aubio.note2freq('A4') |
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| 95 | 440 |
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| 96 | >>> aubio.note2freq('A3') |
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| 97 | 220.1 |
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| 98 | """ |
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| 99 | midi = note2midi(note) |
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| 100 | return miditofreq(midi) |
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