1 | # -*- encoding: utf8 -*- |
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2 | |
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3 | def note2midi(note): |
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4 | " convert a note name to a midi note value " |
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5 | # from C-2 to G8, though we do accept everything in the upper octave |
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6 | _valid_notenames = {'C': 0, 'D': 2, 'E': 4, 'F': 5, 'G': 7, 'A': 9, 'B': 11} |
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7 | _valid_modifiers = {None: 0, u'♮': 0, '#': +1, u'♯': +1, u'\udd2a': +2, 'b': -1, u'♭': -1, u'\ufffd': -2} |
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8 | _valid_octaves = range(-1, 10) |
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9 | if not (1 < len(note) < 5): |
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10 | raise ValueError, "string of 2 to 4 characters expected, got %d (%s)" % (len(note), note) |
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11 | notename, modifier, octave = [None]*3 |
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12 | |
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13 | if len(note) == 4: |
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14 | notename, modifier, octave_sign, octave = note |
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15 | octave = octave_sign + octave |
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16 | elif len(note) == 3: |
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17 | notename, modifier, octave = note |
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18 | if modifier == '-': |
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19 | octave = modifier + octave |
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20 | modifier = None |
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21 | else: |
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22 | notename, octave = note |
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23 | |
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24 | notename = notename.upper() |
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25 | octave = int(octave) |
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26 | |
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27 | if notename not in _valid_notenames: |
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28 | raise ValueError, "%s is not a valid note name" % notename |
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29 | if modifier not in _valid_modifiers: |
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30 | raise ValueError, "only # and b are acceptable modifiers, not %s" % modifier |
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31 | if octave not in _valid_octaves: |
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32 | raise ValueError, "%s is not a valid octave" % octave |
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33 | |
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34 | midi = 12 + octave * 12 + _valid_notenames[notename] + _valid_modifiers[modifier] |
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35 | if midi > 127: |
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36 | raise ValueError, "%s is outside of the range C-2 to G8" % note |
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37 | return midi |
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