1 files changed, 66 insertions, 0 deletions
diff --git a/python/lib/aubio/midiconv.py b/python/lib/aubio/midiconv.py
new file mode 100644
index 0000000..80f28d0
--- /dev/null
+++ b/python/lib/aubio/midiconv.py
@@ -0,0 +1,66 @@
+# -*- coding: utf-8 -*-
+""" utilities to convert midi note number to and from note names """
+
+__all__ = ['note2midi', 'midi2note', 'freq2note']
+
+import sys
+py3 = sys.version_info[0] == 3
+if py3:
+    str_instances = str
+    int_instances = int
+else:
+    str_instances = (str, unicode)
+    int_instances = (int, long)
+
+def note2midi(note):
+    " convert note name to midi note number, e.g. [C-1, G9] -> [0, 127] "
+    _valid_notenames = {'C': 0, 'D': 2, 'E': 4, 'F': 5, 'G': 7, 'A': 9, 'B': 11}
+    _valid_modifiers = {None: 0, u'♮': 0, '#': +1, u'♯': +1, u'\udd2a': +2,
+                        'b': -1, u'♭': -1, u'\ufffd': -2}
+    _valid_octaves = range(-1, 10)
+    if not isinstance(note, str_instances):
+        raise TypeError("a string is required, got %s (%s)" % (note, str(type(note))))
+    if len(note) not in range(2, 5):
+        raise ValueError("string of 2 to 4 characters expected, got %d (%s)" \
+                         % (len(note), note))
+    notename, modifier, octave = [None]*3
+
+    if len(note) == 4:
+        notename, modifier, octave_sign, octave = note
+        octave = octave_sign + octave
+    elif len(note) == 3:
+        notename, modifier, octave = note
+        if modifier == '-':
+            octave = modifier + octave
+            modifier = None
+    else:
+        notename, octave = note
+
+    notename = notename.upper()
+    octave = int(octave)
+
+    if notename not in _valid_notenames:
+        raise ValueError("%s is not a valid note name" % notename)
+    if modifier not in _valid_modifiers:
+        raise ValueError("%s is not a valid modifier" % modifier)
+    if octave not in _valid_octaves:
+        raise ValueError("%s is not a valid octave" % octave)
+
+    midi = 12 + octave * 12 + _valid_notenames[notename] + _valid_modifiers[modifier]
+    if midi > 127:
+        raise ValueError("%s is outside of the range C-2 to G8" % note)
+    return midi
+
+def midi2note(midi):
+    " convert midi note number to note name, e.g. [0, 127] -> [C-1, G9] "
+    if not isinstance(midi, int_instances):
+        raise TypeError("an integer is required, got %s" % midi)
+    if midi not in range(0, 128):
+        raise ValueError("an integer between 0 and 127 is excepted, got %d" % midi)
+    _valid_notenames = ['C', 'C#', 'D', 'D#', 'E', 'F', 'F#', 'G', 'G#', 'A', 'A#', 'B']
+    return _valid_notenames[midi % 12] + str(int(midi / 12) - 1)
+
+def freq2note(freq):
+    " convert frequency in Hz to nearest note name, e.g. [0, 22050.] -> [C-1, G9] "
+    from aubio import freqtomidi
+    return midi2note(int(freqtomidi(freq)))