-# -*- encoding: utf8 -*-
+# -*- coding: utf-8 -*-
+""" utilities to convert midi note number to and from note names """
+
+import sys
+from ._aubio import freqtomidi, miditofreq
+
+__all__ = ['note2midi', 'midi2note', 'freq2note', 'note2freq']
+
+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 a note name to a midi note value "
- # from C-2 to G8, though we do accept everything in the upper octave
- _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 (1 < len(note) < 5):
- raise ValueError, "string of 2 to 4 characters expected, got %d (%s)" % (len(note), note)
- notename, modifier, octave = [None]*3
+ """Convert note name to midi note number.
+
+ Input string `note` should be composed of one note root
+ and one octave, with optionally one modifier in between.
+
+ List of valid components:
+
+ - note roots: `C`, `D`, `E`, `F`, `G`, `A`, `B`,
+ - modifiers: `b`, `#`, as well as unicode characters
+ `𝄫`, `♭`, `♮`, `♯` and `𝄪`,
+ - octave numbers: `-1` -> `11`.
+
+ Parameters
+ ----------
+ note : str
+ note name
+
+ Returns
+ -------
+ int
+ corresponding midi note number
+
+ Examples
+ --------
+ >>> aubio.note2midi('C#4')
+ 61
+ >>> aubio.note2midi('B♭5')
+ 82
+
+ Raises
+ ------
+ TypeError
+ If `note` was not a string.
+ ValueError
+ If an error was found while converting `note`.
+
+ See Also
+ --------
+ midi2note, freqtomidi, miditofreq
+ """
+ _valid_notenames = {'C': 0, 'D': 2, 'E': 4, 'F': 5, 'G': 7,
+ 'A': 9, 'B': 11}
+ _valid_modifiers = {
+ u'𝄫': -2, # double flat
+ u'♭': -1, 'b': -1, '\u266d': -1, # simple flat
+ u'♮': 0, '\u266e': 0, None: 0, # natural
+ '#': +1, u'♯': +1, '\u266f': +1, # sharp
+ u'𝄪': +2, # double sharp
+ }
+ _valid_octaves = range(-1, 10)
+ if not isinstance(note, str_instances):
+ msg = "a string is required, got {:s} ({:s})"
+ raise TypeError(msg.format(str(type(note)), repr(note)))
+ if len(note) not in range(2, 5):
+ msg = "string of 2 to 4 characters expected, got {:d} ({:s})"
+ raise ValueError(msg.format(len(note), note))
+ notename, modifier, octave = [None] * 3
if len(note) == 4:
notename, modifier, octave_sign, octave = note
octave = int(octave)
if notename not in _valid_notenames:
- raise ValueError, "%s is not a valid note name" % notename
+ raise ValueError("%s is not a valid note name" % notename)
if modifier not in _valid_modifiers:
- raise ValueError, "only # and b are acceptable modifiers, not %s" % modifier
+ raise ValueError("%s is not a valid modifier" % modifier)
if octave not in _valid_octaves:
- raise ValueError, "%s is not a valid octave" % octave
+ raise ValueError("%s is not a valid octave" % octave)
- midi = 12 + octave * 12 + _valid_notenames[notename] + _valid_modifiers[modifier]
+ midi = (octave + 1) * 12 + _valid_notenames[notename] \
+ + _valid_modifiers[modifier]
if midi > 127:
- raise ValueError, "%s is outside of the range C-2 to G8" % note
+ 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.
+
+ Parameters
+ ----------
+ midi : int [0, 128]
+ input midi note number
+
+ Returns
+ -------
+ str
+ note name
+
+ Examples
+ --------
+ >>> aubio.midi2note(70)
+ 'A#4'
+ >>> aubio.midi2note(59)
+ 'B3'
+
+ Raises
+ ------
+ TypeError
+ If `midi` was not an integer.
+ ValueError
+ If `midi` is out of the range `[0, 128]`.
+
+ See Also
+ --------
+ note2midi, miditofreq, freqtomidi
+ """
+ if not isinstance(midi, int_instances):
+ raise TypeError("an integer is required, got %s" % midi)
+ if midi not in range(0, 128):
+ msg = "an integer between 0 and 127 is excepted, got {:d}"
+ raise ValueError(msg.format(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.
+
+ Parameters
+ ----------
+ freq : float [0, 23000[
+ input frequency, in Hz
+
+ Returns
+ -------
+ str
+ name of the nearest note
+
+ Example
+ -------
+ >>> aubio.freq2note(440)
+ 'A4'
+ >>> aubio.freq2note(220.1)
+ 'A3'
+ """
+ nearest_note = int(freqtomidi(freq) + .5)
+ return midi2note(nearest_note)
+
+
+def note2freq(note):
+ """Convert note name to corresponding frequency, in Hz.
+
+ Parameters
+ ----------
+ note : str
+ input note name
+
+ Returns
+ -------
+ freq : float [0, 23000[
+ frequency, in Hz
+
+ Example
+ -------
+ >>> aubio.note2freq('A4')
+ 440
+ >>> aubio.note2freq('A3')
+ 220.1
+ """
+ midi = note2midi(note)
+ return miditofreq(midi)
projects / aubio.git / blobdiff