# -*- 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)
[docs]def note2midi(note):
"""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 = 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 = (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)
return midi
[docs]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)
[docs]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)
[docs]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)