Source code for aubio.midiconv

# -*- 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)