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Source code for librosa.core.notation
#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""Music notation utilities"""
import re
import numpy as np
from .._cache import cache
from ..util.exceptions import ParameterError
from ..util.decorators import deprecate_positional_args
__all__ = [
"key_to_degrees",
"key_to_notes",
"mela_to_degrees",
"mela_to_svara",
"thaat_to_degrees",
"list_mela",
"list_thaat",
]
THAAT_MAP = dict(
bilaval=[0, 2, 4, 5, 7, 9, 11],
khamaj=[0, 2, 4, 5, 7, 9, 10],
kafi=[0, 2, 3, 5, 7, 9, 10],
asavari=[0, 2, 3, 5, 7, 8, 10],
bhairavi=[0, 1, 3, 5, 7, 8, 10],
kalyan=[0, 2, 4, 6, 7, 9, 11],
marva=[0, 1, 4, 6, 7, 9, 11],
poorvi=[0, 1, 4, 6, 7, 8, 11],
todi=[0, 1, 3, 6, 7, 8, 11],
bhairav=[0, 1, 4, 5, 7, 8, 11],
)
# Enumeration will start from 1
MELAKARTA_MAP = {
k: i
for i, k in enumerate(
[
"kanakangi",
"ratnangi",
"ganamurthi",
"vanaspathi",
"manavathi",
"tanarupi",
"senavathi",
"hanumathodi",
"dhenuka",
"natakapriya",
"kokilapriya",
"rupavathi",
"gayakapriya",
"vakulabharanam",
"mayamalavagaula",
"chakravakom",
"suryakantham",
"hatakambari",
"jhankaradhwani",
"natabhairavi",
"keeravani",
"kharaharapriya",
"gaurimanohari",
"varunapriya",
"mararanjini",
"charukesi",
"sarasangi",
"harikambhoji",
"dheerasankarabharanam",
"naganandini",
"yagapriya",
"ragavardhini",
"gangeyabhushani",
"vagadheeswari",
"sulini",
"chalanatta",
"salagam",
"jalarnavam",
"jhalavarali",
"navaneetham",
"pavani",
"raghupriya",
"gavambodhi",
"bhavapriya",
"subhapanthuvarali",
"shadvidhamargini",
"suvarnangi",
"divyamani",
"dhavalambari",
"namanarayani",
"kamavardhini",
"ramapriya",
"gamanasrama",
"viswambhari",
"syamalangi",
"shanmukhapriya",
"simhendramadhyamam",
"hemavathi",
"dharmavathi",
"neethimathi",
"kanthamani",
"rishabhapriya",
"latangi",
"vachaspathi",
"mechakalyani",
"chitrambari",
"sucharitra",
"jyotisvarupini",
"dhatuvardhini",
"nasikabhushani",
"kosalam",
"rasikapriya",
],
1,
)
}
[docs]def thaat_to_degrees(thaat):
"""Construct the svara indices (degrees) for a given thaat
Parameters
----------
thaat : str
The name of the thaat
Returns
-------
indices : np.ndarray
A list of the seven svara indices (starting from 0=Sa)
contained in the specified thaat
See Also
--------
key_to_degrees
mela_to_degrees
list_thaat
Examples
--------
>>> librosa.thaat_to_degrees('bilaval')
array([ 0, 2, 4, 5, 7, 9, 11])
>>> librosa.thaat_to_degrees('todi')
array([ 0, 1, 3, 6, 7, 8, 11])
"""
return np.asarray(THAAT_MAP[thaat.lower()])
[docs]def mela_to_degrees(mela):
"""Construct the svara indices (degrees) for a given melakarta raga
Parameters
----------
mela : str or int
Either the name or integer index ([1, 2, ..., 72]) of the melakarta raga
Returns
-------
degrees : np.ndarray
A list of the seven svara indices (starting from 0=Sa)
contained in the specified raga
See Also
--------
thaat_to_degrees
key_to_degrees
list_mela
Examples
--------
Melakarta #1 (kanakangi):
>>> librosa.mela_to_degrees(1)
array([0, 1, 2, 5, 7, 8, 9])
Or using a name directly:
>>> librosa.mela_to_degrees('kanakangi')
array([0, 1, 2, 5, 7, 8, 9])
"""
if isinstance(mela, str):
index = MELAKARTA_MAP[mela.lower()] - 1
elif 0 < mela <= 72:
index = mela - 1
else:
raise ParameterError("mela={} must be in range [1, 72]".format(mela))
# always have Sa [0]
degrees = [0]
# Fill in Ri and Ga
lower = index % 36
if 0 <= lower < 6:
# Ri1, Ga1
degrees.extend([1, 2])
elif 6 <= lower < 12:
# Ri1, Ga2
degrees.extend([1, 3])
elif 12 <= lower < 18:
# Ri1, Ga3
degrees.extend([1, 4])
elif 18 <= lower < 24:
# Ri2, Ga2
degrees.extend([2, 3])
elif 24 <= lower < 30:
# Ri2, Ga3
degrees.extend([2, 4])
else:
# Ri3, Ga3
degrees.extend([3, 4])
# Determine Ma
if index < 36:
# Ma1
degrees.append(5)
else:
# Ma2
degrees.append(6)
# always have Pa [7]
degrees.append(7)
# Determine Dha and Ni
upper = index % 6
if upper == 0:
# Dha1, Ni1
degrees.extend([8, 9])
elif upper == 1:
# Dha1, Ni2
degrees.extend([8, 10])
elif upper == 2:
# Dha1, Ni3
degrees.extend([8, 11])
elif upper == 3:
# Dha2, Ni2
degrees.extend([9, 10])
elif upper == 4:
# Dha2, Ni3
degrees.extend([9, 11])
else:
# Dha3, Ni3
degrees.extend([10, 11])
return np.array(degrees)
[docs]@deprecate_positional_args
@cache(level=10)
def mela_to_svara(mela, *, abbr=True, unicode=True):
"""Spell the Carnatic svara names for a given melakarta raga
This function exists to resolve enharmonic equivalences between
pitch classes:
- Ri2 / Ga1
- Ri3 / Ga2
- Dha2 / Ni1
- Dha3 / Ni2
For svara outside the raga, names are chosen to preserve orderings
so that all Ri precede all Ga, and all Dha precede all Ni.
Parameters
----------
mela : str or int
the name or numerical index of the melakarta raga
abbr : bool
If `True`, use single-letter svara names: S, R, G, ...
If `False`, use full names: Sa, Ri, Ga, ...
unicode : bool
If `True`, use unicode symbols for numberings, e.g., Ri\u2081
If `False`, use low-order ASCII, e.g., Ri1.
Returns
-------
svara : list of strings
The svara names for each of the 12 pitch classes.
See Also
--------
key_to_notes
mela_to_degrees
list_mela
Examples
--------
Melakarta #1 (Kanakangi) uses R1, G1, D1, N1
>>> librosa.mela_to_svara(1)
['S', 'R₁', 'G₁', 'G₂', 'G₃', 'M₁', 'M₂', 'P', 'D₁', 'N₁', 'N₂', 'N₃']
#19 (Jhankaradhwani) uses R2 and G2 so the third svara are Ri:
>>> librosa.mela_to_svara(19)
['S', 'R₁', 'R₂', 'G₂', 'G₃', 'M₁', 'M₂', 'P', 'D₁', 'N₁', 'N₂', 'N₃']
#31 (Yagapriya) uses R3 and G3, so third and fourth svara are Ri:
>>> librosa.mela_to_svara(31)
['S', 'R₁', 'R₂', 'R₃', 'G₃', 'M₁', 'M₂', 'P', 'D₁', 'N₁', 'N₂', 'N₃']
#34 (Vagadheeswari) uses D2 and N2, so Ni1 becomes Dha2:
>>> librosa.mela_to_svara(34)
['S', 'R₁', 'R₂', 'R₃', 'G₃', 'M₁', 'M₂', 'P', 'D₁', 'D₂', 'N₂', 'N₃']
#36 (Chalanatta) uses D3 and N3, so Ni2 becomes Dha3:
>>> librosa.mela_to_svara(36)
['S', 'R₁', 'R₂', 'R₃', 'G₃', 'M₁', 'M₂', 'P', 'D₁', 'D₂', 'D₃', 'N₃']
# You can also query by raga name instead of index:
>>> librosa.mela_to_svara('chalanatta')
['S', 'R₁', 'R₂', 'R₃', 'G₃', 'M₁', 'M₂', 'P', 'D₁', 'D₂', 'D₃', 'N₃']
"""
# The following will be constant for all ragas
svara_map = [
"Sa",
"Ri\u2081",
None, # Ri2/Ga1
None, # Ri3/Ga2
"Ga\u2083",
"Ma\u2081",
"Ma\u2082",
"Pa",
"Dha\u2081",
None, # Dha2/Ni1
None, # Dha3/Ni2
"Ni\u2083",
]
if isinstance(mela, str):
mela_idx = MELAKARTA_MAP[mela.lower()] - 1
elif 0 < mela <= 72:
mela_idx = mela - 1
else:
raise ParameterError("mela={} must be in range [1, 72]".format(mela))
# Determine Ri2/Ga1
lower = mela_idx % 36
if lower < 6:
# First six will have Ri1/Ga1
svara_map[2] = "Ga\u2081"
else:
# All others have either Ga2/Ga3
# So we'll call this Ri2
svara_map[2] = "Ri\u2082"
# Determine Ri3/Ga2
if lower < 30:
# First thirty should get Ga2
svara_map[3] = "Ga\u2082"
else:
# Only the last six have Ri3
svara_map[3] = "Ri\u2083"
upper = mela_idx % 6
# Determine Dha2/Ni1
if upper == 0:
# these are the only ones with Ni1
svara_map[9] = "Ni\u2081"
else:
# Everyone else has Dha2
svara_map[9] = "Dha\u2082"
# Determine Dha3/Ni2
if upper == 5:
# This one has Dha3
svara_map[10] = "Dha\u2083"
else:
# Everyone else has Ni2
svara_map[10] = "Ni\u2082"
if abbr:
svara_map = [
s.translate(str.maketrans({"a": "", "h": "", "i": ""})) for s in svara_map
]
if not unicode:
svara_map = [
s.translate(str.maketrans({"\u2081": "1", "\u2082": "2", "\u2083": "3"}))
for s in svara_map
]
return list(svara_map)
[docs]def list_mela():
"""List melakarta ragas by name and index.
Melakarta raga names are transcribed from [#]_, with the exception of #45
(subhapanthuvarali).
.. [#] Bhagyalekshmy, S. (1990).
Ragas in Carnatic music.
South Asia Books.
Returns
-------
mela_map : dict
A dictionary mapping melakarta raga names to indices (1, 2, ..., 72)
Examples
--------
>>> librosa.list_mela()
{'kanakangi': 1,
'ratnangi': 2,
'ganamurthi': 3,
'vanaspathi': 4,
...}
See Also
--------
mela_to_degrees
mela_to_svara
list_thaat
"""
return MELAKARTA_MAP.copy()
[docs]def list_thaat():
"""List supported thaats by name.
Returns
-------
thaats : list
A list of supported thaats
Examples
--------
>>> librosa.list_thaat()
['bilaval',
'khamaj',
'kafi',
'asavari',
'bhairavi',
'kalyan',
'marva',
'poorvi',
'todi',
'bhairav']
See Also
--------
list_mela
thaat_to_degrees
"""
return list(THAAT_MAP.keys())
[docs]@deprecate_positional_args
@cache(level=10)
def key_to_notes(key, *, unicode=True):
"""Lists all 12 note names in the chromatic scale, as spelled according to
a given key (major or minor).
This function exists to resolve enharmonic equivalences between different
spellings for the same pitch (e.g. C♯ vs D♭), and is primarily useful when producing
human-readable outputs (e.g. plotting) for pitch content.
Note names are decided by the following rules:
1. If the tonic of the key has an accidental (sharp or flat), that accidental will be
used consistently for all notes.
2. If the tonic does not have an accidental, accidentals will be inferred to minimize
the total number used for diatonic scale degrees.
3. If there is a tie (e.g., in the case of C:maj vs A:min), sharps will be preferred.
Parameters
----------
key : string
Must be in the form TONIC:key. Tonic must be upper case (``CDEFGAB``),
key must be lower-case (``maj`` or ``min``).
Single accidentals (``b!♭`` for flat, or ``#♯`` for sharp) are supported.
Examples: ``C:maj, Db:min, A♭:min``.
unicode : bool
If ``True`` (default), use Unicode symbols (♯𝄪♭𝄫)for accidentals.
If ``False``, Unicode symbols will be mapped to low-order ASCII representations::
♯ -> #, 𝄪 -> ##, ♭ -> b, 𝄫 -> bb
Returns
-------
notes : list
``notes[k]`` is the name for semitone ``k`` (starting from C)
under the given key. All chromatic notes (0 through 11) are
included.
See Also
--------
midi_to_note
Examples
--------
`C:maj` will use all sharps
>>> librosa.key_to_notes('C:maj')
['C', 'C♯', 'D', 'D♯', 'E', 'F', 'F♯', 'G', 'G♯', 'A', 'A♯', 'B']
`A:min` has the same notes
>>> librosa.key_to_notes('A:min')
['C', 'C♯', 'D', 'D♯', 'E', 'F', 'F♯', 'G', 'G♯', 'A', 'A♯', 'B']
`A♯:min` will use sharps, but spell note 0 (`C`) as `B♯`
>>> librosa.key_to_notes('A#:min')
['B♯', 'C♯', 'D', 'D♯', 'E', 'E♯', 'F♯', 'G', 'G♯', 'A', 'A♯', 'B']
`G♯:maj` will use a double-sharp to spell note 7 (`G`) as `F𝄪`:
>>> librosa.key_to_notes('G#:maj')
['B♯', 'C♯', 'D', 'D♯', 'E', 'E♯', 'F♯', 'F𝄪', 'G♯', 'A', 'A♯', 'B']
`F♭:min` will use double-flats
>>> librosa.key_to_notes('Fb:min')
['D𝄫', 'D♭', 'E𝄫', 'E♭', 'F♭', 'F', 'G♭', 'A𝄫', 'A♭', 'B𝄫', 'B♭', 'C♭']
"""
# Parse the key signature
match = re.match(
r"^(?P<tonic>[A-Ga-g])"
r"(?P<accidental>[#♯b!♭]?)"
r":(?P<scale>(maj|min)(or)?)$",
key,
)
if not match:
raise ParameterError("Improper key format: {:s}".format(key))
pitch_map = {"C": 0, "D": 2, "E": 4, "F": 5, "G": 7, "A": 9, "B": 11}
acc_map = {"#": 1, "": 0, "b": -1, "!": -1, "♯": 1, "♭": -1}
tonic = match.group("tonic").upper()
accidental = match.group("accidental")
offset = acc_map[accidental]
scale = match.group("scale")[:3].lower()
# Determine major or minor
major = scale == "maj"
# calculate how many clockwise steps we are on CoF (== # sharps)
if major:
tonic_number = ((pitch_map[tonic] + offset) * 7) % 12
else:
tonic_number = ((pitch_map[tonic] + offset) * 7 + 9) % 12
# Decide if using flats or sharps
# Logic here is as follows:
# 1. respect the given notation for the tonic.
# Sharp tonics will always use sharps, likewise flats.
# 2. If no accidental in the tonic, try to minimize accidentals.
# 3. If there's a tie for accidentals, use sharp for major and flat for minor.
if offset < 0:
# use flats explicitly
use_sharps = False
elif offset > 0:
# use sharps explicitly
use_sharps = True
elif 0 <= tonic_number < 6:
use_sharps = True
elif tonic_number > 6:
use_sharps = False
# Basic note sequences for simple keys
notes_sharp = ["C", "C♯", "D", "D♯", "E", "F", "F♯", "G", "G♯", "A", "A♯", "B"]
notes_flat = ["C", "D♭", "D", "E♭", "E", "F", "G♭", "G", "A♭", "A", "B♭", "B"]
# These apply when we have >= 6 sharps
sharp_corrections = [
(5, "E♯"),
(0, "B♯"),
(7, "F𝄪"),
(2, "C𝄪"),
(9, "G𝄪"),
(4, "D𝄪"),
(11, "A𝄪"),
]
# These apply when we have >= 6 flats
flat_corrections = [
(11, "C♭"),
(4, "F♭"),
(9, "B𝄫"),
(2, "E𝄫"),
(7, "A𝄫"),
(0, "D𝄫"),
] # last would be (5, 'G𝄫')
# Apply a mod-12 correction to distinguish B#:maj from C:maj
n_sharps = tonic_number
if tonic_number == 0 and tonic == "B":
n_sharps = 12
if use_sharps:
# This will only execute if n_sharps >= 6
for n in range(0, n_sharps - 6 + 1):
index, name = sharp_corrections[n]
notes_sharp[index] = name
notes = notes_sharp
else:
n_flats = (12 - tonic_number) % 12
# This will only execute if tonic_number <= 6
for n in range(0, n_flats - 6 + 1):
index, name = flat_corrections[n]
notes_flat[index] = name
notes = notes_flat
# Finally, apply any unicode down-translation if necessary
if not unicode:
translations = str.maketrans({"♯": "#", "𝄪": "##", "♭": "b", "𝄫": "bb"})
notes = list(n.translate(translations) for n in notes)
return notes
[docs]def key_to_degrees(key):
"""Construct the diatonic scale degrees for a given key.
Parameters
----------
key : str
Must be in the form TONIC:key. Tonic must be upper case (``CDEFGAB``),
key must be lower-case (``maj`` or ``min``).
Single accidentals (``b!♭`` for flat, or ``#♯`` for sharp) are supported.
Examples: ``C:maj, Db:min, A♭:min``.
Returns
-------
degrees : np.ndarray
An array containing the semitone numbers (0=C, 1=C#, ... 11=B)
for each of the seven scale degrees in the given key, starting
from the tonic.
See Also
--------
key_to_notes
Examples
--------
>>> librosa.key_to_degrees('C:maj')
array([ 0, 2, 4, 5, 7, 9, 11])
>>> librosa.key_to_degrees('C#:maj')
array([ 1, 3, 5, 6, 8, 10, 0])
>>> librosa.key_to_degrees('A:min')
array([ 9, 11, 0, 2, 4, 5, 7])
"""
notes = dict(
maj=np.array([0, 2, 4, 5, 7, 9, 11]), min=np.array([0, 2, 3, 5, 7, 8, 10])
)
match = re.match(
r"^(?P<tonic>[A-Ga-g])"
r"(?P<accidental>[#♯b!♭]?)"
r":(?P<scale>(maj|min)(or)?)$",
key,
)
if not match:
raise ParameterError("Improper key format: {:s}".format(key))
pitch_map = {"C": 0, "D": 2, "E": 4, "F": 5, "G": 7, "A": 9, "B": 11}
acc_map = {"#": 1, "": 0, "b": -1, "!": -1, "♯": 1, "♭": -1}
tonic = match.group("tonic").upper()
accidental = match.group("accidental")
offset = acc_map[accidental]
scale = match.group("scale")[:3].lower()
return (notes[scale] + pitch_map[tonic] + offset) % 12