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pitch

Diapason

Tuning reference.

Parameters:

Name Type Description Default
reference_midi_number int

The reference pitch MIDI number

 69
reference_hertz float

The frequency of the reference pitch in Hertz

 440.0
Source code in staff/pitch.py 
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@dataclass(frozen=True)
class Diapason:
    """Tuning reference.

    Args:
        reference_midi_number: The reference pitch MIDI number
        reference_hertz: The frequency of the reference pitch in Hertz
    """

    reference_midi_number: int = 69
    reference_hertz: float = 440.0

    def __post_init__(self):
        if (self.reference_midi_number < 0) or (self.reference_midi_number > 127):
            raise ValueError(f"invalid MIDI note number `{self.reference_midi_number}`")

        if self.reference_hertz <= 0:
            raise ValueError(f"invalid Hertz value `{self.reference_hertz}`")

Frequency

Frequency representation.

Parameters:

Name Type Description Default
hertz float

The frequency in Hertz (cycles-per-second)

 required

Implements total_ordering against Frequency.

Implements the following operations:

- `__add__` against `Frequency`
- `__sub__` against `Frequency`
- `__mul__` against `int` and `float`
- `__rmul__` against `int` and `float`
- `__truediv__` against `int` and `float`
- `__floor_div__` against `int` and `float`
- `__round__`

Implements total ordering.

Examples:

Converting to a MIDIPitch:

>>> Frequency(hertz=440).to_midi()
MIDIPitch(number=69, bend=MIDIBend(bend=0, bend_range=200))

>>> Frequency(hertz=450).to_midi()
MIDIPitch(number=69, bend=MIDIBend(bend=1594, bend_range=200))

The distance between two Frequency instances (exponential) in Cents (linear):

>>> Frequency(880).cents_distance(Frequency(440))
Cents(cents=-1200.0)

>>> round(Frequency(440).cents_distance(Frequency(660)), 2)
Cents(cents=701.96)

Adding Cents (linear) to Frequency (exponential):

>>> Frequency(40).plus_cents(Cents(2400))
Frequency(hertz=160.0)

>>> round(Frequency(40).plus_cents(Cents(2401)), 2)
Frequency(hertz=160.09)

Frequency arithmetic is simple:

>>> Frequency(hertz=440) + Frequency(hertz=220)
Frequency(hertz=660)

>>> Frequency(hertz=660) - Frequency(hertz=220)
Frequency(hertz=440)

>>> Frequency(hertz=440) * 2
Frequency(hertz=880)

>>> Frequency(hertz=440) / 2
Frequency(hertz=220.0)

>>> round(Frequency(hertz=261.6255653005986), 2)
Frequency(hertz=261.63)

As is comparison:

>>> Frequency(220) > Frequency(110)
True
Source code in staff/pitch.py 
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@total_ordering
@dataclass(frozen=True)
class Frequency:
    """Frequency representation.

    Args:
        hertz: The frequency in Hertz (cycles-per-second)

    Implements `total_ordering` against `Frequency`.

    Implements the following operations:

        - `__add__` against `Frequency`
        - `__sub__` against `Frequency`
        - `__mul__` against `int` and `float`
        - `__rmul__` against `int` and `float`
        - `__truediv__` against `int` and `float`
        - `__floor_div__` against `int` and `float`
        - `__round__`

    Implements total ordering.

    Examples:
        Converting to a `MIDIPitch`:

        >>> Frequency(hertz=440).to_midi()
        MIDIPitch(number=69, bend=MIDIBend(bend=0, bend_range=200))

        >>> Frequency(hertz=450).to_midi()
        MIDIPitch(number=69, bend=MIDIBend(bend=1594, bend_range=200))

        The distance between two `Frequency` instances (exponential) in `Cents`
        (linear):

        >>> Frequency(880).cents_distance(Frequency(440))
        Cents(cents=-1200.0)

        >>> round(Frequency(440).cents_distance(Frequency(660)), 2)
        Cents(cents=701.96)

        Adding `Cents` (linear) to `Frequency` (exponential):

        >>> Frequency(40).plus_cents(Cents(2400))
        Frequency(hertz=160.0)

        >>> round(Frequency(40).plus_cents(Cents(2401)), 2)
        Frequency(hertz=160.09)

        `Frequency` arithmetic is simple:

        >>> Frequency(hertz=440) + Frequency(hertz=220)
        Frequency(hertz=660)

        >>> Frequency(hertz=660) - Frequency(hertz=220)
        Frequency(hertz=440)

        >>> Frequency(hertz=440) * 2
        Frequency(hertz=880)

        >>> Frequency(hertz=440) / 2
        Frequency(hertz=220.0)

        >>> round(Frequency(hertz=261.6255653005986), 2)
        Frequency(hertz=261.63)

        As is comparison:

        >>> Frequency(220) > Frequency(110)
        True
    """

    hertz: float

    def __post_init__(self):
        if self.hertz <= 0:
            raise ValueError(f"hertz must be greater than 0. Got {self.hertz}")

    def to_midi(
        self,
        midi_bend_range: int = 200,
        diapason: Diapason = Diapason(),
        octave_divs: int = 12,
    ) -> MIDIPitch:
        """Frequency to MIDIPitch conversion."""
        midi_float = (
            octave_divs * log2(self.hertz / diapason.reference_hertz)
            + diapason.reference_midi_number
        )
        try:
            bend = Cents(100 * divmod(midi_float, int(midi_float))[1]).to_midi_bend(
                bend_range=midi_bend_range
            )
        except ZeroDivisionError:
            # MIDI note 0
            bend = Cents(100 * midi_float).to_midi_bend(bend_range=midi_bend_range)
        return MIDIPitch(
            number=floor(midi_float),
            bend=bend,
            diapason=diapason,
            octave_divs=octave_divs,
        )

    def cents_distance(self, other: Frequency) -> Cents:
        """Cents distance between two frequencies."""
        if not isinstance(other, Frequency):
            raise TypeError("other must be an instance of Frequency.")
        return Cents((1200 * log2(other.hertz / self.hertz)))

    def plus_cents(self, cents: Cents) -> Frequency:
        """Frequency cents distance away."""
        if not isinstance(cents, Cents):
            raise TypeError("cents must be an instance of Cents.")
        return Frequency(hertz=self.hertz * 2 ** (cents.proportion_of_octave))

    def __gt__(self, other: Frequency) -> bool:
        if not isinstance(other, Frequency):
            raise TypeError(f"cannot compare Frequency with type '{type(other)}'")
        return self.hertz > other.hertz

    def _operate(
        self,
        other: Union[int, float],
        oper: Callable,
    ) -> Frequency:
        return Frequency(hertz=oper(self.hertz, other))

    def __add__(self, other: Frequency) -> Frequency:
        if not isinstance(other, Frequency):
            raise TypeError(
                f"unsupported operand type(s) for +: 'Frequency' and '{type(other)}'"
            )
        return Frequency(self.hertz + other.hertz)

    def __sub__(self, other: Frequency) -> Frequency:
        if not isinstance(other, Frequency):
            raise TypeError(
                f"unsupported operand type(s) for -: 'Frequency' and '{type(other)}'"
            )
        return Frequency(self.hertz - other.hertz)

    def __mul__(self, other: Union[int, float]) -> Frequency:
        return self._operate(other, operator.mul)

    def __rmul__(self, other: Union[int, float]) -> Frequency:
        return self._operate(other, operator.mul)

    def __truediv__(self, other: Union[int, float]) -> Frequency:
        return self._operate(other, operator.truediv)

    def __floordiv__(self, other: Union[int, float]) -> Frequency:
        return self._operate(other, operator.floordiv)

    def __round__(self, ndigits: int) -> Frequency:
        return Frequency(hertz=round(self.hertz, ndigits))

cents_distance(other)

Cents distance between two frequencies.

Source code in staff/pitch.py 
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def cents_distance(self, other: Frequency) -> Cents:
    """Cents distance between two frequencies."""
    if not isinstance(other, Frequency):
        raise TypeError("other must be an instance of Frequency.")
    return Cents((1200 * log2(other.hertz / self.hertz)))

plus_cents(cents)

Frequency cents distance away.

Source code in staff/pitch.py 
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def plus_cents(self, cents: Cents) -> Frequency:
    """Frequency cents distance away."""
    if not isinstance(cents, Cents):
        raise TypeError("cents must be an instance of Cents.")
    return Frequency(hertz=self.hertz * 2 ** (cents.proportion_of_octave))

to_midi(midi_bend_range=200, diapason=Diapason(), octave_divs=12)

Frequency to MIDIPitch conversion.

Source code in staff/pitch.py 
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def to_midi(
    self,
    midi_bend_range: int = 200,
    diapason: Diapason = Diapason(),
    octave_divs: int = 12,
) -> MIDIPitch:
    """Frequency to MIDIPitch conversion."""
    midi_float = (
        octave_divs * log2(self.hertz / diapason.reference_hertz)
        + diapason.reference_midi_number
    )
    try:
        bend = Cents(100 * divmod(midi_float, int(midi_float))[1]).to_midi_bend(
            bend_range=midi_bend_range
        )
    except ZeroDivisionError:
        # MIDI note 0
        bend = Cents(100 * midi_float).to_midi_bend(bend_range=midi_bend_range)
    return MIDIPitch(
        number=floor(midi_float),
        bend=bend,
        diapason=diapason,
        octave_divs=octave_divs,
    )

Cents

Cents representation.

Parameters:

Name Type Description Default
cents float

The cents value. There are 1200 cents per octave.

 required

Implements the following operations:

- `__add__` against `Cents`
- `__sub__` against `Cents`
- `__mul__` against `int` and `float`
- `__rmul__` against `int` and `float`
- `__truediv__` against `int` and `float` (though the result is rounded
    to the **closest** int)
- `__floor_div__` against `int` and `float`

Implements total ordering.

Examples:

Cents as a proportion of the octave:

>>> Cents(600).proportion_of_octave
0.5

Cents can be converted to MIDIBend:

>>> Cents(1.96).to_midi_bend()
MIDIBend(bend=80, bend_range=200)

>>> Cents(-15.64).to_midi_bend()
MIDIBend(bend=-641, bend_range=200)

Cents arithmetic is simple:

>>> Cents(100) + Cents(500)
Cents(cents=600)

>>> Cents(600) - Cents(100)
Cents(cents=500)

>>> Cents(600) * 2
Cents(cents=1200)

>>> Cents(1200) / 2
Cents(cents=600)

>>> round(Cents(1.96), 0)
Cents(cents=2.0)

As is comparison:

>>> Cents(600) > Cents(100)
True
Source code in staff/pitch.py 
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@total_ordering
@dataclass(frozen=True)
class Cents:
    """Cents representation.

    Args:
        cents: The cents value. There are 1200 cents per octave.

    Implements the following operations:

        - `__add__` against `Cents`
        - `__sub__` against `Cents`
        - `__mul__` against `int` and `float`
        - `__rmul__` against `int` and `float`
        - `__truediv__` against `int` and `float` (though the result is rounded
            to the **closest** int)
        - `__floor_div__` against `int` and `float`

    Implements total ordering.

    Examples:
        `Cents` as a proportion of the octave:

        >>> Cents(600).proportion_of_octave
        0.5

        `Cents` can be converted to `MIDIBend`:

        >>> Cents(1.96).to_midi_bend()
        MIDIBend(bend=80, bend_range=200)

        >>> Cents(-15.64).to_midi_bend()
        MIDIBend(bend=-641, bend_range=200)

        `Cents` arithmetic is simple:

        >>> Cents(100) + Cents(500)
        Cents(cents=600)

        >>> Cents(600) - Cents(100)
        Cents(cents=500)

        >>> Cents(600) * 2
        Cents(cents=1200)

        >>> Cents(1200) / 2
        Cents(cents=600)

        >>> round(Cents(1.96), 0)
        Cents(cents=2.0)

        As is comparison:
        >>> Cents(600) > Cents(100)
        True
    """

    cents: float

    @property
    def proportion_of_octave(self) -> float:
        """Ratio of these cents against a standard 1200 cent octave.

        Returns:
            The proportion (ratio) of these cents against the 1200 cent octave
        """
        return self.cents / 1200.0

    def to_midi_bend(self, bend_range: int = 200) -> MIDIBend:
        """MIDI bend value required to achieve these cents.

        Args:
            bend_range: The set pitch-bend range

        Returns:
            The MIDIBend equivalent of these cents
        """
        return MIDIBend(
            bend=round((8192 / bend_range) * self.cents),
            bend_range=bend_range,
        )

    def __gt__(self, other: Cents) -> bool:
        if not isinstance(other, Cents):
            raise TypeError(f"cannot compare Cents with type '{type(other)}'")
        return self.cents > other.cents

    def _operate(
        self,
        other: Union[int, float],
        oper: Callable,
    ) -> Cents:
        if not isinstance(other, (int, float)):
            raise TypeError(
                f"unsupported operand type(s) for {oper.__name__}: "
                f"'Cents' and '{type(other)}'"
            )
        return Cents(cents=round(oper(self.cents, other)))

    def __add__(self, other: Cents) -> Cents:
        if not isinstance(other, Cents):
            raise TypeError(
                f"unsupported operand type(s) for +: 'Cents' and '{type(other)}'"
            )
        return Cents(self.cents + other.cents)

    def __sub__(self, other: Cents) -> Cents:
        if not isinstance(other, Cents):
            raise TypeError(
                f"unsupported operand type(s) for -: 'Cents' and '{type(other)}'"
            )
        return Cents(self.cents - other.cents)

    def __mul__(self, other: Union[int, float]) -> Cents:
        return self._operate(other, operator.mul)

    def __rmul__(self, other: Union[int, float]) -> Cents:
        return self._operate(other, operator.mul)

    def __truediv__(self, other: Union[int, float]) -> Cents:
        return self._operate(other, operator.truediv)

    def __floordiv__(self, other: Union[int, float]) -> Cents:
        return self._operate(other, operator.floordiv)

    def __round__(self, ndigits: Optional[int] = None) -> Cents:
        return Cents(cents=round(self.cents, ndigits))

proportion_of_octave: float property

Ratio of these cents against a standard 1200 cent octave.

Returns:

Type Description
float

The proportion (ratio) of these cents against the 1200 cent octave

to_midi_bend(bend_range=200)

MIDI bend value required to achieve these cents.

Parameters:

Name Type Description Default
bend_range int

The set pitch-bend range

 200

Returns:

Type Description
MIDIBend

The MIDIBend equivalent of these cents
Source code in staff/pitch.py 
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def to_midi_bend(self, bend_range: int = 200) -> MIDIBend:
    """MIDI bend value required to achieve these cents.

    Args:
        bend_range: The set pitch-bend range

    Returns:
        The MIDIBend equivalent of these cents
    """
    return MIDIBend(
        bend=round((8192 / bend_range) * self.cents),
        bend_range=bend_range,
    )

MIDIPitch

MIDI pitch representation which includes pitch-bend.

Parameters:

Name Type Description Default
number int

MIDI note number.

 required
bend MIDIBend

MIDI pitch-wheel bend.

 MIDIBend(bend=0, bend_range=200)
diapason Diapason

Tuning reference.

 Diapason()
octave_divs int

Equal divisions of the octave. Typically 12.

 field(default=12, compare=False)

Implements total ordering.

Examples:

MIDIPitches can be initialized using a string:

>>> MIDIPitch.from_string("c4")
MIDIPitch(number=60, bend=MIDIBend(bend=0, bend_range=200))

>>> MIDIPitch.from_string("c#4")
MIDIPitch(number=61, bend=MIDIBend(bend=0, bend_range=200))

>>> MIDIPitch.from_string("db4")
MIDIPitch(number=61, bend=MIDIBend(bend=0, bend_range=200))

or a number:

>>> MIDIPitch(60)
MIDIPitch(number=60, bend=MIDIBend(bend=0, bend_range=200))

They can be converted to Frequency:

>>> round(MIDIPitch(60).frequency, 2)
Frequency(hertz=261.63)

A Diapason can be used to set tuning:

>>> diapason = Diapason(reference_midi_number=69, reference_hertz=438)
>>> pitch = MIDIPitch(60, diapason=diapason)
>>> round(pitch.frequency, 2)
Frequency(hertz=260.44)

Octave divisions other than 12 can be used, changing the MIDI note key mapping:

>>> round(MIDIPitch(60, octave_divs=24).frequency, 2)
Frequency(hertz=339.29)

Given a pitch that isn't twelve-tone equal-temperament, a MIDIBend will be applied (note that Frequency.to_midi returns a MIDIPitch):

>>> Frequency(100).to_midi().bend
MIDIBend(bend=1433, bend_range=200)

They can be compared:

>>> MIDIPitch.from_string("c#4") == MIDIPitch.from_string("db4")
True
Source code in staff/pitch.py 
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@total_ordering
@dataclass(frozen=True, repr=False)
class MIDIPitch:
    """MIDI pitch representation which includes pitch-bend.

    Args:
        number: MIDI note number.
        bend: MIDI pitch-wheel bend.
        diapason: Tuning reference.
        octave_divs: Equal divisions of the octave. Typically 12.

    Implements total ordering.

    Examples:
        `MIDIPitches` can be initialized using a string:

        >>> MIDIPitch.from_string("c4")
        MIDIPitch(number=60, bend=MIDIBend(bend=0, bend_range=200))

        >>> MIDIPitch.from_string("c#4")
        MIDIPitch(number=61, bend=MIDIBend(bend=0, bend_range=200))

        >>> MIDIPitch.from_string("db4")
        MIDIPitch(number=61, bend=MIDIBend(bend=0, bend_range=200))

        or a number:

        >>> MIDIPitch(60)
        MIDIPitch(number=60, bend=MIDIBend(bend=0, bend_range=200))

        They can be converted to `Frequency`:

        >>> round(MIDIPitch(60).frequency, 2)
        Frequency(hertz=261.63)

        A `Diapason` can be used to set tuning:

        >>> diapason = Diapason(reference_midi_number=69, reference_hertz=438)
        >>> pitch = MIDIPitch(60, diapason=diapason)
        >>> round(pitch.frequency, 2)
        Frequency(hertz=260.44)

        Octave divisions other than 12 can be used, changing the MIDI note key
        mapping:

        >>> round(MIDIPitch(60, octave_divs=24).frequency, 2)
        Frequency(hertz=339.29)

        Given a pitch that isn't twelve-tone equal-temperament, a `MIDIBend`
        will be applied (note that `Frequency.to_midi` returns a `MIDIPitch`):

        >>> Frequency(100).to_midi().bend
        MIDIBend(bend=1433, bend_range=200)

        They can be compared:

        >>> MIDIPitch.from_string("c#4") == MIDIPitch.from_string("db4")
        True
    """

    number: int
    bend: MIDIBend = MIDIBend(bend=0, bend_range=200)
    diapason: Diapason = Diapason()
    octave_divs: int = field(default=12, compare=False)

    def __post_init__(self):
        if (self.number < 0) or (self.number > 127):
            raise ValueError(f"number must be between 0 and 127. Got {self.number}")

    def __repr__(self):
        return f"MIDIPitch(number={self.number}, bend={self.bend})"

    def __hash__(self) -> int:
        return hash(self.number_precise)

    @property
    def number_precise(self) -> float:
        """The MIDI number with the bend as the fractional part of a float.

        Returns:
            The precise MIDI number including the bend.

        Examples:
            >>> MIDIPitch(60, bend=MIDIBend(100, bend_range=200)).number_precise
            60.5
        """
        return self.number + (self.bend.bend / self.bend.bend_range)

    @property
    def frequency(self) -> Frequency:
        """Convert MIDIPitch to Frequency.

        Returns:
            The MIDIPitch frequency
        """
        fhz = Frequency(
            2
            ** ((self.number - self.diapason.reference_midi_number) / self.octave_divs)
            * self.diapason.reference_hertz
        )
        if self.bend == MIDIBend(bend=0):
            return fhz
        cents = self.bend.cents
        return fhz.plus_cents(cents=cents)

    @property
    def pitch_class(self) -> int:
        """The approximate pitch class of the pitch.

        Note:
            This is more utility than function. It uses the integer MIDI number
            not the precise number that includes the pitch bend.

        Returns:
            The pitch class of the pitch.
        """
        return self.number % self.octave_divs

    @property
    def pitch_class_precise(self) -> MIDIPitch:
        """The lowest octave equivalent of the precise pitch.

        Note:
            This is recommended for microtonal pitches.

        Returns:
            The `MIDIPitch` which is the lowest octave equivalent.
        """
        lower_bound = MIDIPitch(0).frequency.hertz
        frequency = self.frequency.hertz
        candidate = frequency / 2.0
        if candidate < lower_bound:
            return Frequency(hertz=frequency).to_midi(
                midi_bend_range=self.bend.bend_range,
                diapason=self.diapason,
                octave_divs=self.octave_divs,
            )
        while candidate >= lower_bound:
            frequency = candidate
            candidate = frequency / 2.0
        return Frequency(hertz=frequency).to_midi(
            midi_bend_range=self.bend.bend_range,
            diapason=self.diapason,
            octave_divs=self.octave_divs,
        )

    @classmethod
    def from_string(cls, pitch: str, c4_number: int = 60) -> MIDIPitch:
        """Create a MIDIPitch from a string representations.

        Pitch strings are written as a combination of the pitch note class letter,
        a maximum of one accidental, and an integer representing the octave.
        Sharps are represented by the '#' symbols and flats by 'b'.

        Args:
            pitch: The pitch in string representation.
            c4_number: The MIDI number representing C4.

        Raises:
            ValueError: if an invalid pitch string is given.
        """
        if not isinstance(pitch, str):
            raise TypeError("pitch must be expressed as a 'str'")
        if not isinstance(c4_number, int):
            raise TypeError("c4_number must be expressed as a 'int'")

        pitches = [
            ["b#", "c"],
            ["c#", "db"],
            ["d"],
            ["d#", "eb"],
            ["e", "fb"],
            ["f", "e#"],
            ["f#", "gb"],
            ["g"],
            ["g#", "ab"],
            ["a"],
            ["a#", "bb"],
            ["b", "cb"],
        ]
        pitch = pitch.strip().lower()
        idx = 1
        while pitch[-idx].isnumeric():
            idx += 1
        idx -= 1
        if pitch[-(idx + 1)] == "-":
            idx += 1
        octave = int(pitch[-idx:])
        pitch_class = pitch[:-idx]
        found = False
        pc_number = 0
        for idx, enharmonics in enumerate(pitches):
            if pitch_class in enharmonics:
                pc_number = idx
                found = True
                break
        if not found:
            raise ValueError(f"invalid pitch string : {pitch}")
        if pitch_class == "b#":
            octave += 1
        elif pitch_class == "cb":
            octave -= 1
        return MIDIPitch((c4_number + pc_number) + (octave - 4) * 12)

    def octave_up(self) -> MIDIPitch:
        return Frequency(self.frequency.hertz * 2).to_midi(
            midi_bend_range=self.bend.bend_range,
            diapason=self.diapason,
            octave_divs=self.octave_divs,
        )

    def octave_down(self) -> MIDIPitch:
        return Frequency(self.frequency.hertz / 2).to_midi(
            midi_bend_range=self.bend.bend_range,
            diapason=self.diapason,
            octave_divs=self.octave_divs,
        )

    def __gt__(self, other: MIDIPitch) -> bool:
        if not isinstance(other, MIDIPitch):
            raise TypeError(f"cannot compare MIDIPitch with type '{type(other)}'")
        return self.frequency > other.frequency

frequency: Frequency property

Convert MIDIPitch to Frequency.

Returns:

Type Description
Frequency

The MIDIPitch frequency

number_precise: float property

The MIDI number with the bend as the fractional part of a float.

Returns:

Type Description
float

The precise MIDI number including the bend.

Examples:

>>> MIDIPitch(60, bend=MIDIBend(100, bend_range=200)).number_precise
60.5

pitch_class: int property

The approximate pitch class of the pitch.

Note

This is more utility than function. It uses the integer MIDI number not the precise number that includes the pitch bend.

Returns:

Type Description
int

The pitch class of the pitch.

pitch_class_precise: MIDIPitch property

The lowest octave equivalent of the precise pitch.

Note

This is recommended for microtonal pitches.

Returns:

Type Description
MIDIPitch

The MIDIPitch which is the lowest octave equivalent.

from_string(pitch, c4_number=60) classmethod

Create a MIDIPitch from a string representations.

Pitch strings are written as a combination of the pitch note class letter, a maximum of one accidental, and an integer representing the octave. Sharps are represented by the '#' symbols and flats by 'b'.

Parameters:

Name Type Description Default
pitch str

The pitch in string representation.

 required
c4_number int

The MIDI number representing C4.

 60

Raises:

Type Description
ValueError

if an invalid pitch string is given.
Source code in staff/pitch.py 
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@classmethod
def from_string(cls, pitch: str, c4_number: int = 60) -> MIDIPitch:
    """Create a MIDIPitch from a string representations.

    Pitch strings are written as a combination of the pitch note class letter,
    a maximum of one accidental, and an integer representing the octave.
    Sharps are represented by the '#' symbols and flats by 'b'.

    Args:
        pitch: The pitch in string representation.
        c4_number: The MIDI number representing C4.

    Raises:
        ValueError: if an invalid pitch string is given.
    """
    if not isinstance(pitch, str):
        raise TypeError("pitch must be expressed as a 'str'")
    if not isinstance(c4_number, int):
        raise TypeError("c4_number must be expressed as a 'int'")

    pitches = [
        ["b#", "c"],
        ["c#", "db"],
        ["d"],
        ["d#", "eb"],
        ["e", "fb"],
        ["f", "e#"],
        ["f#", "gb"],
        ["g"],
        ["g#", "ab"],
        ["a"],
        ["a#", "bb"],
        ["b", "cb"],
    ]
    pitch = pitch.strip().lower()
    idx = 1
    while pitch[-idx].isnumeric():
        idx += 1
    idx -= 1
    if pitch[-(idx + 1)] == "-":
        idx += 1
    octave = int(pitch[-idx:])
    pitch_class = pitch[:-idx]
    found = False
    pc_number = 0
    for idx, enharmonics in enumerate(pitches):
        if pitch_class in enharmonics:
            pc_number = idx
            found = True
            break
    if not found:
        raise ValueError(f"invalid pitch string : {pitch}")
    if pitch_class == "b#":
        octave += 1
    elif pitch_class == "cb":
        octave -= 1
    return MIDIPitch((c4_number + pc_number) + (octave - 4) * 12)

MIDIBend

MIDI bend value with bend wheel range.

Parameters:

Name Type Description Default
bend int

MIDI pitch bend value (in range -8192, 8192)

 0
bend_range int

MIDI bend wheel range in cents. Typically 200 (2 semitones), but with some MPE instruments and controllers the bend range is set to 2400 (24 semitones).

 200
Source code in staff/pitch.py 
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@dataclass(frozen=True)
class MIDIBend:
    """MIDI bend value with bend wheel range.

    Args:
        bend: MIDI pitch bend value (in range -8192, 8192)
        bend_range: MIDI bend wheel range in cents. Typically 200 (2 semitones),
            but with some MPE instruments and controllers the bend range is set
            to 2400 (24 semitones).
    """

    bend: int = 0
    bend_range: int = 200

    def __post_init__(self):
        if (self.bend < -8192) or (self.bend > 8192):
            raise ValueError(f"bend must be between -8192 and 8192. Got {self.bend}")

        if self.bend_range <= 0:
            raise ValueError(
                f"bend_range must be greater than 0. Got {self.bend_range}"
            )

    @property
    def cents(self) -> Cents:
        """Get this MIDI bend value as cents.

        Returns:
            The MIDIBend as cents
        """
        return Cents((self.bend / 8192) * self.bend_range)

cents: Cents property

Get this MIDI bend value as cents.

Returns:

Type Description
Cents

The MIDIBend as cents