"""Representation processors.
This module defines the processors for commonly used representations.
Classes
-------
- NoteRepresentationProcessor
- EventRepresentationProcessor
- PianoRollRepresentationProcessor
- PitchRepresentationProcessor
"""
from typing import Union
import numpy as np
from numpy import ndarray
from .inputs import (
from_event_representation,
from_note_representation,
from_pianoroll_representation,
from_pitch_representation,
)
from .music import Music
from .outputs import (
to_event_representation,
to_note_representation,
to_pianoroll_representation,
to_pitch_representation,
)
__all__ = [
"NoteRepresentationProcessor",
"EventRepresentationProcessor",
"PianoRollRepresentationProcessor",
"PitchRepresentationProcessor",
]
[docs]class NoteRepresentationProcessor:
"""Note-based representation processor.
The note-based represetantion represents music as a sequence of
(pitch, time, duration, velocity) tuples. For example, a note
Note(time=0, duration=4, pitch=60, velocity=64) will be encoded as a
tuple (0, 4, 60, 64). The output shape is L * D, where L is th
number of notes and D is 4 when `encode_velocity` is True, otherwise
D is 3. The values of the second dimension represent pitch, time,
duration and velocity (discarded when `encode_velocity` is False).
Attributes
----------
use_start_end : bool, default: False
Whether to use 'start' and 'end' to encode the timing rather
than 'time' and 'duration'.
encode_velocity : bool, default: True
Whether to encode note velocities.
dtype : dtype, type or str, default: int
Data type of the return array.
default_velocity : int, default: 64
Default velocity value to use when decoding if `encode_velocity`
is False.
"""
def __init__(
self,
use_start_end: bool = False,
encode_velocity: bool = True,
dtype: Union[np.dtype, type, str] = int,
default_velocity: int = 64,
):
self.use_start_end = use_start_end
self.encode_velocity = encode_velocity
self.dtype = dtype
self.default_velocity = default_velocity
[docs] def encode(self, music: Music) -> ndarray:
"""Encode a Music object into note-based representation.
Parameters
----------
music : :class:`muspy.Music` object
Music object to encode.
Returns
-------
ndarray (np.uint8)
Encoded array in note-based representation.
See Also
--------
:func:`muspy.to_note_representation` :
Convert a Music object into note-based representation.
"""
return to_note_representation(
music,
use_start_end=self.use_start_end,
encode_velocity=self.encode_velocity,
dtype=self.dtype,
)
[docs] def decode(self, array: ndarray) -> Music:
"""Decode note-based representation into a Music object.
Parameters
----------
array : ndarray
Array in note-based representation to decode. Cast to
integer if not of integer type.
Returns
-------
:class:`muspy.Music` object
Decoded Music object.
See Also
--------
:func:`muspy.from_note_representation` :
Return a Music object converted from note-based
representation.
"""
return from_note_representation(
array,
use_start_end=self.use_start_end,
encode_velocity=self.encode_velocity,
default_velocity=self.default_velocity,
)
[docs]class EventRepresentationProcessor:
"""Event-based representation processor.
The event-based represetantion represents music as a sequence of
events, including note-on, note-off, time-shift and velocity events.
The output shape is M x 1, where M is the number of events. The
values encode the events. The default configuration uses 0-127 to
encode note-one events, 128-255 for note-off events, 256-355 for
time-shift events, and 356 to 387 for velocity events.
Attributes
----------
use_single_note_off_event : bool, default: False
Whether to use a single note-off event for all the pitches. If
True, the note-off event will close all active notes, which can
lead to lossy conversion for polyphonic music.
use_end_of_sequence_event : bool, default: False
Whether to append an end-of-sequence event to the encoded
sequence.
encode_velocity : bool, default: False
Whether to encode velocities.
force_velocity_event : bool, default: True
Whether to add a velocity event before every note-on event. If
False, velocity events are only used when the note velocity is
changed (i.e., different from the previous one).
max_time_shift : int, default: 100
Maximum time shift (in ticks) to be encoded as an separate
event. Time shifts larger than `max_time_shift` will be
decomposed into two or more time-shift events.
velocity_bins : int, default: 32
Number of velocity bins to use.
default_velocity : int, default: 64
Default velocity value to use when decoding.
"""
def __init__(
self,
use_single_note_off_event: bool = False,
use_end_of_sequence_event: bool = False,
encode_velocity: bool = False,
force_velocity_event: bool = True,
max_time_shift: int = 100,
velocity_bins: int = 32,
default_velocity: int = 64,
):
self.use_single_note_off_event = use_single_note_off_event
self.use_end_of_sequence_event = use_end_of_sequence_event
self.encode_velocity = encode_velocity
self.force_velocity_event = force_velocity_event
self.max_time_shift = max_time_shift
self.velocity_bins = velocity_bins
self.default_velocity = default_velocity
[docs] def encode(self, music: Music) -> ndarray:
"""Encode a Music object into event-based representation.
Parameters
----------
music : :class:`muspy.Music` object
Music object to encode.
Returns
-------
ndarray (np.uint16)
Encoded array in event-based representation.
See Also
--------
:func:`muspy.to_event_representation` :
Convert a Music object into event-based representation.
"""
return to_event_representation(
music,
use_single_note_off_event=self.use_single_note_off_event,
use_end_of_sequence_event=self.use_end_of_sequence_event,
encode_velocity=self.encode_velocity,
force_velocity_event=self.force_velocity_event,
max_time_shift=self.max_time_shift,
velocity_bins=self.velocity_bins,
)
[docs] def decode(self, array: ndarray) -> Music:
"""Decode event-based representation into a Music object.
Parameters
----------
array : ndarray
Array in event-based representation to decode. Cast to
integer if not of integer type.
Returns
-------
:class:`muspy.Music` object
Decoded Music object.
See Also
--------
:func:`muspy.from_event_representation` :
Return a Music object converted from event-based
representation.
"""
return from_event_representation(
array,
use_single_note_off_event=self.use_single_note_off_event,
use_end_of_sequence_event=self.use_end_of_sequence_event,
max_time_shift=self.max_time_shift,
velocity_bins=self.velocity_bins,
default_velocity=self.default_velocity,
)
[docs]class PitchRepresentationProcessor:
"""Pitch-based representation processor.
The pitch-based represetantion represents music as a sequence of
pitch, rest and (optional) hold tokens. Only monophonic melodies are
compatible with this representation. The output shape is T x 1,
where T is the number of time steps. The values indicate whether the
current time step is a pitch (0-127), a rest (128) or, optionally, a
hold (129).
Attributes
----------
use_hold_state : bool, default: False
Whether to use a special state for holds.
default_velocity : int, default: 64
Default velocity value to use when decoding.
"""
def __init__(
self, use_hold_state: bool = False, default_velocity: int = 64,
):
self.use_hold_state = use_hold_state
self.default_velocity = default_velocity
[docs] def encode(self, music: Music) -> ndarray:
"""Encode a Music object into pitch-based representation.
Parameters
----------
music : :class:`muspy.Music` object
Music object to encode.
Returns
-------
ndarray (np.uint8)
Encoded array in pitch-based representation.
See Also
--------
:func:`muspy.to_pitch_representation` :
Convert a Music object into pitch-based representation.
"""
return to_pitch_representation(
music, use_hold_state=self.use_hold_state
)
[docs] def decode(self, array: ndarray) -> Music:
"""Decode pitch-based representation into a Music object.
Parameters
----------
array : ndarray
Array in pitch-based representation to decode. Cast to
integer if not of integer type.
Returns
-------
:class:`muspy.Music` object
Decoded Music object.
See Also
--------
:func:`muspy.from_pitch_representation` :
Return a Music object converted from pitch-based
representation.
"""
return from_pitch_representation(
array,
use_hold_state=self.use_hold_state,
default_velocity=self.default_velocity,
)
[docs]class PianoRollRepresentationProcessor:
"""Piano-roll representation processor.
The piano-roll represetantion represents music as a time-pitch
matrix, where the columns are the time steps and the rows are the
pitches. The values indicate the presence of pitches at different
time steps. The output shape is T x 128, where T is the number of
time steps.
Attributes
----------
encode_velocity : bool, default: True
Whether to encode velocities. If True, a binary-valued array
will be return. Otherwise, an integer array will be return.
default_velocity : int, default: 64
Default velocity value to use when decoding if `encode_velocity`
is False.
"""
def __init__(
self, encode_velocity: bool = True, default_velocity: int = 64,
):
self.encode_velocity = encode_velocity
self.default_velocity = default_velocity
[docs] def encode(self, music: Music) -> ndarray:
"""Encode a Music object into piano-roll representation.
Parameters
----------
music : :class:`muspy.Music` object
Music object to encode.
Returns
-------
ndarray (np.uint8)
Encoded array in piano-roll representation.
See Also
--------
:func:`muspy.to_pianoroll_representation` :
Convert a Music object into piano-roll representation.
"""
return to_pianoroll_representation(
music, encode_velocity=self.encode_velocity
)
[docs] def decode(self, array: ndarray) -> Music:
"""Decode piano-roll representation into a Music object.
Parameters
----------
array : ndarray
Array in piano-roll representation to decode. Cast to
integer if not of integer type. If `encode_velocity` is
True, casted to boolean if not of boolean type.
Returns
-------
:class:`muspy.Music` object
Decoded Music object.
See Also
--------
:func:`muspy.from_pianoroll_representation` :
Return a Music object converted from piano-roll
representation.
"""
return from_pianoroll_representation(
array,
encode_velocity=self.encode_velocity,
default_velocity=self.default_velocity,
)