"""Piano-roll input interface."""
from operator import attrgetter
from typing import List
import numpy as np
from numpy import ndarray
from pypianoroll import Multitrack
from pypianoroll import Track as PypianorollTrack
from ..classes import Metadata, Note, Tempo, Track
from ..music import DEFAULT_RESOLUTION, Music
def _pianoroll_to_notes(
array: ndarray, encode_velocity: bool, default_velocity: int
) -> List[Note]:
binarized = array > 0
diff = np.diff(binarized, axis=0, prepend=0, append=0)
notes = []
for i in range(128):
boundaries = np.nonzero(diff[:, i])[0]
for note_idx in range(len(boundaries) // 2):
start = boundaries[2 * note_idx]
end = boundaries[2 * note_idx + 1]
if encode_velocity:
velocity = array[start, i]
else:
velocity = default_velocity
note = Note(
time=start, pitch=i, duration=end - start, velocity=velocity,
)
notes.append(note)
notes.sort(key=attrgetter("time", "pitch", "duration", "velocity"))
return notes
def from_pypianoroll_track(
track: PypianorollTrack, default_velocity: int = 64
) -> Track:
"""Return a Pypianoroll Track object as a Track object.
Parameters
----------
track : :class:`pypianoroll.Track`
Pypianoroll Track object to convert.
default_velocity : int
Default velocity value to use when decoding. Defaults to 64.
Returns
-------
:class:`muspy.Track`
Converted track.
"""
# Convert piano roll to notes
notes = _pianoroll_to_notes(
track.pianoroll, track.pianoroll.dtype == np.bool_, default_velocity
)
return Track(
notes=notes,
name=track.name if track.name else None,
program=track.program,
is_drum=track.is_drum,
)
[docs]def from_pypianoroll(
multitrack: Multitrack, default_velocity: int = 64
) -> Music:
"""Return a Pypianoroll Multitrack object as a Music object.
Parameters
----------
multitrack : :class:`pypianoroll.Multitrack`
Pypianoroll Multitrack object to convert.
default_velocity : int
Default velocity value to use when decoding. Defaults to 64.
Returns
-------
music : :class:`muspy.Music`
Converted MusPy Music object.
"""
# Tempos
tempo_change_timings = np.diff(multitrack.tempo, prepend=-1).nonzero()[0]
tempos = [
Tempo(time, qpm=multitrack.tempo[time])
for time in tempo_change_timings
]
# Tracks
tracks = [
from_pypianoroll_track(track, default_velocity)
for track in multitrack.tracks
]
return Music(
resolution=multitrack.resolution,
metadata=Metadata(title=multitrack.name) if multitrack.name else None,
tempos=tempos,
tracks=tracks,
)
[docs]def from_pianoroll_representation(
array: ndarray,
resolution: int = DEFAULT_RESOLUTION,
program: int = 0,
is_drum: bool = False,
encode_velocity: bool = True,
default_velocity: int = 64,
) -> Music:
"""Decode pitch-based representation into a Music object.
Parameters
----------
array : ndarray
Array in piano-roll representation to decode. Will be casted to
integer if not of integer type. If `encode_velocity` is True,
will be casted to boolean if not of boolean type.
resolution : int
Time steps per quarter note. Defaults to
`muspy.DEFAULT_RESOLUTION`.
program : int, optional
Program number according to General MIDI specification [1].
Acceptable values are 0 to 127. Defaults to 0 (Acoustic Grand
Piano).
is_drum : bool, optional
A boolean indicating if it is a percussion track. Defaults to
False.
encode_velocity : bool
Whether to encode velocities. Defaults to True.
default_velocity : int
Default velocity value to use when decoding. Defaults to 64.
Returns
-------
:class:`muspy.Music`
Decoded Music object.
References
----------
[1] https://www.midi.org/specifications/item/gm-level-1-sound-set
"""
if encode_velocity and not np.issubdtype(array.dtype, np.integer):
array = array.astype(np.int)
elif not encode_velocity and not np.issubdtype(array.dtype, np.bool):
array = array.astype(np.bool)
# Convert piano roll to notes
notes = _pianoroll_to_notes(array, encode_velocity, default_velocity)
# Create the Track and Music objects
track = Track(program=program, is_drum=is_drum, notes=notes)
music = Music(resolution=resolution, tracks=[track])
return music