Read & Write
Pypianoroll currently supports reading from and writing to MIDI files.
Functions
- pypianoroll.read(path: Union[str, pathlib.Path], **kwargs) pypianoroll.multitrack.Multitrack[source]
Read a MIDI file into a Multitrack object.
- Parameters
path (str or Path) – Path to the file to read.
**kwargs – Keyword arguments to pass to
pypianoroll.from_pretty_midi().
See also
pypianoroll.write()Write a Multitrack object to a MIDI file.
pypianoroll.load()Load a NPZ file into a Multitrack object.
- pypianoroll.write(path: str, multitrack: Multitrack)[source]
Write a Multitrack object to a MIDI file.
- Parameters
path (str) – Path to write the file.
multitrack (
pypianoroll.Multitrack) – Multitrack to save.
See also
pypianoroll.read()Read a MIDI file into a Multitrack object.
pypianoroll.save()Save a Multitrack object to a NPZ file.
- pypianoroll.from_pretty_midi(midi: pretty_midi.pretty_midi.PrettyMIDI, resolution: int = 24, mode: str = 'max', algorithm: str = 'normal', collect_onsets_only: bool = False, first_beat_time: Optional[float] = None) pypianoroll.multitrack.Multitrack[source]
Return a Multitrack object converted from a PrettyMIDI object.
Parse a
pretty_midi.PrettyMIDIobject. The data type of the resulting piano rolls is automatically determined (int if ‘mode’ is ‘sum’ and np.uint8 if mode is ‘max’).- Parameters
midi (
pretty_midi.PrettyMIDI) – PrettyMIDI object to parse.mode ({'max', 'sum'}, default: 'max') – Merging strategy for duplicate notes.
algorithm ({'normal', 'strict', 'custom'}, default: 'normal') – Algorithm for finding the location of the first beat (see Notes).
collect_onsets_only (bool, default: False) – True to collect only the onset of the notes (i.e. note on events) in all tracks, where the note off and duration information are discarded. False to parse regular piano rolls.
first_beat_time (float, optional) – Location of the first beat, in sec. Required and only effective when using ‘custom’ algorithm.
- Returns
Converted Multitrack object.
- Return type
Notes
There are three algorithms for finding the location of the first beat:
‘normal’ : Estimate the location of the first beat using
pretty_midi.PrettyMIDI.estimate_beat_start().‘strict’ : Set the location of the first beat to the time of the first time signature change. Raise a RuntimeError if no time signature change is found.
‘custom’ : Set the location of the first beat to the value of argument first_beat_time. Raise a ValueError if first_beat_time is not given.
If an incomplete beat before the first beat is found, an additional beat will be added before the (estimated) beat starting time. However, notes before the (estimated) beat starting time for more than one beat are dropped.
- pypianoroll.to_pretty_midi(multitrack: Multitrack, default_tempo: float = None, default_velocity: int = 64) pretty_midi.pretty_midi.PrettyMIDI[source]
Return a Multitrack object as a PrettyMIDI object.
- Parameters
default_tempo (int, default: pypianoroll.DEFAULT_TEMPO (120)) – Default tempo to use. If attribute tempo is available, use its first element.
default_velocity (int, default: pypianoroll.DEFAULT_VELOCITY (64)) – Default velocity to assign to binarized tracks.
- Returns
Converted PrettyMIDI object.
- Return type
Notes
Tempo changes are not supported.
Time signature changes are not supported.
The velocities of the converted piano rolls will be clipped to [0, 127].
Adjacent nonzero values of the same pitch will be considered a single note with their mean as its velocity.
Note
Writing the tempo array and downbeat array to tempo change and time signature change events are not supported yet.