Events API Reference

Events represent individual musical occurrences or annotations within a Score or Track. All event classes are parameterized by time unit (Tick, Quarter, or Second).

Concepts: Events

Common Event Patterns & Methods

Most event classes share these characteristics and methods:

  • Time Unit Parameterization: Classes exist for each time unit (e.g., NoteTick, NoteQuarter, NoteSecond). The ttype property returns the time unit.
  • time Attribute: The time at which the event occurs.
  • Comparison (__eq__, __ne__): Events are comparable (e.g., event1 == event2). Equality checks if all attributes are identical. Events of different types or time units are never equal. Comparison (<, >, etc.) primarily uses time, with tie-breaking rules specific to the event type.
  • Copying: Support copy.copy() (shallow, usually sufficient as events are often simple data structures) and copy.deepcopy().
  • Serialization (Pickling): Support pickle.dump() and pickle.load() via __getstate__ and __setstate__.
  • shift_time(offset): Returns a new event shifted by offset.
  • shift_time_inplace(offset): Modifies the event's time inplace.
  • to(ttype, ...): Returns a new event converted to the target ttype. Event types with duration (Note, Pedal) accept an optional min_dur argument for the to("tick", min_dur=...) conversion.
  • NumPy Conversion (for lists): Event lists like NoteList often have .numpy() and EventFactory.from_numpy() methods (See Track API).

Note

Represents a musical note.

Attributes:

  • time (int|float): Start time.
  • duration (int|float): Duration.
  • pitch (int): MIDI pitch (0-127).
  • velocity (int): MIDI velocity (1-127). A velocity of 0 might indicate a note-off in some contexts, but Symusic typically uses explicit durations.

Specific Methods:

  • end(): Returns time + duration.
  • empty(): Returns True if duration <= 0 or velocity <= 0.
  • shift_pitch(offset): Returns a new note with shifted pitch.
  • shift_pitch_inplace(offset): Shifts pitch inplace.
  • shift_velocity(offset): Returns a new note with shifted velocity.
  • shift_velocity_inplace(offset): Shifts velocity inplace.

Factory: symusic.Note(time, duration, pitch, velocity, ttype="tick")

ControlChange

Represents a MIDI Control Change (CC) message.

Attributes:

  • time (int|float): Event time.
  • number (int): CC number (0-127).
  • value (int): CC value (0-127).

Factory: symusic.ControlChange(time, number, value, ttype="tick")

PitchBend

Represents a MIDI Pitch Bend message.

Attributes:

  • time (int|float): Event time.
  • value (int): Pitch bend value (-8192 to 8191, where 0 is center).

Factory: symusic.PitchBend(time, value, ttype="tick")

Pedal

Represents a sustain pedal event with duration.

Attributes:

  • time (int|float): Pedal press (onset) time.
  • duration (int|float): Duration the pedal is held down.

Specific Methods:

  • end(): Returns time + duration (pedal release time).

Factory: symusic.Pedal(time, duration, ttype="tick")

TimeSignature

Represents a time signature (meter) change. Global event stored in Score.time_signatures.

Attributes:

  • time (int|float): Time the time signature takes effect.
  • numerator (int): Numerator (e.g., 4 in 4/4).
  • denominator (int): Denominator (e.g., 4 in 4/4).

Factory: symusic.TimeSignature(time, numerator, denominator, ttype="tick")

KeySignature

Represents a key signature change. Global event stored in Score.key_signatures.

Attributes:

  • time (int|float): Time the key signature takes effect.
  • key (int): Number of sharps (positive) or flats (negative). Corresponds to MIDI key signature meta-message sf value.
  • tonality (int): 0 for major, 1 for minor. Corresponds to MIDI mi value.

Specific Methods:

  • degree(): Calculates a numerical representation useful for harmonic analysis (implementation-defined).

Factory: symusic.KeySignature(time, key, tonality, ttype="tick")

Tempo

Represents a tempo change. Global event stored in Score.tempos.

Attributes:

  • time (int|float): Time the tempo takes effect.
  • qpm (float): Tempo in Quarter Notes Per Minute (BPM).

Internal Attribute (Not directly exposed in Python):

  • mspq (int): Microseconds per quarter note (often used internally for precision). qpm is derived from/converts to this.

Factory: symusic.Tempo(time, qpm, ttype="tick")

TextMeta

Represents a text event associated with a specific time.

Attributes:

  • time (int|float): Time of the text event.
  • text (str): The text content.

Usage:

  • Stored in Track.lyrics for lyrics.
  • Stored in Score.markers for global markers.

Factory: symusic.TextMeta(time, text, ttype="tick")

Event Lists (e.g., NoteList, TempoList)

Events are stored in specialized list-like containers within Score and Track objects. See the Track API Reference for methods common to these lists (append, sort, filter, numpy, from_numpy, etc.).