scamp.playback_implementations.SoundfontPlaybackImplementation

class scamp.playback_implementations.SoundfontPlaybackImplementation(*args, **kwargs)[source]

Bases: scamp.playback_implementations._MIDIPlaybackImplementation

Playback implementation that does Soundfont playback, via the MIDI protocol.

Parameters

  • host_instrument – The ScampInstrument that will use this playback implementation for playback. When this PlaybackImplementation is constructed, it is automatically added to the list of PlaybackImplementations that the host instrument uses.

  • bank_and_preset – The bank and preset within the given soundfont to use for playback

  • soundfont – String representing the soundfont to use for playback. Defaults to the one defined in playback_settings.default_soundfont

  • num_channels – How many MIDI channels to use for this instrument. Where channel-wide messages (such as pitch-bend messages) are involved, it is essential to have several channels at our disposal.

  • audio_driver – name of the audio_driver to use. Defaults to the one defined in playback_settings.default_audio_driver

  • max_pitch_bend – max pitch bend allowed on this instrument. Defaults to the one defined in playback_settings.default_max_soundfont_pitch_bend.

  • note_on_and_off_only – This enforces a rule of no dynamic pitch bends, expression (volume) changes, or other cc messages. Valuable when using start_note instead of play_note in music that doesn’t do any dynamic pitch/volume/parameter changes. Without this flag, notes will all be placed on separate MIDI channels, since they could potentially change pitch or volume; with this flags, we know they won’t, so they can share the same MIDI channels, only using an extra one due to microtonality.

Methods

cc(chan, cc_number, value_from_0_to_1)

Sends an arbitrary midi CC message

expression(chan, expression_from_0_to_1)

Sends a midi expression message

note_off(chan, pitch)

Sends a note_off MIDI message

note_on(chan, pitch, velocity_from_0_to_1)

Sends a note_on MIDI message

pitch_bend(chan, bend_in_semitones)

Sends a MIDI pitch bend message

set_max_pitch_bend(semitones)

Sets the max pitch bend for this MIDI device

Inherited Methods

change_note_parameter(note_id, …)

Method that implements the change of a parameter other than pitch or volume

change_note_pitch(note_id, new_pitch)

Method that implements the change of a note’s pitch

change_note_volume(note_id, new_volume)

Method that implements the change of a note’s volume

duplicate()

Returns a copy of this object by serializing to and from JSON.

end_note(note_id)

Method that implements the end of a note

get_shared_resource(key)

Gets the shared resource for this type of playback implementation under the given key.

has_shared_resource(key)

Checks whether there is a shared resource for this type of playback implementation under the given key.

json_dumps()

Dump this object as a JSON string.

json_loads(s)

Load this object from a JSON string.

load_from_json(file_path)

Load this object from a JSON file with the given path.

save_to_json(file_path)

Save this object to a JSON file using the given path.

set_host_instrument(host_instrument)

Sets the host instrument for this PlaybackImplementation.

set_shared_resource(key, value)

Sets a shared resource for this type of playback implementation under the given key.

start_note(note_id, pitch, volume, properties)

Method that implements the start of a note

Attributes

resource_dictionary

Dictionary of shared resources for this type of playback implementation.
note_on(chan: int, pitch: int, velocity_from_0_to_1: float)[source]

Sends a note_on MIDI message

Parameters

  • chan – channel to send message on

  • pitch – integer MIDI pitch value

  • velocity_from_0_to_1 – velocity to send (NB: scaled from 0 to 1)

note_off(chan: int, pitch: int)[source]

Sends a note_off MIDI message

Parameters

  • chan – channel to send message on

  • pitch – integer MIDI pitch value

pitch_bend(chan: int, bend_in_semitones: float)[source]

Sends a MIDI pitch bend message

Parameters

  • chan – channel to send message on

  • bend_in_semitones – the pitch bend amount (in semitones!)

set_max_pitch_bend(semitones: int)[source]

Sets the max pitch bend for this MIDI device

Parameters

max_bend_in_semitones – value to set as maximum pitch bend

expression(chan: int, expression_from_0_to_1: float)[source]

Sends a midi expression message

Parameters

  • chan – channel to send message on

  • expression_from_0_to_1 – expression to send (NB: scaled from 0 to 1)

Returns

cc(chan: int, cc_number: int, value_from_0_to_1: float)[source]

Sends an arbitrary midi CC message

Parameters

  • chan – channel to send the message on

  • cc_number – number representing the type of the control change message

  • value_from_0_to_1 – value to send (NB: scaled from 0 to 1)

change_note_parameter(note_id, parameter_name, new_value)

Method that implements the change of a parameter other than pitch or volume

Parameters

  • note_id – unique identifier of the note to effect

  • parameter_name – name of the parameter to change

  • new_value – new floating-point value of that parameter

change_note_pitch(note_id, new_pitch)

Method that implements the change of a note’s pitch

Parameters

  • note_id – unique identifier of the note whose pitch to change

  • new_pitch – new (floating-point) MIDI pitch value

change_note_volume(note_id, new_volume)

Method that implements the change of a note’s volume

Parameters

  • note_id – unique identifier of the note whose volume to change

  • new_volume – new floating point volume value from 0 to 1

duplicate() → T

Returns a copy of this object by serializing to and from JSON.

end_note(note_id)

Method that implements the end of a note

Parameters

note_id – unique identifier of the note to end

get_shared_resource(key)

Gets the shared resource for this type of playback implementation under the given key.

Parameters

key – key name for this resource

has_shared_resource(key) → bool

Checks whether there is a shared resource for this type of playback implementation under the given key.

Parameters

key – key name for this resource

json_dumps() → str

Dump this object as a JSON string. This uses a custom encoder that recognizes and appropriately converts any attributes that are object inheriting from SavesToJSON.

classmethod json_loads(s: str) → T

Load this object from a JSON string. This uses a custom decoder that looks for a “_type” key in any object/dictionary being parsed and converts it to the class specified (assuming it a subclass of SavesToJSON).

Parameters

s – a string representing this object in JSON format

classmethod load_from_json(file_path: str) → T

Load this object from a JSON file with the given path. This uses a custom decoder that looks for a “_type” key in any object/dictionary being parsed and converts it to the class specified (assuming it a subclass of SavesToJSON).

Parameters

file_path – path for loading the file

property resource_dictionary

Dictionary of shared resources for this type of playback implementation. For instance, SoundfontPlaybackImplementation uses this to store an instance of SoundfontHost. Only one instance of fluidsynth (and therefore SoundfontHost) needs to be running for all instruments in the ensemble, so this is a way of pooling that resource.

save_to_json(file_path: str) → None

Save this object to a JSON file using the given path. This uses a custom encoder that recognizes and appropriately converts any attributes that are object inheriting from SavesToJSON.

Parameters

file_path – path for saving the file

set_host_instrument(host_instrument: scamp.instruments.ScampInstrument)

Sets the host instrument for this PlaybackImplementation. Ordinarily, the host instrument is supplied as an argument to the __init__ method, which then automatically calls this method. However, it is also possible to pass the value None to the host instrument argument initially and later set it with this method.

Parameters

host_instrument – The ScampInstrument that will use this playback implementation for playback. This PlaybackImplementation will be added to the host instrument’s playback_implementations attribute.

set_shared_resource(key, value)

Sets a shared resource for this type of playback implementation under the given key.

Parameters

  • key – key name for this resource

  • value – value to set for that key

start_note(note_id, pitch, volume, properties, other_parameter_values: dict = None)

Method that implements the start of a note

Parameters

  • note_id – unique identifier for the note we are starting

  • pitch – floating-point MIDI pitch value

  • volume – floating-point volume value (from 0 to 1)

  • properties – a NotePropertiesDictionary

  • other_parameter_values – dictionary mapping parameter name to parameter value for parameters other than pitch and volume. (This information was extracted from the properties dictionary.)