Classes

WebAudioAPI

WebAudioAPI

Methods

analyzeAudio(analysisType, opt trackName) → {Any}

webAudioAPI.src.js, line 483

Analyzes the current realtime audio output according to the specified analysisType.

The trackName parameter is optional, and if left blank, will cause the analysis to be carried out on the aggregate output over all tracks and all applied effects.

The type of return value from this function will depend on the analysis being carried out and can be determined by examining the corresponding concrete definitions of the AnalysisBase interface.

Parameters:

Name	Type	Attributes	Description
analysisType	number		Audio AnalysisType to execute
trackName	string	<optional>	Name of the track whose audio should be analyzed

Returns:

Any -

Result of the specified analysis

See:

• AnalysisType

async applyMasterEffect(effectName, effectType)

webAudioAPI.src.js, line 724

Applies a new master effect to the aggregate output from all tracks at the specified time.

Calling this function affects the sequential ordering in which master effects will be processed, with each new call appending the corresponding effect to the end of the processing sequence.

The parameters of the added effect will be set to their default values such that the result of adding the effect will not be audible. In order to manipulate and utilize this effect, use the updateMasterEffect() function.

If a master effect with the specified effectName has already been applied, then calling this function will simply re-order the effect to move it to the very end of the effect processing sequence, without changing its parameter values.

Parameters:

Name	Type	Description
effectName	string	User-defined name to associate with the master effect
effectType	number	Master EffectType to apply

See:

• EffectType

async applyTrackEffect(trackName, effectName, effectType)

webAudioAPI.src.js, line 762

Applies a new effect to the specified track at the specified time.

Calling this function affects the sequential ordering in which effects will be processed within the specified track, with each new call appending the corresponding effect to the end of the processing sequence.

The parameters of the added effect will be set to their default values such that the result of adding the effect will not be audible. In order to manipulate and utilize this effect, use the updateTrackEffect() function.

If an effect with the specified effectName has already been applied to the specified track, then calling this function will simply re-order the effect to move it to the very end of the effect processing sequence, without changing its parameter values.

Parameters:

Name	Type	Description
trackName	string	Name of the track on which to apply the effect
effectName	string	User-defined name to associate with the track effect
effectType	number	Track-specific EffectType to apply

See:

• EffectType

clearAllTracks()

webAudioAPI.src.js, line 573

Cancels all current and scheduled audio from playing on all existing tracks.

clearTrack(name)

webAudioAPI.src.js, line 565

Cancels all current and scheduled audio from playing on the specified track.

Parameters:

Name	Type	Description
name	string	Name of the track to clear

async connectAudioInputDeviceToTrack(trackName, audioInputDeviceName)

webAudioAPI.src.js, line 961

Connects an audio input device to the specified audio track.

Note: A single audio input device can be connected to multiple audio tracks, but an audio track can only be connected to a single audio input device.

Parameters:

Name	Type	Description
trackName	string	Name of the track to which to connect the audio input device
audioInputDeviceName	string	Name of the audio input device to connect to the track

async connectMidiDeviceToTrack(trackName, midiDeviceName)

webAudioAPI.src.js, line 939

Connects a MIDI device to the specified audio track.

Note: A single MIDI device can be connected to multiple audio tracks, but an audio track can only be connected to a single MIDI device.

Parameters:

Name	Type	Description
trackName	string	Name of the track to which to connect the MIDI device
midiDeviceName	string	Name of the MIDI device to connect to the track

convertNoteDurationToSeconds(duration) → {number}

webAudioAPI.src.js, line 633

Converts a note Duration into a corresponding number of seconds given the current Tempo settings.

Parameters:

Name	Type	Description
duration	number	Note Duration to convert to seconds

Returns:

number -

Number of seconds corresponding to the specified duration at current Tempo settings

convertSecondsToNoteDuration(seconds) → {number}

webAudioAPI.src.js, line 644

Converts a number of seconds into the nearest corresponding note Duration given the current Tempo settings.

Parameters:

Name	Type	Description
seconds	number	Number of seconds to convert to a note Duration

Returns:

number -

Note Duration corresponding to the specified seconds at current Tempo settings

createAudioBufferFromSamples(sampleRate, samples) → {AudioBuffer}

webAudioAPI.src.js, line 1441

Converts a 2D array of floating point samples into an AudioBuffer object with the specified sampleRate.

Parameters:

Name	Type	Description
sampleRate	number	Sample rate at which the audio data was recorded
samples	Array.<Array.<number>>	2D array of floating point audio samples to encode

Returns:

AudioBuffer -

Newly created AudioBuffer containing the audio data

See:

• AudioBuffer

createTrack(name)

webAudioAPI.src.js, line 534

Creates a track capable of playing sequential audio. A single track can only utilize a single instrument at a time.

Parameters:

Name	Type	Description
name	string	Name of the newly created track

async decodeAudioClip(audioClip) → {AudioBuffer}

webAudioAPI.src.js, line 462

Decodes an ArrayBuffer containing an audio clip into an AudioBuffer object.

Parameters:

Name	Type	Description
audioClip	ArrayBuffer | Blob	Array buffer or blob containing the audio clip to decode

Returns:

AudioBuffer -

Decoded audio buffer for the specified audio clip

See:

• ArrayBuffer
• Blob

deregisterMidiDeviceCallback(midiDeviceName)

webAudioAPI.src.js, line 911

Removes a user-registered callback from the specified MIDI device so that it will no longer fire upon reception of a MIDI event.

Parameters:

Name	Type	Description
midiDeviceName	string	Name of the MIDI device for which to stop receiving events

async disconnectAudioInputDeviceFromTrack(trackName)

webAudioAPI.src.js, line 985

Disconnects all audio input devices from the specified audio track.

Parameters:

Name	Type	Description
trackName	string	Name of the track from which to disconnect the audio input devices

async disconnectMidiDeviceFromTrack(trackName)

webAudioAPI.src.js, line 974

Disconnects all MIDI devices from the specified audio track.

Parameters:

Name	Type	Description
trackName	string	Name of the track from which to disconnect the MIDI devices

async encodeAudioAs(encodingType, sampleRate, samples) → {Blob}

webAudioAPI.src.js, line 1425

Encodes a 2D array of floating point samples into a Blob containing raw audio data according to the specified sampleRate and EncodingType specified in the encodingType parameter.

Parameters:

Name	Type	Description
encodingType	number	Numeric value corresponding to the desired EncodingType
sampleRate	number	Sample rate at which the audio data was recorded
samples	Array.<Array.<number>>	2D array of floating point audio samples to encode

Returns:

Blob -

Data Blob containing the newly encoded audio data

See:

• Blob
• EncodingType

getAvailableAnalysisTypes() → {Object.<string, number>}

webAudioAPI.src.js, line 323

Returns a listing of all available audio analysis types in the WebAudioAPI library.

This function can be used to enumerate available analysis options for displaying on a web page.

Returns:

Object.<string, number> -

Listing of all available audio analysis types in the WebAudioAPI library

See:

• AnalysisType

async getAvailableAudioInputDevices() → {Promise.<Array.<string>>}

webAudioAPI.src.js, line 384

Returns a listing of the available audio input devices connected to the client device.

Individual results from this function call can be passed directly to the connectAudioInputDeviceToTrack() function to attach an input device to a specified audio track.

Returns:

Promise.<Array.<string>> -

Listing of all available audio input devices connected to the client

async getAvailableAudioOutputDevices() → {Promise.<Array.<string>>}

webAudioAPI.src.js, line 423

Returns a listing of the available audio output devices connected to the client device.

Individual results from this function call can be passed directly to the selectAudioOutputDevice() function to choose where to direct all audio output.

Returns:

Promise.<Array.<string>> -

Listing of all available audio output devices connected to the client

getAvailableEffectParameters(effectType) → {Array.<EffectParameter>}

webAudioAPI.src.js, line 265

Returns a list of effect-specific EffectParameters for manipulation in the effectOptions parameter of the updateMasterEffect() or the updateTrackEffect() function.

This function can be used to enumerate available effect parameters for displaying on a web page. Note, however, that the effectType parameter must be the numeric value associated with a certain EffectType, not a string-based key.

Parameters:

Name	Type	Description
effectType	number	The EffectType for which to return a parameter list

Returns:

Array.<EffectParameter> -

List of effect-specific parameters available for updating

See:

• EffectType
• EffectParameter

getAvailableEffects() → {Object.<string, number>}

webAudioAPI.src.js, line 246

Returns a listing of all available effects in the WebAudioAPI library.

This function can be used to enumerate available effect options for displaying on a web page. Note, however, that the effectType parameter passed to either the applyMasterEffect() or the applyTrackEffect() function must be the numeric value associated with a certain EffectType, not a string-based key.

Returns:

Object.<string, number> -

Listing of all available effect types in the WebAudioAPI library

See:

• EffectType

getAvailableEncoders() → {Object.<string, number>}

webAudioAPI.src.js, line 310

Returns a listing of all available encoders in the WebAudioAPI library.

This function can be used to enumerate available encoding options for displaying on a web page.

Returns:

Object.<string, number> -

Listing of all available encoding types in the WebAudioAPI library

See:

• EncodingType

async getAvailableInstruments(instrumentLibraryLocation) → {Promise.<Array.<string>>}

webAudioAPI.src.js, line 337

Returns a listing of the available instruments located in the specified asset library.

Individual results from this function call can be passed directly to the updateInstrument() function to load a specific instrument into an audio track.

Parameters:

Name	Type	Description
instrumentLibraryLocation	string	Absolute or relative URL pointing to a WebAudioAPI instrument library

Returns:

Promise.<Array.<string>> -

Listing of all available instrument names

getAvailableKeySignatures() → {Object.<string, number>}

webAudioAPI.src.js, line 183

Returns a full listing of recognized key signatures by the WebAudioAPI library.

This function can be used to enumerate available key signatures for displaying on a web page. Note, however, that the keySignature parameter passed to the updateKeySignature() function must be the location of the desired key on the circle of fifths associated with a certain KeySignature, not a string-based key signature.

Returns:

Object.<string, number> -

Listing of recognized key signatures by the WebAudioAPI library

See:

• KeySignature

async getAvailableMidiDevices() → {Promise.<Array.<string>>}

webAudioAPI.src.js, line 360

Returns a listing of the available MIDI devices connected to the client device.

Individual results from this function call can be passed directly to the connectMidiDeviceToTrack() function to attach a MIDI device to a specified audio track.

Returns:

Promise.<Array.<string>> -

Listing of all available MIDI devices connected to the client device

getAvailableModificationParameters(modificationType) → {Object.<string, Object.<string, Array.<string>>>}

webAudioAPI.src.js, line 295

Returns a list of modification-specific parameters for use in the modificationOptions parameter of the getModification() function or an empty list if the specified modification does not require any parameters.

This function can be used to enumerate available modification parameters for displaying on a web page. Note, however, that the modificationType parameter must be the numeric value associated with a certain ModificationType, not a string-based key.

The object returned from this function will contain 2 keys: 'required' and 'optional'. These keys can be used to access sub-objects with 2 keys: 'singleNote' and 'sequence'. These keys hold arrays containing the string-based names of parameters that are available for manipulation within the given modification.

Parameter values within the "sequence" array indicate parameters that have meaning when used with the playSequence() function. Parameter values within the "singleNote" array indicate parameters that have meaning when used with the playNote() function.

Parameters:

Name	Type	Description
modificationType	number	The ModificationType for which to return a parameter list

Returns:

Object.<string, Object.<string, Array.<string>>> -

List of modification-specific parameter keys and when they are required

See:

• ModificationType

getAvailableNoteDurations() → {Object.<string, number>}

webAudioAPI.src.js, line 213

Returns a full listing of recognized note durations by the WebAudioAPI library.

This function can be used to enumerate available duration options for displaying on a web page. Note, however, that the duration parameter passed to the playNote() function must be the numeric value associated with a certain Duration, not a string-based key.

Returns:

Object.<string, number> -

Listing of recognized note durations by the WebAudioAPI library

See:

• Duration

getAvailableNoteModifications() → {Object.<string, number>}

webAudioAPI.src.js, line 229

Returns a listing of all available note modifications in the WebAudioAPI library.

This function can be used to enumerate available note modification options for displaying on a web page. Note, however, that the modification type parameter passed to the getModification() function must include the numeric value associated with a certain ModificationType, not a string-based key.

Returns:

Object.<string, number> -

Listing of all available note modifications in the WebAudioAPI library

See:

• ModificationType

getAvailableNotes() → {Object.<string, number>}

webAudioAPI.src.js, line 198

Returns a full listing of recognized musical notes by the WebAudioAPI library.

This function can be used to enumerate available note options for displaying on a web page. Note, however, that the note parameter passed to the playNote() function must be the numeric MIDI value associated with a certain Note, not a string-based key.

Returns:

Object.<string, number> -

Listing of recognized musical notes by the WebAudioAPI library

See:

• Note

getCurrentMasterEffectParameters(effectName) → {Object}

webAudioAPI.src.js, line 820

Returns the current parameter settings for the specified master effect.

Parameters:

Name	Type	Description
effectName	string	Name of the master effect for which to retrieve current settings

Returns:

Object -

Effect-specific parameter values with keys as returned by getAvailableEffectParameters()

getCurrentTime() → {number}

webAudioAPI.src.js, line 167

Returns the current global time since the WebAudioAPI library was started or resumed using the start() function.

Returns:

number -

Current global time since the WebAudioAPI library was started

getCurrentTrackEffectParameters(trackName, effectName) → {Object}

webAudioAPI.src.js, line 834

Returns the current parameter settings for a track-specific effect.

Parameters:

Name	Type	Description
trackName	string	Name of the track for which to retrieve current effect settings
effectName	string	Name of the track effect for which to retrieve current settings

Returns:

Object -

Effect-specific parameter values with keys as returned by getAvailableEffectParameters()

getKeySignature() → {Key}

webAudioAPI.src.js, line 622

Returns the current global Key parameters for all audio tracks.

Returns:

Key -

Global Key parameters and settings

getModification(modificationType, opt modificationOptions) → {ModificationDetails}

webAudioAPI.src.js, line 518

Returns a properly formatted structure containing the relevant musical modification and parameters passed into this function.

Note that the modificationOptions parameter should normally be either omitted/undefined or an Object containing the required keys as returned by the getAvailableModificationParameters() function; however, if there is only one required key, you may simply pass a numerical value to modificationOptions instead of explicitly enumerating an Object with the single required key.

Parameters:

Name	Type	Attributes	Description
modificationType	number		Number corresponding to the ModificationType to generate
modificationOptions	Object | number	<optional>	Potential modification-specific options as returned by getAvailableModificationParameters()

Returns:

ModificationDetails -

A structure containing the relevant musical modification details passed into this function

See:

• ModificationType

getTempo() → {Tempo}

webAudioAPI.src.js, line 613

Returns the current global Tempo parameters for all audio tracks.

Returns:

Tempo -

Global Tempo parameters and settings

getVersion() → {string}

webAudioAPI.src.js, line 157

Returns the current WebAudioAPI library version number.

Returns:

string -

Current library version number

async playChord(trackName, chord, startTime, opt modifications, opt areDrumNotes) → {Promise.<number>}

webAudioAPI.src.js, line 1051

Schedules a chord of notes to be played on a specific track.

Note that the chord parameter should be an array of [note, duration, mods] tuples, where the note parameter should correspond to a valid MIDI note number, the duration parameter should correspond to the beat scaling factor associated with one of the note durations from getAvailableNoteDurations(), and mods may either be a single modification to the chord, a list of modifications, or omitted completely.

The modifications parameter is optional, and if included, may either be a single ModificationDetails structure or a list of such structures. This structure should be obtained from the getModification() function.

Parameters:

Name	Type	Attributes	Default	Description
trackName	string			Name of the track on which to play the note
chord	Array.<Array>			Array of [note, duration, mods] corresponding to the chord to be played
startTime	number			Global API time at which to start playing the chord
modifications	Array.<ModificationDetails>	<optional>		Optional individual or list of modifications to apply to the chord
areDrumNotes	boolean	<optional>	false	Optional flag indicating whether this chord contains only drum notes (i.e., not affected by key or duration)

Returns:

Promise.<number> -

Duration (in seconds) of the chord being played

See:

• Note
• Duration
• ModificationType
• getModification()

async playClip(trackName, audioClip, startTime, opt duration) → {Promise.<number>}

webAudioAPI.src.js, line 1129

Schedules an audio clip to be played on a specific track for some duration of time.

The format of the audio clip in the audioClip parameter may be a data buffer containing raw audio-encoded data (such as from a WAV file), a blob containing audio-encoded data, an already-decoded audio buffer, or a MidiClip or AudioClip that was recorded using this library.

If the duration parameter is not specified or is set to null, the audio clip will play to completion.

Parameters:

Name	Type	Attributes	Description
trackName	string		Name of the track on which to play the clip
audioClip	ArrayBuffer | AudioBuffer | Blob | MidiClip | AudioClip		Object containing audio data to play
startTime	number		Global API time at which to start playing the clip
duration	number	<optional>	Number of seconds for which to continue playing the clip

Returns:

Promise.<number> -

Duration (in seconds) of the clip being played

See:

• ArrayBuffer
• Blob
• MidiClip

async playFile(trackName, fileURL, startTime, opt duration) → {Promise.<number>}

webAudioAPI.src.js, line 1149

Schedules an audio file to be played on a specific track for some duration of time.

If the duration parameter is not specified or is set to null, the audio file will play to completion.

Parameters:

Name	Type	Attributes	Description
trackName	string		Name of the track on which to play the file
fileURL	string		URL location pointing to an audio file
startTime	string		Global API time at which to start playing the file
duration	number	<optional>	Number of seconds for which to continue playing the file

Returns:

Promise.<number> -

Duration (in seconds) of the file being played

async playNote(trackName, note, startTime, duration, opt modifications, opt isDrumNote) → {Promise.<number>}

webAudioAPI.src.js, line 1017

Schedules a note to be played on a specific track for some duration of time.

Note that the duration parameter should correspond to the beat scaling factor associated with one of the note durations from getAvailableNoteDurations(). Likewise, the note parameter should correspond to a MIDI note number as associated with one of the notes returned from getAvailableNotes().

The modifications parameter is optional, and if included, may either be a single ModificationDetails structure or a list of such structures. This structure should be obtained from the getModification() function.

Parameters:

Name	Type	Attributes	Default	Description
trackName	string			Name of the track on which to play the note
note	number			MIDI Note number to be played
startTime	number			Global API time at which to start playing the note
duration	number			Duration for which to continue playing the note
modifications	ModificationDetails | Array.<ModificationDetails>	<optional>		Optional individual or list of modifications to apply to the note
isDrumNote	boolean	<optional>	false	Optional flag indicating whether this note is a drum note (i.e., not affected by key or duration)

Returns:

Promise.<number> -

Duration (in seconds) of the note being played

See:

• Note
• Duration
• ModificationType
• getModification()

async playSequence(trackName, sequence, startTime, opt modifications, opt areDrumNotes) → {Promise.<number>}

webAudioAPI.src.js, line 1090

Schedules a musical sequence to be played on a specific track.

Note that the sequence parameter should be an array containing either chords (as defined in the playChord() function) or [note, duration, mods] tuples, where the note parameter should correspond to a valid MIDI note number, the duration parameter should correspond to the beat scaling factor associated with one of the note durations from getAvailableNoteDurations(), and mods may either be a single modification that affects the whole sequence, a list of modifications, or omitted completely.

The modifications parameter is optional, and if included, may either be a single ModificationDetails structure or a list of such structures. This structure should be obtained from the getModification() function.

Parameters:

Name	Type	Attributes	Default	Description
trackName	string			Name of the track on which to play the note
sequence	Array.<(Array|Array.<Array>)>			Array of [note, duration, mods] and/or chords corresponding to the sequence to be played
startTime	number			Global API time at which to start playing the sequence
modifications	Array.<ModificationDetails>	<optional>		Optional individual or list of modifications to apply to the sequence
areDrumNotes	boolean	<optional>	false	Optional flag indicating whether this sequence contains only drum notes (i.e., not affected by key or duration)

Returns:

Promise.<number> -

Duration (in seconds) of the sequence being played

See:

• Note
• Duration
• ModificationType
• getModification()

recordAudioClip(trackName, startTime, opt duration) → {AudioClip}

webAudioAPI.src.js, line 1207

Schedules an audio clip to be recorded on a specific track for some duration of time.

If the duration parameter is not specified or is set to null, the audio clip will continue to record until manually stopped by the finalize() function on the returned AudioClip object.

Note that the recorded audio clip will not include any effects that might exist on the target track. This is so that recording on an effect-modified track and then immediately playing back on the same track will not cause the effects to be doubled.

Parameters:

Name	Type	Attributes	Description
trackName	string		Name of the track on which to record the audio clip
startTime	number		Global API time at which to start recording the audio clip
duration	number	<optional>	Number of seconds for which to continue recording the audio clip

Returns:

AudioClip -

Reference to an AudioClip object representing the audio data to be recorded

See:

• AudioClip

recordMidiClip(trackName, startTime, opt duration) → {MidiClip}

webAudioAPI.src.js, line 1230

Schedules a MIDI clip to be recorded on a specific track for some duration of time.

If the duration parameter is not specified or is set to null, the MIDI clip will continue to record until manually stopped by the finalize() function on the returned MidiClip object.

Note that the recorded MIDI clip will not include any effects that might exist on the target track. This is so that recording on an effect-modified track and then immediately playing back on the same track will not cause the effects to be doubled.

Parameters:

Name	Type	Attributes	Description
trackName	string		Name of the track on which to record the MIDI clip
startTime	number		Global API time at which to start recording the MIDI clip
duration	number	<optional>	Number of seconds for which to continue recording the MIDI clip

Returns:

MidiClip -

Reference to a MidiClip object representing the MIDI data to be recorded

See:

• MidiClip

recordOutput(opt trackName, opt startTime, opt duration) → {AudioRecording}

webAudioAPI.src.js, line 1258

Schedules an audio recording to be executed on the cumulative output of the specified audio track for some duration of time.

If the trackName parameter is not specified or is set to null, the audio recording will include the cumulative output of all audio tracks and effects.

If the startTime parameter is not specified or is set to null, the audio recording will begin immediately.

If the duration parameter is not specified or is set to null, the audio recording will continue until manually stopped by the finalize() function on the returned AudioRecording object.

Note that the recorded audio will include all existing effects.

Parameters:

Name	Type	Attributes	Description
trackName	string	<optional>	Name of the track from which to record all audio output
startTime	number	<optional>	Global API time at which to start recording the audio output
duration	number	<optional>	Number of seconds for which to continue recording the audio output

Returns:

AudioRecording -

Reference to an AudioRecording object representing the audio recording

See:

• AudioRecording

registerMidiDeviceCallback(midiDeviceName, midiEventCallback)

webAudioAPI.src.js, line 892

Registers a callback function to receive incoming events from the specified MIDI device.

The midiEventCallback parameter should be a function that receives one parameter of type MIDIMessageEvent.

Note: A callback may be registered for a MIDI device that is also connected to an audio track; however, only one top-level event callback can be registered to a MIDI device at a time.

Parameters:

Name	Type	Description
midiDeviceName	string	Name of the MIDI device for which to receive events
midiEventCallback	MidiEventCallback	Callback to fire when a MIDI event is received

removeAllTracks()

webAudioAPI.src.js, line 555

Removes all existing audio tracks and cancels all current and scheduled audio.

async removeInstrument(trackName)

webAudioAPI.src.js, line 602

Removes the instrument used to play back audio on the specified track.

Parameters:

Name	Type	Description
trackName	string	Name of the track from which to remove the current instrument

async removeMasterEffect(effectName) → {Promise.<(Effect|null)>}

webAudioAPI.src.js, line 847

Removes the specified master effect from being applied.

Parameters:

Name	Type	Description
effectName	string	Name of the master effect to be removed

Returns:

Promise.<(Effect|null)> -

The effect that was removed, if any

See:

• Effect

removeTrack(name)

webAudioAPI.src.js, line 545

Removes the specified audio track and cancels any audio scheduled for playback on this track from playing or starting to play in the future.

Parameters:

Name	Type	Description
name	string	Name of the track to remove

async removeTrackEffect(trackName, effectName)

webAudioAPI.src.js, line 873

Removes the specified effect from being applid on the corresponding track.

Parameters:

Name	Type	Description
trackName	string	Name of the track from which to remove the effect
effectName	string	Name of the track effect to be removed

async selectAudioOutputDevice(audioOutputDeviceName)

webAudioAPI.src.js, line 924

Redirects all audio output to the specified device.

Parameters:

Name	Type	Description
audioOutputDeviceName	string	Name of the output device to which to direct all audio

async start()

webAudioAPI.src.js, line 1456

Starts the WebAudioAPI library and allows audio playback to resume.

async startNote(trackName, note, opt velocity) → {Promise.<Object>}

webAudioAPI.src.js, line 1168

Immediately begins playing a note on the specified track. Playback continues until the note is explicitly stopped using the stopNote() function.

Note that the note parameter should correspond to a MIDI note number as associated with one of the notes returned from getAvailableNotes().

Parameters:

Name	Type	Attributes	Default	Description
trackName	string			Name of the track on which to start playing the note
note	number			MIDI Note number to be played
velocity	number	<optional>	0.75	Intensity of the note to play between [0.0, 1.0]

Returns:

Promise.<Object> -

Reference to the newly scheduled note

See:

• Note

stop()

webAudioAPI.src.js, line 1464

Stops the WebAudioAPI library and pauses any currently playing audio.

async stopNote(trackName, note)

webAudioAPI.src.js, line 1184

Immediately stop playing a note on the specified track. The note to be stopped must be a reference to an actively playing note that was previously returned from the startNote() function.

Parameters:

Name	Type	Description
trackName	string	Name of the track on which to stop playing the note
note	Object	Reference to an active note that was started using startNote()

async updateInstrument(trackName, instrumentName)

webAudioAPI.src.js, line 587

Updates the instrument used to play back audio on the specified track.

The instrument name must refer to a valid instrument as returned by the getAvailableInstruments() function.

Parameters:

Name	Type	Description
trackName	string	Name of the track for which to update the instrument
instrumentName	string	Name of the instrument to assign to the track

updateKeySignature(keySignature)

webAudioAPI.src.js, line 681

Updates the global key signature parameters for all audio tracks.

The keySignature parameter should correspond to the location of the desired key on the circle of fifths as returned by the getAvailableKeySignatures() function. Alternately, you can specify the number of sharps as a positive value or the number of flats as a negative value.

Parameters:

Name	Type	Description
keySignature	number	Numerical KeySignature indicator based on its circle of fifths position

async updateMasterEffect(effectName, effectOptions, opt updateTime, opt transitionLength)

webAudioAPI.src.js, line 784

Updates the parameters of a master effect at the specified time.

Calling this function will not affect the sequential processing order of any applied effects.

Note that the updateTime parameter can be omitted to immediately cause the requested changes to take effect.

Parameters:

Name	Type	Attributes	Description
effectName	string		Name of the master effect to be updated
effectOptions	Object		Effect-specific options as returned by getAvailableEffectParameters()
updateTime	number	<optional>	Global API time at which to update the effect
transitionLength	number	<optional>	Number of seconds over which to update the effect

updateTempo(beatBase, beatsPerMinute, timeSignatureNumerator, timeSignatureDenominator)

webAudioAPI.src.js, line 663

Updates the global tempo parameters for all audio tracks.

The beatBase parameter should correspond to the beat scaling factor associated with one of the note durations from getAvailableNoteDurations().

Any parameter may be set to null to keep it unchanged between consecutive function calls.

Parameters:

Name	Type	Description
beatBase	number | null	Note Duration corresponding to a global beat
beatsPerMinute	number | null	Number of global beats per minute
timeSignatureNumerator	number | null	Number of beats per measure
timeSignatureDenominator	number | null	Note Duration corresponding to a measure beat

async updateTrackEffect(trackName, effectName, effectOptions, opt updateTime, opt transitionLength)

webAudioAPI.src.js, line 808

Updates the parameters of a track-specific effect at the specified time.

Calling this function will not affect the sequential processing order of any applied effects.

Note that the updateTime parameter can be omitted to immediately cause the requested changes to take effect.

Parameters:

Name	Type	Attributes	Description
trackName	string		Name of the track for which to update the effect
effectName	string		Name of the track effect to be updated
effectOptions	Object		Effect-specific options as returned by getAvailableEffectParameters()
updateTime	number	<optional>	Global API time at which to update the effect
transitionLength	number	<optional>	Number of seconds over which to update the effect