WebAudio

This domain allows inspection of Web Audio API. https://webaudio.github.io/web-audio-api/

This CDP domain is experimental.

• Types

• Commands

• Events

Types

Generally, you do not need to instantiate CDP types yourself. Instead, the API creates objects for you as return values from commands, and then you can use those objects as arguments to other commands.

class GraphObjectId

An unique ID for a graph object (AudioContext, AudioNode, AudioParam) in Web Audio API

class ContextType(value, names=None, *, module=None, qualname=None, type=None, start=1, boundary=None)

Enum of BaseAudioContext types

REALTIME = 'realtime'

OFFLINE = 'offline'

class ContextState(value, names=None, *, module=None, qualname=None, type=None, start=1, boundary=None)

Enum of AudioContextState from the spec

SUSPENDED = 'suspended'

RUNNING = 'running'

CLOSED = 'closed'

INTERRUPTED = 'interrupted'

class NodeType

Enum of AudioNode types

class ChannelCountMode(value, names=None, *, module=None, qualname=None, type=None, start=1, boundary=None)

Enum of AudioNode::ChannelCountMode from the spec

CLAMPED_MAX = 'clamped-max'

EXPLICIT = 'explicit'

MAX_ = 'max'

class ChannelInterpretation(value, names=None, *, module=None, qualname=None, type=None, start=1, boundary=None)

Enum of AudioNode::ChannelInterpretation from the spec

DISCRETE = 'discrete'

SPEAKERS = 'speakers'

class ParamType

Enum of AudioParam types

class AutomationRate(value, names=None, *, module=None, qualname=None, type=None, start=1, boundary=None)

Enum of AudioParam::AutomationRate from the spec

A_RATE = 'a-rate'

K_RATE = 'k-rate'

class ContextRealtimeData(current_time, render_capacity, callback_interval_mean, callback_interval_variance)

Fields in AudioContext that change in real-time.

current_time: float

The current context time in second in BaseAudioContext.

render_capacity: float

The time spent on rendering graph divided by render quantum duration, and multiplied by 100. 100 means the audio renderer reached the full capacity and glitch may occur.

callback_interval_mean: float

A running mean of callback interval.

callback_interval_variance: float

A running variance of callback interval.

class BaseAudioContext(context_id, context_type, context_state, callback_buffer_size, max_output_channel_count, sample_rate, realtime_data=None)

Protocol object for BaseAudioContext

context_id: GraphObjectId

context_type: ContextType

context_state: ContextState

callback_buffer_size: float

Platform-dependent callback buffer size.

max_output_channel_count: float

Number of output channels supported by audio hardware in use.

sample_rate: float

Context sample rate.

realtime_data: Optional[ContextRealtimeData] = None

class AudioListener(listener_id, context_id)

Protocol object for AudioListener

listener_id: GraphObjectId

context_id: GraphObjectId

class AudioNode(node_id, context_id, node_type, number_of_inputs, number_of_outputs, channel_count, channel_count_mode, channel_interpretation)

Protocol object for AudioNode

node_id: GraphObjectId

context_id: GraphObjectId

node_type: NodeType

number_of_inputs: float

number_of_outputs: float

channel_count: float

channel_count_mode: ChannelCountMode

channel_interpretation: ChannelInterpretation

class AudioParam(param_id, node_id, context_id, param_type, rate, default_value, min_value, max_value)

Protocol object for AudioParam

param_id: GraphObjectId

node_id: GraphObjectId

context_id: GraphObjectId

param_type: ParamType

rate: AutomationRate

default_value: float

min_value: float

max_value: float

Commands

Each command is a generator function. The return type Generator[x, y, z] indicates that the generator yields arguments of type x, it must be resumed with an argument of type y, and it returns type z. In this library, types x and y are the same for all commands, and z is the return type you should pay attention to. For more information, see Getting Started: Commands.

disable()

Disables the WebAudio domain.

Return type:

Generator[Dict[str, Any], Dict[str, Any], None]

enable()

Enables the WebAudio domain and starts sending context lifetime events.

Return type:

Generator[Dict[str, Any], Dict[str, Any], None]

get_realtime_data(context_id)

Fetch the realtime data from the registered contexts.

Parameters:

context_id (GraphObjectId) –

Return type:

Generator[Dict[str, Any], Dict[str, Any], ContextRealtimeData]

Returns:

Events

Generally, you do not need to instantiate CDP events yourself. Instead, the API creates events for you and then you use the event’s attributes.

class ContextCreated(context)

Notifies that a new BaseAudioContext has been created.

context: BaseAudioContext

class ContextWillBeDestroyed(context_id)

Notifies that an existing BaseAudioContext will be destroyed.

context_id: GraphObjectId

class ContextChanged(context)

Notifies that existing BaseAudioContext has changed some properties (id stays the same)..

context: BaseAudioContext

class AudioListenerCreated(listener)

Notifies that the construction of an AudioListener has finished.

listener: AudioListener

class AudioListenerWillBeDestroyed(context_id, listener_id)

Notifies that a new AudioListener has been created.

context_id: GraphObjectId

listener_id: GraphObjectId

class AudioNodeCreated(node)

Notifies that a new AudioNode has been created.

node: AudioNode

class AudioNodeWillBeDestroyed(context_id, node_id)

Notifies that an existing AudioNode has been destroyed.

context_id: GraphObjectId

node_id: GraphObjectId

class AudioParamCreated(param)

Notifies that a new AudioParam has been created.

param: AudioParam

class AudioParamWillBeDestroyed(context_id, node_id, param_id)

Notifies that an existing AudioParam has been destroyed.

context_id: GraphObjectId

node_id: GraphObjectId

param_id: GraphObjectId

class NodesConnected(context_id, source_id, destination_id, source_output_index, destination_input_index)

Notifies that two AudioNodes are connected.

context_id: GraphObjectId

source_id: GraphObjectId

destination_id: GraphObjectId

source_output_index: Optional[float]

destination_input_index: Optional[float]

class NodesDisconnected(context_id, source_id, destination_id, source_output_index, destination_input_index)

Notifies that AudioNodes are disconnected. The destination can be null, and it means all the outgoing connections from the source are disconnected.

context_id: GraphObjectId

source_id: GraphObjectId

destination_id: GraphObjectId

source_output_index: Optional[float]

destination_input_index: Optional[float]

class NodeParamConnected(context_id, source_id, destination_id, source_output_index)

Notifies that an AudioNode is connected to an AudioParam.

context_id: GraphObjectId

source_id: GraphObjectId

destination_id: GraphObjectId

source_output_index: Optional[float]

class NodeParamDisconnected(context_id, source_id, destination_id, source_output_index)

Notifies that an AudioNode is disconnected to an AudioParam.

context_id: GraphObjectId

source_id: GraphObjectId

destination_id: GraphObjectId

source_output_index: Optional[float]