AudioWorkletNode
Note: Although the interface is available outside secure contexts, the BaseAudioContext.audioWorklet
property is not, thus custom AudioWorkletProcessor
s cannot be defined outside them.
The AudioWorkletNode
interface of the Web Audio API represents a base class for a user-defined AudioNode
, which can be connected to an audio routing graph along with other nodes. It has an associated AudioWorkletProcessor
, which does the actual audio processing in a Web Audio rendering thread.
Constructor
AudioWorkletNode()
-
Creates a new instance of an
AudioWorkletNode
object.
Instance properties
Also Inherits properties from its parent, AudioNode
.
AudioWorkletNode.port
Read only-
Returns a
MessagePort
used for bidirectional communication between the node and its associatedAudioWorkletProcessor
. The other end is available under theport
property of the processor. AudioWorkletNode.parameters
Read only-
Returns an
AudioParamMap
— a collection ofAudioParam
objects. They are instantiated during the creation of the underlyingAudioWorkletProcessor
. If theAudioWorkletProcessor
has a staticparameterDescriptors
getter, theAudioParamDescriptor
array returned from it is used to createAudioParam
objects on theAudioWorkletNode
. With this mechanism it is possible to make your ownAudioParam
objects accessible from yourAudioWorkletNode
. You can then use their values in the associatedAudioWorkletProcessor
.
Events
processorerror
-
Fired when an error is thrown in associated
AudioWorkletProcessor
. Once fired, the processor and consequently the node will output silence throughout its lifetime.
Instance methods
Also inherits methods from its parent, AudioNode
.
The AudioWorkletNode
interface does not define any methods of its own.
Examples
In this example we create a custom AudioWorkletNode
that outputs random noise.
First, we need to define a custom AudioWorkletProcessor
, which will output random noise, and register it. Note that this should be done in a separate file.
js
// random-noise-processor.js
class RandomNoiseProcessor extends AudioWorkletProcessor {
process(inputs, outputs, parameters) {
const output = outputs[0];
output.forEach((channel) => {
for (let i = 0; i < channel.length; i++) {
channel[i] = Math.random() * 2 - 1;
}
});
return true;
}
}
registerProcessor("random-noise-processor", RandomNoiseProcessor);
Next, in our main script file we'll load the processor, create an instance of AudioWorkletNode
passing it the name of the processor, and connect the node to an audio graph.
js
const audioContext = new AudioContext();
await audioContext.audioWorklet.addModule("random-noise-processor.js");
const randomNoiseNode = new AudioWorkletNode(
audioContext,
"random-noise-processor"
);
randomNoiseNode.connect(audioContext.destination);
Specifications
Specification |
---|
Web Audio API # AudioWorkletNode |
Browser compatibility
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