AudioWorkletGlobalScope: currentTime property
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since April 2021.
The read-only currentTime
property of the AudioWorkletGlobalScope
interface returns a double that represents the ever-increasing context time of the audio block being processed. It is equal to the currentTime
property of the BaseAudioContext
the worklet belongs to.
Value
A floating-point number representing the time.
Examples
The AudioWorkletProcessor
has access to the specific AudioWorkletGlobalScope
properties:
// AudioWorkletProcessor defined in : test-processor.js
class TestProcessor extends AudioWorkletProcessor {
constructor() {
super();
// Logs the current sample-frame and time at the moment of instantiation.
// They are accessible from the AudioWorkletGlobalScope.
console.log(currentFrame);
console.log(currentTime);
}
// The process method is required - output silence,
// which the outputs are already filled with.
process(inputs, outputs, parameters) {
return true;
}
}
// Logs the sample rate, that is not going to change ever,
// because it's a read-only property of a BaseAudioContext
// and is set only during its instantiation.
console.log(sampleRate);
// You can declare any variables and use them in your processors
// for example it may be an ArrayBuffer with a wavetable.
const usefulVariable = 42;
console.log(usefulVariable);
registerProcessor("test-processor", TestProcessor);
The main script loads the processor, creates an instance of AudioWorkletNode
, passes the name of the processor to it, and connects the node to an audio graph. We should see the output of console.log()
calls in the console:
const audioContext = new AudioContext();
await audioContext.audioWorklet.addModule("test-processor.js");
const testNode = new AudioWorkletNode(audioContext, "test-processor");
testNode.connect(audioContext.destination);
Specifications
Specification |
---|
Web Audio API # dom-audioworkletglobalscope-currenttime |
Browser compatibility
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