AudioWorkletProcessor

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构造函数
特性
方法
事件
用法注意事项
范例
规范
浏览器兼容性
另请参阅
相关话题

AudioWorkletProcessor 接口在 Web 音频 API represents an audio processing code behind a custom AudioWorkletNode . It lives in the AudioWorkletGlobalScope and runs on the Web Audio rendering thread. In turn, an AudioWorkletNode based on it runs on the main thread.

构造函数


							AudioWorkletProcessor

and classes that derive from it cannot be instantiated directly from a user-supplied code. Instead, they are created only internally by the creation of an associated


								AudioWorkletNode

s. The constructor of the deriving class is getting called with an options object, so you can perform a custom initialization procedures — see constructor page for details.

AudioWorkletProcessor(): Creates a new instance of an AudioWorkletProcessor 对象。

特性

port 只读: 返回 MessagePort used for bidirectional communication between the processor and the AudioWorkletNode which it belongs to. The other end is available under the port property of the node.

方法

AudioWorkletProcessor interface does not define any methods of its own. However, you must provide a process() method, which is called in order to process the audio stream.

事件

AudioWorkletProcessor interface doesn't respond to any events.

用法注意事项

Deriving classes

To define custom audio processing code you have to derive a class from the AudioWorkletProcessor interface. Although not defined on the interface, the deriving class must have the process method. This method gets called for each block of 128 sample-frames and takes input and output arrays and calculated values of custom AudioParam s (if they are defined) as parameters. You can use inputs and audio parameter values to fill the outputs array, which by default holds silence.

Optionally, if you want custom AudioParam s on your node, you can supply a parameterDescriptors property as a static getter on the processor. The array of AudioParamDescriptor -based objects returned is used internally to create the AudioParam s during the instantiation of the AudioWorkletNode .

结果 AudioParam s reside in the 参数 property of the node and can be automated using standard methods such as linearRampToValueAtTime . Their calculated values will be passed into the process() method of the processor for you to shape the node output accordingly.

Processing audio

An example algorithm of creating a custom audio processing mechanism is:

Create a separate file;
In the file:
1. Extend the AudioWorkletProcessor class (see "Deriving classes" section ) and supply your own process() method in it;
2. Register the processor using AudioWorkletGlobalScope.registerProcessor() 方法；
Load the file using addModule() method on your audio context's audioWorklet property;
创建 AudioWorkletNode based on the processor. The processor will be instantiated internally by the AudioWorkletNode 构造函数。
Connect the node to the other nodes.

范例

In the example below we create a custom AudioWorkletNode that outputs white noise.

First, we need to define a custom AudioWorkletProcessor , which will output white noise, and register it. Note that this should be done in a separate file.

// white-noise-processor.js
class WhiteNoiseProcessor 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('white-noise-processor', WhiteNoiseProcessor)

Next, in our main script file we'll load the processor, create an instance of AudioWorkletNode , passing it the name of the processor, then connect the node to an audio graph.

const audioContext = new AudioContext()
await audioContext.audioWorklet.addModule('white-noise-processor.js')
const whiteNoiseNode = new AudioWorkletNode(audioContext, 'white-noise-processor')
whiteNoiseNode.connect(audioContext.destination)

规范

规范	状态	注释
Web 音频 API The definition of 'AudioWorkletProcessor' in that specification.	工作草案

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`AudioWorkletProcessor`	Chrome 64	Edge 79	Firefox 76	IE 不支持 No	Opera ?	Safari 不支持 No	WebView Android 64	Chrome Android 64	Firefox Android 不支持 No	Opera Android ?	Safari iOS 不支持 No	Samsung Internet Android 9.0
`AudioWorkletProcessor()` 构造函数	Chrome 64	Edge 79	Firefox 76	IE 不支持 No	Opera ?	Safari 不支持 No	WebView Android 64	Chrome Android 64	Firefox Android 不支持 No	Opera Android ?	Safari iOS 不支持 No	Samsung Internet Android 9.0
`port`	Chrome 64	Edge 79	Firefox 76	IE 不支持 No	Opera ?	Safari 不支持 No	WebView Android 64	Chrome Android 64	Firefox Android 不支持 No	Opera Android ?	Safari iOS 不支持 No	Samsung Internet Android 9.0

图例

完整支持
不支持
兼容性未知 ?

另请参阅

元数据

最后修改： Apr 27, 2020

Web 音频 API
AudioWorkletProcessor
构造函数
1. AudioWorkletProcessor()
特性
1. parameterDescriptors (static getter)
2. port
方法
1. process
Related pages for Web Audio API

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