AudioParamDescriptor
The AudioParamDescriptor dictionary of the Web Audio API specifies properties for an AudioParam objects. It is used to create custom AudioParams on an AudioWorkletNode. If the underlying AudioWorkletProcessor has a parameterDescriptors static getter, then the returned array of objects based on this dictionary is used internally by AudioWorkletNode constructor to populate its parameters property accordingly.
属性
name-
The
DOMStringwhich represents the name of theAudioParam. Under this name theAudioParamwill be available in theparametersproperty of the node, and under this name theAudioWorkletProcessor.processmethod will acquire the calculated values of thisAudioParam. automationRate可选-
Either
"a-rate", or"k-rate"string which represents an automation rate of thisAudioParam. Defaults to"a-rate". minValue可选-
A
floatwhich represents minimum value of theAudioParam. Defaults to-3.4028235e38. maxValue可选-
A
floatwhich represents maximum value of theAudioParam. Defaults to3.4028235e38. defaultValue可选-
A
floatwhich represents initial value of theAudioParam. Defaults to0.
示例
下面的代码片段展示了自定义的 AudioWorkletProcessor 中的静态方法 parameterDescriptors 返回该类型的描述符(这是 AudioWorkletNode.parameters 中完整示例的一部分)。
// white-noise-processor.js
class WhiteNoiseProcessor extends AudioWorkletProcessor {
static get parameterDescriptors() {
return [
{
name: "customGain",
defaultValue: 1,
minValue: 0,
maxValue: 1,
automationRate: "a-rate",
},
];
}
// …
}
规范
| Specification |
|---|
| Web Audio API> # AudioParamDescriptor> |