DynamicsCompressorNode.ratio

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句法
范例
规范
浏览器兼容性
另请参阅
相关话题

ratio 特性为 DynamicsCompressorNode interface Is a k-rate AudioParam representing the amount of change, in dB, needed in the input for a 1 dB change in the output.

ratio property's default value is 12 and it can be set between 1 and 20 .

Describes the effect of different ratio on the output signal

句法

var audioCtx = new AudioContext();
var compressor = audioCtx.createDynamicsCompressor();
compressor.ratio.value = 12;

值

AudioParam .

注意 : Though the AudioParam returned is read-only, the value it represents is not.

范例

The below code demonstrates a simple usage of createDynamicsCompressor() to add compression to an audio track. For a more complete example, have a look at our basic Compressor example ( view the source code ).

// Create a MediaElementAudioSourceNode
// Feed the HTMLMediaElement into it
var source = audioCtx.createMediaElementSource(myAudio);
// Create a compressor node
var compressor = audioCtx.createDynamicsCompressor();
compressor.threshold.setValueAtTime(-50, audioCtx.currentTime);
compressor.knee.setValueAtTime(40, audioCtx.currentTime);
compressor.ratio.setValueAtTime(12, audioCtx.currentTime);
compressor.attack.setValueAtTime(0, audioCtx.currentTime);
compressor.release.setValueAtTime(0.25, audioCtx.currentTime);
// connect the AudioBufferSourceNode to the destination
source.connect(audioCtx.destination);
button.onclick = function() {
  var active = button.getAttribute('data-active');
  if(active == 'false') {
    button.setAttribute('data-active', 'true');
    button.innerHTML = 'Remove compression';
    source.disconnect(audioCtx.destination);
    source.connect(compressor);
    compressor.connect(audioCtx.destination);
  } else if(active == 'true') {
    button.setAttribute('data-active', 'false');
    button.innerHTML = 'Add compression';
    source.disconnect(compressor);
    compressor.disconnect(audioCtx.destination);
    source.connect(audioCtx.destination);
  }
}

规范

规范	状态	注释
Web 音频 API The definition of 'ratio' 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
`ratio`	Chrome 14	Edge 12	Firefox 25	IE 不支持 No	Opera 15	Safari 6	WebView Android Yes	Chrome Android 18	Firefox Android 26	Opera Android 14	Safari iOS Yes	Samsung Internet Android 1.0

图例

完整支持
不支持

另请参阅

使用 Web 音频 API

元数据

最后修改： 2020 年 1 月 22 日

Web 音频 API
DynamicsCompressorNode
构造函数
1. DynamicsCompressorNode()
特性
1. attack
2. knee
3. ratio
4. reduction
5. release
6. threshold
继承：
1. AudioNode
2. EventTarget
Related pages for Web Audio API

在此页

句法

值

范例

规范

浏览器兼容性

图例

另请参阅

相关话题