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• 句法
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

knee 特性为 DynamicsCompressorNode 接口是 k-rate AudioParam containing a decibel value representing the range above the threshold where the curve smoothly transitions to the compressed portion.

knee property's default value is 30 and it can be set between 0 and 40 .

句法

var audioCtx = new AudioContext();
var compressor = audioCtx.createDynamicsCompressor();
compressor.knee.value = 40;
					

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 'knee' 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
knee	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

完整支持

不支持

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

相关话题

1. Web 音频 API
2. DynamicsCompressorNode
3. 构造函数

   1. DynamicsCompressorNode()
4. 特性

   1. attack
   2. knee
   3. ratio
   4. reduction
   5. release
   6. threshold
5. 继承：

   1. AudioNode
   2. EventTarget
6. Related pages for Web Audio API

   1. AnalyserNode
   2. AudioBuffer
   3. AudioBufferSourceNode
   4. AudioContext
   5. AudioContextOptions
   6. AudioDestinationNode
   7. AudioListener
   8. AudioNode
   9. AudioNodeOptions
   10. AudioParam
   11. AudioProcessingEvent
   12. AudioScheduledSourceNode
   13. AudioWorklet
   14. AudioWorkletGlobalScope
   15. AudioWorkletNode
   16. AudioWorkletProcessor
   17. BaseAudioContext
   18. BiquadFilterNode
   19. ChannelMergerNode
   20. ChannelSplitterNode
   21. ConstantSourceNode
   22. ConvolverNode
   23. DelayNode
   24. GainNode
   25. IIRFilterNode
   26. MediaElementAudioSourceNode
   27. MediaStreamAudioDestinationNode
   28. MediaStreamAudioSourceNode
   29. OfflineAudioCompletionEvent
   30. OfflineAudioContext
   31. OscillatorNode
   32. PannerNode
   33. PeriodicWave
   34. StereoPannerNode
   35. WaveShaperNode