BaseAudioContext.createGain()

在此页

句法
范例
规范
浏览器兼容性
另请参阅
相关话题

createGain() 方法在 BaseAudioContext interface creates a GainNode , which can be used to control the overall gain (or volume) of the audio graph.

句法

var gainNode = AudioContext.createGain();

返回值

A GainNode which takes as input one or more audio sources and outputs audio whose volume has been adjusted in gain (volume) to a level specified by the node's GainNode.gain a-rate 参数。

范例

The following example shows basic usage of an AudioContext to create a GainNode , which is then used to mute and unmute the audio when a Mute button is clicked by changing the gain property value.

The below snippet wouldn't work as is — for a complete working example, check out our Voice-change-O-matic demo ( view source )。

<div>
  <button class="mute">Mute button</button>
</div>

var audioCtx = new (window.AudioContext || window.webkitAudioContext)();
var gainNode = audioCtx.createGain();
var mute = document.querySelector('.mute');
var source;
if (navigator.mediaDevices.getUserMedia) {
 navigator.mediaDevices.getUserMedia (
   // constraints - only audio needed for this app
   {
     audio: true
   },
   // Success callback
   function(stream) {
     source = audioCtx.createMediaStreamSource(stream);
   },
   // Error callback
   function(err) {
     console.log('The following gUM error occured: ' + err);
   }
  );
} else {
   console.log('getUserMedia not supported on your browser!');
}
source.connect(gainNode);
gainNode.connect(audioCtx.destination);
  ...
mute.onclick = voiceMute;
function voiceMute() {
  if(mute.id == "") {
    // 0 means mute. If you still hear something, make sure you haven't
    // connected your source into the output in addition to using the GainNode.
    gainNode.gain.setValueAtTime(0, audioCtx.currentTime);
    mute.id = "activated";
    mute.innerHTML = "Unmute";
  } else {
    gainNode.gain.setValueAtTime(1, audioCtx.currentTime);
    mute.id = "";
    mute.innerHTML = "Mute";
  }
}

规范

规范	状态	注释
Web 音频 API The definition of 'createGain()' 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
`createGain`	Chrome 10 Prefixed 10 Prefixed Prefixed Implemented with the vendor prefix: webkit	Edge ≤18	Firefox 53 53 注意事项注意事项 Originally implemented on `AudioContext` in Firefox 25.	IE 不支持 No	Opera 22 22 15 Prefixed Prefixed Implemented with the vendor prefix: webkit	Safari 6 Prefixed 6 Prefixed Prefixed Implemented with the vendor prefix: webkit	WebView Android Yes	Chrome Android 33	Firefox Android 53 53 注意事项注意事项 Originally implemented on `AudioContext` in Firefox Android 26.	Opera Android 22 22 14 Prefixed Prefixed Implemented with the vendor prefix: webkit	Safari iOS 6 Prefixed 6 Prefixed Prefixed Implemented with the vendor prefix: webkit	Samsung Internet Android 2.0

图例

完整支持
不支持
见实现注意事项。
要求使用供应商前缀或不同名称。

另请参阅

使用 Web 音频 API

元数据

最后修改： 2020 年 6 月 9 日

在此页

句法

返回值

范例

规范

浏览器兼容性

图例

另请参阅

相关话题