AudioProcessingEvent

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弃用
This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the 兼容性表格 at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

Web 音频 API AudioProcessingEvent represents events that occur when a ScriptProcessorNode input buffer is ready to be processed.

注意 : As of the August 29 2014 Web Audio API spec publication, this feature has been marked as deprecated, and is soon to be replaced by AudioWorklet .

特性

The list below includes the properties inherited from its parent, 事件 .

特性	类型	描述
`target` 只读	`EventTarget`	The event target (the topmost target in the DOM tree).
`type` 只读	`DOMString`	The type of event.
`bubbles` 只读	`boolean`	Does the event normally bubble?
`cancelable` 只读	`boolean`	Is it possible to cancel the event?
`playbackTime` 只读	`double`	The time when the audio will be played, as defined by the time of `AudioContext.currentTime`
`inputBuffer` 只读	`AudioBuffer`	The buffer containing the input audio data to be processed. The number of channels is defined as a parameter, `numberOfInputChannels` , of the factory method `AudioContext.createScriptProcessor()` . Note the the returned `AudioBuffer` is only valid in the scope of the `onaudioprocess` 函数。
`outputBuffer` 只读	`AudioBuffer`	The buffer where the output audio data should be written. The number of channels is defined as a parameter, `numberOfOutputChannels` , of the factory method `AudioContext.createScriptProcessor()` . Note the the returned `AudioBuffer` is only valid in the scope of the `onaudioprocess` 函数。

范例

The following example shows basic usage of a ScriptProcessorNode to take a track loaded via AudioContext.decodeAudioData() , process it, adding a bit of white noise to each audio sample of the input track (buffer) and play it through the AudioDestinationNode . For each channel and each sample frame, the scriptNode.onaudioprocess function takes the associated audioProcessingEvent and uses it to loop through each channel of the input buffer, and each sample in each channel, and add a small amount of white noise, before setting that result to be the output sample in each case.

注意 : For a full working example, see our script-processor-node github repo (also view the 源代码 )。

var myScript = document.querySelector('script');
var myPre = document.querySelector('pre');
var playButton = document.querySelector('button');
// Create AudioContext and buffer source
var audioCtx = new AudioContext();
source = audioCtx.createBufferSource();
// Create a ScriptProcessorNode with a bufferSize of 4096 and a single input and output channel
var scriptNode = audioCtx.createScriptProcessor(4096, 1, 1);
console.log(scriptNode.bufferSize);
// load in an audio track via XHR and decodeAudioData
function getData() {
  request = new XMLHttpRequest();
  request.open('GET', 'viper.ogg', true);
  request.responseType = 'arraybuffer';
  request.onload = function() {
    var audioData = request.response;
    audioCtx.decodeAudioData(audioData, function(buffer) {
    myBuffer = buffer;
    source.buffer = myBuffer;
  },
    function(e){"Error with decoding audio data" + e.err});
  }
  request.send();
}
// Give the node a function to process audio events
scriptNode.onaudioprocess = function(audioProcessingEvent) {
  // The input buffer is the song we loaded earlier
  var inputBuffer = audioProcessingEvent.inputBuffer;
  // The output buffer contains the samples that will be modified and played
  var outputBuffer = audioProcessingEvent.outputBuffer;
  // Loop through the output channels (in this case there is only one)
  for (var channel = 0; channel < outputBuffer.numberOfChannels; channel++) {
    var inputData = inputBuffer.getChannelData(channel);
    var outputData = outputBuffer.getChannelData(channel);
    // Loop through the 4096 samples
    for (var sample = 0; sample < inputBuffer.length; sample++) {
      // make output equal to the same as the input
      outputData[sample] = inputData[sample];
      // add noise to each output sample
      outputData[sample] += ((Math.random() * 2) - 1) * 0.2;
    }
  }
}
getData();
// wire up play button
playButton.onclick = function() {
  source.connect(scriptNode);
  scriptNode.connect(audioCtx.destination);
  source.start();
}
// When the buffer source stops playing, disconnect everything
source.onended = function() {
  source.disconnect(scriptNode);
  scriptNode.disconnect(audioCtx.destination);
}

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
`AudioProcessingEvent` 弃用	Chrome 14	Edge ≤18	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
`AudioProcessingEvent()` 构造函数弃用	Chrome 57	Edge ≤79	Firefox ?	IE 不支持 No	Opera ?	Safari ?	WebView Android 57	Chrome Android 57	Firefox Android ?	Opera Android ?	Safari iOS ?	Samsung Internet Android 7.0
`inputBuffer` 弃用	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
`outputBuffer` 弃用	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
`playbackTime` 弃用	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
兼容性未知 ?
弃用。不要用于新网站。

另请参阅

使用 Web 音频 API

元数据

最后修改： Dec 24, 2019

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特性

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