BaseAudioContext.decodeAudioData()

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句法
范例
规范
浏览器兼容性
另请参阅
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decodeAudioData() 方法在 BaseAudioContext Interface is used to asynchronously decode audio file data contained in an ArrayBuffer . In this case the ArrayBuffer is loaded from XMLHttpRequest and FileReader . The decoded AudioBuffer is resampled to the AudioContext 's sampling rate, then passed to a callback or promise.

This is the preferred method of creating an audio source for Web Audio API from an audio track. This method only works on complete file data, not fragments of audio file data.

句法

Older callback syntax:

baseAudioContext.decodeAudioData(ArrayBuffer, successCallback, errorCallback);

Newer promise-based syntax:

Promise<decodedData> baseAudioContext.decodeAudioData(ArrayBuffer);

参数

ArrayBuffer: An ArrayBuffer containing the audio data to be decoded, usually grabbed from XMLHttpRequest , WindowOrWorkerGlobalScope.fetch() or FileReader .
successCallback: A callback function to be invoked when the decoding successfully finishes. The single argument to this callback is an AudioBuffer 表示 decodedData (the decoded PCM audio data). Usually you'll want to put the decoded data into an AudioBufferSourceNode , from which it can be played and manipulated how you want.
errorCallback

返回值

Void, or a Promise object that fulfills with the decodedData .

范例

In this section we will first cover the older callback-based system and then the newer promise-based syntax.

Older callback syntax

在此范例中， getData() function uses XHR to load an audio track, setting the responseType of the request to arraybuffer so that it returns an array buffer as its response that we then store in the audioData variable . We then pass this buffer into a decodeAudioData() function; the success callback takes the successfully decoded PCM data, puts it into an AudioBufferSourceNode created using AudioContext.createBufferSource() , connects the source to the AudioContext.destination and sets it to loop.

The buttons in the example simply run getData() to load the track and start it playing, and stop it playing, respectively. When the stop() method is called on the source, the source is cleared out.

注意 : You can run the example live (或 view the source )。

// define variables
var audioCtx = new (window.AudioContext || window.webkitAudioContext)();
var source;
var pre = document.querySelector('pre');
var myScript = document.querySelector('script');
var play = document.querySelector('.play');
var stop = document.querySelector('.stop');
// use XHR to load an audio track, and
// decodeAudioData to decode it and stick it in a buffer.
// Then we put the buffer into the source
function getData() {
  source = audioCtx.createBufferSource();
  var request = new XMLHttpRequest();
  request.open('GET', 'viper.ogg', true);
  request.responseType = 'arraybuffer';
  request.onload = function() {
    var audioData = request.response;
    audioCtx.decodeAudioData(audioData, function(buffer) {
        source.buffer = buffer;
        source.connect(audioCtx.destination);
        source.loop = true;
      },
      function(e){ console.log("Error with decoding audio data" + e.err); });
  }
  request.send();
}
// wire up buttons to stop and play audio
play.onclick = function() {
  getData();
  source.start(0);
  play.setAttribute('disabled', 'disabled');
}
stop.onclick = function() {
  source.stop(0);
  play.removeAttribute('disabled');
}
// dump script to pre element
pre.innerHTML = myScript.innerHTML;

New promise-based syntax

ctx.decodeAudioData(audioData).then(function(decodedData) {
 // use the decoded data here
});

规范

规范	状态	注释
Web 音频 API The definition of 'decodeAudioData()' 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
`decodeAudioData`	Chrome 10 Prefixed 10 Prefixed Prefixed Implemented with the vendor prefix: webkit	Edge ≤18	Firefox 53 注意事项 53 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 注意事项 53 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
Promise-based syntax	Chrome 49	Edge ≤79	Firefox 53 注意事项 53 注意事项 Originally implemented on `AudioContext` in Firefox 36.	IE 不支持 No	Opera Yes	Safari 不支持 No	WebView Android 49	Chrome Android 49	Firefox Android 53 注意事项 53 注意事项 Originally implemented on `AudioContext` in Firefox Android 36.	Opera Android ?	Safari iOS 不支持 No	Samsung Internet Android 5.0

图例

完整支持
不支持
兼容性未知 ?

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 7 月 29 日

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句法

参数

返回值

范例

Older callback syntax

New promise-based syntax

规范

浏览器兼容性

图例

另请参阅

相关话题