AudioContext.getOutputTimestamp()

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getOutputTimestamp() 特性为 AudioContext interface returns a new AudioTimestamp object containing two audio timestamp values relating to the current audio context.

The two values are as follows:

AudioTimestamp.contextTime : The time of the sample frame currently being rendered by the audio output device (i.e., output audio stream position), in the same units and origin as the context's AudioContext.currentTime . Basically, this is the time after the audio context was first created.
AudioTimestamp.performanceTime : An estimation of the moment when the sample frame corresponding to the stored contextTime value was rendered by the audio output device, in the same units and origin as performance.now() . This is the time after the document containing the audio context was first rendered.

句法

var timestamp = AudioContext.getOutputTimestamp()

参数

None.

An AudioTimestamp object, which has the following properties.

contextTime : A point in the time coordinate system of the currentTime 为 BaseAudioContext ; the time after the audio context was first created.
performanceTime : A point in the time coordinate system of a 性能 interface; the time after the document containing the audio context was first rendered

范例

In the following code we start to play an audio file after a play button is clicked, and start off a requestAnimationFrame loop running, which constantly outputs the contextTime and performanceTime .

You can see full code of this example at output-timestamp ( see it live also ).

play.addEventListener('click', () => {
  if(!audioCtx) {
    audioCtx = new window.AudioContext();
  }
  getData();
  source.start(0);
  play.setAttribute('disabled', 'disabled');
  rAF = requestAnimationFrame(outputTimestamps);
});
stop.addEventListener('click', () => {
  source.stop(0);
  play.removeAttribute('disabled');
  cancelAnimationFrame(rAF);
});
// function to output timestamps
function outputTimestamps() {
  let ts = audioCtx.getOutputTimestamp()
  console.log('Context time: ' + ts.contextTime + ' | Performance time: ' + ts.performanceTime);
  rAF = requestAnimationFrame(outputTimestamps);
}

规范

规范	状态	注释
Web 音频 API The definition of 'getOutputTimestamp()' in that specification.	工作草案	初始定义。

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
`getOutputTimestamp`	Chrome 57	Edge ≤79	Firefox 70	IE 不支持 No	Opera 44	Safari 不支持 No	WebView Android 57	Chrome Android 57	Firefox Android 不支持 No	Opera Android 43	Safari iOS 不支持 No	Samsung Internet Android 7.0

图例

完整支持
不支持
实验。期望将来行为有所改变。

元数据

最后修改： 2020 年 1 月 22 日

Web 音频 API
AudioContext
构造函数
1. AudioContext()
特性
1. baseLatency
2. outputLatency
方法
1. baseLatency
2. close()
3. ~~createJavaScriptNode()~~
4. createMediaElementSource()
5. createMediaStreamDestination()
6. createMediaStreamSource()
7. createMediaStreamTrackSource()
8. ~~createWaveTable()~~
9. getOutputTimestamp()
10. outputLatency
11. resume()
12. suspend()
继承：
1. EventTarget
Related pages for Web Audio API

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