AudioBufferSourceNode.playbackRate

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playbackRate 特性为 AudioBufferSourceNode interface Is a k-rate AudioParam that defines the speed at which the audio asset will be played.

A value of 1.0 indicates it should play at the same speed as its sampling rate, values less than 1.0 cause the sound to play more slowly, while values greater than 1.0 result in audio playing faster than normal. The default value is 1.0 . When set to another value, the AudioBufferSourceNode resamples the audio before sending it to the output.

句法

AudioBufferSourceNode.playbackRate.value = playbackRateProportion;

值

AudioParam whose value is a floating-point value indicating the playback rate of the audio as a decimal proportion of the original sampling rate.

Consider a sound buffer containing audio sampled at 44.1 kHz (44,100 samples per second). Let's see what a few values of playbackRate do:

A playbackRate of 1.0 plays the audio at full speed, or 44,100 Hz.
A playbackRate of 0.5 plays the audio at half speed, or 22,050 Hz.
A playbackRate of 2.0 doubles the audio's playback rate to 88,200 Hz.

范例

在此范例中， AudioContext.decodeAudioData() function is used to decode an audio track, and put it into an AudioBufferSourceNode . Buttons are provided to play and stop the audio playback, and a slider control is used to change the playbackRate property value on the fly.

You can run the example live (或 view the source .) Play the song and alter the playback rate for some fun results.

<input class="playback-rate-control" type="range" min="0.25" max="3" step="0.05" value="1">
<span class="playback-rate-value">1.0</span>

function getData() {
  source = audioCtx.createBufferSource();
  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;
        source.playbackRate.value = playbackControl.value;
        source.connect(audioCtx.destination);
        source.loop = true;
      },
      function(e){"Error with decoding audio data" + e.err});
  }
  request.send();
}
// wire up buttons to stop and play audio, and range slider control
play.onclick = function() {
  getData();
  source.start(0);
  play.setAttribute('disabled', 'disabled');
  playbackControl.removeAttribute('disabled');
}
stop.onclick = function() {
  source.stop(0);
  play.removeAttribute('disabled');
  playbackControl.setAttribute('disabled', 'disabled');
}
playbackControl.oninput = function() {
  source.playbackRate.value = playbackControl.value;
  playbackValue.innerHTML = playbackControl.value;
}

规范

规范	状态	注释
Web 音频 API The definition of 'playbackRate' 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
`playbackRate`	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

另请参阅

使用 Web 音频 API

元数据

最后修改： 2020 年 1 月 22 日

Web 音频 API
AudioBufferSourceNode
构造函数
1. AudioBufferSourceNode()
特性
1. buffer
2. detune
3. loop
4. loopEnd
5. loopStart
6. playbackRate
方法
1. start()
继承：
Related pages for Web Audio API

在此页

句法

值

范例

规范

浏览器兼容性

图例

另请参阅

相关话题