AudioBufferSourceNode.loopStart

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句法
范例
规范
浏览器兼容性
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loopStart 特性为 AudioBufferSourceNode interface is a floating-point value indicating, in seconds, where in the AudioBuffer the restart of the play must happen.

loopStart property's default value is 0 .

句法

AudioBufferSourceNode.loopStart = startOffsetInSeconds;
startOffsetInSeconds = AudioBufferSourceNode.loopStart;

值

A floating-point number indicating the offset, in seconds, into the audio buffer at which each loop should begin during playback. This value is only used when the loop 参数为 true .

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 slider controls are used to change the playbackRate , loopStart ，和 loopEnd properties on the fly.

When the audio is played to the end, it loops, but you can control how long the loops last by altering loopStart and loopEnd . For example, if you set their values to 20 and 25, respectively, the audio will start to loop between 20 and 25 seconds in to the track.

For a full working example, see this code running live ，或 view the source .

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;
        songLength = buffer.duration;
        source.buffer = myBuffer;
        source.playbackRate.value = playbackControl.value;
        source.connect(audioCtx.destination);
        source.loop = true;
        loopstartControl.setAttribute('max', Math.floor(songLength));
        loopendControl.setAttribute('max', Math.floor(songLength));
      },
      function(e){"Error with decoding audio data" + e.err});
  }
  request.send();
}
  ...
loopstartControl.oninput = function() {
  source.loopStart = loopstartControl.value;
  loopstartValue.innerHTML = loopstartControl.value;
}
loopendControl.oninput = function() {
  source.loopEnd = loopendControl.value;
  loopendValue.innerHTML = loopendControl.value;
}

规范

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

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

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句法

值

范例

规范

浏览器兼容性

图例

另请参阅

相关话题