AudioBuffer.duration

AudioBuffer接口的 duration 属性返回一个双精度数，表示缓冲区中存储的 PCM 数据的持续时间（以秒为单位）

语法

js
var myArrayBuffer = audioCtx.createBuffer(2, frameCount, audioCtx.sampleRate);
myArrayBuffer.duration;

值

双精度值

例子

js
// Stereo
var channels = 2;

// Create an empty two second stereo buffer at the
// sample rate of the AudioContext
var frameCount = audioCtx.sampleRate * 2.0;
var myArrayBuffer = audioCtx.createBuffer(2, frameCount, audioCtx.sampleRate);

button.onclick = function () {
  // Fill the buffer with white noise;
  // just random values between -1.0 and 1.0
  for (var channel = 0; channel < channels; channel++) {
    // This gives us the actual ArrayBuffer that contains the data
    var nowBuffering = myArrayBuffer.getChannelData(channel);
    for (var i = 0; i < frameCount; i++) {
      // Math.random() is in [0; 1.0]
      // audio needs to be in [-1.0; 1.0]
      nowBuffering[i] = Math.random() * 2 - 1;
    }
  }

  console.log(myArrayBuffer.duration);
};

规范

Specification
Web Audio API
# dom-audiobuffer-duration

浏览器兼容性

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See also