创建AudioAnalyser对象, 使用[link:https://developer.mozilla.org/en-US/docs/Web/API/AnalyserNode AnalyserNode]
去分析音频数据.
使用了 [link:https://developer.mozilla.org/en-US/docs/Web/API/Web_Audio_API Web Audio API].
[example:webaudio_sandbox webaudio / sandbox]
[example:webaudio_visualizer webaudio / visualizer]
// create an AudioListener and add it to the camera
var listener = new v3d.AudioListener();
camera.add(listener);
// create an Audio source
var sound = new v3d.Audio(listener);
// load a sound and set it as the Audio object's buffer
var audioLoader = new v3d.AudioLoader();
audioLoader.load('sounds/ambient.ogg', function(buffer) {
sound.setBuffer(buffer);
sound.setLoop(true);
sound.setVolume(0.5);
sound.play();
});
// create an AudioAnalyser, passing in the sound and desired fftSize
var analyser = new v3d.AudioAnalyser(sound, 32);
// get the average frequency of the sound
var data = analyser.getAverageFrequency();
创建[page:AudioAnalyser AudioAnalyser].
[link:https://developer.mozilla.org/en-US/docs/Web/API/AnalyserNode AnalyserNode]用来分析音频数据.
2的幂次方最高为2048, 用来表示确定频域的FFT (傅立叶变换)大小. 这个[link:https://developer.mozilla.org/en-US/docs/Web/API/AnalyserNode/fftSize page]有详细信息.
用来分析数据的Uint8Array的大小由[link:https://developer.mozilla.org/en-US/docs/Web/API/AnalyserNode/frequencyBinCount analyser.frequencyBinCount] 确定.
使用网络音频的[link:https://developer.mozilla.org/en-US/docs/Web/API/AnalyserNode/getByteFrequencyData getByteFrequencyData] 方法. 看这个页面.
通过方法[page:AudioAnalyser.getFrequencyData getFrequencyData]获取平均频率.