在JavaScript中控制音频平衡(L/R)

Question

我想在使用此代码

时控制音频余额

var oscillator = audioCtx.createOscillator();
oscillator.type = 'square';
oscillator.frequency.value = frequency; // value in hertz
oscillator.connect(audioCtx.destination);
oscillator.start();
setTimeout(function(){oscillator.stop();}, duration);   

以及我播放本地MP3文件时。我该怎么做？

Answer 1

使用createStereoPanner：

将StereoPannerNode添加到链条

var oscillator = audioCtx.createOscillator();
var panner = audioCtx.createStereoPanner();
oscillator.type = 'square';
oscillator.frequency.value = frequency;  // value in hertz
oscillator.connect(panner);              // connect audio source to panner
panner.connect(audioCtx.destination);    // connect panner to output
oscillator.start();

现在您可以使用：

控制L/R

panner.pan.value = someValue;   // value in the range -1 (L) to 1 (R)

功能示例：

var audioCtx = new (AudioContext || webkitAudioContext)();
var oscillator = audioCtx.createOscillator();
var panner = audioCtx.createStereoPanner();
oscillator.type = 'square';
oscillator.frequency.value = 440; // value in hertz
oscillator.connect(panner);
panner.connect(audioCtx.destination);
oscillator.start();
document.querySelector("input").oninput = function() {
  panner.pan.value = +this.value; 
};
setInterval(function() {
  oscillator.frequency.value = Math.round(Math.random() * 10) * 400 + 200;
}, 100);

<label>L <input type=range min=-1 max=1 value=0 step=0.01> R</label>