生成正弦波并在浏览器中播放

Question

我需要一个示例代码,可以:

1. 生成正弦波(样本数组)然后

2. 玩吧.

所有这些都是在浏览器中使用JavaScript中的一些HTML5 API完成的

(我正在标记这个网络音频,虽然我不是100%确定它是适用的)

Answer 1

这是如何使用跨浏览器在浏览器中播放441 Hertz正弦波音AudioContext.

window.AudioContext = window.AudioContext || window.webkitAudioContext;

var context = new AudioContext();

function playSound(arr) {
    var buf = new Float32Array(arr.length)
    for (var i = 0; i < arr.length; i++) buf[i] = arr[i]
    var buffer = context.createBuffer(1, buf.length, context.sampleRate)
    buffer.copyToChannel(buf, 0)
    var source = context.createBufferSource();
    source.buffer = buffer;
    source.connect(context.destination);
    source.start(0);
}

function sineWaveAt(sampleNumber, tone) {
    var sampleFreq = context.sampleRate / tone
    return Math.sin(sampleNumber / (sampleFreq / (Math.PI*2)))
}

var arr = [], volume = 0.2, seconds = 0.5, tone = 441

for (var i = 0; i < context.sampleRate * seconds; i++) {
    arr[i] = sineWaveAt(i, tone) * volume
}

playSound(arr)