Created
April 5, 2014 19:32
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Generate Wave sample
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<p><script>(function(){ | |
/* | |
Generate Wave sample | |
*/ | |
var time = 1.0, // 1[sec] | |
sampling = 44100, // Samples per second | |
chan = 2, | |
waveLen = time * sampling * chan; | |
function genWave(buf) | |
{ | |
var hz = 440,//[hz] | |
PI2 = 3.141592*2, | |
vol = 10000, | |
L = 0, R = 0, wl = waveLen; | |
for (var i = 0; i < wl; ++i){ | |
L = R = Math.floor(vol*Math.sin(i*hz*PI2/44100.0)); | |
buf[2*i ] = L; | |
buf[2*i+1] = R; | |
} | |
} | |
function createAudio() | |
{ | |
var i, wave, l1, l2, y, | |
wlen = waveLen, | |
wbuf = new Int32Array(wlen); | |
genWave(wbuf); | |
// Create wave header | |
var sizeInt = 4; | |
l1 = wlen * sizeInt - 8, | |
l2 = l1 - 36; | |
wave = String.fromCharCode( | |
82,73,70,70, | |
l1 & 255,(l1 >> 8) & 255,(l1 >> 16) & 255,l1 >> 24, | |
87,65,86,69,102,109,116,32,16,0,0,0,1,0,2,0, | |
68,172,0,0,16,177,2,0,4,0,16,0,100,97,116,97, | |
l2 & 255,(l2 >> 8) & 255,(l2 >> 16) & 255,l2 >> 24 | |
); | |
for (var i = 0; i < wlen; i++){ | |
y = wbuf[i]; | |
y = y < -32767 ? -32767 : (y > 32767 ? 32767 : y); // clipping | |
wave += String.fromCharCode(y & 255, (y >> 8) & 255); | |
} | |
return new Audio("data:audio/wav;base64," + btoa(wave)); | |
}; | |
var audio = createAudio(); | |
audio.play(); | |
// disp time | |
var d = document.createElement("div"); | |
document.body.appendChild(d); | |
setInterval(function(){ | |
d.innerHTML = "Time="+audio.currentTime; | |
},16); | |
})()</script> |
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