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(function () {
'use strict';
if (!importScripts) {
var importScripts = (function (globalEval) {
var xhr = new XMLHttpRequest;
return function importScripts() {
var
args = Array.prototype.slice.call(arguments)
, len = args.length
, i = 0
, meta
, data
, content
;
for (; i < len; i++) {
if (args[i].substr(0, 5).toLowerCase() === "data:") {
data = args[i];
content = data.indexOf(",");
meta = data.substr(5, content).toLowerCase();
data = decodeURIComponent(data.substr(content + 1));
if (/;\s*base64\s*[;,]/.test(meta)) {
data = atob(data);
}
if (/;\s*charset=[uU][tT][fF]-?8\s*[;,]/.test(meta)) {
data = decodeURIComponent(escape(data));
}
} else {
xhr.open("GET", args[i], false);
xhr.send(null);
data = xhr.responseText;
}
globalEval(data);
}
};
}(eval));
}
importScripts('assets/libs/audio-recorder/lame.min.js');
var mp3Encoder, maxSamples = 1152, samplesMono, lame, config, dataBuffer;
var clearBuffer = function () {
dataBuffer = [];
};
var appendToBuffer = function (mp3Buf) {
dataBuffer.push(new Int8Array(mp3Buf));
};
var init = function (prefConfig) {
config = prefConfig || {};
lame = new lamejs();
mp3Encoder = new lame.Mp3Encoder(1, config.sampleRate || 44100, config.bitRate || 128);
clearBuffer();
self.postMessage({
cmd: 'init'
});
};
var floatTo16BitPCM = function (input, output) {
for (var i = 0; i < input.length; i++) {
var s = Math.max(-1, Math.min(1, input[i]));
output[i] = (s < 0 ? s * 0x8000 : s * 0x7FFF);
}
};
var convertBuffer = function (arrayBuffer) {
var data = new Float32Array(arrayBuffer);
var out = new Int16Array(arrayBuffer.length);
floatTo16BitPCM(data, out);
return out;
};
var encode = function (arrayBuffer) {
samplesMono = convertBuffer(arrayBuffer);
var remaining = samplesMono.length;
for (var i = 0; remaining >= 0; i += maxSamples) {
var left = samplesMono.subarray(i, i + maxSamples);
var mp3buf = mp3Encoder.encodeBuffer(left);
appendToBuffer(mp3buf);
remaining -= maxSamples;
}
};
var finish = function () {
appendToBuffer(mp3Encoder.flush());
self.postMessage({
cmd: 'end',
buf: dataBuffer
});
clearBuffer();
};
self.onmessage = function (e) {
switch (e.data.cmd) {
case 'init':
init(e.data.config);
break;
case 'encode':
encode(e.data.buf);
break;
case 'finish':
finish();
break;
}
};
})();