Add voice notes

// FREEBIE

components/recorderjs/recorder.js

@@ -0,0 +1,97 @@
+(function(window){
+
+  var WORKER_PATH = 'recorderWorker.js';
+
+  var Recorder = function(source, cfg){
+    var config = cfg || {};
+    var bufferLen = config.bufferLen || 4096;
+    this.context = source.context;
+    this.node = (this.context.createScriptProcessor ||
+                 this.context.createJavaScriptNode).call(this.context,
+                                                         bufferLen, 2, 2);
+    var worker = new Worker(config.workerPath || WORKER_PATH);
+    worker.postMessage({
+      command: 'init',
+      config: {
+        sampleRate: this.context.sampleRate
+      }
+    });
+    var recording = false,
+      currCallback;
+
+    var self = this;
+    this.node.onaudioprocess = function(e){
+      if (!recording) return;
+      self.ondata && self.ondata(e.inputBuffer.getChannelData(0));
+      worker.postMessage({
+        command: 'record',
+        buffer: [
+          e.inputBuffer.getChannelData(0),
+          e.inputBuffer.getChannelData(1)
+        ]
+      });
+    }
+
+    this.configure = function(cfg){
+      for (var prop in cfg){
+        if (cfg.hasOwnProperty(prop)){
+          config[prop] = cfg[prop];
+        }
+      }
+    }
+
+    this.record = function(){
+      recording = true;
+    }
+
+    this.stop = function(){
+      recording = false;
+    }
+
+    this.clear = function(){
+      worker.postMessage({ command: 'clear' });
+    }
+
+    this.getBuffer = function(cb) {
+      currCallback = cb || config.callback;
+      worker.postMessage({ command: 'getBuffer' })
+    }
+
+    this.exportWAV = function(cb, type){
+      currCallback = cb || config.callback;
+      type = type || config.type || 'audio/wav';
+      if (!currCallback) throw new Error('Callback not set');
+      worker.postMessage({
+        command: 'exportWAV',
+        type: type
+      });
+    }
+
+    this.shutdown = function(){
+      worker.terminate();
+      source.disconnect();
+      this.node.disconnect();
+    };
+
+    worker.onmessage = function(e){
+      var blob = e.data;
+      currCallback(blob);
+    }
+
+    source.connect(this.node);
+    this.node.connect(this.context.destination);    //this should not be necessary
+  };
+
+  Recorder.forceDownload = function(blob, filename){
+    var url = (window.URL || window.webkitURL).createObjectURL(blob);
+    var link = window.document.createElement('a');
+    link.href = url;
+    link.download = filename || 'output.wav';
+    var click = document.createEvent("Event");
+    click.initEvent("click", true, true);
+    link.dispatchEvent(click);
+  }
+
+  window.Recorder = Recorder;
+
+})(window);

components/recorderjs/recorderWorker.js

@@ -0,0 +1,131 @@
+var recLength = 0,
+  recBuffersL = [],
+  recBuffersR = [],
+  sampleRate;
+
+this.onmessage = function(e){
+  switch(e.data.command){
+    case 'init':
+      init(e.data.config);
+      break;
+    case 'record':
+      record(e.data.buffer);
+      break;
+    case 'exportWAV':
+      exportWAV(e.data.type);
+      break;
+    case 'getBuffer':
+      getBuffer();
+      break;
+    case 'clear':
+      clear();
+      break;
+  }
+};
+
+function init(config){
+  sampleRate = config.sampleRate;
+}
+
+function record(inputBuffer){
+  recBuffersL.push(inputBuffer[0]);
+  recBuffersR.push(inputBuffer[1]);
+  recLength += inputBuffer[0].length;
+}
+
+function exportWAV(type){
+  var bufferL = mergeBuffers(recBuffersL, recLength);
+  var bufferR = mergeBuffers(recBuffersR, recLength);
+  var interleaved = interleave(bufferL, bufferR);
+  var dataview = encodeWAV(interleaved);
+  var audioBlob = new Blob([dataview], { type: type });
+
+  this.postMessage(audioBlob);
+}
+
+function getBuffer() {
+  var buffers = [];
+  buffers.push( mergeBuffers(recBuffersL, recLength) );
+  buffers.push( mergeBuffers(recBuffersR, recLength) );
+  this.postMessage(buffers);
+}
+
+function clear(){
+  recLength = 0;
+  recBuffersL = [];
+  recBuffersR = [];
+}
+
+function mergeBuffers(recBuffers, recLength){
+  var result = new Float32Array(recLength);
+  var offset = 0;
+  for (var i = 0; i < recBuffers.length; i++){
+    result.set(recBuffers[i], offset);
+    offset += recBuffers[i].length;
+  }
+  return result;
+}
+
+function interleave(inputL, inputR){
+  var length = inputL.length + inputR.length;
+  var result = new Float32Array(length);
+
+  var index = 0,
+    inputIndex = 0;
+
+  while (index < length){
+    result[index++] = inputL[inputIndex];
+    result[index++] = inputR[inputIndex];
+    inputIndex++;
+  }
+  return result;
+}
+
+function floatTo16BitPCM(output, offset, input){
+  for (var i = 0; i < input.length; i++, offset+=2){
+    var s = Math.max(-1, Math.min(1, input[i]));
+    output.setInt16(offset, s < 0 ? s * 0x8000 : s * 0x7FFF, true);
+  }
+}
+
+function writeString(view, offset, string){
+  for (var i = 0; i < string.length; i++){
+    view.setUint8(offset + i, string.charCodeAt(i));
+  }
+}
+
+function encodeWAV(samples){
+  var buffer = new ArrayBuffer(44 + samples.length * 2);
+  var view = new DataView(buffer);
+
+  /* RIFF identifier */
+  writeString(view, 0, 'RIFF');
+  /* RIFF chunk length */
+  view.setUint32(4, 36 + samples.length * 2, true);
+  /* RIFF type */
+  writeString(view, 8, 'WAVE');
+  /* format chunk identifier */
+  writeString(view, 12, 'fmt ');
+  /* format chunk length */
+  view.setUint32(16, 16, true);
+  /* sample format (raw) */
+  view.setUint16(20, 1, true);
+  /* channel count */
+  view.setUint16(22, 2, true);
+  /* sample rate */
+  view.setUint32(24, sampleRate, true);
+  /* byte rate (sample rate * block align) */
+  view.setUint32(28, sampleRate * 4, true);
+  /* block align (channel count * bytes per sample) */
+  view.setUint16(32, 4, true);
+  /* bits per sample */
+  view.setUint16(34, 16, true);
+  /* data chunk identifier */
+  writeString(view, 36, 'data');
+  /* data chunk length */
+  view.setUint32(40, samples.length * 2, true);
+
+  floatTo16BitPCM(view, 44, samples);
+
+  return view;
+}