added changes on checking similarity

static/js/recorder.js

@@ -34,8 +34,12 @@
           throw new TypeError("Cannot call a class as a function");
       }
   }
+
+  
   
   var Recorder = exports.Recorder = (function () {
+
+
       function Recorder(source, cfg) {
           var _this = this;
   
@@ -88,7 +92,8 @@
                           record(e.data.buffer);
                           break;
                       case 'exportWAV':
-                          exportWAV(e.data.type);
+                          console.log(e.currentTarget.sampleRate);
+                          exportWAV(e.data.type,e.currentTarget.sampleRate);
                           break;
                       case 'getBuffer':
                           getBuffer();
@@ -111,8 +116,34 @@
                   }
                   recLength += inputBuffer[0].length;
               }
+
+              function downsampleBuffer(buffer, rate) {
+                if (rate == sampleRate) {
+                    return buffer;
+                }
+                if (rate > sampleRate) {
+                    throw "downsampling rate show be smaller than original sample rate";
+                }
+                var sampleRateRatio = sampleRate / rate;
+                var newLength = Math.round(buffer.length / sampleRateRatio);
+                var result = new Float32Array(newLength);
+                var offsetResult = 0;
+                var offsetBuffer = 0;
+                while (offsetResult < result.length) {
+                    var nextOffsetBuffer = Math.round((offsetResult + 1) * sampleRateRatio);
+                    var accum = 0, count = 0;
+                    for (var i = offsetBuffer; i < nextOffsetBuffer && i < buffer.length; i++) {
+                        accum += buffer[i];
+                        count++;
+                    }
+                    result[offsetResult] = accum / count;
+                    offsetResult++;
+                    offsetBuffer = nextOffsetBuffer;
+                }
+                return result;
+            }
   
-              function exportWAV(type) {
+              function exportWAV(type,sampleRate) {
                   var buffers = [];
                   for (var channel = 0; channel < numChannels; channel++) {
                       buffers.push(mergeBuffers(recBuffers[channel], recLength));
@@ -123,7 +154,11 @@
                   } else {
                       interleaved = buffers[0];
                   }
-                  var dataview = encodeWAV(interleaved);
+
+                  var downsampledBuffer = downsampleBuffer(interleaved, sampleRate);
+                var dataview = encodeWAV(downsampledBuffer);
+                  /* var dataview = encodeWAV(interleaved); */
+                  
                   var audioBlob = new Blob([dataview], { type: type });
   
                   self.postMessage({ command: 'exportWAV', data: audioBlob });
@@ -172,6 +207,10 @@
                       inputIndex++;
                   }
                   return result;
+                    /* var result = new Float32Array(inputL.length); */
+                    /* for (var i = 0; i < inputL.length; ++i) */
+                        /* result[i] = 0.5 * (inputL[i] + inputR[i]); */
+                    /* return result; */
               }
   
               function floatTo16BitPCM(output, offset, input) {