Updating License and README to reflect Vail Systems.

LICENSE

@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) 2015 Joshua Jung
+Copyright (c) 2015 Vail Systems (Chicago, IL)
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.md

@@ -1,2 +1,24 @@
 # node-mfcc
-Node.JS implementation of the MFCC algorithm
+Node.JS implementation of the MFCC algorithm.
+
+The MIT License (MIT)
+
+Copyright (c) 2015 Vail Systems
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

mfcc.js

@@ -48,7 +48,10 @@ for (var i = 0; i < fftBins; i++) bins[i] = [];
 
 var wr = new wav.Reader(),
     filterBank = mfcc.constructFilterBank(fftBins, nMelSpecBins, minFreq, maxFreq, sampleRate),
-    dct = new mfcc.DCT();
+    dct = new mfcc.DCT({
+        lifter: undefined, 
+        numCoefficients: 12
+    });
 
 wr.on('data', function (buffer, offset, length) {
     framer.frame(buffer, function (frame) {

src/mfcc.js

@@ -8,26 +8,25 @@
 \*===========================================================================*/
 var DCT = function (options) {
     this.cosMap = null,
-    this.options = options || {
-        numMfccBins: 12
-    };
+    this.options = options || {};
 
+    this.options.numCoefficients = this.options.numCoefficients || 12;
     this.options.lifter = this.options.lifter || this.lifterLinear;
 };
 
 DCT.prototype = {
     lifterLinear: function (scalar, ix) {
-      return scalar * ix;
+      return scalar * (ix+1);
     },
     // Builds a cosine map for the given block size. This allows multiple block sizes to be
     // memoized automagically.
-    memoizeCosines: function(blockSize) {
+    memoizeCosines: function(melSpecBins) {
       DCT.cosMap = DCT.cosMap || {};
-      DCT.cosMap[blockSize] = new Array(blockSize * 12);
+      DCT.cosMap[melSpecBins] = new Array(melSpecBins* 12);
 
       for (var i = 0; i < 12; i++) {
-        for (var m = 0; m < blockSize; m++) {
-          DCT.cosMap[blockSize][m + (i * blockSize)] = Math.cos(Math.PI * (i / blockSize) * (m + 0.5));
+        for (var melBin = 0; melBin < melSpecBins; melBin++) {
+          DCT.cosMap[melSpecBins][melBin + (i * melSpecBins)] = Math.cos(Math.PI * ((i+1) / melSpecBins) * (melBin + 0.5));
         }
       }
     },
@@ -41,10 +40,10 @@ DCT.prototype = {
       // n: number of MFCC bins
       // m: number of Spectrum bins
       // Usually n == 12 and 20 <= m <= 40
-      var bins = [];
-      while (bins.length < this.options.numMfccBins) bins.push(0);
+      var coefficients = [];
+      while (coefficients.length < this.options.numCoefficients) coefficients.push(0);
 
-      return bins.map(function (bin, ix) {
+      return coefficients.map(function (__, ix) {
         var scalar = spectrum.reduce(function (prev, cur, ix_, arr) {
           return prev + (cur * DCT.cosMap[L][ix_ + (ix * L)]);
         });