User:Corban/AudioAPI: Difference between revisions

User:Corban/AudioAPI (view source)

19 bytes removed , 26 February 2010

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@@ Line 70: / Line 70: @@
    <body>
      <script>
-     var spectrum = [];
+     var spectrum;
-     var signal = [];
+     var signal;
      var peak = [];
@@ Line 77: / Line 77: @@
        signal   = event.mozFrameBuffer;
        spectrum = event.mozSpectrum;
+       var speclen = spectrum.length;
        // calculate spectrum from complex values
-       for ( var i = 0; i < spectrum.length; i++ ) {
+       for ( var i = 0; i < speclen; i++ ) {
-	var j = i + 0.02 * spectrum.length;
+	var j = i + 0.02 * speclen;
-	var log = Math.log(j/spectrum.length * (spectrum.length - j)) * Math.sqrt(j/spectrum.length);
+	var log = Math.log(j/speclen * (speclen - j)) * Math.sqrt(j/speclen);
          var magnitude = spectrum.item(i) * 2048 * log * 2;
          if ( typeof(peak[i]) == 'undefined' || peak[i] < magnitude ) {