Waveform updates, RMS and midpoint only

audiogram/waveform.js

       perPoint = Math.floor(perFrame / samplesPerFrame),
       range = d3.range(samplesPerFrame),
       maxFrame,
-      maxMedian = max = 0;
+      maxRms = maxMid = 0;
 
   var unadjusted = d3.range(numFrames).map(function(frame){
 
     var frameSamples = samples.slice(frame * perFrame, (frame + 1) * perFrame),
         points = range.map(function(point){
 
-          var pointSamples = frameSamples.slice(point * perPoint, (point + 1) * perPoint);
+          var pointSamples = frameSamples.slice(point * perPoint, (point + 1) * perPoint),
+              midpoint = pointSamples[Math.floor(pointSamples.length / 2)];
 
           var rms = Math.sqrt(d3.sum(pointSamples.map(function(d){
             return d * d;
           })) / perPoint);
 
-          if (rms > max) {
-            max = rms;
+          if (rms > maxRms) {
+            maxRms = rms;
+            maxFrame = frame;
+          }
+
+          if (Math.abs(midpoint) > maxMid) {
+            maxMid = Math.abs(midpoint);
           }
 
           // Min value, max value, and midpoint value
-          return [-rms, rms, pointSamples[Math.floor(pointSamples.length / 2)]];
+          return [rms, midpoint];
 
-        }),
-        median = d3.median(points.map(function(point){
-          return point[1];
-        }));
-
-    if (median > maxMedian) {
-      maxMedian = median;
-      maxFrame = frame;
-    }
+        });
 
     return points;
 
   });
 
-  // Scale up to -1 / 1
-  var adjustment = 1 / max;
-
   var adjusted = unadjusted.map(function(frame){
     return frame.map(function(point){
-      return point.map(function(p){ return adjustment * p; });
+      return [
+        point[0] / maxRms,
+        point[1] / maxMid
+      ];
     });
   });
 

renderer/patterns.js

 
     var top = data.map(function(d,i){
 
-      return [x(i), baseline - height(d[1])];
+      return [x(i), baseline - height(d[0])];
 
     });
 
     var bottom = data.map(function(d,i){
 
-      return [x(i), baseline + height(-d[0])];
+      return [x(i), baseline + height(d[0])];
 
     }).reverse();
 
 
     data.forEach(function(val, i){
 
-      var h = height(-val[0]) + height(val[1]),
+      var h = height(val[0]) * 2,
           x = barX(i),
-          y = baseline - height(val[1]);
+          y = baseline - height(val[0]);
 
       context.fillRect(x, y, barWidth, h);
 
 
     data.forEach(function(val, i){
 
-      var bricks = Math.max(1, Math.floor(height(val[1]) / (brickHeight + brickGap))),
+      var bricks = Math.max(1, Math.floor(height(val[0]) / (brickHeight + brickGap))),
           x = barX(i);
 
       d3.range(bricks).forEach(function(b){

test/frame-test.js

 
 var waveform = [
   [
-    [0, 0], [-1, 1], [0, 0]
+    [0, 0], [1, 1], [0, 0]
   ],
   [
-    [-1, 1], [-0.1, 0.1], [-1, 1]
+    [1, 1], [0.1, 0.1], [1, 1]
   ]
 ];
 

test/waveform-test.js

 
       test.assert(waveform.every(function(frame){
         return frame.length === options.samplesPerFrame && frame.every(function(f){
-          return f.length === 3 && f.every(function(d){ return typeof d === "number"; }) && f[0] <= 0 && f[0] >= -1 && f[1] >= 0 && f[1] <= 1 && f[2] >= -1 && f[2] <= 1;
+          return f.length === 2 && f.every(function(d){ return typeof d === "number"; }) && f[0] >= 0 && f[0] <= 1 && f[1] >= -1 && f[1] <= 1;
         });
       }));