Smooth local mic meter

public/app.js

@@ -53,6 +53,7 @@ let localMicGainNode;
 let localMicAnalyserNode;
 let localMicDestination;
 let micMeterAnimationFrame = 0;
+let micMeterLevel = 0;
 let screenStream;
 let localPresentationTile;
 let events;
@@ -757,6 +758,7 @@ function stopMicMeter() {
     cancelAnimationFrame(micMeterAnimationFrame);
     micMeterAnimationFrame = 0;
   }
+  micMeterLevel = 0;
   selfMicMeter.value = 0;
 }
 
@@ -772,7 +774,10 @@ function startMicMeter() {
       const centered = (sample - 128) / 128;
       sum += centered * centered;
     }
-    selfMicMeter.value = Math.min(1, Math.sqrt(sum / samples.length) * 3);
+    const targetLevel = Math.min(1, Math.sqrt(sum / samples.length) * 3);
+    const smoothing = targetLevel > micMeterLevel ? 0.35 : 0.12;
+    micMeterLevel += (targetLevel - micMeterLevel) * smoothing;
+    selfMicMeter.value = micMeterLevel;
     micMeterAnimationFrame = requestAnimationFrame(tick);
   };
   tick();