Improve microphone level sensitivity using logarithmic (dB) scaling

pkg/audio/level.go

@@ -4,7 +4,7 @@ import (
 	"math"
 )
 
-// CalculateRMSLevel calculates the RMS level of PCM samples and returns 0-100
+// CalculateRMSLevel calculates the RMS level of PCM samples and returns 0-100 (Logarithmic/dB)
 func CalculateRMSLevel(samples []int16) int {
 	if len(samples) == 0 {
 		return 0
@@ -16,15 +16,33 @@ func CalculateRMSLevel(samples []int16) int {
 	}
 
 	rms := math.Sqrt(sum / float64(len(samples)))
-	// Normalize to 0-100 (max int16 is 32767)
-	level := int(rms / 32767.0 * 100.0)
+
+	// Normalize to 0.0 - 1.0
+	val := rms / 32768.0
+	if val < 0.000001 { // Avoid log(0)
+		return 0
+	}
+
+	// Convert to dB
+	db := 20 * math.Log10(val)
+
+	// Map -50dB (silence floor) to 0dB (max) to 0-100
+	const minDB = -50.0
+
+	if db < minDB {
+		return 0
+	}
+
+	// Scale
+	level := int((db - minDB) * (100.0 / (0 - minDB)))
+
 	if level > 100 {
 		level = 100
 	}
 	return level
 }
 
-// CalculatePeakLevel returns the peak level of PCM samples as 0-100
+// CalculatePeakLevel returns the peak level of PCM samples as 0-100 (Logarithmic/dB)
 func CalculatePeakLevel(samples []int16) int {
 	if len(samples) == 0 {
 		return 0
@@ -40,7 +58,26 @@ func CalculatePeakLevel(samples []int16) int {
 		}
 	}
 
-	return int(float64(peak) / 32767.0 * 100.0)
+	// Normalize
+	val := float64(peak) / 32768.0
+	if val < 0.000001 {
+		return 0
+	}
+
+	db := 20 * math.Log10(val)
+	const minDB = -50.0
+
+	if db < minDB {
+		// Linear falloff for very low signals to avoid clutter
+		return 0
+	}
+
+	level := int((db - minDB) * (100.0 / (0 - minDB)))
+	if level > 100 {
+		level = 100
+	}
+
+	return level
 }
 
 // LevelToBar converts a 0-100 level to a visual bar string