Recording bug that makes other people too quiet fixed.

diskwriter/diskwriter.go

@@ -33,6 +33,7 @@ const (
 	sourceBufferSize  = 16
 	encoderBufferSize = 50
 	sourceStaleAfter  = 2 * time.Second
+	activeSampleLevel = 512
 	limiterThreshold  = 28000
 	limiterRatio      = 4
 )
@@ -494,19 +495,28 @@ func mixPCMFrames(frames [][]byte) []byte {
 	}
 
 	var mixed []int32
-	gain := 1.0
-	if len(frames) > 1 {
-		gain = 1 / math.Sqrt(float64(len(frames)))
-	}
+	activeFrames := 0
 
 	for _, frame := range frames {
 		if mixed == nil {
 			mixed = make([]int32, samplesPerFrame*channels)
 		}
+		active := false
 		for i := range mixed {
 			sample := int16(binary.LittleEndian.Uint16(frame[i*2:]))
+			if !active && abs16(sample) >= activeSampleLevel {
+				active = true
+			}
 			mixed[i] += int32(sample)
 		}
+		if active {
+			activeFrames++
+		}
+	}
+
+	gain := 1.0
+	if activeFrames > 1 {
+		gain = 1 / math.Sqrt(float64(activeFrames))
 	}
 
 	out := make([]byte, bytesPerFrame)
@@ -518,6 +528,13 @@ func mixPCMFrames(frames [][]byte) []byte {
 	return out
 }
 
+func abs16(sample int16) int16 {
+	if sample < 0 {
+		return -sample
+	}
+	return sample
+}
+
 func limitSample(sample int32) int32 {
 	if sample > limiterThreshold {
 		sample = limiterThreshold + (sample-limiterThreshold)/limiterRatio

diskwriter/diskwriter_test.go

@@ -153,6 +153,23 @@ func TestMixFrameHandlesQuietAndLoudSources(t *testing.T) {
 	}
 }
 
+func TestMixFrameDoesNotAttenuateSpeakerForSilentOpenMics(t *testing.T) {
+	speaker := make(chan []byte, 1)
+	silent1 := make(chan []byte, 1)
+	silent2 := make(chan []byte, 1)
+	speaker <- pcmFrame(12000)
+	silent1 <- pcmFrame(0)
+	silent2 <- pcmFrame(0)
+
+	out := mixFrame([]chan []byte{speaker, silent1, silent2})
+	for i := 0; i < len(out); i += 2 {
+		got := int16(binary.LittleEndian.Uint16(out[i:]))
+		if got != 12000 {
+			t.Fatalf("sample %d = %d, expected unattenuated speaker 12000", i/2, got)
+		}
+	}
+}
+
 func TestMixFrameLimiterBoundsOverloadedSamples(t *testing.T) {
 	a := make(chan []byte, 1)
 	b := make(chan []byte, 1)

distro-packages/Arch-Linux/skald-git/PKGBUILD

@@ -2,7 +2,7 @@
 # shellcheck shell=bash disable=SC2034,SC2154
 
 pkgname=skald-git
-pkgver=0.0.0.r1532.g3e06de7
+pkgver=0.0.0.r1533.g3df0c22
 pkgrel=1
 pkgdesc='Audio-only hall-based conferencing server'
 arch=('x86_64' 'aarch64')