nicer volume sliders

source/core/StarAudio.cpp

@@ -13,6 +13,26 @@
 
 namespace Star {
 
+float const DefaultPerceptualRangeDb = 40.f;
+float const DefaultPerceptualBoostRangeDb = 6.f;
+// https://github.com/discord/perceptual
+float perceptualToAmplitude(float perceptual, float normalizedMax, float range, float boostRange) {
+  if (perceptual == 0.f) return 0.f;
+  float dB = perceptual > normalizedMax
+    ? ((perceptual - normalizedMax) / normalizedMax) * boostRange
+    : (perceptual / normalizedMax) * range - range;
+  return normalizedMax * pow(10.f, dB / 20.f);
+}
+
+float amplitudeToPerceptual(float amp, float normalizedMax, float range, float boostRange) {
+  if (amp == 0.f) return 0.f;
+  float const dB = 20.f * log10(amp / normalizedMax);
+  float perceptual = dB > 0.f
+    ? dB / boostRange + 1
+    : (range + dB) / range;
+  return normalizedMax * perceptual;
+}
+
 namespace {
   struct WaveData {
     ByteArrayPtr byteArray;

source/core/StarAudio.hpp

@@ -4,6 +4,15 @@
 
 namespace Star {
 
+extern float const DefaultPerceptualRangeDb;
+extern float const DefaultPerceptualBoostRangeDb;
+
+float perceptualToAmplitude(float perceptual, float normalizedMax = 1.f,
+  float range = DefaultPerceptualRangeDb, float boostRange = DefaultPerceptualBoostRangeDb);
+
+float amplitudeToPerceptual(float amp, float normalizedMax = 1.f,
+  float range = DefaultPerceptualRangeDb, float boostRange = DefaultPerceptualBoostRangeDb);
+
 STAR_CLASS(CompressedAudioImpl);
 STAR_CLASS(UncompressedAudioImpl);
 STAR_CLASS(Audio);

source/frontend/StarMainMixer.cpp

@@ -37,6 +37,7 @@ void MainMixer::update(float dt, bool muteSfx, bool muteMusic) {
         }
       } else if (!m_mutedGroups.contains(group)) {
         float volumeSetting = Root::singleton().configuration()->get(settingName).toFloat() / 100.0f;
+        volumeSetting = perceptualToAmplitude(volumeSetting);
         if (!m_groupVolumes.contains(group) || volumeSetting != m_groupVolumes[group]) {
           m_mixer->setGroupVolume(group, volumeSetting);
           m_groupVolumes[group] = volumeSetting;

source/frontend/StarVoice.cpp

@@ -6,6 +6,7 @@
 #include "StarRoot.hpp"
 #include "StarLogging.hpp"
 #include "StarInterpolation.hpp"
+#include "StarAudio.hpp"
 #include "opus/opus.h"
 
 #include "SDL2/SDL.h"
@@ -197,8 +198,10 @@ void Voice::loadJson(Json const& config, bool skipSave) {
 		resetDevice();
 
   m_threshold = config.getFloat("threshold", m_threshold);
-  m_inputVolume  = config.getFloat("inputVolume", m_inputVolume);
-  m_outputVolume = config.getFloat("outputVolume",   m_outputVolume);
+  m_inputAmplitude = perceptualToAmplitude(
+		m_inputVolume = config.getFloat("inputVolume", m_inputVolume));
+  m_outputAmplitude = perceptualToAmplitude(
+		m_outputVolume = config.getFloat("outputVolume", m_outputVolume));
 	
 	if (change(m_loopback, config.getBool("loopback", m_loopback), changed))
 		m_clientSpeaker->playing = false;
@@ -321,7 +324,7 @@ void Voice::readAudioData(uint8_t* stream, int len) {
 		}
 	}
 
-	m_clientSpeaker->decibelLevel = getAudioLoudness((int16_t*)stream, sampleCount, m_inputVolume);
+	m_clientSpeaker->decibelLevel = getAudioLoudness((int16_t*)stream, sampleCount, m_inputAmplitude);
 
 	if (!m_loopback) {
 		if (active && !m_clientSpeaker->playing)
@@ -411,7 +414,7 @@ void Voice::mix(int16_t* buffer, size_t frameCount, unsigned channels) {
 	if (mix) {
 		finalBuffer.resize(sharedBuffer.size(), 0);
 
-		float vol = m_outputVolume;
+		float vol = m_outputAmplitude;
 		for (size_t i = 0; i != sharedBuffer.size(); ++i)
 			finalBuffer[i] = (int16_t)clamp<int>(sharedBuffer[i] * vol, INT16_MIN, INT16_MAX);
 
@@ -678,9 +681,9 @@ void Voice::thread() {
 				}
 				m_capturedChunksFrames -= VOICE_FRAME_SIZE;
 
-				if (m_inputVolume != 1.0f) {
+				if (m_inputAmplitude != 1.0f) {
 					for (size_t i = 0; i != samples.size(); ++i)
-						samples[i] *= m_inputVolume;
+						samples[i] *= m_inputAmplitude;
 				}
 
 				if (int encodedSize = opus_encode(m_encoder.get(), samples.data(), VOICE_FRAME_SIZE, (unsigned char*)encoded.ptr(), encoded.size())) {

source/frontend/StarVoice.hpp

@@ -176,6 +176,10 @@ private:
   
   float m_outputVolume = 1.0f;
   float m_inputVolume = 1.0f;
+
+  float m_outputAmplitude = 1.0f;
+  float m_inputAmplitude = 1.0f;
+
   float m_threshold = -50.0f;
   
   int64_t m_lastSentTime = 0;