Add Audio Noise Reduction

interface/src/Audio.cpp

@@ -65,6 +65,10 @@ Audio::Audio(Oscilloscope* scope, int16_t initialJitterBufferSamples, QObject* p
     _measuredJitter(0),
     _jitterBufferSamples(initialJitterBufferSamples),
     _lastInputLoudness(0),
+    _averageInputLoudness(0),
+    _noiseGateOpen(false),
+    _noiseGateEnabled(true),
+    _noiseGateFramesToClose(0),
     _lastVelocity(0),
     _lastAcceleration(0),
     _totalPacketsReceived(0),
@@ -348,12 +352,40 @@ void Audio::handleAudioInput() {
                              _inputFormat, _desiredInputFormat);
 
             float loudness = 0;
-
+            float thisSample = 0;
+            int samplesOverNoiseGate = 0;
+            
+            const float NOISE_GATE_HEIGHT = 3.f;
+            const int NOISE_GATE_WIDTH = 5;
+            const int NOISE_GATE_CLOSE_FRAME_DELAY = 30;
+            
             for (int i = 0; i < NETWORK_BUFFER_LENGTH_SAMPLES_PER_CHANNEL; i++) {
-                loudness += fabsf(monoAudioSamples[i]);
+                thisSample = fabsf(monoAudioSamples[i]);
+                loudness += thisSample;
+                //  Noise Reduction:  Count peaks above the average loudness
+                if (thisSample > (_averageInputLoudness * NOISE_GATE_HEIGHT)) {
+                    samplesOverNoiseGate++;
+                }
             }
-
             _lastInputLoudness = loudness / NETWORK_BUFFER_LENGTH_SAMPLES_PER_CHANNEL;
+            const float LOUDNESS_AVERAGING_FRAMES = 1000.f;   //  This will be about 10 seconds
+            _averageInputLoudness = (1.f - 1.f / LOUDNESS_AVERAGING_FRAMES) * _averageInputLoudness + (1.f / LOUDNESS_AVERAGING_FRAMES) * _lastInputLoudness;
+            
+            if (_noiseGateEnabled) {
+                if (samplesOverNoiseGate > NOISE_GATE_WIDTH) {
+                    _noiseGateOpen = true;
+                    _noiseGateFramesToClose = NOISE_GATE_CLOSE_FRAME_DELAY;
+                } else {
+                    if (--_noiseGateFramesToClose == 0) {
+                        _noiseGateOpen = false;
+                    }
+                }
+                if (!_noiseGateOpen) {
+                    for (int i = 0; i < NETWORK_BUFFER_LENGTH_SAMPLES_PER_CHANNEL; i++) {
+                        monoAudioSamples[i] = 0;
+                    }
+                }
+            }
 
             // add input data just written to the scope
             QMetaObject::invokeMethod(_scope, "addSamples", Qt::QueuedConnection,
@@ -524,6 +556,10 @@ void Audio::toggleMute() {
     muteToggled();
 }
 
+void Audio::toggleAudioNoiseReduction() {
+    _noiseGateEnabled = !_noiseGateEnabled;
+}
+
 void Audio::render(int screenWidth, int screenHeight) {
     if (_audioInput && _audioOutput) {
         glLineWidth(2.0);

interface/src/Audio.h

@@ -45,7 +45,9 @@ public:
     
     void render(int screenWidth, int screenHeight);
     
-    float getLastInputLoudness() const { return _lastInputLoudness; }
+    float getLastInputLoudness() const { return glm::max(_lastInputLoudness - _averageInputLoudness, 0.f); }
+    
+    void setNoiseGateEnabled(bool noiseGateEnabled) { _noiseGateEnabled = noiseGateEnabled; }
     
     void setLastAcceleration(const glm::vec3 lastAcceleration) { _lastAcceleration = lastAcceleration; }
     void setLastVelocity(const glm::vec3 lastVelocity) { _lastVelocity = lastVelocity; }
@@ -73,6 +75,7 @@ public slots:
     void handleAudioInput();
     void reset();
     void toggleMute();
+    void toggleAudioNoiseReduction();
     
     virtual void handleAudioByteArray(const QByteArray& audioByteArray);
 
@@ -106,6 +109,10 @@ private:
     float _measuredJitter;
     int16_t _jitterBufferSamples;
     float _lastInputLoudness;
+    float _averageInputLoudness;
+    bool _noiseGateOpen;
+    bool _noiseGateEnabled;
+    int _noiseGateFramesToClose;
     glm::vec3 _lastVelocity;
     glm::vec3 _lastAcceleration;
     int _totalPacketsReceived;

interface/src/Menu.cpp

@@ -457,6 +457,11 @@ Menu::Menu() :
     addCheckableActionToQMenuAndActionHash(renderDebugMenu, MenuOption::CoverageMapV2, Qt::SHIFT | Qt::CTRL | Qt::Key_P);
 
     QMenu* audioDebugMenu = developerMenu->addMenu("Audio Debugging Tools");
+    addCheckableActionToQMenuAndActionHash(audioDebugMenu, MenuOption::AudioNoiseReduction,
+                                           0,
+                                           true,
+                                           appInstance->getAudio(),
+                                           SLOT(toggleAudioNoiseReduction()));
     addCheckableActionToQMenuAndActionHash(audioDebugMenu, MenuOption::EchoServerAudio);
     addCheckableActionToQMenuAndActionHash(audioDebugMenu, MenuOption::EchoLocalAudio);
     addCheckableActionToQMenuAndActionHash(audioDebugMenu, MenuOption::MuteAudio,

interface/src/Menu.h

@@ -187,6 +187,7 @@ namespace MenuOption {
     const QString Enable3DTVMode = "Enable 3DTV Mode";
     const QString EnableOcclusionCulling = "Enable Occlusion Culling";
     const QString EnableVoxelPacketCompression = "Enable Voxel Packet Compression";
+    const QString AudioNoiseReduction = "Audio Noise Reduction";
     const QString EchoServerAudio = "Echo Server Audio";
     const QString EchoLocalAudio = "Echo Local Audio";
     const QString MuteAudio = "Mute Microphone";

libraries/avatars/src/AvatarData.cpp

@@ -107,7 +107,6 @@ QByteArray AvatarData::toByteArray() {
     destinationBuffer += sizeof(_headData->_lookAtPosition);
      
     // Instantaneous audio loudness (used to drive facial animation)
-    //destinationBuffer += packFloatToByte(destinationBuffer, std::min(MAX_AUDIO_LOUDNESS, _audioLoudness), MAX_AUDIO_LOUDNESS);
     memcpy(destinationBuffer, &_headData->_audioLoudness, sizeof(float));
     destinationBuffer += sizeof(float);
 
@@ -215,7 +214,6 @@ int AvatarData::parseData(const QByteArray& packet) {
     sourceBuffer += sizeof(_headData->_lookAtPosition);
     
     // Instantaneous audio loudness (used to drive facial animation)
-    //sourceBuffer += unpackFloatFromByte(sourceBuffer, _audioLoudness, MAX_AUDIO_LOUDNESS);
     memcpy(&_headData->_audioLoudness, sourceBuffer, sizeof(float));
     sourceBuffer += sizeof(float);