Merge pull request #7985 from ZappoMan/addAudioLimiter

add audio peak limiter to audio mixer

assignment-client/src/audio/AudioMixer.cpp

@@ -339,21 +339,18 @@ bool AudioMixer::prepareMixForListeningNode(Node* node) {
         }
     });
 
-    int nonZeroSamples = 0;
+    // use the per listner AudioLimiter to render the mixed data...
+    listenerNodeData->audioLimiter.render(_mixedSamples, _clampedSamples, AudioConstants::NETWORK_FRAME_SAMPLES_PER_CHANNEL);
 
-    // enumerate the mixed samples and clamp any samples outside the min/max
-    // also check if we ended up with a silent frame
+    // check for silent audio after the peak limitor has converted the samples
+    bool hasAudio = false;
     for (int i = 0; i < AudioConstants::NETWORK_FRAME_SAMPLES_STEREO; ++i) {
-
-        _clampedSamples[i] = int16_t(glm::clamp(int(_mixedSamples[i] * AudioConstants::MAX_SAMPLE_VALUE),
-                                                AudioConstants::MIN_SAMPLE_VALUE,
-                                                AudioConstants::MAX_SAMPLE_VALUE));
-        if (_clampedSamples[i] != 0.0f) {
-            ++nonZeroSamples;
+        if (_clampedSamples[i] != 0) {
+            hasAudio = true;
+            break;
         }
     }
-
-    return (nonZeroSamples > 0);
+    return hasAudio;
 }
 
 void AudioMixer::sendAudioEnvironmentPacket(SharedNodePointer node) {

assignment-client/src/audio/AudioMixerClientData.cpp

@@ -25,6 +25,7 @@
 
 AudioMixerClientData::AudioMixerClientData(const QUuid& nodeID) :
     NodeData(nodeID),
+    audioLimiter(AudioConstants::SAMPLE_RATE, AudioConstants::STEREO),
     _outgoingMixedAudioSequenceNumber(0),
     _downstreamAudioStreamStats()
 {

assignment-client/src/audio/AudioMixerClientData.h

@@ -16,11 +16,13 @@
 
 #include <AABox.h>
 #include <AudioHRTF.h>
+#include <AudioLimiter.h>
 #include <UUIDHasher.h>
 
 #include "PositionalAudioStream.h"
 #include "AvatarAudioStream.h"
 
+
 class AudioMixerClientData : public NodeData {
     Q_OBJECT
 public:
@@ -61,6 +63,8 @@ public:
     // uses randomization to have the AudioMixer send a stats packet to this node around every second
     bool shouldSendStats(int frameNumber);
 
+    AudioLimiter audioLimiter;
+
 signals:
     void injectorStreamFinished(const QUuid& streamIdentifier);
 

libraries/audio/src/AudioConstants.h

@@ -18,6 +18,9 @@
 
 namespace AudioConstants {
     const int SAMPLE_RATE = 24000;
+    const int MONO = 1;
+    const int STEREO = 2;
+
 
     typedef int16_t AudioSample;
 

script-archive/tests/audio/testPeakLimiter.js

@@ -0,0 +1,19 @@
+var audioOptions = {
+  volume: 1.0,
+  loop: true,
+  position: MyAvatar.position
+}
+
+//var sineWave = Script.resolvePath("./1760sine.wav"); // use relative file
+var sineWave = "https://s3-us-west-1.amazonaws.com/highfidelity-dev/1760sine.wav"; // use file from S3
+var sound = SoundCache.getSound(sineWave);
+var injectorCount = 0;
+var MAX_INJECTOR_COUNT = 40;
+
+Script.update.connect(function() {
+    if (sound.downloaded && injectorCount < MAX_INJECTOR_COUNT) {
+        injectorCount++;
+        print("stating injector:" + injectorCount);
+        Audio.playSound(sound, audioOptions);
+    }
+});