diff --git a/libraries/audio/src/AudioNoiseGate.cpp b/libraries/audio/src/AudioNoiseGate.cpp
deleted file mode 100644
index 604897af8a..0000000000
--- a/libraries/audio/src/AudioNoiseGate.cpp
+++ /dev/null
@@ -1,164 +0,0 @@
-//
-// AudioNoiseGate.cpp
-// libraries/audio
-//
-// Created by Stephen Birarda on 2014-12-16.
-// Copyright 2014 High Fidelity, Inc.
-//
-// Distributed under the Apache License, Version 2.0.
-// See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
-//
-
-#include "AudioNoiseGate.h"
-
-#include <cstdlib>
-#include <string.h>
-
-#include "AudioConstants.h"
-
-const float AudioNoiseGate::CLIPPING_THRESHOLD = 0.90f;
-
-AudioNoiseGate::AudioNoiseGate() :
- _lastLoudness(0.0f),
- _didClipInLastBlock(false),
- _dcOffset(0.0f),
- _measuredFloor(0.0f),
- _sampleCounter(0),
- _isOpen(false),
- _blocksToClose(0) {}
-
-void AudioNoiseGate::removeDCOffset(int16_t* samples, int numSamples) {
- //
- // DC Offset correction
- //
- // Measure the DC offset over a trailing number of blocks, and remove it from the input signal.
- // This causes the noise background measurements and server muting to be more accurate. Many off-board
- // ADC's have a noticeable DC offset.
- //
- const float DC_OFFSET_AVERAGING = 0.99f;
- float measuredDcOffset = 0.0f;
- // Remove trailing DC offset from samples
- for (int i = 0; i < numSamples; i++) {
- measuredDcOffset += samples[i];
- samples[i] -= (int16_t) _dcOffset;
- }
- // Update measured DC offset
- measuredDcOffset /= numSamples;
- if (_dcOffset == 0.0f) {
- // On first block, copy over measured offset
- _dcOffset = measuredDcOffset;
- } else {
- _dcOffset = DC_OFFSET_AVERAGING * _dcOffset + (1.0f - DC_OFFSET_AVERAGING) * measuredDcOffset;
- }
-}
-
-void AudioNoiseGate::gateSamples(int16_t* samples, int numSamples) {
- //
- // Impose Noise Gate
- //
- // The Noise Gate is used to reject constant background noise by measuring the noise
- // floor observed at the microphone and then opening the 'gate' to allow microphone
- // signals to be transmitted when the microphone samples average level exceeds a multiple
- // of the noise floor.
- //
- // NOISE_GATE_HEIGHT: How loud you have to speak relative to noise background to open the gate.
- // Make this value lower for more sensitivity and less rejection of noise.
- // NOISE_GATE_WIDTH: The number of samples in an audio block for which the height must be exceeded
- // to open the gate.
- // NOISE_GATE_CLOSE_BLOCK_DELAY: Once the noise is below the gate height for the block, how many blocks
- // will we wait before closing the gate.
- // NOISE_GATE_BLOCKS_TO_AVERAGE: How many audio blocks should we average together to compute noise floor.
- // More means better rejection but also can reject continuous things like singing.
- // NUMBER_OF_NOISE_SAMPLE_BLOCKS: How often should we re-evaluate the noise floor?
-
- float loudness = 0;
- int thisSample = 0;
- int samplesOverNoiseGate = 0;
-
- const float NOISE_GATE_HEIGHT = 7.0f;
- const int NOISE_GATE_WIDTH = 5;
- const int NOISE_GATE_CLOSE_BLOCK_DELAY = 5;
- const int NOISE_GATE_BLOCKS_TO_AVERAGE = 5;
-
- // Check clipping, and check if should open noise gate
- _didClipInLastBlock = false;
-
- for (int i = 0; i < numSamples; i++) {
- thisSample = std::abs(samples[i]);
- if (thisSample >= ((float) AudioConstants::MAX_SAMPLE_VALUE * CLIPPING_THRESHOLD)) {
- _didClipInLastBlock = true;
- }
-
- loudness += thisSample;
- // Noise Reduction: Count peaks above the average loudness
- if (thisSample > (_measuredFloor * NOISE_GATE_HEIGHT)) {
- samplesOverNoiseGate++;
- }
- }
-
- _lastLoudness = fabs(loudness / numSamples);
-
- // If Noise Gate is enabled, check and turn the gate on and off
- float averageOfAllSampleBlocks = 0.0f;
- _sampleBlocks[_sampleCounter++] = _lastLoudness;
- if (_sampleCounter == NUMBER_OF_NOISE_SAMPLE_BLOCKS) {
- float smallestSample = std::numeric_limits<float>::max();
- for (int i = 0; i <= NUMBER_OF_NOISE_SAMPLE_BLOCKS - NOISE_GATE_BLOCKS_TO_AVERAGE; i += NOISE_GATE_BLOCKS_TO_AVERAGE) {
- float thisAverage = 0.0f;
- for (int j = i; j < i + NOISE_GATE_BLOCKS_TO_AVERAGE; j++) {
- thisAverage += _sampleBlocks[j];
- averageOfAllSampleBlocks += _sampleBlocks[j];
- }
- thisAverage /= NOISE_GATE_BLOCKS_TO_AVERAGE;
-
- if (thisAverage < smallestSample) {
- smallestSample = thisAverage;
- }
- }
- averageOfAllSampleBlocks /= NUMBER_OF_NOISE_SAMPLE_BLOCKS;
- _measuredFloor = smallestSample;
- _sampleCounter = 0;
-
- }
-
- _closedInLastBlock = false;
- _openedInLastBlock = false;
-
- if (samplesOverNoiseGate > NOISE_GATE_WIDTH) {
- _openedInLastBlock = !_isOpen;
- _isOpen = true;
- _blocksToClose = NOISE_GATE_CLOSE_BLOCK_DELAY;
- } else {
- if (--_blocksToClose == 0) {
- _closedInLastBlock = _isOpen;
- _isOpen = false;
- }
- }
- if (!_isOpen) {
- // First block after being closed gets faded to silence, we fade across
- // the entire block on fading out. All subsequent blocks are muted by being slammed
- // to zeros
- if (_closedInLastBlock) {
- float fadeSlope = (1.0f / numSamples);
- for (int i = 0; i < numSamples; i++) {
- float fadedSample = (1.0f - ((float)i * fadeSlope)) * (float)samples[i];
- samples[i] = (int16_t)fadedSample;
- }
- } else {
- memset(samples, 0, numSamples * sizeof(int16_t));
- }
- _lastLoudness = 0;
- }
-
- if (_openedInLastBlock) {
- // would be nice to do a little crossfade from silence, but we only want to fade
- // across the first 1/10th of the block, because we don't want to miss early
- // transients.
- int fadeSamples = numSamples / 10; // fade over 1/10th of the samples
- float fadeSlope = (1.0f / fadeSamples);
- for (int i = 0; i < fadeSamples; i++) {
- float fadedSample = (float)i * fadeSlope * (float)samples[i];
- samples[i] = (int16_t)fadedSample;
- }
- }
-}
diff --git a/libraries/audio/src/AudioNoiseGate.h b/libraries/audio/src/AudioNoiseGate.h
deleted file mode 100644
index 8430f120e5..0000000000
--- a/libraries/audio/src/AudioNoiseGate.h
+++ /dev/null
@@ -1,48 +0,0 @@
-//
-// AudioNoiseGate.h
-// libraries/audio
-//
-// Created by Stephen Birarda on 2014-12-16.
-// Copyright 2014 High Fidelity, Inc.
-//
-// Distributed under the Apache License, Version 2.0.
-// See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
-//
-
-#ifndef hifi_AudioNoiseGate_h
-#define hifi_AudioNoiseGate_h
-
-#include <stdint.h>
-
-const int NUMBER_OF_NOISE_SAMPLE_BLOCKS = 300;
-
-class AudioNoiseGate {
-public:
- AudioNoiseGate();
-
- void gateSamples(int16_t* samples, int numSamples);
- void removeDCOffset(int16_t* samples, int numSamples);
-
- bool clippedInLastBlock() const { return _didClipInLastBlock; }
- bool closedInLastBlock() const { return _closedInLastBlock; }
- bool openedInLastBlock() const { return _openedInLastBlock; }
- bool isOpen() const { return _isOpen; }
- float getMeasuredFloor() const { return _measuredFloor; }
- float getLastLoudness() const { return _lastLoudness; }
-
- static const float CLIPPING_THRESHOLD;
-
-private:
- float _lastLoudness;
- bool _didClipInLastBlock;
- float _dcOffset;
- float _measuredFloor;
- float _sampleBlocks[NUMBER_OF_NOISE_SAMPLE_BLOCKS];
- int _sampleCounter;
- bool _isOpen;
- bool _closedInLastBlock { false };
- bool _openedInLastBlock { false };
- int _blocksToClose;
-};
-
-#endif // hifi_AudioNoiseGate_h