Mirrors/overte-HifiExperiments
3
0
Fork 0
mirror of https://github.com/HifiExperiments/overte.git synced 2025-08-05 17:53:51 +02:00
Code Issues Projects Releases Packages Wiki Activity Actions

move the audio noise gate to its own class

Browse source
This commit is contained in:
Stephen Birarda 2014-12-16 16:31:29 -08:00
parent 0429b338c0
commit be184719b5
4 changed files with 217 additions and 157 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

160
interface/src/Audio.cpp
View file

@ -46,8 +46,6 @@
#include "Audio.h"
static const int NUMBER_OF_NOISE_SAMPLE_FRAMES = 300;
static const int RECEIVED_AUDIO_STREAM_CAPACITY_FRAMES = 100;
Audio::Audio() :
@ -68,21 +66,11 @@ Audio::Audio() :
_isStereoInput(false),
_averagedLatency(0.0),
_lastInputLoudness(0),
_inputFrameCounter(0),
_quietestFrame(std::numeric_limits<float>::max()),
_loudestFrame(0.0f),
_timeSinceLastClip(-1.0),
_dcOffset(0),
_noiseGateMeasuredFloor(0),
_noiseGateSampleCounter(0),
_noiseGateOpen(false),
_noiseGateEnabled(true),
_audioSourceInjectEnabled(false),
_noiseGateFramesToClose(0),
_totalInputAudioSamples(0),
_muted(false),
_shouldEchoLocally(false),
_shouldEchoToServer(false),
_isNoiseGateEnabled(true),
_audioSourceInjectEnabled(false),
_reverb(false),
_reverbOptions(&_scriptReverbOptions),
_gverbLocal(NULL),
@ -91,12 +79,11 @@ Audio::Audio() :
_toneSourceEnabled(true),
_outgoingAvatarAudioSequenceNumber(0),
_audioOutputIODevice(_receivedAudioStream),
_stats(&_receivedAudioStream)
_stats(&_receivedAudioStream),
_inputGate()
{
// clear the array of locally injected samples
memset(_localProceduralSamples, 0, AudioConstants::NETWORK_FRAME_BYTES_PER_CHANNEL);
// Create the noise sample array
_noiseSampleFrames = new float[NUMBER_OF_NOISE_SAMPLE_FRAMES];
connect(&_receivedAudioStream, &MixedProcessedAudioStream::processSamples, this, &Audio::processReceivedSamples, Qt::DirectConnection);
@ -586,6 +573,8 @@ void Audio::handleLocalEchoAndReverb(QByteArray& inputByteArray) {
}
}
const float CLIPPING_THRESHOLD = 0.90f;
void Audio::handleAudioInput() {
static char audioDataPacket[MAX_PACKET_SIZE];
@ -655,131 +644,24 @@ void Audio::handleAudioInput() {
inputSamplesRequired, numNetworkSamples,
_inputFormat, _desiredInputFormat);
// only impose the noise gate and perform tone injection if we sending mono audio
if (!_isStereoInput) {
//
// 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 frame for which the height must be exceeded
// to open the gate.
// NOISE_GATE_CLOSE_FRAME_DELAY: Once the noise is below the gate height for the frame, how many frames
// will we wait before closing the gate.
// NOISE_GATE_FRAMES_TO_AVERAGE: How many audio frames should we average together to compute noise floor.
// More means better rejection but also can reject continuous things like singing.
// NUMBER_OF_NOISE_SAMPLE_FRAMES: How often should we re-evaluate the noise floor?
float loudness = 0;
float thisSample = 0;
int samplesOverNoiseGate = 0;
const float NOISE_GATE_HEIGHT = 7.0f;
const int NOISE_GATE_WIDTH = 5;
const int NOISE_GATE_CLOSE_FRAME_DELAY = 5;
const int NOISE_GATE_FRAMES_TO_AVERAGE = 5;
const float DC_OFFSET_AVERAGING = 0.99f;
const float CLIPPING_THRESHOLD = 0.90f;
//
// Check clipping, adjust DC offset, and check if should open noise gate
//
float measuredDcOffset = 0.0f;
// Increment the time since the last clip
if (_timeSinceLastClip >= 0.0f) {
_timeSinceLastClip += (float) AudioConstants::NETWORK_FRAME_SAMPLES_PER_CHANNEL
/ (float) AudioConstants::SAMPLE_RATE;
}
for (int i = 0; i < AudioConstants::NETWORK_FRAME_SAMPLES_PER_CHANNEL; i++) {
measuredDcOffset += networkAudioSamples[i];
networkAudioSamples[i] -= (int16_t) _dcOffset;
thisSample = fabsf(networkAudioSamples[i]);
if (thisSample >= ((float)AudioConstants::MAX_SAMPLE_VALUE * CLIPPING_THRESHOLD)) {
_timeSinceLastClip = 0.0f;
}
loudness += thisSample;
// Noise Reduction: Count peaks above the average loudness
if (_noiseGateEnabled && (thisSample > (_noiseGateMeasuredFloor * NOISE_GATE_HEIGHT))) {
samplesOverNoiseGate++;
}
}
measuredDcOffset /= AudioConstants::NETWORK_FRAME_SAMPLES_PER_CHANNEL;
if (_dcOffset == 0.0f) {
// On first frame, copy over measured offset
_dcOffset = measuredDcOffset;
} else {
_dcOffset = DC_OFFSET_AVERAGING * _dcOffset + (1.0f - DC_OFFSET_AVERAGING) * measuredDcOffset;
}
_lastInputLoudness = fabs(loudness / AudioConstants::NETWORK_FRAME_SAMPLES_PER_CHANNEL);
if (_quietestFrame > _lastInputLoudness) {
_quietestFrame = _lastInputLoudness;
}
if (_loudestFrame < _lastInputLoudness) {
_loudestFrame = _lastInputLoudness;
}
const int FRAMES_FOR_NOISE_DETECTION = 400;
if (_inputFrameCounter++ > FRAMES_FOR_NOISE_DETECTION) {
_quietestFrame = std::numeric_limits<float>::max();
_loudestFrame = 0.0f;
_inputFrameCounter = 0;
}
// If Noise Gate is enabled, check and turn the gate on and off
if (!_audioSourceInjectEnabled && _noiseGateEnabled) {
float averageOfAllSampleFrames = 0.0f;
_noiseSampleFrames[_noiseGateSampleCounter++] = _lastInputLoudness;
if (_noiseGateSampleCounter == NUMBER_OF_NOISE_SAMPLE_FRAMES) {
float smallestSample = FLT_MAX;
for (int i = 0; i <= NUMBER_OF_NOISE_SAMPLE_FRAMES - NOISE_GATE_FRAMES_TO_AVERAGE; i += NOISE_GATE_FRAMES_TO_AVERAGE) {
float thisAverage = 0.0f;
for (int j = i; j < i + NOISE_GATE_FRAMES_TO_AVERAGE; j++) {
thisAverage += _noiseSampleFrames[j];
averageOfAllSampleFrames += _noiseSampleFrames[j];
}
thisAverage /= NOISE_GATE_FRAMES_TO_AVERAGE;
if (thisAverage < smallestSample) {
smallestSample = thisAverage;
}
}
averageOfAllSampleFrames /= NUMBER_OF_NOISE_SAMPLE_FRAMES;
_noiseGateMeasuredFloor = smallestSample;
_noiseGateSampleCounter = 0;
}
if (samplesOverNoiseGate > NOISE_GATE_WIDTH) {
_noiseGateOpen = true;
_noiseGateFramesToClose = NOISE_GATE_CLOSE_FRAME_DELAY;
} else {
if (--_noiseGateFramesToClose == 0) {
_noiseGateOpen = false;
}
}
if (!_noiseGateOpen) {
memset(networkAudioSamples, 0, AudioConstants::NETWORK_FRAME_BYTES_PER_CHANNEL);
_lastInputLoudness = 0;
}
}
// only impose the noise gate and perform tone injection if we are sending mono audio
if (!_isStereoInput && _isNoiseGateEnabled) {
_inputGate.gateSamples(networkAudioSamples, numNetworkSamples);
_lastInputLoudness = _inputGate.getLastLoudness();
_timeSinceLastClip = _inputGate.getTimeSinceLastClip();
} else {
float loudness = 0.0f;
for (int i = 0; i < AudioConstants::NETWORK_FRAME_SAMPLES_STEREO; i++) {
loudness += fabsf(networkAudioSamples[i]);
for (int i = 0; i < numNetworkSamples; i++) {
float thisSample = fabsf(networkAudioSamples[i]);
loudness += thisSample;
if (thisSample > (AudioConstants::MAX_SAMPLE_VALUE * AudioNoiseGate::CLIPPING_THRESHOLD)) {
_timeSinceLastClip = 0.0f;
}
}
_lastInputLoudness = fabs(loudness / AudioConstants::NETWORK_FRAME_SAMPLES_PER_CHANNEL);
_lastInputLoudness = fabs(loudness / numNetworkSamples);
}
} else {
// our input loudness is 0, since we're muted
@ -943,10 +825,6 @@ void Audio::toggleMute() {
muteToggled();
}
void Audio::toggleAudioNoiseReduction() {
_noiseGateEnabled = !_noiseGateEnabled;
}
void Audio::setIsStereoInput(bool isStereoInput) {
if (isStereoInput != _isStereoInput) {
_isStereoInput = isStereoInput;

25
interface/src/Audio.h
View file

@ -32,6 +32,7 @@
#include "InterfaceConfig.h"
#include "audio/AudioIOStats.h"
#include "audio/AudioNoiseGate.h"
#include "AudioStreamStats.h"
#include "Recorder.h"
#include "RingBufferHistory.h"
@ -82,12 +83,10 @@ public:
const MixedProcessedAudioStream& getReceivedAudioStream() const { return _receivedAudioStream; }
float getLastInputLoudness() const { return glm::max(_lastInputLoudness - _noiseGateMeasuredFloor, 0.0f); }
float getLastInputLoudness() const { return glm::max(_lastInputLoudness - _inputGate.getMeasuredFloor(), 0.0f); }
float getTimeSinceLastClip() const { return _timeSinceLastClip; }
float getAudioAverageInputLoudness() const { return _lastInputLoudness; }
void setNoiseGateEnabled(bool noiseGateEnabled) { _noiseGateEnabled = noiseGateEnabled; }
void setReceivedAudioStreamSettings(const InboundAudioStream::Settings& settings) { _receivedAudioStream.setSettings(settings); }
int getDesiredJitterBufferFrames() const { return _receivedAudioStream.getDesiredJitterBufferFrames(); }
@ -116,11 +115,13 @@ public slots:
void reset();
void audioMixerKilled();
void toggleMute();
void toggleAudioNoiseReduction();
void toggleAudioSourceInject();
void selectAudioSourcePinkNoise();
void selectAudioSourceSine440();
void toggleAudioNoiseReduction() { _isNoiseGateEnabled = !_isNoiseGateEnabled; }
void toggleLocalEcho() { _shouldEchoLocally = !_shouldEchoLocally; }
void toggleServerEcho() { _shouldEchoToServer = !_shouldEchoToServer; }
@ -179,24 +180,14 @@ private:
QElapsedTimer _timeSinceLastReceived;
float _averagedLatency;
float _lastInputLoudness;
int _inputFrameCounter;
float _quietestFrame;
float _loudestFrame;
float _timeSinceLastClip;
float _dcOffset;
float _noiseGateMeasuredFloor;
float* _noiseSampleFrames;
int _noiseGateSampleCounter;
bool _noiseGateOpen;
bool _noiseGateEnabled;
bool _audioSourceInjectEnabled;
int _noiseGateFramesToClose;
int _totalInputAudioSamples;
bool _muted;
bool _shouldEchoLocally;
bool _shouldEchoToServer;
bool _isNoiseGateEnabled;
bool _audioSourceInjectEnabled;
bool _reverb;
AudioEffectOptions _scriptReverbOptions;
@ -244,6 +235,8 @@ private:
WeakRecorderPointer _recorder;
AudioIOStats _stats;
AudioNoiseGate _inputGate;
};

145
interface/src/audio/AudioNoiseGate.cpp Normal file
View file

@ -0,0 +1,145 @@
//
// AudioNoiseGate.cpp
// interface/src/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 <float.h>
#include <string.h>
#include <AudioConstants.h>
#include "AudioNoiseGate.h"
const int NUMBER_OF_NOISE_SAMPLE_FRAMES = 300;
const float AudioNoiseGate::CLIPPING_THRESHOLD = 0.90f;
AudioNoiseGate::AudioNoiseGate() {
// Create the noise sample array
_sampleFrames = new float[NUMBER_OF_NOISE_SAMPLE_FRAMES];
}
AudioNoiseGate::~AudioNoiseGate() {
delete[] _sampleFrames;
}
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 frame for which the height must be exceeded
// to open the gate.
// NOISE_GATE_CLOSE_FRAME_DELAY: Once the noise is below the gate height for the frame, how many frames
// will we wait before closing the gate.
// NOISE_GATE_FRAMES_TO_AVERAGE: How many audio frames should we average together to compute noise floor.
// More means better rejection but also can reject continuous things like singing.
// NUMBER_OF_NOISE_SAMPLE_FRAMES: How often should we re-evaluate the noise floor?
float loudness = 0;
float thisSample = 0;
int samplesOverNoiseGate = 0;
const float NOISE_GATE_HEIGHT = 7.0f;
const int NOISE_GATE_WIDTH = 5;
const int NOISE_GATE_CLOSE_FRAME_DELAY = 5;
const int NOISE_GATE_FRAMES_TO_AVERAGE = 5;
const float DC_OFFSET_AVERAGING = 0.99f;
//
// Check clipping, adjust DC offset, and check if should open noise gate
//
float measuredDcOffset = 0.0f;
// Increment the time since the last clip
if (_timeSinceLastClip >= 0.0f) {
_timeSinceLastClip += (float) AudioConstants::NETWORK_FRAME_SAMPLES_PER_CHANNEL
/ (float) AudioConstants::SAMPLE_RATE;
}
for (int i = 0; i < AudioConstants::NETWORK_FRAME_SAMPLES_PER_CHANNEL; i++) {
measuredDcOffset += samples[i];
samples[i] -= (int16_t) _dcOffset;
thisSample = fabsf(samples[i]);
if (thisSample >= ((float)AudioConstants::MAX_SAMPLE_VALUE * CLIPPING_THRESHOLD)) {
_timeSinceLastClip = 0.0f;
}
loudness += thisSample;
// Noise Reduction: Count peaks above the average loudness
if (thisSample > (_measuredFloor * NOISE_GATE_HEIGHT)) {
samplesOverNoiseGate++;
}
}
measuredDcOffset /= AudioConstants::NETWORK_FRAME_SAMPLES_PER_CHANNEL;
if (_dcOffset == 0.0f) {
// On first frame, copy over measured offset
_dcOffset = measuredDcOffset;
} else {
_dcOffset = DC_OFFSET_AVERAGING * _dcOffset + (1.0f - DC_OFFSET_AVERAGING) * measuredDcOffset;
}
_lastLoudness = fabs(loudness / AudioConstants::NETWORK_FRAME_SAMPLES_PER_CHANNEL);
if (_quietestFrame > _lastLoudness) {
_quietestFrame = _lastLoudness;
}
if (_loudestFrame < _lastLoudness) {
_loudestFrame = _lastLoudness;
}
const int FRAMES_FOR_NOISE_DETECTION = 400;
if (_inputFrameCounter++ > FRAMES_FOR_NOISE_DETECTION) {
_quietestFrame = std::numeric_limits<float>::max();
_loudestFrame = 0.0f;
_inputFrameCounter = 0;
}
// If Noise Gate is enabled, check and turn the gate on and off
float averageOfAllSampleFrames = 0.0f;
_sampleFrames[_sampleCounter++] = _lastLoudness;
if (_sampleCounter == NUMBER_OF_NOISE_SAMPLE_FRAMES) {
float smallestSample = FLT_MAX;
for (int i = 0; i <= NUMBER_OF_NOISE_SAMPLE_FRAMES - NOISE_GATE_FRAMES_TO_AVERAGE; i += NOISE_GATE_FRAMES_TO_AVERAGE) {
float thisAverage = 0.0f;
for (int j = i; j < i + NOISE_GATE_FRAMES_TO_AVERAGE; j++) {
thisAverage += _sampleFrames[j];
averageOfAllSampleFrames += _sampleFrames[j];
}
thisAverage /= NOISE_GATE_FRAMES_TO_AVERAGE;
if (thisAverage < smallestSample) {
smallestSample = thisAverage;
}
}
averageOfAllSampleFrames /= NUMBER_OF_NOISE_SAMPLE_FRAMES;
_measuredFloor = smallestSample;
_sampleCounter = 0;
}
if (samplesOverNoiseGate > NOISE_GATE_WIDTH) {
_isOpen = true;
_framesToClose = NOISE_GATE_CLOSE_FRAME_DELAY;
} else {
if (--_framesToClose == 0) {
_isOpen = false;
}
}
if (!_isOpen) {
memset(samples, 0, AudioConstants::NETWORK_FRAME_BYTES_PER_CHANNEL);
_lastLoudness = 0;
}
}

44
interface/src/audio/AudioNoiseGate.h Normal file
View file

@ -0,0 +1,44 @@
//
// AudioNoiseGate.h
// interface/src/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>
class AudioNoiseGate {
public:
AudioNoiseGate();
~AudioNoiseGate();
void gateSamples(int16_t* samples, int numSamples);
float getTimeSinceLastClip() const { return _timeSinceLastClip; }
float getMeasuredFloor() const { return _measuredFloor; }
float getLastLoudness() const { return _lastLoudness; }
static const float CLIPPING_THRESHOLD;
private:
int _inputFrameCounter;
float _lastLoudness;
float _quietestFrame;
float _loudestFrame;
float _timeSinceLastClip;
float _dcOffset;
float _measuredFloor;
float* _sampleFrames;
int _sampleCounter;
bool _isOpen;
int _framesToClose;
};
#endif // hifi_AudioNoiseGate_h