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sdrangel/plugins/channeltx/modssb/ssbmodsource.cpp
2024-08-27 09:54:09 +02:00

763 lines
24 KiB
C++

///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2019-2022 Edouard Griffiths, F4EXB <f4exb06@gmail.com> //
// Copyright (C) 2022 Jiří Pinkava <jiri.pinkava@rossum.ai> //
// //
// This program is free software; you can redistribute it and/or modify //
// it under the terms of the GNU General Public License as published by //
// the Free Software Foundation as version 3 of the License, or //
// (at your option) any later version. //
// //
// This program is distributed in the hope that it will be useful, //
// but WITHOUT ANY WARRANTY; without even the implied warranty of //
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
// GNU General Public License V3 for more details. //
// //
// You should have received a copy of the GNU General Public License //
// along with this program. If not, see <http://www.gnu.org/licenses/>. //
///////////////////////////////////////////////////////////////////////////////////
#include <QDebug>
#include "dsp/spectrumvis.h"
#include "dsp/misc.h"
#include "dsp/datafifo.h"
#include "util/messagequeue.h"
#include "maincore.h"
#include "ssbmodsource.h"
const int SSBModSource::m_ssbFftLen = 1024;
const int SSBModSource::m_levelNbSamples = 480; // every 10ms
SSBModSource::SSBModSource() :
m_audioFifo(12000),
m_feedbackAudioFifo(12000)
{
m_audioFifo.setLabel("SSBModSource.m_audioFifo");
m_feedbackAudioFifo.setLabel("SSBModSource.m_feedbackAudioFifo");
m_SSBFilter = new fftfilt(m_settings.m_lowCutoff / (float) m_audioSampleRate, m_settings.m_bandwidth / (float) m_audioSampleRate, m_ssbFftLen);
m_DSBFilter = new fftfilt((2.0f * m_settings.m_bandwidth) / (float) m_audioSampleRate, 2 * m_ssbFftLen);
m_SSBFilterBuffer = new Complex[m_ssbFftLen>>1]; // filter returns data exactly half of its size
m_DSBFilterBuffer = new Complex[m_ssbFftLen];
std::fill(m_SSBFilterBuffer, m_SSBFilterBuffer+(m_ssbFftLen>>1), Complex{0,0});
std::fill(m_DSBFilterBuffer, m_DSBFilterBuffer+m_ssbFftLen, Complex{0,0});
m_audioBuffer.resize(24000);
m_audioBufferFill = 0;
m_audioReadBuffer.resize(24000);
m_audioReadBufferFill = 0;
m_feedbackAudioBuffer.resize(4800);
m_feedbackAudioBufferFill = 0;
m_demodBuffer.resize(1<<12);
m_demodBufferFill = 0;
m_sum.real(0.0f);
m_sum.imag(0.0f);
m_undersampleCount = 0;
m_sumCount = 0;
m_magsq = 0.0;
m_toneNco.setFreq(1000.0, (float) m_audioSampleRate);
m_audioCompressor.initSimple(
m_audioSampleRate,
(float) m_settings.m_cmpPreGainDB, // pregain (dB)
(float) m_settings.m_cmpThresholdDB, // threshold (dB)
20, // knee (dB)
12, // ratio (dB)
0.003f,// attack (s)
0.25 // release (s)
);
applySettings(m_settings, true);
applyChannelSettings(m_channelSampleRate, m_channelFrequencyOffset, true);
}
SSBModSource::~SSBModSource()
{
delete m_SSBFilter;
delete m_DSBFilter;
delete[] m_SSBFilterBuffer;
delete[] m_DSBFilterBuffer;
}
void SSBModSource::pull(SampleVector::iterator begin, unsigned int nbSamples)
{
std::for_each(
begin,
begin + nbSamples,
[this](Sample& s) {
pullOne(s);
}
);
}
void SSBModSource::pullOne(Sample& sample)
{
Complex ci;
if (m_interpolatorDistance > 1.0f) // decimate
{
modulateSample();
while (!m_interpolator.decimate(&m_interpolatorDistanceRemain, m_modSample, &ci))
{
modulateSample();
}
}
else
{
if (m_interpolator.interpolate(&m_interpolatorDistanceRemain, m_modSample, &ci))
{
modulateSample();
}
}
m_interpolatorDistanceRemain += m_interpolatorDistance;
ci *= m_carrierNco.nextIQ(); // shift to carrier frequency
ci *= 0.891235351562f * SDR_TX_SCALEF; //scaling at -1 dB to account for possible filter overshoot
double magsq = ci.real() * ci.real() + ci.imag() * ci.imag();
magsq /= (SDR_TX_SCALED*SDR_TX_SCALED);
m_movingAverage(magsq);
m_magsq = m_movingAverage.asDouble();
sample.m_real = (FixReal) ci.real();
sample.m_imag = (FixReal) ci.imag();
}
void SSBModSource::prefetch(unsigned int nbSamples)
{
unsigned int nbSamplesAudio = (nbSamples * (unsigned int) ((Real) m_audioSampleRate / (Real) m_channelSampleRate));
pullAudio(nbSamplesAudio);
}
void SSBModSource::pullAudio(unsigned int nbSamplesAudio)
{
QMutexLocker mlock(&m_mutex);
if (nbSamplesAudio > m_audioBuffer.size()) {
m_audioBuffer.resize(nbSamplesAudio);
}
std::copy(&m_audioReadBuffer[0], &m_audioReadBuffer[nbSamplesAudio], &m_audioBuffer[0]);
m_audioBufferFill = 0;
if (m_audioReadBufferFill > nbSamplesAudio) // copy back remaining samples at the start of the read buffer
{
std::copy(&m_audioReadBuffer[nbSamplesAudio], &m_audioReadBuffer[m_audioReadBufferFill], &m_audioReadBuffer[0]);
m_audioReadBufferFill = m_audioReadBufferFill - nbSamplesAudio; // adjust current read buffer fill pointer
}
}
void SSBModSource::modulateSample()
{
pullAF(m_modSample);
if (m_settings.m_feedbackAudioEnable) {
pushFeedback(m_modSample * m_settings.m_feedbackVolumeFactor * 16384.0f);
}
calculateLevel(m_modSample);
if (m_settings.m_audioBinaural)
{
m_demodBuffer[m_demodBufferFill] = (qint16) (m_modSample.real() * std::numeric_limits<int16_t>::max());
m_demodBufferFill++;
m_demodBuffer[m_demodBufferFill] = (qint16) (m_modSample.imag() * std::numeric_limits<int16_t>::max());
m_demodBufferFill++;
}
else
{
// take projection on real axis
m_demodBuffer[m_demodBufferFill] = (qint16) (m_modSample.real() * std::numeric_limits<int16_t>::max());
m_demodBufferFill++;
}
if (m_demodBufferFill >= m_demodBuffer.size())
{
QList<ObjectPipe*> dataPipes;
MainCore::instance()->getDataPipes().getDataPipes(m_channel, "demod", dataPipes);
if (!dataPipes.empty())
{
for (auto& dataPipe : dataPipes)
{
DataFifo *fifo = qobject_cast<DataFifo*>(dataPipe->m_element);
if (fifo)
{
fifo->write(
(quint8*) &m_demodBuffer[0],
m_demodBuffer.size() * sizeof(qint16),
m_settings.m_audioBinaural ? DataFifo::DataTypeCI16 : DataFifo::DataTypeI16
);
}
}
}
m_demodBufferFill = 0;
}
}
void SSBModSource::pullAF(Complex& sample)
{
if (m_settings.m_audioMute)
{
sample.real(0.0f);
sample.imag(0.0f);
return;
}
Complex ci;
fftfilt::cmplx *filtered;
int n_out = 0;
int decim = 1<<(m_settings.m_spanLog2 - 1);
auto decim_mask = (unsigned char) ((decim - 1) & 0xFF); // counter LSB bit mask for decimation by 2^(m_scaleLog2 - 1)
switch (m_settings.m_modAFInput)
{
case SSBModSettings::SSBModInputTone:
if (m_settings.m_dsb)
{
Real t = m_toneNco.next()/1.25f;
sample.real(t);
sample.imag(t);
}
else
{
if (m_settings.m_usb) {
sample = m_toneNco.nextIQ();
} else {
sample = m_toneNco.nextQI();
}
}
break;
case SSBModSettings::SSBModInputFile:
if (m_ifstream && m_ifstream->is_open())
{
if (m_ifstream->eof() && m_settings.m_playLoop)
{
m_ifstream->clear();
m_ifstream->seekg(0, std::ios::beg);
}
if (m_ifstream->eof())
{
ci.real(0.0f);
ci.imag(0.0f);
}
else
{
if (m_settings.m_audioBinaural)
{
Complex c;
m_ifstream->read(reinterpret_cast<char*>(&c), sizeof(Complex));
if (m_settings.m_audioFlipChannels)
{
ci.real(c.imag() * m_settings.m_volumeFactor);
ci.imag(c.real() * m_settings.m_volumeFactor);
}
else
{
ci = c * m_settings.m_volumeFactor;
}
}
else
{
Real real;
m_ifstream->read(reinterpret_cast<char*>(&real), sizeof(Real));
if (m_settings.m_agc)
{
ci.real(clamp<float>(m_audioCompressor.compress(real), -1.0f, 1.0f));
ci.imag(0.0f);
ci *= m_settings.m_volumeFactor;
}
else
{
ci.real(real * m_settings.m_volumeFactor);
ci.imag(0.0f);
}
}
}
}
else
{
ci.real(0.0f);
ci.imag(0.0f);
}
break;
case SSBModSettings::SSBModInputAudio:
if (m_settings.m_audioBinaural)
{
if (m_settings.m_audioFlipChannels)
{
ci.real((m_audioBuffer[m_audioBufferFill].r / SDR_TX_SCALEF) * m_settings.m_volumeFactor);
ci.imag((m_audioBuffer[m_audioBufferFill].l / SDR_TX_SCALEF) * m_settings.m_volumeFactor);
}
else
{
ci.real((m_audioBuffer[m_audioBufferFill].l / SDR_TX_SCALEF) * m_settings.m_volumeFactor);
ci.imag((m_audioBuffer[m_audioBufferFill].r / SDR_TX_SCALEF) * m_settings.m_volumeFactor);
}
}
else
{
if (m_settings.m_agc)
{
float xsample = (m_audioBuffer[m_audioBufferFill].l + m_audioBuffer[m_audioBufferFill].r) / 65536.0f;
ci.real(clamp<float>(m_audioCompressor.compress(xsample), -1.0f, 1.0f));
ci.imag(0.0f);
ci *= m_settings.m_volumeFactor;
}
else
{
ci.real(((m_audioBuffer[m_audioBufferFill].l + m_audioBuffer[m_audioBufferFill].r) / 65536.0f) * m_settings.m_volumeFactor);
ci.imag(0.0f);
}
}
if (m_audioBufferFill < m_audioBuffer.size() - 1)
{
m_audioBufferFill++;
}
else
{
qDebug("SSBModSource::pullAF: starve audio samples: size: %lu", m_audioBuffer.size());
m_audioBufferFill = (unsigned int) (m_audioBuffer.size() - 1);
}
break;
case SSBModSettings::SSBModInputCWTone:
if (!m_cwKeyer) {
break;
}
Real fadeFactor;
if (m_cwKeyer->getSample())
{
m_cwKeyer->getCWSmoother().getFadeSample(true, fadeFactor);
if (m_settings.m_dsb)
{
Real t = m_toneNco.next() * fadeFactor;
sample.real(t);
sample.imag(t);
}
else
{
if (m_settings.m_usb) {
sample = m_toneNco.nextIQ() * fadeFactor;
} else {
sample = m_toneNco.nextQI() * fadeFactor;
}
}
}
else
{
if (m_cwKeyer->getCWSmoother().getFadeSample(false, fadeFactor))
{
if (m_settings.m_dsb)
{
Real t = (m_toneNco.next() * fadeFactor)/1.25f;
sample.real(t);
sample.imag(t);
}
else
{
if (m_settings.m_usb) {
sample = m_toneNco.nextIQ() * fadeFactor;
} else {
sample = m_toneNco.nextQI() * fadeFactor;
}
}
}
else
{
sample.real(0.0f);
sample.imag(0.0f);
m_toneNco.setPhase(0);
}
}
break;
default:
sample.real(0.0f);
sample.imag(0.0f);
break;
}
if ((m_settings.m_modAFInput == SSBModSettings::SSBModInputFile)
|| (m_settings.m_modAFInput == SSBModSettings::SSBModInputAudio)) // real audio
{
if (m_settings.m_dsb)
{
n_out = m_DSBFilter->runDSB(ci, &filtered);
if (n_out > 0)
{
memcpy((void *) m_DSBFilterBuffer, (const void *) filtered, n_out*sizeof(Complex));
m_DSBFilterBufferIndex = 0;
}
sample = m_DSBFilterBuffer[m_DSBFilterBufferIndex];
m_DSBFilterBufferIndex++;
}
else
{
n_out = m_SSBFilter->runSSB(ci, &filtered, m_settings.m_usb);
if (n_out > 0)
{
memcpy((void *) m_SSBFilterBuffer, (const void *) filtered, n_out*sizeof(Complex));
m_SSBFilterBufferIndex = 0;
}
sample = m_SSBFilterBuffer[m_SSBFilterBufferIndex];
m_SSBFilterBufferIndex++;
}
if (n_out > 0)
{
for (int i = 0; i < n_out; i++)
{
// Downsample by 2^(m_scaleLog2 - 1) for SSB band spectrum display
// smart decimation with bit gain using float arithmetic (23 bits significand)
m_sum += filtered[i];
if (!(m_undersampleCount++ & decim_mask))
{
Real avgr = (m_sum.real() / (float) decim) * 0.891235351562f * SDR_TX_SCALEF; //scaling at -1 dB to account for possible filter overshoot
Real avgi = (m_sum.imag() / (float) decim) * 0.891235351562f * SDR_TX_SCALEF;
if (!m_settings.m_dsb && !m_settings.m_usb)
{ // invert spectrum for LSB
m_sampleBuffer.push_back(Sample((FixReal) avgi, (FixReal) avgr));
}
else
{
m_sampleBuffer.push_back(Sample((FixReal) avgr, (FixReal)avgi));
}
m_sum.real(0.0);
m_sum.imag(0.0);
}
}
}
} // Real audio
else if ((m_settings.m_modAFInput == SSBModSettings::SSBModInputTone)
|| (m_settings.m_modAFInput == SSBModSettings::SSBModInputCWTone)) // tone
{
m_sum += sample;
if (!(m_undersampleCount++ & decim_mask))
{
Real avgr = (m_sum.real() / (float) decim) * 0.891235351562f * SDR_TX_SCALEF; //scaling at -1 dB to account for possible filter overshoot
Real avgi = (m_sum.imag() / (float) decim) * 0.891235351562f * SDR_TX_SCALEF;
if (!m_settings.m_dsb && !m_settings.m_usb)
{ // invert spectrum for LSB
m_sampleBuffer.push_back(Sample((FixReal) avgi, (FixReal) avgr));
}
else
{
m_sampleBuffer.push_back(Sample((FixReal) avgr, (FixReal) avgi));
}
m_sum.real(0.0);
m_sum.imag(0.0);
}
if (m_sumCount < (m_settings.m_dsb ? m_ssbFftLen : m_ssbFftLen>>1))
{
n_out = 0;
m_sumCount++;
}
else
{
n_out = m_sumCount;
m_sumCount = 0;
}
}
if (n_out > 0)
{
if (m_spectrumSink) {
m_spectrumSink->feed(m_sampleBuffer.begin(), m_sampleBuffer.end(), !m_settings.m_dsb);
}
m_sampleBuffer.clear();
}
}
void SSBModSource::pushFeedback(Complex c)
{
Complex ci;
if (m_feedbackInterpolatorDistance < 1.0f) // interpolate
{
while (!m_feedbackInterpolator.interpolate(&m_feedbackInterpolatorDistanceRemain, c, &ci))
{
processOneSample(ci);
m_feedbackInterpolatorDistanceRemain += m_feedbackInterpolatorDistance;
}
}
else // decimate
{
if (m_feedbackInterpolator.decimate(&m_feedbackInterpolatorDistanceRemain, c, &ci))
{
processOneSample(ci);
m_feedbackInterpolatorDistanceRemain += m_feedbackInterpolatorDistance;
}
}
}
void SSBModSource::processOneSample(const Complex& ci)
{
if (m_settings.m_modAFInput == SSBModSettings::SSBModInputCWTone) // minimize latency for CW
{
m_feedbackAudioBuffer[0].l = (qint16) ci.real();
m_feedbackAudioBuffer[0].r = (qint16) ci.imag();
m_feedbackAudioFifo.writeOne((const quint8*) &m_feedbackAudioBuffer[0]);
}
else
{
m_feedbackAudioBuffer[m_feedbackAudioBufferFill].l = (qint16) ci.real();
m_feedbackAudioBuffer[m_feedbackAudioBufferFill].r = (qint16) ci.imag();
++m_feedbackAudioBufferFill;
if (m_feedbackAudioBufferFill >= m_feedbackAudioBuffer.size())
{
uint res = m_feedbackAudioFifo.write((const quint8*)&m_feedbackAudioBuffer[0], m_feedbackAudioBufferFill);
if (res != m_feedbackAudioBufferFill)
{
qDebug("SSBModSource::pushFeedback: %u/%u audio samples written m_feedbackInterpolatorDistance: %f",
res, m_feedbackAudioBufferFill, m_feedbackInterpolatorDistance);
m_feedbackAudioFifo.clear();
}
m_feedbackAudioBufferFill = 0;
}
}
}
void SSBModSource::calculateLevel(const Complex& sample)
{
Real t = sample.real();
if (m_levelCalcCount < m_levelNbSamples)
{
m_peakLevel = std::max(std::fabs(m_peakLevel), t);
m_levelSum += t * t;
m_levelCalcCount++;
}
else
{
m_rmsLevel = sqrt(m_levelSum / m_levelNbSamples);
m_peakLevelOut = m_peakLevel;
m_peakLevel = 0.0f;
m_levelSum = 0.0f;
m_levelCalcCount = 0;
}
}
void SSBModSource::applyAudioSampleRate(int sampleRate)
{
if (sampleRate < 0)
{
qWarning("SSBModSource::applyAudioSampleRate: invalid sample rate %d", sampleRate);
return;
}
qDebug("SSBModSource::applyAudioSampleRate: %d", sampleRate);
m_interpolatorDistanceRemain = 0;
m_interpolatorConsumed = false;
m_interpolatorDistance = (Real) sampleRate / (Real) m_channelSampleRate;
m_interpolator.create(48, sampleRate, m_settings.m_bandwidth, 3.0);
float band = m_settings.m_bandwidth;
float lowCutoff = m_settings.m_lowCutoff;
bool usb = m_settings.m_usb;
if (band < 100.0f) // at least 100 Hz
{
band = 100.0f;
lowCutoff = 0;
}
if (band - lowCutoff < 100.0f) {
lowCutoff = band - 100.0f;
}
m_SSBFilter->create_filter(lowCutoff / (float) sampleRate, band / (float) sampleRate);
m_DSBFilter->create_dsb_filter((2.0f * band) / (float) sampleRate);
m_settings.m_bandwidth = band;
m_settings.m_lowCutoff = lowCutoff;
m_settings.m_usb = usb;
m_toneNco.setFreq(m_settings.m_toneFrequency, (float) sampleRate);
if (m_cwKeyer)
{
m_cwKeyer->setSampleRate(sampleRate);
m_cwKeyer->reset();
}
m_audioCompressor.m_rate = (float) sampleRate;
m_audioCompressor.initState();
m_audioSampleRate = sampleRate;
applyFeedbackAudioSampleRate(m_feedbackAudioSampleRate);
QList<ObjectPipe*> pipes;
MainCore::instance()->getMessagePipes().getMessagePipes(m_channel, "reportdemod", pipes);
if (!pipes.empty())
{
for (const auto& pipe : pipes)
{
MessageQueue* messageQueue = qobject_cast<MessageQueue*>(pipe->m_element);
MainCore::MsgChannelDemodReport *msg = MainCore::MsgChannelDemodReport::create(m_channel, sampleRate);
messageQueue->push(msg);
}
}
}
void SSBModSource::applyFeedbackAudioSampleRate(int sampleRate)
{
if (sampleRate < 0)
{
qWarning("SSBModSource::applyFeedbackAudioSampleRate: invalid sample rate %d", sampleRate);
return;
}
qDebug("SSBModSource::applyFeedbackAudioSampleRate: %d", sampleRate);
m_feedbackInterpolatorDistanceRemain = 0;
m_feedbackInterpolatorConsumed = false;
m_feedbackInterpolatorDistance = (Real) sampleRate / (Real) m_audioSampleRate;
Real cutoff = (float) (std::min(sampleRate, m_audioSampleRate)) / 2.2f;
m_feedbackInterpolator.create(48, sampleRate, cutoff, 3.0);
m_feedbackAudioSampleRate = sampleRate;
}
void SSBModSource::applySettings(const SSBModSettings& settings, bool force)
{
float band = settings.m_bandwidth;
float lowCutoff = settings.m_lowCutoff;
bool usb = settings.m_usb;
if ((settings.m_bandwidth != m_settings.m_bandwidth) ||
(settings.m_lowCutoff != m_settings.m_lowCutoff) || force)
{
if (band < 100.0f) // at least 100 Hz
{
band = 100.0f;
lowCutoff = 0;
}
if (band - lowCutoff < 100.0f) {
lowCutoff = band - 100.0f;
}
m_interpolatorDistanceRemain = 0;
m_interpolatorConsumed = false;
m_interpolatorDistance = (Real) m_audioSampleRate / (Real) m_channelSampleRate;
m_interpolator.create(48, m_audioSampleRate, band, 3.0);
m_SSBFilter->create_filter(lowCutoff / (float) m_audioSampleRate, band / (float) m_audioSampleRate);
m_DSBFilter->create_dsb_filter((2.0f * band) / (float) m_audioSampleRate);
}
if ((settings.m_toneFrequency != m_settings.m_toneFrequency) || force) {
m_toneNco.setFreq(settings.m_toneFrequency, (float) m_audioSampleRate);
}
if ((settings.m_dsb != m_settings.m_dsb) || force)
{
if (settings.m_dsb)
{
std::fill(m_DSBFilterBuffer, m_DSBFilterBuffer+m_ssbFftLen, Complex{0,0});
m_DSBFilterBufferIndex = 0;
}
else
{
std::fill(m_SSBFilterBuffer, m_SSBFilterBuffer+(m_ssbFftLen>>1), Complex{0,0});
m_SSBFilterBufferIndex = 0;
}
}
if ((settings.m_modAFInput != m_settings.m_modAFInput) || force)
{
if (settings.m_modAFInput == SSBModSettings::SSBModInputAudio) {
connect(&m_audioFifo, SIGNAL(dataReady()), this, SLOT(handleAudio()));
} else {
disconnect(&m_audioFifo, SIGNAL(dataReady()), this, SLOT(handleAudio()));
}
}
if ((settings.m_cmpThresholdDB != m_settings.m_cmpThresholdDB) ||
(settings.m_cmpPreGainDB != m_settings.m_cmpPreGainDB) || force)
{
m_audioCompressor.initSimple(
m_audioSampleRate,
(float) settings.m_cmpPreGainDB, // pregain (dB)
(float) settings.m_cmpThresholdDB, // threshold (dB)
20, // knee (dB)
12, // ratio (dB)
0.003f,// attack (s)
0.25 // release (s)
);
}
m_settings = settings;
m_settings.m_bandwidth = band;
m_settings.m_lowCutoff = lowCutoff;
m_settings.m_usb = usb;
}
void SSBModSource::applyChannelSettings(int channelSampleRate, int channelFrequencyOffset, bool force)
{
qDebug() << "SSBModSource::applyChannelSettings:"
<< " channelSampleRate: " << channelSampleRate
<< " channelFrequencyOffset: " << channelFrequencyOffset;
if ((channelFrequencyOffset != m_channelFrequencyOffset)
|| (channelSampleRate != m_channelSampleRate) || force) {
m_carrierNco.setFreq((float) channelFrequencyOffset, (float) channelSampleRate);
}
if ((channelSampleRate != m_channelSampleRate) || force)
{
m_interpolatorDistanceRemain = 0;
m_interpolatorConsumed = false;
m_interpolatorDistance = (Real) m_audioSampleRate / (Real) channelSampleRate;
m_interpolator.create(48, m_audioSampleRate, m_settings.m_bandwidth, 3.0);
}
m_channelSampleRate = channelSampleRate;
m_channelFrequencyOffset = channelFrequencyOffset;
}
void SSBModSource::handleAudio()
{
unsigned int nbRead;
while ((nbRead = m_audioFifo.read(reinterpret_cast<quint8*>(&m_audioReadBuffer[m_audioReadBufferFill]), 4096)) != 0)
{
if (m_audioReadBufferFill + nbRead + 4096 < m_audioReadBuffer.size()) {
m_audioReadBufferFill += nbRead;
}
}
}