// returns the audio level for each channel
QVector<qreal> getBufferLevels(const QAudioBuffer& buffer)
{
QVector<qreal> values;
if (!buffer.format().isValid() || buffer.format().byteOrder() != QAudioFormat::LittleEndian)
return values;
if (buffer.format().codec() != "audio/pcm")
return values;
int channelCount = buffer.format().channelCount();
values.fill(0, channelCount);
qreal peak_value = getPeakValue(buffer.format());
if (qFuzzyCompare(peak_value, qreal(0)))
return values;
switch (buffer.format().sampleType()) {
case QAudioFormat::Unknown:
case QAudioFormat::UnSignedInt:
if (buffer.format().sampleSize() == 32)
values = getBufferLevels(buffer.constData<quint32>(), buffer.frameCount(), channelCount);
if (buffer.format().sampleSize() == 16)
values = getBufferLevels(buffer.constData<quint16>(), buffer.frameCount(), channelCount);
if (buffer.format().sampleSize() == 8)
values = getBufferLevels(buffer.constData<quint8>(), buffer.frameCount(), channelCount);
for (int i = 0; i < values.size(); ++i)
values[i] = qAbs(values.at(i) - peak_value / 2) / (peak_value / 2);
break;
case QAudioFormat::Float:
if (buffer.format().sampleSize() == 32) {
values = getBufferLevels(buffer.constData<float>(), buffer.frameCount(), channelCount);
for (int i = 0; i < values.size(); ++i)
values[i] /= peak_value;
}
break;
case QAudioFormat::SignedInt:
if (buffer.format().sampleSize() == 32)
values = getBufferLevels(buffer.constData<qint32>(), buffer.frameCount(), channelCount);
if (buffer.format().sampleSize() == 16)
values = getBufferLevels(buffer.constData<qint16>(), buffer.frameCount(), channelCount);
if (buffer.format().sampleSize() == 8)
values = getBufferLevels(buffer.constData<qint8>(), buffer.frameCount(), channelCount);
for (int i = 0; i < values.size(); ++i)
values[i] /= peak_value;
break;
}
return values;
}
// process audio buffer for fft calculations
void MainWindow::processBuffer(QAudioBuffer buffer){
qreal peakValue;
int duration;
if(buffer.frameCount() < 512)
return;
// return left and right audio mean levels
levelLeft = levelRight = 0;
// It only knows how to process stereo audio frames
// mono frames = :P
if(buffer.format().channelCount() != 2)
return;
sample.resize(buffer.frameCount());
// audio is signed int
if(buffer.format().sampleType() == QAudioFormat::SignedInt){
QAudioBuffer::S16S *data = buffer.data<QAudioBuffer::S16S>();
// peak value changes according to sample size.
if (buffer.format().sampleSize() == 32)
peakValue=INT_MAX;
else if (buffer.format().sampleSize() == 16)
peakValue=SHRT_MAX;
else
peakValue=CHAR_MAX;
// scale everything to [0,1]
for(int i=0; i<buffer.frameCount(); i++){
// for visualization purposes, we only need one of the
// left/right channels
sample[i] = data[i].left/peakValue;
levelLeft+= abs(data[i].left)/peakValue;
levelRight+= abs(data[i].right)/peakValue;
}
}
// audio is unsigned int
else if(buffer.format().sampleType() == QAudioFormat::UnSignedInt){
QAudioBuffer::S16U *data = buffer.data<QAudioBuffer::S16U>();
if (buffer.format().sampleSize() == 32)
peakValue=UINT_MAX;
else if (buffer.format().sampleSize() == 16)
peakValue=USHRT_MAX;
else
peakValue=UCHAR_MAX;
for(int i=0; i<buffer.frameCount(); i++){
sample[i] = data[i].left/peakValue;
levelLeft+= abs(data[i].left)/peakValue;
levelRight+= abs(data[i].right)/peakValue;
}
}
// audio is float type
else if(buffer.format().sampleType() == QAudioFormat::Float){
QAudioBuffer::S32F *data = buffer.data<QAudioBuffer::S32F>();
peakValue = 1.00003;
for(int i=0; i<buffer.frameCount(); i++){
sample[i] = data[i].left/peakValue;
// test if sample[i] is infinity (it works)
// some tests produced infinity values :p
if(sample[i] != sample[i]){
sample[i] = 0;
}
else{
levelLeft+= abs(data[i].left)/peakValue;
levelRight+= abs(data[i].right)/peakValue;
}
}
}
// if the probe is listening to the audio
// do fft calculations
// when it is done, calculator will tell us
if(probe->isActive()){
duration = buffer.format().durationForBytes(buffer.frameCount())/1000;
//qDebug() << "duracao =" << duration;
calculator->calc(sample, duration);
}
// tells anyone interested about left and right mean levels
emit levels(levelLeft/buffer.frameCount(),levelRight/buffer.frameCount());
}
void AudioBuffer::init(QAudioBuffer &qtbuffer){
qDebug() << "void AudioBuffer::init(...) called";
QAudioFormat audioFormat = qtbuffer.format();
this->hzFreq = audioFormat.sampleRate();
this->durationInMs = qtbuffer.duration()*1000;
QAudioFormat::SampleType sampleType
= audioFormat.sampleType();
int frameCount = qtbuffer.frameCount();
int nChannels = audioFormat.channelCount();
int bytesPerFrame = audioFormat.bytesPerFrame();
int bytesPerValue = bytesPerFrame/nChannels;
void *firstData = qtbuffer.data();
this->bufferSize = frameCount;
this->buffer = QSharedPointer<SharedBuffer>(
new SharedBuffer);
this->buffer->buffer = new int[this->bufferSize];
this->mean = 0;
const int tempReducFactor = 500;
qint64 meanOfSquare = 0;
for(int i=0; i<frameCount; i++){
int currentValue = 0;
for(int j=0; j<nChannels; j++){
int currentPos
= i*bytesPerFrame
+ j*bytesPerValue;
void *valPos = (void *)(((quint8 *)firstData) + currentPos);
if(sampleType == QAudioFormat::SignedInt){
if(bytesPerValue == 1){
quint8 val = *((quint8*)valPos);
currentValue += val;
}else if(bytesPerValue == 2){
quint16 val = *((quint16*)valPos);
currentValue += val;
}else if(bytesPerValue == 4){
quint32 val = *((quint32*)valPos);
currentValue += val;
}else if(bytesPerValue == 8){
quint64 val = *((quint64*)valPos);
currentValue += val;
}
}else if(sampleType == QAudioFormat::UnSignedInt){
if(bytesPerValue == 1){
qint8 val = *((qint8*)valPos);
currentValue += val;
}else if(bytesPerValue == 2){
qint16 val = *((qint16*)valPos);
currentValue += val;
}else if(bytesPerValue == 4){
qint32 val = *((qint32*)valPos);
currentValue += val;
}else if(bytesPerValue == 8){
qint64 val = *((qint64*)valPos);
currentValue += val;
}
}else if(sampleType == QAudioFormat::Float){
qreal val = *((qreal*)valPos);
currentValue += val;
}
}
currentValue /= nChannels;
currentValue /= tempReducFactor;
this->buffer->buffer[i] = currentValue;
this->mean += currentValue;
meanOfSquare += currentValue*currentValue;
if(meanOfSquare < 0){
Q_ASSERT(false);
}
}
this->mean /= frameCount;
meanOfSquare /= frameCount;
qint64 squaredMean =
this->mean
* this->mean;
this->var = meanOfSquare
- squaredMean;
this->var *= tempReducFactor * tempReducFactor;
this->mean *= tempReducFactor;
this->sd = qSqrt(this->var);
qDebug() << "void AudioBuffer::init(...) end";
}