Added basic variable decimation

plugins/samplesource/rtlsdr/rtlsdrgui.cpp

@@ -129,6 +129,15 @@ void RTLSDRGui::on_centerFrequency_changed(quint64 value)
 	sendSettings();
 }
 
+void RTLSDRGui::on_decim_valueChanged(int value)
+{
+	if ((value <0) || (value > 4))
+		return;
+	ui->decimText->setText(tr("%1").arg(1<<value));
+	m_settings.m_log2Decim = value;
+	sendSettings();
+}
+
 void RTLSDRGui::on_ppm_valueChanged(int value)
 {
 	if((value > 99) || (value < -99))

plugins/samplesource/rtlsdr/rtlsdrgui.h

@@ -44,6 +44,7 @@ private:
 
 private slots:
 	void on_centerFrequency_changed(quint64 value);
+	void on_decim_valueChanged(int value);
 	void on_ppm_valueChanged(int value);
 	void on_gain_valueChanged(int value);
 	void on_samplerate_valueChanged(int value);

plugins/samplesource/rtlsdr/rtlsdrgui.ui

@@ -261,6 +261,59 @@
      </item>
     </layout>
    </item>
+   <item>
+    <widget class="Line" name="line_5">
+     <property name="orientation">
+      <enum>Qt::Horizontal</enum>
+     </property>
+    </widget>
+   </item>
+   <item>
+    <layout class="QGridLayout" name="gridLayout_4" columnstretch="0,0,0">
+     <property name="spacing">
+      <number>3</number>
+     </property>
+     <item row="0" column="0">
+      <widget class="QLabel" name="label_decim">
+       <property name="text">
+        <string>Dec.</string>
+       </property>
+      </widget>
+     </item>
+     <item row="0" column="1">
+      <widget class="QSlider" name="decim">
+       <property name="maximum">
+        <number>4</number>
+       </property>
+       <property name="pageStep">
+        <number>4</number>
+       </property>
+       <property name="value">
+        <number>4</number>
+       </property>
+       <property name="orientation">
+        <enum>Qt::Horizontal</enum>
+       </property>
+      </widget>
+     </item>
+     <item row="0" column="2">
+      <widget class="QLabel" name="decimText">
+       <property name="minimumSize">
+        <size>
+         <width>40</width>
+         <height>0</height>
+        </size>
+       </property>
+       <property name="text">
+        <string>16</string>
+       </property>
+       <property name="alignment">
+        <set>Qt::AlignRight|Qt::AlignTrailing|Qt::AlignVCenter</set>
+       </property>
+      </widget>
+     </item>
+    </layout>
+   </item>
    <item>
     <widget class="Line" name="line">
      <property name="orientation">

plugins/samplesource/rtlsdr/rtlsdrinput.cpp

@@ -36,6 +36,7 @@ void RTLSDRInput::Settings::resetToDefaults()
 	m_gain = 0;
 	m_samplerate = 1024000;
 	m_loPpmCorrection = 0;
+	m_log2Decim = 4;
 }
 
 QByteArray RTLSDRInput::Settings::serialize() const
@@ -44,6 +45,7 @@ QByteArray RTLSDRInput::Settings::serialize() const
 	s.writeS32(1, m_gain);
 	s.writeS32(2, m_samplerate);
 	s.writeS32(3, m_loPpmCorrection);
+	s.writeU32(4, m_log2Decim);
 	return s.final();
 }
 
@@ -60,6 +62,7 @@ bool RTLSDRInput::Settings::deserialize(const QByteArray& data)
 		d.readS32(1, &m_gain, 0);
 		//d.readS32(2, &m_samplerate, 0);
 		d.readS32(3, &m_loPpmCorrection, 0);
+		d.readU32(4, &m_log2Decim, 4);
 		return true;
 	} else {
 		resetToDefaults();
@@ -186,16 +189,26 @@ const QString& RTLSDRInput::getDeviceDescription() const
 int RTLSDRInput::getSampleRate() const
 {
 	int rate = m_settings.m_samplerate;
+	return (rate / (1<<m_settings.m_log2Decim));
+	/*
 	if (rate < 800000)
 		return (rate / 4);
 	if ((rate == 1152000) || (rate == 2048000))
 		return (rate / 8);
 	return (rate / 16);
+	*/
 }
 
 quint64 RTLSDRInput::getCenterFrequency() const
 {
-	return m_generalSettings.m_centerFrequency;
+	if (m_settings.m_log2Decim == 0) // Little wooby-doop if no decimation
+	{
+		return m_generalSettings.m_centerFrequency + (m_settings.m_samplerate / 4);
+	}
+	else
+	{
+		return m_generalSettings.m_centerFrequency;
+	}
 }
 
 bool RTLSDRInput::handleMessage(Message* message)
@@ -245,6 +258,13 @@ bool RTLSDRInput::applySettings(const GeneralSettings& generalSettings, const Se
 		}
 	}
 
+	if((m_settings.m_log2Decim != settings.m_log2Decim) || force) {
+		if(m_dev != NULL) {
+			m_settings.m_log2Decim = settings.m_log2Decim;
+			m_rtlSDRThread->setLog2Decimation(settings.m_log2Decim);
+		}
+	}
+
 	m_generalSettings.m_centerFrequency = generalSettings.m_centerFrequency;
 	if(m_dev != NULL) {
 		if(rtlsdr_set_center_freq( m_dev, m_generalSettings.m_centerFrequency

plugins/samplesource/rtlsdr/rtlsdrinput.h

@@ -30,6 +30,7 @@ public:
 		qint32 m_gain;
 		qint32 m_samplerate;
 		qint32 m_loPpmCorrection;
+		quint32 m_log2Decim;
 
 		Settings();
 		void resetToDefaults();

plugins/samplesource/rtlsdr/rtlsdrthread.cpp

@@ -28,7 +28,8 @@ RTLSDRThread::RTLSDRThread(rtlsdr_dev_t* dev, SampleFifo* sampleFifo, QObject* p
 	m_dev(dev),
 	m_convertBuffer(BLOCKSIZE),
 	m_sampleFifo(sampleFifo),
-	m_samplerate(288000)
+	m_samplerate(288000),
+	m_log2Decim(4)
 {
 }
 
@@ -57,6 +58,11 @@ void RTLSDRThread::setSamplerate(int samplerate)
 	m_samplerate = samplerate;
 }
 
+void RTLSDRThread::setLog2Decimation(unsigned int log2_decim)
+{
+	m_log2Decim = log2_decim;
+}
+
 void RTLSDRThread::run()
 {
 	int res;
@@ -74,6 +80,18 @@ void RTLSDRThread::run()
 	m_running = false;
 }
 
+void RTLSDRThread::decimate1(SampleVector::iterator* it, const quint8* buf, qint32 len)
+{
+	qint16 xreal, yimag;
+	for (int pos = 0; pos < len; pos += 2) {
+		xreal = buf[pos+0];
+		yimag = buf[pos+1];
+		Sample s( xreal << 3, yimag << 3 );
+		**it = s;
+		(*it)++;
+	}
+}
+
 void RTLSDRThread::decimate2(SampleVector::iterator* it, const quint8* buf, qint32 len)
 {
 	qint16 xreal, yimag;
@@ -146,18 +164,40 @@ void RTLSDRThread::decimate16(SampleVector::iterator* it, const quint8* buf, qin
 
 
 
-//  Decimate everything by 16x, except 288kHz by 4x
-//  and 1152kHz, 2048kHz by 8x
+//  Decimate according to specified log2 (ex: log2=4 => decim=16)
 void RTLSDRThread::callback(const quint8* buf, qint32 len)
 {
 	SampleVector::iterator it = m_convertBuffer.begin();
 
+	switch (m_log2Decim)
+	{
+	case 0:
+		decimate1(&it, buf, len);
+		break;
+	case 1:
+		decimate2(&it, buf, len);
+		break;
+	case 2:
+		decimate4(&it, buf, len);
+		break;
+	case 3:
+		decimate8(&it, buf, len);
+		break;
+	case 4:
+		decimate16(&it, buf, len);
+		break;
+	default:
+		break;
+	}
+
+	/*
 	if (m_samplerate < 800000)
 		decimate4(&it, buf, len);
 	else if ((m_samplerate == 1152000)||(m_samplerate == 2048000))
 		decimate8(&it, buf, len);
 	else
 		decimate16(&it, buf, len);
+	*/
 
 	m_sampleFifo->write(m_convertBuffer.begin(), it);
 

plugins/samplesource/rtlsdr/rtlsdrthread.h

@@ -35,6 +35,7 @@ public:
 	void startWork();
 	void stopWork();
 	void setSamplerate(int samplerate);
+	void setLog2Decimation(unsigned int log2_decim);
 
 private:
 	QMutex m_startWaitMutex;
@@ -46,11 +47,13 @@ private:
 	SampleFifo* m_sampleFifo;
 
 	int m_samplerate;
+	unsigned int m_log2Decim;
 
 	IntHalfbandFilter m_decimator2;
 	IntHalfbandFilter m_decimator4;
 
 	void run();
+	void decimate1(SampleVector::iterator* it, const quint8* buf, qint32 len);
 	void decimate2(SampleVector::iterator* it, const quint8* buf, qint32 len);
 	void decimate4(SampleVector::iterator* it, const quint8* buf, qint32 len);
 	void decimate8(SampleVector::iterator* it, const quint8* buf, qint32 len);