ATV Demodulator: bug fixes and performance improvements

plugins/channelrx/demodatv/atvdemodgui.cpp

@@ -565,17 +565,17 @@ void ATVDemodGUI::on_fmDeviation_valueChanged(int value)
 
 void ATVDemodGUI::on_amScaleFactor_valueChanged(int value)
 {
+    m_settings.m_amScalingFactor = value;
     ui->amScaleFactor->setValue(m_settings.m_amScalingFactor);
     ui->amScaleFactorText->setText(QString("%1").arg(m_settings.m_amScalingFactor));
-    m_settings.m_amScalingFactor = value;
     applySettings();
 }
 
 void ATVDemodGUI::on_amScaleOffset_valueChanged(int value)
 {
+    m_settings.m_amOffsetFactor = value;
     ui->amScaleOffset->setValue(m_settings.m_amOffsetFactor);
     ui->amScaleOffsetText->setText(QString("%1").arg(m_settings.m_amOffsetFactor));
-    m_settings.m_amOffsetFactor = value;
     applySettings();
 }
 

plugins/channelrx/demodatv/atvdemodsink.cpp

@@ -87,20 +87,13 @@ ATVDemodSink::~ATVDemodSink()
 
 void ATVDemodSink::feed(const SampleVector::const_iterator& begin, const SampleVector::const_iterator& end)
 {
-    float fltI;
-    float fltQ;
-    Complex ci;
-
     //********** Let's rock and roll buddy ! **********
 
     //********** Accessing ATV Screen context **********
 
     for (SampleVector::const_iterator it = begin; it != end; ++it /* ++it **/)
     {
-
-        fltI = it->real();
-        fltQ = it->imag();
-        Complex c(fltI, fltQ);
+        Complex c(it->real(), it->imag());
 
         if (m_settings.m_inputFrequencyOffset != 0) {
             c *= m_nco.nextIQ();
@@ -112,6 +105,7 @@ void ATVDemodSink::feed(const SampleVector::const_iterator& begin, const SampleV
         }
         else
         {
+            Complex ci;
             if (m_interpolator.decimate(&m_interpolatorDistanceRemain, c, &ci))
             {
                 demod(ci);
@@ -129,7 +123,6 @@ void ATVDemodSink::feed(const SampleVector::const_iterator& begin, const SampleV
 
 void ATVDemodSink::demod(Complex& c)
 {
-    float divSynchroBlack = 1.0f - m_settings.m_levelBlack;
     float sampleNormI;
     float sampleNormQ;
     float sampleNorm;
@@ -226,7 +219,7 @@ void ATVDemodSink::demod(Complex& c)
         sampleNorm = sqrt(magSq);
         float sampleRaw = sampleNorm / SDR_RX_SCALEF;
         m_ampAverage(sampleRaw);
-        sample = sampleRaw / (2.0 * m_ampAverage.asFloat()); // AGC
+        sample = sampleRaw / (2.0f * m_ampAverage.asFloat()); // AGC
     }
     else if ((m_settings.m_atvModulation == ATVDemodSettings::ATV_USB) || (m_settings.m_atvModulation == ATVDemodSettings::ATV_LSB))
     {
@@ -318,12 +311,12 @@ void ATVDemodSink::demod(Complex& c)
     sample = (sample < 0.0f) ? 0.0f : (sample > 1.0f) ? 1.0f : sample;
 
     if ((m_videoTabIndex == 1) && (m_scopeSink != 0)) { // feed scope buffer only if scope is present and visible
-        m_scopeSampleBuffer.push_back(Sample(sample*SDR_RX_SCALEF, 0.0f));
+        m_scopeSampleBuffer.push_back(Sample(sample * (SDR_RX_SCALEF - 1.0f), 0.0f));
     }
 
     //********** gray level **********
     // -0.3 -> 0.7 / 0.7
-    sampleVideo = (int) (255.0*(sample - m_settings.m_levelBlack) / (1.0f - m_settings.m_levelBlack));
+    sampleVideo = (int) ((sample - m_settings.m_levelBlack) * m_sampleRangeCorrection);
 
     // 0 -> 255
     sampleVideo = (sampleVideo < 0) ? 0 : (sampleVideo > 255) ? 255 : sampleVideo;
@@ -605,5 +598,9 @@ void ATVDemodSink::applySettings(const ATVDemodSettings& settings, bool force)
         m_objPhaseDiscri.setFMScaling(1.0f / settings.m_fmDeviation);
     }
 
+    if ((settings.m_levelBlack != m_settings.m_levelBlack) || force) {
+        m_sampleRangeCorrection = 255.0f / (1.0f - m_settings.m_levelBlack);
+    }
+
     m_settings = settings;
 }

plugins/channelrx/demodatv/atvdemodsink.h

@@ -165,6 +165,8 @@ private:
 
     SampleVector m_sampleBuffer;
 
+    float m_sampleRangeCorrection;
+
     //*************** RF  ***************
 
     MovingAverageUtil<double, double, 32> m_magSqAverage;

sdrbase/util/movingaverage.h

@@ -75,7 +75,9 @@ class MovingAverageUtilVar
       : m_num_samples(0), m_index(0), m_total(0)
     {
         m_samples.resize(size);
-    }
+		m_samplesSizeInvF = 1.0f / size;
+		m_samplesSizeInvD = 1.0 / size;
+	}
 
     void reset()
     {
@@ -88,7 +90,9 @@ class MovingAverageUtilVar
     {
         reset();
         m_samples.resize(size);
-    }
+		m_samplesSizeInvF = 1.0f / size;
+		m_samplesSizeInvD = 1.0 / size;
+	}
 
     unsigned int size() const
     {
@@ -107,12 +111,14 @@ class MovingAverageUtilVar
             T& oldest = m_samples[m_index];
             m_total += sample - oldest;
             oldest = sample;
-            m_index = (m_index + 1) % m_samples.size();
+            m_index++;
+            if (m_index == m_samples.size())
+                m_index = 0;
         }
     }
 
-    double asDouble() const { return ((double)m_total) / m_samples.size(); }
-    float asFloat() const { return ((float)m_total) / m_samples.size(); }
+    double asDouble() const { return m_total * m_samplesSizeInvD; }
+    float asFloat() const { return m_total * m_samplesSizeInvF; }
     operator T() const { return  m_total / m_samples.size(); }
 
   private:
@@ -120,6 +126,8 @@ class MovingAverageUtilVar
     unsigned int m_num_samples;
     unsigned int m_index;
     Total m_total;
+	float m_samplesSizeInvF;
+	double m_samplesSizeInvD;
 };