DATV: added LDPC max bit flip control and future soft LDPC control. Updated documentation

plugins/channelrx/demoddatv/datvdemodgui.cpp

@@ -281,6 +281,8 @@ void DATVDemodGUI::displaySettings()
     ui->chkHardMetric->setChecked(m_settings.m_hardMetric);
     ui->chkFastlock->setChecked(m_settings.m_fastLock);
     ui->chkViterbi->setChecked(m_settings.m_viterbi);
+    ui->softLDPC->setChecked(m_settings.m_softLDPC);
+    ui->maxBitflips->setValue(m_settings.m_maxBitflips);
 
     if (m_settings.m_standard == DATVDemodSettings::dvb_version::DVB_S)
     {
@@ -288,10 +290,15 @@ void DATVDemodGUI::displaySettings()
         ui->chkHardMetric->setEnabled(true);
         ui->chkFastlock->setEnabled(true);
         ui->chkViterbi->setEnabled(true);
+        ui->softLDPC->setEnabled(false);
+        ui->maxBitflips->setEnabled(false);
         ui->chkAllowDrift->setStyleSheet("QCheckBox { color: white }");
         ui->chkHardMetric->setStyleSheet("QCheckBox { color: white }");
         ui->chkFastlock->setStyleSheet("QCheckBox { color: white }");
         ui->chkViterbi->setStyleSheet("QCheckBox { color: white }");
+        ui->softLDPC->setStyleSheet("QCheckBox { color: gray }");
+        ui->maxBitflips->setStyleSheet("QSpinBox { color: gray }");
+        ui->maxBitflipsLabel->setStyleSheet("QLabel { color: gray }");
     }
     else
     {
@@ -299,10 +306,15 @@ void DATVDemodGUI::displaySettings()
         ui->chkHardMetric->setEnabled(false);
         ui->chkFastlock->setEnabled(false);
         ui->chkViterbi->setEnabled(false);
+        ui->softLDPC->setEnabled(true);
+        ui->maxBitflips->setEnabled(true);
         ui->chkAllowDrift->setStyleSheet("QCheckBox { color: gray }");
         ui->chkHardMetric->setStyleSheet("QCheckBox { color: gray }");
         ui->chkFastlock->setStyleSheet("QCheckBox { color: gray }");
         ui->chkViterbi->setStyleSheet("QCheckBox { color: gray }");
+        ui->softLDPC->setStyleSheet("QCheckBox { color: white }");
+        ui->maxBitflips->setStyleSheet("QSpinBox { color: white }");
+        ui->maxBitflipsLabel->setStyleSheet("QLabel { color: white }");
     }
 
     if (m_settings.m_standard == DATVDemodSettings::dvb_version::DVB_S) {
@@ -508,10 +520,15 @@ void DATVDemodGUI::on_cmbStandard_currentIndexChanged(int index)
         ui->chkHardMetric->setEnabled(true);
         ui->chkFastlock->setEnabled(true);
         ui->chkViterbi->setEnabled(true);
+        ui->softLDPC->setEnabled(false);
+        ui->maxBitflips->setEnabled(false);
         ui->chkAllowDrift->setStyleSheet("QCheckBox { color: white }");
         ui->chkHardMetric->setStyleSheet("QCheckBox { color: white }");
         ui->chkFastlock->setStyleSheet("QCheckBox { color: white }");
         ui->chkViterbi->setStyleSheet("QCheckBox { color: white }");
+        ui->softLDPC->setStyleSheet("QCheckBox { color: gray }");
+        ui->maxBitflips->setStyleSheet("QSpinBox { color: gray }");
+        ui->maxBitflipsLabel->setStyleSheet("QLabel { color: gray }");
     }
     else
     {
@@ -519,10 +536,15 @@ void DATVDemodGUI::on_cmbStandard_currentIndexChanged(int index)
         ui->chkHardMetric->setEnabled(false);
         ui->chkFastlock->setEnabled(false);
         ui->chkViterbi->setEnabled(false);
+        ui->softLDPC->setEnabled(true);
+        ui->maxBitflips->setEnabled(true);
         ui->chkAllowDrift->setStyleSheet("QCheckBox { color: gray }");
         ui->chkHardMetric->setStyleSheet("QCheckBox { color: gray }");
         ui->chkFastlock->setStyleSheet("QCheckBox { color: gray }");
         ui->chkViterbi->setStyleSheet("QCheckBox { color: gray }");
+        ui->softLDPC->setStyleSheet("QCheckBox { color: white }");
+        ui->maxBitflips->setStyleSheet("QSpinBox { color: white }");
+        ui->maxBitflipsLabel->setStyleSheet("QLabel { color: white }");
     }
 
     if (m_settings.m_standard == DATVDemodSettings::dvb_version::DVB_S) {
@@ -560,6 +582,18 @@ void DATVDemodGUI::on_cmbFEC_currentIndexChanged(const QString &arg1)
     applySettings();
 }
 
+void DATVDemodGUI::on_softLDPC_clicked()
+{
+    m_settings.m_softLDPC = ui->softLDPC->isChecked();
+    applySettings();
+}
+
+void DATVDemodGUI::on_maxBitflips_valueChanged(int value)
+{
+    m_settings.m_maxBitflips = value;
+    applySettings();
+}
+
 void DATVDemodGUI::on_chkViterbi_clicked()
 {
     m_settings.m_viterbi = ui->chkViterbi->isChecked();

plugins/channelrx/demoddatv/datvdemodgui.h

@@ -67,6 +67,8 @@ private slots:
     void on_cmbStandard_currentIndexChanged(int index);
     void on_cmbModulation_currentIndexChanged(const QString &arg1);
     void on_cmbFEC_currentIndexChanged(const QString &arg1);
+    void on_softLDPC_clicked();
+    void on_maxBitflips_valueChanged(int value);
     void on_chkViterbi_clicked();
     void on_chkHardMetric_clicked();
     void on_resetDefaults_clicked();

plugins/channelrx/demoddatv/datvdemodgui.ui

@@ -216,7 +216,7 @@
        <x>0</x>
        <y>0</y>
        <width>496</width>
-       <height>250</height>
+       <height>281</height>
       </rect>
      </property>
      <property name="minimumSize">
@@ -225,12 +225,6 @@
        <height>250</height>
       </size>
      </property>
-     <property name="maximumSize">
-      <size>
-       <width>496</width>
-       <height>250</height>
-      </size>
-     </property>
      <property name="title">
       <string>DATV Settings</string>
      </property>
@@ -286,7 +280,7 @@
         <x>230</x>
         <y>20</y>
         <width>261</width>
-        <height>221</height>
+        <height>251</height>
        </rect>
       </property>
       <property name="frameShape">
@@ -451,7 +445,7 @@
         <rect>
          <x>10</x>
          <y>120</y>
-         <width>111</width>
+         <width>121</width>
          <height>20</height>
         </rect>
        </property>
@@ -524,7 +518,7 @@
        <property name="geometry">
         <rect>
          <x>70</x>
-         <y>200</y>
+         <y>230</y>
          <width>181</width>
          <height>20</height>
         </rect>
@@ -540,7 +534,7 @@
        <property name="geometry">
         <rect>
          <x>10</x>
-         <y>180</y>
+         <y>210</y>
          <width>111</width>
          <height>16</height>
         </rect>
@@ -594,7 +588,7 @@
        <property name="geometry">
         <rect>
          <x>130</x>
-         <y>180</y>
+         <y>210</y>
          <width>121</width>
          <height>16</height>
         </rect>
@@ -610,7 +604,7 @@
        <property name="geometry">
         <rect>
          <x>10</x>
-         <y>200</y>
+         <y>230</y>
          <width>61</width>
          <height>15</height>
         </rect>
@@ -623,7 +617,7 @@
        <property name="geometry">
         <rect>
          <x>10</x>
-         <y>150</y>
+         <y>180</y>
          <width>91</width>
          <height>22</height>
         </rect>
@@ -651,7 +645,7 @@
        <property name="geometry">
         <rect>
          <x>140</x>
-         <y>150</y>
+         <y>180</y>
          <width>41</width>
          <height>23</height>
         </rect>
@@ -673,7 +667,7 @@
        <property name="geometry">
         <rect>
          <x>106</x>
-         <y>150</y>
+         <y>180</y>
          <width>28</width>
          <height>23</height>
         </rect>
@@ -686,7 +680,7 @@
        <property name="geometry">
         <rect>
          <x>180</x>
-         <y>150</y>
+         <y>180</y>
          <width>28</width>
          <height>23</height>
         </rect>
@@ -699,7 +693,7 @@
        <property name="geometry">
         <rect>
          <x>210</x>
-         <y>150</y>
+         <y>180</y>
          <width>41</width>
          <height>23</height>
         </rect>
@@ -730,13 +724,67 @@
         <string>...</string>
        </property>
       </widget>
+      <widget class="QCheckBox" name="softLDPC">
+       <property name="geometry">
+        <rect>
+         <x>10</x>
+         <y>150</y>
+         <width>111</width>
+         <height>20</height>
+        </rect>
+       </property>
+       <property name="toolTip">
+        <string>Soft LDPC decoder (LDPC tool)</string>
+       </property>
+       <property name="text">
+        <string>SOFT LDPC</string>
+       </property>
+      </widget>
+      <widget class="QLabel" name="maxBitflipsLabel">
+       <property name="geometry">
+        <rect>
+         <x>140</x>
+         <y>150</y>
+         <width>61</width>
+         <height>21</height>
+        </rect>
+       </property>
+       <property name="text">
+        <string>MAX BFL</string>
+       </property>
+      </widget>
+      <widget class="QSpinBox" name="maxBitflips">
+       <property name="geometry">
+        <rect>
+         <x>200</x>
+         <y>150</y>
+         <width>51</width>
+         <height>20</height>
+        </rect>
+       </property>
+       <property name="toolTip">
+        <string>LDPC maximum bitflips (hard decoder)</string>
+       </property>
+       <property name="alignment">
+        <set>Qt::AlignRight|Qt::AlignTrailing|Qt::AlignVCenter</set>
+       </property>
+       <property name="minimum">
+        <number>0</number>
+       </property>
+       <property name="maximum">
+        <number>500</number>
+       </property>
+       <property name="value">
+        <number>0</number>
+       </property>
+      </widget>
      </widget>
     </widget>
     <widget class="QWidget" name="horizontalLayoutWidget">
      <property name="geometry">
       <rect>
-       <x>0</x>
+       <x>10</x>
-       <y>310</y>
+       <y>350</y>
        <width>481</width>
        <height>33</height>
       </rect>
@@ -828,16 +876,13 @@
     <widget class="QWidget" name="horizontalLayoutWidget_2">
      <property name="geometry">
       <rect>
-       <x>0</x>
+       <x>10</x>
-       <y>250</y>
+       <y>290</y>
        <width>481</width>
        <height>31</height>
       </rect>
      </property>
      <layout class="QHBoxLayout" name="merLayout">
-      <property name="leftMargin">
-       <number>6</number>
-      </property>
       <item>
        <widget class="QLabel" name="merLabel">
         <property name="text">
@@ -891,16 +936,13 @@
     <widget class="QWidget" name="horizontalLayoutWidget_3">
      <property name="geometry">
       <rect>
-       <x>0</x>
+       <x>10</x>
-       <y>280</y>
+       <y>320</y>
        <width>481</width>
        <height>31</height>
       </rect>
      </property>
      <layout class="QHBoxLayout" name="cnrLayout">
-      <property name="leftMargin">
-       <number>6</number>
-      </property>
       <item>
        <widget class="QLabel" name="cnrLabel">
         <property name="text">

plugins/channelrx/demoddatv/datvdemodsettings.cpp

@@ -42,6 +42,8 @@ void DATVDemodSettings::resetToDefaults()
     m_standard = DVB_S;
     m_modulation = BPSK;
     m_fec = FEC12;
+    m_softLDPC = false;
+    m_maxBitflips = 0;
     m_symbolRate = 250000;
     m_notchFilters = 0;
     m_allowDrift = false;
@@ -103,6 +105,8 @@ QByteArray DATVDemodSettings::serialize() const
     s.writeU32(29, m_reverseAPIPort);
     s.writeU32(30, m_reverseAPIDeviceIndex);
     s.writeU32(31, m_reverseAPIChannelIndex);
+    s.writeBool(32, m_softLDPC);
+    s.writeS32(33, m_maxBitflips);
 
     return s.final();
 }
@@ -185,6 +189,9 @@ bool DATVDemodSettings::deserialize(const QByteArray& data)
         d.readU32(31, &utmp, 0);
         m_reverseAPIChannelIndex = utmp > 99 ? 99 : utmp;
 
+        d.readBool(32, &m_softLDPC, false);
+        d.readS32(33, &m_maxBitflips, 0);
+
         validateSystemConfiguration();
 
         return true;
@@ -209,6 +216,8 @@ void DATVDemodSettings::debug(const QString& msg) const
         << " m_rollOff: " << m_rollOff
         << " m_viterbi: " << m_viterbi
         << " m_fec: " << m_fec
+        << " m_softLDPC: " << m_softLDPC
+        << " m_maxBitflips: " << m_maxBitflips
         << " m_modulation: " << m_modulation
         << " m_standard: " << m_standard
         << " m_notchFilters: " << m_notchFilters
@@ -229,6 +238,8 @@ bool DATVDemodSettings::isDifferent(const DATVDemodSettings& other)
         || (m_rollOff != other.m_rollOff)
         || (m_viterbi != other.m_viterbi)
         || (m_fec != other.m_fec)
+        || (m_softLDPC != other.m_softLDPC)
+        || (m_maxBitflips != other.m_maxBitflips)
         || (m_modulation != other.m_modulation)
         || (m_standard != other.m_standard)
         || (m_notchFilters != other.m_notchFilters)

plugins/channelrx/demoddatv/datvdemodsettings.h

@@ -80,6 +80,8 @@ struct DATVDemodSettings
     dvb_version m_standard;
     DATVModulation m_modulation;
     DATVCodeRate m_fec;
+    bool m_softLDPC;
+    int m_maxBitflips;
     bool m_audioMute;
     QString m_audioDeviceName;
     int m_symbolRate;

plugins/channelrx/demoddatv/datvdemodsink.cpp

@@ -1137,7 +1137,7 @@ void DATVDemodSink::InitDATVS2Framework()
     );
     leansdr::s2_fecdec<bool, leansdr::hard_sb> *fecdec = (leansdr::s2_fecdec<bool, leansdr::hard_sb> * ) r_fecdec;
 
-    fecdec->bitflips=0;
+    fecdec->bitflips=m_settings.m_maxBitflips;
 
     /*
     fecdec->bitflips = cfg.ldpc_bf; //int TODO
@@ -1217,12 +1217,12 @@ void DATVDemodSink::feed(const SampleVector::const_iterator& begin, const Sample
 
             if(m_settings.m_standard==DATVDemodSettings::DVB_S2)
             {
-                printf("SWITCHING TO DVBS-2\r\n");
+                qDebug("DATVDemodSink::feed: init DVBS-2");
                 InitDATVS2Framework();
             }
             else
             {
-                printf("SWITCHING TO DVBS\r\n");
+                qDebug("DATVDemodSink::feed: init DVBS");
                 InitDATVFramework();
             }
         }

plugins/channelrx/demoddatv/readme.md

@@ -40,15 +40,23 @@ Power of signal received in the channel (dB)
 
 ![DATV Demodulator plugin DATV GUI](../../../doc/img/DATVDemod_pluginDATV.png)
 
-<h4>B.3: Output transport stream to UDP</h4>
+<h4>B.3: MER estimation</h4>
+
+This gauge gives the MER estimation. The averaged value appears on the right.
+
+<h4>B.3: CNR estimation</h4>
+
+This gauge gives the CNR estimation. The averaged value appears on the right.
+
+<h4>B.5: Output transport stream to UDP</h4>
 
 Activate output of transport stream to UDP with 7 TS blocks per UDP frame
 
-<h4>B.4: UDP address</h4>
+<h4>B.6: UDP address</h4>
 
 This is the address of the TS UDP
 
-<h4>B.5: UDP port</h4>
+<h4>B.7: UDP port</h4>
 
 This is the port of the TS UDP
 
@@ -155,6 +163,20 @@ The mode and rate selection can be done manually but if a discrepancy in the num
 
 The controls specific to DVB-S are disabled and greyed out. These are: Fast Lock, Allow Drift, Hard Metric and Viterbi.
 
+<h5>B.2b.6: DVB-S2 specific - Soft LDPC decoder</h5>
+
+Not implemented yet
+
+<h5>B.2b.7: DVB-S2 specific - LDPC maximum number of bit flips allowed</h5>
+
+May vary between 0 and 500. On strong signals (17 dB SNR or more) you may set it to 0 thus saving processing on occasional bit flips that will not cause significant degradation. When SNR decreases you may set it to a medium value of about 200 allowing bit flips corrections to take place and decoding of signals down to about 10dB MER. A higher value towards the maximum (500) will not make a significant difference and is allowed mostly for experimentation.
+
+If you have enough processing power it is fine to always leave it at 200.
+
+Comparatively:
+  - with max = 0 you need ~15 dB MER which corresponds to ~16 dB CNR
+  - with max = 200 you need ~10 dB MER which corresponds to ~13 dB CNR
+
 <h3>C: DATV video stream</h3>
 
 ![DATV Demodulator plugin video GUI](../../../doc/img/DATVDemod_pluginVideo.png)