SDRDaemonSink: calculate Tx delay in UDP sink

plugins/samplesink/sdrdaemonsink/sdrdaemonsinkgui.cpp

@@ -38,6 +38,7 @@
 
 #include "device/devicesinkapi.h"
 #include "device/deviceuiset.h"
+#include "udpsinkfec.h"
 #include "sdrdaemonsinkgui.h"
 
 SDRdaemonSinkGui::SDRdaemonSinkGui(DeviceUISet *deviceUISet, QWidget* parent) :
@@ -214,7 +215,8 @@ void SDRdaemonSinkGui::updateSampleRate()
 
 void SDRdaemonSinkGui::updateTxDelayTooltip()
 {
-    double delay = ((127*126*m_settings.m_txDelay) / m_settings.m_sampleRate)/(128 + m_settings.m_nbFECBlocks);
+    int samplesPerBlock = UDPSinkFEC::bytesPerBlock / (SDR_TX_SAMP_SZ <= 16 ? 4 : 8);
+    double delay = ((127*samplesPerBlock*m_settings.m_txDelay) / m_settings.m_sampleRate)/(128 + m_settings.m_nbFECBlocks);
     ui->txDelayText->setToolTip(tr("%1 us").arg(QString::number(delay*1e6, 'f', 0)));
 }
 

plugins/samplesink/sdrdaemonsink/sdrdaemonsinkoutput.cpp

@@ -98,8 +98,7 @@ bool SDRdaemonSinkOutput::start()
 	m_lastQueueLength = -2; // set first value out of bounds
 	m_chunkSizeCorrection = 0;
 
-    double delay = ((127*126*m_settings.m_txDelay) / m_settings.m_sampleRate)/(128 + m_settings.m_nbFECBlocks);
+    m_sdrDaemonSinkThread->setTxDelay(m_settings.m_txDelay);
-    m_sdrDaemonSinkThread->setTxDelay((int) (delay*1e6));
 
 	mutexLocker.unlock();
 	//applySettings(m_generalSettings, m_settings, true);
@@ -280,16 +279,8 @@ void SDRdaemonSinkOutput::applySettings(const SDRdaemonSinkSettings& settings, b
 
     if (changeTxDelay)
     {
-        double delay = ((127*126*settings.m_txDelay) / settings.m_sampleRate)/(128 + settings.m_nbFECBlocks);
+        if (m_sdrDaemonSinkThread != 0) {
-        qDebug("SDRdaemonSinkOutput::applySettings: Tx delay: %f us", delay*1e6);
+            m_sdrDaemonSinkThread->setTxDelay(settings.m_txDelay);
-
-        if (m_sdrDaemonSinkThread != 0)
-        {
-            // delay is calculated as a fraction of the nominal UDP block process time
-            // frame size: 127 * 126 samples
-            // divided by sample rate gives the frame process time
-            // divided by the number of actual blocks including FEC blocks gives the block (i.e. UDP block) process time
-            m_sdrDaemonSinkThread->setTxDelay((int) (delay*1e6));
         }
     }
 

plugins/samplesink/sdrdaemonsink/sdrdaemonsinkthread.h

@@ -50,7 +50,7 @@ public:
 
 	void setSamplerate(int samplerate);
     void setNbBlocksFEC(uint32_t nbBlocksFEC) { m_udpSinkFEC.setNbBlocksFEC(nbBlocksFEC); };
-    void setTxDelay(uint32_t txDelay) { m_udpSinkFEC.setTxDelay(txDelay); };
+    void setTxDelay(float txDelay) { m_udpSinkFEC.setTxDelay(txDelay); };
     void setDataAddress(const QString& address, uint16_t port) { m_udpSinkFEC.setRemoteAddress(address, port); }
 
     bool isRunning() const { return m_running; }

plugins/samplesink/sdrdaemonsink/udpsinkfec.cpp

@@ -33,6 +33,7 @@ UDPSinkFEC::UDPSinkFEC() :
     m_sampleBits(SDR_TX_SAMP_SZ),
     m_nbSamples(0),
     m_nbBlocksFEC(0),
+    m_txDelayRatio(0.0),
     m_txDelay(0),
     m_txBlockIndex(0),
     m_txBlocksIndex(0),
@@ -66,16 +67,31 @@ UDPSinkFEC::~UDPSinkFEC()
     delete m_udpThread;
 }
 
-void UDPSinkFEC::setTxDelay(uint32_t txDelay)
+void UDPSinkFEC::setTxDelay(float txDelayRatio)
 {
-    qDebug() << "UDPSinkFEC::setTxDelay: txDelay: " << txDelay;
+    // delay is calculated from the fraction of the nominal UDP block process time
-    m_txDelay = txDelay;
+    // frame size: 127 * (126 or 63 samples depending on I or Q sample bytes of 2 or 4 bytes respectively)
+    // divided by sample rate gives the frame process time
+    // divided by the number of actual blocks including FEC blocks gives the block (i.e. UDP block) process time
+    m_txDelayRatio = txDelayRatio;
+    int samplesPerBlock = bytesPerBlock / (m_sampleBytes*2);
+    double delay = ((127*samplesPerBlock*txDelayRatio) / m_sampleRate)/(128 + m_nbBlocksFEC);
+    m_txDelay = delay * 1e6;
+    qDebug() << "UDPSinkFEC::setTxDelay: txDelay: " << txDelayRatio << " m_txDelay: " << m_txDelay << " us";
 }
 
 void UDPSinkFEC::setNbBlocksFEC(uint32_t nbBlocksFEC)
 {
     qDebug() << "UDPSinkFEC::setNbBlocksFEC: nbBlocksFEC: " << nbBlocksFEC;
     m_nbBlocksFEC = nbBlocksFEC;
+    setTxDelay(m_txDelayRatio);
+}
+
+void UDPSinkFEC::setSampleRate(uint32_t sampleRate)
+{
+    qDebug() << "UDPSinkFEC::setSampleRate: sampleRate: " << sampleRate;
+    m_sampleRate = sampleRate;
+    setTxDelay(m_txDelayRatio);
 }
 
 void UDPSinkFEC::setRemoteAddress(const QString& address, uint16_t port)

plugins/samplesink/sdrdaemonsink/udpsinkfec.h

@@ -110,14 +110,11 @@ public:
         return ret;
     }
 
-    /** Set sample rate given in Hz */
+    /** Set sample rate given in S/s */
-    void setSampleRate(uint32_t sampleRate) { m_sampleRate = sampleRate; }
+    void setSampleRate(uint32_t sampleRate);
-
-    void setSampleBytes(uint8_t sampleBytes) { m_sampleBytes = (sampleBytes & 0x0F) + (m_sampleBytes & 0xF0); }
-    void setSampleBits(uint8_t sampleBits) { m_sampleBits = sampleBits; }
 
     void setNbBlocksFEC(uint32_t nbBlocksFEC);
-    void setTxDelay(uint32_t txDelay);
+    void setTxDelay(float txDelayRatio);
     void setRemoteAddress(const QString& address, uint16_t port);
 
     /** Return true if the stream is OK, return false if there is an error. */
@@ -142,6 +139,7 @@ private:
 
     MetaDataFEC m_currentMetaFEC;        //!< Meta data for current frame
     uint32_t m_nbBlocksFEC;              //!< Variable number of FEC blocks
+    float m_txDelayRatio;                //!< Delay in ratio of nominal frame period
     uint32_t m_txDelay;                  //!< Delay in microseconds (usleep) between each sending of an UDP datagram
     SuperBlock m_txBlocks[4][256];       //!< UDP blocks to send with original data + FEC
     SuperBlock m_superBlock;             //!< current super block being built