Merge branch 'vsonnier-vso_waterfall_fixes_and_improvements'

CMakeLists.txt

@@ -6,8 +6,8 @@ list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules/")
 
 SET(CUBICSDR_VERSION_MAJOR "0")
 SET(CUBICSDR_VERSION_MINOR "2")
-SET(CUBICSDR_VERSION_PATCH "1")
+SET(CUBICSDR_VERSION_PATCH "2")
-SET(CUBICSDR_VERSION_SUFFIX "-alpha-bookmark1")
+SET(CUBICSDR_VERSION_SUFFIX "-alpha")
 SET(CUBICSDR_VERSION "${CUBICSDR_VERSION_MAJOR}.${CUBICSDR_VERSION_MINOR}.${CUBICSDR_VERSION_PATCH}${CUBICSDR_VERSION_SUFFIX}")
 
 SET(CPACK_PACKAGE_VERSION "${CUBICSDR_VERSION_MAJOR}.${CUBICSDR_VERSION_MINOR}.${CUBICSDR_VERSION_PATCH}")

src/AppFrame.cpp

@@ -164,7 +164,7 @@ AppFrame::AppFrame() :
 #if CUBICSDR_ENABLE_VIEW_DEMOD
     wxBoxSizer *demodVisuals = new wxBoxSizer(wxVERTICAL);
 
-    wxGetApp().getDemodSpectrumProcessor()->setup(1024);
+    wxGetApp().getDemodSpectrumProcessor()->setup(DEFAULT_DMOD_FFT_SIZE);
     demodSpectrumCanvas = new SpectrumCanvas(demodPanel, attribList);
     demodSpectrumCanvas->setView(wxGetApp().getConfig()->getCenterFreq(), 300000);
     demodVisuals->Add(demodSpectrumCanvas, 3, wxEXPAND | wxALL, 0);
@@ -173,7 +173,7 @@ AppFrame::AppFrame() :
     demodVisuals->AddSpacer(1);
 
     demodWaterfallCanvas = new WaterfallCanvas(demodPanel, attribList);
-    demodWaterfallCanvas->setup(1024, 128);
+    demodWaterfallCanvas->setup(DEFAULT_DMOD_FFT_SIZE, DEFAULT_DEMOD_WATERFALL_LINES_NB);
     demodWaterfallCanvas->setView(wxGetApp().getConfig()->getCenterFreq(), 300000);
     demodWaterfallCanvas->attachSpectrumCanvas(demodSpectrumCanvas);
     demodWaterfallCanvas->setMinBandwidth(8000);
@@ -181,6 +181,8 @@ AppFrame::AppFrame() :
     demodVisuals->Add(demodWaterfallCanvas, 6, wxEXPAND | wxALL, 0);
     wxGetApp().getDemodSpectrumProcessor()->attachOutput(demodWaterfallCanvas->getVisualDataQueue());
     demodWaterfallCanvas->getVisualDataQueue()->set_max_num_items(3);
+    demodWaterfallCanvas->setLinesPerSecond((int)(DEFAULT_DEMOD_WATERFALL_LINES_NB / DEMOD_WATERFALL_DURATION_IN_SECONDS));
+
 
     demodVisuals->SetMinSize(wxSize(128,-1));
 
@@ -209,7 +211,7 @@ AppFrame::AppFrame() :
     scopeCanvas->setHelpTip("Audio Visuals, drag left/right to toggle Scope or Spectrum, 'B' to toggle decibels display.");
     scopeCanvas->SetMinSize(wxSize(128,-1));
     demodScopeTray->Add(scopeCanvas, 8, wxEXPAND | wxALL, 0);
-    wxGetApp().getScopeProcessor()->setup(1024);
+    wxGetApp().getScopeProcessor()->setup(DEFAULT_SCOPE_FFT_SIZE);
     wxGetApp().getScopeProcessor()->attachOutput(scopeCanvas->getInputQueue());
 
     demodScopeTray->AddSpacer(1);
@@ -293,7 +295,7 @@ AppFrame::AppFrame() :
     wxPanel *spectrumPanel = new wxPanel(mainVisSplitter, wxID_ANY);
     wxBoxSizer *spectrumSizer = new wxBoxSizer(wxHORIZONTAL);
 
-    wxGetApp().getSpectrumProcessor()->setup(2048);
+    wxGetApp().getSpectrumProcessor()->setup(DEFAULT_FFT_SIZE);
     spectrumCanvas = new SpectrumCanvas(spectrumPanel, attribList);
     spectrumCanvas->setShowDb(true);
     spectrumCanvas->setUseDBOfs(true);
@@ -336,7 +338,7 @@ AppFrame::AppFrame() :
     wxBoxSizer *wfSizer = new wxBoxSizer(wxHORIZONTAL);
            
     waterfallCanvas = new WaterfallCanvas(waterfallPanel, attribList);
-    waterfallCanvas->setup(2048, 512);
+    waterfallCanvas->setup(DEFAULT_FFT_SIZE, DEFAULT_MAIN_WATERFALL_LINES_NB);
 
     waterfallDataThread = new FFTVisualDataThread();
 
@@ -1025,17 +1027,6 @@ void AppFrame::OnMenu(wxCommandEvent& event) {
         lowPerfMode = lowPerfMenuItem->IsChecked();
         wxGetApp().getConfig()->setLowPerfMode(lowPerfMode);
 
-//        long srate = wxGetApp().getSampleRate();
-//        if (srate > CHANNELIZER_RATE_MAX && lowPerfMode) {
-//            if (wxGetApp().getSpectrumProcessor()->getFFTSize() != 1024) {
-//                setMainWaterfallFFTSize(1024);
-//            }
-//        } else if (srate > CHANNELIZER_RATE_MAX) {
-//            if (wxGetApp().getSpectrumProcessor()->getFFTSize() != 2048) {
-//                setMainWaterfallFFTSize(2048);
-//            }
-//        }
-
     } else if (event.GetId() == wxID_SET_TIPS ) {
         if (wxGetApp().getConfig()->getShowTips()) {
             wxGetApp().getConfig()->setShowTips(false);

src/CubicSDR.cpp

@@ -635,15 +635,15 @@ void CubicSDR::setSampleRate(long long rate_in) {
     setFrequency(frequency);
 
     if (rate_in <= CHANNELIZER_RATE_MAX / 8) {
-        appframe->setMainWaterfallFFTSize(512);
+        appframe->setMainWaterfallFFTSize(DEFAULT_FFT_SIZE / 4);
         appframe->getWaterfallDataThread()->getProcessor()->setHideDC(false);
         spectrumVisualThread->getProcessor()->setHideDC(false);
     } else if (rate_in <= CHANNELIZER_RATE_MAX) {
-        appframe->setMainWaterfallFFTSize(1024);
+        appframe->setMainWaterfallFFTSize(DEFAULT_FFT_SIZE / 2);
         appframe->getWaterfallDataThread()->getProcessor()->setHideDC(false);
         spectrumVisualThread->getProcessor()->setHideDC(false);
     } else if (rate_in > CHANNELIZER_RATE_MAX) {
-        appframe->setMainWaterfallFFTSize(2048);
+        appframe->setMainWaterfallFFTSize(DEFAULT_FFT_SIZE);
         appframe->getWaterfallDataThread()->getProcessor()->setHideDC(true);
         spectrumVisualThread->getProcessor()->setHideDC(true);
     }

src/CubicSDRDefs.h

@@ -31,15 +31,31 @@ const char filePathSeparator =
 #define BUF_SIZE (16384*6)
 
 #define DEFAULT_SAMPLE_RATE 2500000
+
+//
 #define DEFAULT_FFT_SIZE 2048
+#define DEFAULT_DMOD_FFT_SIZE (DEFAULT_FFT_SIZE / 2)
+#define DEFAULT_SCOPE_FFT_SIZE (DEFAULT_FFT_SIZE / 2)
+
+//Both must be a power of 2 to prevent terrible OpenGL performance.
+//TODO: Make the waterfall resolutions an option.
+#define DEFAULT_MAIN_WATERFALL_LINES_NB 512 // 1024
+#define DEFAULT_DEMOD_WATERFALL_LINES_NB 256
 
 #define DEFAULT_DEMOD_TYPE "FM"
 #define DEFAULT_DEMOD_BW 200000
 
 #define DEFAULT_WATERFALL_LPS 30
 
+//Dmod waterfall lines per second is adjusted 
+//so that the whole demod waterfall show DEMOD_WATERFALL_DURATION_IN_SECONDS
+//seconds.
+#define DEMOD_WATERFALL_DURATION_IN_SECONDS 4.0
+
 #define CHANNELIZER_RATE_MAX 500000
 
 #define MANUAL_SAMPLE_RATE_MIN 2000000 // 2MHz
 #define MANUAL_SAMPLE_RATE_MAX 200000000 // 200MHz (We are 2017+ after all)
 
+//Represents the amount of time to process in the FFT distributor. 
+#define FFT_DISTRIBUTOR_BUFFER_IN_SECONDS 0.250

src/demod/DemodDefs.h

@@ -59,6 +59,7 @@ class ModemKit;
 class DemodulatorThreadPostIQData: public ReferenceCounter {
 public:
     std::vector<liquid_float_complex> data;
+
     long long sampleRate;
     std::string modemName;
     std::string modemType;

src/panel/WaterfallPanel.cpp

@@ -39,6 +39,7 @@ void WaterfallPanel::refreshTheme() {
 void WaterfallPanel::setPoints(std::vector<float> &points) {
     size_t halfPts = points.size()/2;
     if (halfPts == fft_size) {
+       
         for (unsigned int i = 0; i < fft_size; i++) {
             this->points[i] = points[i*2+1];
         }
@@ -102,6 +103,10 @@ void WaterfallPanel::update() {
         
         unsigned char *waterfall_tex;
         
+        //Creates 2x 2D textures into card memory.
+        //of size half_fft_size * waterfall_lines, which can be BIG.
+        //The limit of the size of Waterfall is the size of the maximum supported 2D texture 
+        //by the graphic card. (half_fft_size * waterfall_lines, i.e DEFAULT_DEMOD_WATERFALL_LINES_NB * DEFAULT_FFT_SIZE/2)
         waterfall_tex = new unsigned char[half_fft_size * waterfall_lines];
         memset(waterfall_tex, 0, half_fft_size * waterfall_lines);
         

src/process/FFTDataDistributor.cpp

@@ -2,13 +2,15 @@
 // SPDX-License-Identifier: GPL-2.0+
 
 #include "FFTDataDistributor.h"
+#include <algorithm>
 
 FFTDataDistributor::FFTDataDistributor() : outputBuffers("FFTDataDistributorBuffers"), fftSize(DEFAULT_FFT_SIZE), linesPerSecond(DEFAULT_WATERFALL_LPS), lineRateAccum(0.0) {
 
 }
 
-void FFTDataDistributor::setFFTSize(unsigned int fftSize) {
+void FFTDataDistributor::setFFTSize(unsigned int size) {
-	this->fftSize = fftSize;
+	 
+    fftSize.store(size);
 }
 
 void FFTDataDistributor::setLinesPerSecond(unsigned int lines) {
@@ -29,25 +31,50 @@ void FFTDataDistributor::process() {
 		input->pop(inp);
 
 		if (inp) {
+            //Settings have changed, set new values and dump all previous samples stored in inputBuffer: 
 			if (inputBuffer.sampleRate != inp->sampleRate || inputBuffer.frequency != inp->frequency) {
 
-                bufferMax = inp->sampleRate / 4;
+                //bufferMax must be at least fftSize (+ margin), else the waterfall get frozen, because no longer updated.
+                bufferMax = std::max((size_t)(inp->sampleRate * FFT_DISTRIBUTOR_BUFFER_IN_SECONDS), (size_t)(1.2 * fftSize.load()));
+
 //                std::cout << "Buffer Max: " << bufferMax << std::endl;
                 bufferOffset = 0;
-                
+                bufferedItems = 0;
 				inputBuffer.sampleRate = inp->sampleRate;
 				inputBuffer.frequency = inp->frequency;
                 inputBuffer.data.resize(bufferMax);
 			}
+
+            //adjust (bufferMax ; inputBuffer.data) in case of FFT size change only.
+            if (bufferMax < (size_t)(1.2 * fftSize.load())) {
+                bufferMax = (size_t)(1.2 * fftSize.load());
+                inputBuffer.data.resize(bufferMax);
+            }
+
+            size_t nbSamplesToAdd = inp->data.size();
+
+            //No room left in inputBuffer.data to accept inp->data.size() more samples.
+            //so make room by sliding left of bufferOffset, which is fine because 
+            //those samples has already been processed.
             if ((bufferOffset + bufferedItems + inp->data.size()) > bufferMax) {
                 memmove(&inputBuffer.data[0], &inputBuffer.data[bufferOffset], bufferedItems*sizeof(liquid_float_complex));
                 bufferOffset = 0;
-            } else {
+                //if there are too much samples, we may even overflow !
-                memcpy(&inputBuffer.data[bufferOffset+bufferedItems],&inp->data[0],inp->data.size()*sizeof(liquid_float_complex));
+                //as a fallback strategy, drop the last incomming new samples not fitting in inputBuffer.data.
-                bufferedItems += inp->data.size();
+                if (bufferedItems + inp->data.size() > bufferMax) {
+                    //clamp nbSamplesToAdd
+                    nbSamplesToAdd = bufferMax - bufferedItems;
+                    std::cout << "FFTDataDistributor::process() incoming samples overflow, dropping the last " << (inp->data.size() - nbSamplesToAdd) << " input samples..." << std::endl;
+                }
             }
+            
+            //store nbSamplesToAdd incoming samples. 
+            memcpy(&inputBuffer.data[bufferOffset+bufferedItems],&inp->data[0], nbSamplesToAdd *sizeof(liquid_float_complex));
+            bufferedItems += nbSamplesToAdd;
+            //
 			inp->decRefCount();
 		} else {
+            //empty inp, wait for another.
 			continue;
 		}
 
@@ -56,12 +83,14 @@ void FFTDataDistributor::process() {
 		// number of lines in input
 		double inputLines = (double)bufferedItems / (double)fftSize;
 
-		// ratio required to achieve the desired rate
+		// ratio required to achieve the desired rate:
+        // it means we can achieive 'lineRateStep' times the target linesPerSecond.
+        // < 1 means we cannot reach it by lack of samples.
 		double lineRateStep = ((double)linesPerSecond * inputTime)/(double)inputLines;
 
+        //we have enough samples to FFT at least one 'line' of 'fftSize' frequencies for display:
 		if (bufferedItems >= fftSize) {
 			size_t numProcessed = 0;
-
 			if (lineRateAccum + (lineRateStep * ((double)bufferedItems/(double)fftSize)) < 1.0) {
 				// move along, nothing to see here..
 				lineRateAccum += (lineRateStep * ((double)bufferedItems/(double)fftSize));
@@ -74,10 +103,12 @@ void FFTDataDistributor::process() {
 					lineRateAccum += lineRateStep;
 
 					if (lineRateAccum >= 1.0) {
+                        //each i represents a FFT computation
 						DemodulatorThreadIQData *outp = outputBuffers.getBuffer();
 						outp->frequency = inputBuffer.frequency;
 						outp->sampleRate = inputBuffer.sampleRate;
-						outp->data.assign(inputBuffer.data.begin()+bufferOffset+i,inputBuffer.data.begin()+bufferOffset+i+fftSize);
+						outp->data.assign(inputBuffer.data.begin()+bufferOffset+i,
+                                          inputBuffer.data.begin()+bufferOffset+i+ fftSize);
 						distribute(outp);
 
 						while (lineRateAccum >= 1.0) {
@@ -86,16 +117,19 @@ void FFTDataDistributor::process() {
 					}
 
 					numProcessed += fftSize;
-				}
+				} //end for 
 			}
+            //advance bufferOffset read pointer, 
+            //reduce size of bufferedItems.
 			if (numProcessed) {
                 bufferedItems -= numProcessed;
                 bufferOffset += numProcessed;
             }
+            //clamp to zero the number of remaining items.
             if (bufferedItems <= 0) {
                 bufferedItems = 0;
                 bufferOffset = 0;
             }
-		}
+		} //end if bufferedItems >= fftSize
-	}
+	} //en while
 }

src/process/FFTDataDistributor.h

@@ -7,20 +7,22 @@
 #include "DemodDefs.h"
 #include <cmath>
 #include <cstring>
+#include <atomic>
 
 class FFTDataDistributor : public VisualProcessor<DemodulatorThreadIQData, DemodulatorThreadIQData> {
 public:
     FFTDataDistributor();
-    void setFFTSize(unsigned int fftSize);
+    void setFFTSize(unsigned int size);
     void setLinesPerSecond(unsigned int lines);
     unsigned int getLinesPerSecond();
 
 protected:
-    void process();
+    virtual void process();
     
     DemodulatorThreadIQData inputBuffer, tempBuffer;
     ReBuffer<DemodulatorThreadIQData> outputBuffers;
-    unsigned int fftSize;
+    std::atomic<unsigned int> fftSize;
+   
     unsigned int linesPerSecond;
     double lineRateAccum;
     size_t bufferMax = 0;

src/process/FFTVisualDataThread.cpp

@@ -30,10 +30,18 @@ void FFTVisualDataThread::run() {
     DemodulatorThreadInputQueue *pipeIQDataIn = static_cast<DemodulatorThreadInputQueue *>(getInputQueue("IQDataInput"));
     SpectrumVisualDataQueue *pipeFFTDataOut = static_cast<SpectrumVisualDataQueue *>(getOutputQueue("FFTDataOutput"));
     
+
     fftQueue.set_max_num_items(100); 
     pipeFFTDataOut->set_max_num_items(100);
+
+    //FFT distributor plumbing:
+    // IQDataInput push samples to process to FFT Data distributor. 
     fftDistrib.setInput(pipeIQDataIn);
+
+    //The FFT distributor has actually 1 output only, so it doesn't distribute at all :) 
     fftDistrib.attachOutput(&fftQueue);
+    
+    //FFT Distributor output is ==> SpectrumVisualProcessor input.
     wproc.setInput(&fftQueue);
     wproc.attachOutput(pipeFFTDataOut);
     wproc.setup(DEFAULT_FFT_SIZE);
@@ -42,7 +50,9 @@ void FFTVisualDataThread::run() {
     
     while(!stopping) {
         
-        std::this_thread::sleep_for(std::chrono::milliseconds(10));
+        //this if fed by FFTDataDistributor which has a buffer of FFT_DISTRIBUTOR_BUFFER_IN_SECONDS
+        //so sleep for << FFT_DISTRIBUTOR_BUFFER_IN_SECONDS not to be overflown
+        std::this_thread::sleep_for(std::chrono::milliseconds((int)(FFT_DISTRIBUTOR_BUFFER_IN_SECONDS * 1000.0 / 25.0)));
 //        std::this_thread::yield();
         
         int fftSize = wproc.getDesiredInputSize();
@@ -59,8 +69,11 @@ void FFTVisualDataThread::run() {
             lpsChanged.store(false);
         }
         
+        //Make FFT Distributor process IQ samples
+        //and package them into ready-to-FFT sample sets (representing 1 line) by wproc
         fftDistrib.run();
       
+        // Make wproc do a FFT of each of the sample sets provided by fftDistrib: 
         while (!wproc.isInputEmpty()) {
             wproc.run();
         }

src/process/ScopeVisualProcessor.cpp

@@ -11,7 +11,7 @@ ScopeVisualProcessor::ScopeVisualProcessor(): outputBuffers("ScopeVisualProcesso
     fft_average_rate = 0.65f;
 	fft_ceil_ma = fft_ceil_maa = 0;
 	fft_floor_ma = fft_floor_maa = 0;
-    maxScopeSamples = 1024;
+    maxScopeSamples = DEFAULT_DMOD_FFT_SIZE;
     fftPlan = nullptr;
 }
 

src/process/ScopeVisualProcessor.h

@@ -29,7 +29,7 @@ public:
     void setScopeEnabled(bool scopeEnable);
     void setSpectrumEnabled(bool spectrumEnable);
 protected:
-    void process();
+    virtual void process();
     ReBuffer<ScopeRenderData> outputBuffers;
 
     std::atomic_bool scopeEnabled;

src/process/SpectrumVisualDataThread.cpp

@@ -16,11 +16,12 @@ SpectrumVisualProcessor *SpectrumVisualDataThread::getProcessor() {
 }
 
 void SpectrumVisualDataThread::run() {
-//    std::cout << "Spectrum visual data thread started." << std::endl;
     
     while(!stopping) {
-        std::this_thread::sleep_for(std::chrono::milliseconds(10));
+        //this if fed by FFTDataDistributor which has a buffer of FFT_DISTRIBUTOR_BUFFER_IN_SECONDS
-//        std::this_thread::yield();
+        //so sleep for << FFT_DISTRIBUTOR_BUFFER_IN_SECONDS not to be overflown
+        std::this_thread::sleep_for(std::chrono::milliseconds((int)(FFT_DISTRIBUTOR_BUFFER_IN_SECONDS * 1000.0 / 25.0)));
+
         sproc.run();
     }
     

src/process/SpectrumVisualProcessor.h

@@ -53,7 +53,7 @@ public:
     float getScaleFactor();
     
 protected:
-    void process();
+    virtual void process();
     
     ReBuffer<SpectrumVisualData> outputBuffers;
     std::atomic_bool is_view;

src/process/VisualProcessor.h

@@ -43,19 +43,22 @@ public:
         return false;
     }
 
+    //Set a (new) 'input' queue for incoming data.
     void setInput(ThreadQueue<InputDataType *> *vis_in) {
         std::lock_guard < std::recursive_mutex > busy_lock(busy_update);
         input = vis_in;
         
     }
     
+    //Add a vis_out queue where to consumed 'input' data will be
+    //dispatched by distribute(). 
     void attachOutput(ThreadQueue<OutputDataType *> *vis_out) {
         // attach an output queue
         std::lock_guard < std::recursive_mutex > busy_lock(busy_update);
         outputs.push_back(vis_out);
-       
     }
     
+    //reverse of attachOutput(), removed an existing attached vis_out.
     void removeOutput(ThreadQueue<OutputDataType *> *vis_out) {
         // remove an output queue
         std::lock_guard < std::recursive_mutex > busy_lock(busy_update);
@@ -64,9 +67,9 @@ public:
         if (i != outputs.end()) {
             outputs.erase(i);
         }
-      
     }
     
+    //Call process() repeateadly until all available 'input' data is consumed.
     void run() {
         
         std::lock_guard < std::recursive_mutex > busy_lock(busy_update);
@@ -78,37 +81,51 @@ public:
     }
     
 protected:
-    virtual void process() {
+    // derived class must implement a  process() interface
-        // process inputs to output
+    //where typically 'input' data is consummed, procerssed, and then dispatched
-        // distribute(output);
+    //with distribute() to all 'outputs'.
-    }
+    virtual void process() = 0;
+
+    //To be used by derived classes implementing 
+    //process() : will dispatch 'item' into as many 
+    //available outputs, previously set by attachOutput().
+    void distribute(OutputDataType *item) {
       
-    void distribute(OutputDataType *output) {
-        // distribute outputs
         std::lock_guard < std::recursive_mutex > busy_lock(busy_update);
-
+        //We will try to distribute 'output' among all 'outputs',
-        output->setRefCount((int)outputs.size());
+        //so 'output' will a-priori be shared among all 'outputs' so set its ref count to this 
+        //amount.
+        item->setRefCount((int)outputs.size());
         for (outputs_i = outputs.begin(); outputs_i != outputs.end(); outputs_i++) {
-
+            //if 'output' failed to be given to an outputs_i, dec its ref count accordingly.
-        	if (!(*outputs_i)->push(output)) {
+        	if (!(*outputs_i)->push(item)) {
-        		output->decRefCount();
+                item->decRefCount();
         	} 
         }
+
+        // Now 'item' refcount matches the times 'item' has been successfully distributed,
+        //i.e shared among the outputs.
     }
 
+    //the incoming data queue 
     ThreadQueue<InputDataType *> *input = nullptr;
-    std::vector<ThreadQueue<OutputDataType *> *> outputs;
-	typename std::vector<ThreadQueue<OutputDataType *> *>::iterator outputs_i;
     
-    //protects input and outputs, must be recursive because ao reentrance
+    //the n-outputs where to process()-ed data is distribute()-ed.
+    std::vector<ThreadQueue<OutputDataType *> *> outputs;
+	
+    typename std::vector<ThreadQueue<OutputDataType *> *>::iterator outputs_i;
+
+    //protects input and outputs, must be recursive because of re-entrance
     std::recursive_mutex busy_update;
 };
 
-
+//Specialization much like VisualDataReDistributor, except 
+//the input (pointer) is directly re-dispatched
+//to outputs, so that all output indeed SHARE the same instance. 
 template<class OutputDataType = ReferenceCounter>
 class VisualDataDistributor : public VisualProcessor<OutputDataType, OutputDataType> {
 protected:
-    void process() {
+    virtual void process() {
         OutputDataType *inp;
         while (VisualProcessor<OutputDataType, OutputDataType>::input->try_pop(inp)) {
             
@@ -126,11 +143,12 @@ protected:
     }
 };
 
-
+//specialization class which process() take an input item and re-dispatch
+//A COPY to every outputs, without further processing. This is a 1-to-n dispatcher. 
 template<class OutputDataType = ReferenceCounter>
 class VisualDataReDistributor : public VisualProcessor<OutputDataType, OutputDataType> {
 protected:
-    void process() {
+    virtual void process() {
         OutputDataType *inp;
         while (VisualProcessor<OutputDataType, OutputDataType>::input->try_pop(inp)) {
             

src/visual/WaterfallCanvas.cpp

@@ -42,7 +42,7 @@ WaterfallCanvas::WaterfallCanvas(wxWindow *parent, std::vector<int> dispAttrs) :
         dragOfs(0), mouseZoom(1), zoom(1), freqMoving(false), freqMove(0.0), hoverAlpha(1.0) {
 
     glContext = new PrimaryGLContext(this, &wxGetApp().GetContext(this));
-    linesPerSecond = 30;
+    linesPerSecond = DEFAULT_WATERFALL_LPS;
     lpsIndex = 0;
     preBuf = false;
     SetCursor(wxCURSOR_CROSS);