Include default firfilter taps in binary and enable by default

7 files changed, 75 insertions, 49 deletions

diff --git a/doc/example.ini b/doc/example.ini
index 6a4b0f4..8403e8f 100644
--- a/doc/example.ini
+++ b/doc/example.ini
@@ -114,10 +114,12 @@ dac_clk_rate=0
 
 [firfilter]
 ; The FIR Filter can be used to create a better spectral quality.
+enabled=1
+
 ; The filter taps can be calculated with the python script
 ; doc/fir-filter/generate-filter.py
-enabled=0
-filtertapsfile=simple_taps.txt
+; If filtertapsfile is not given, the default taps are used.
+;filtertapsfile=simple_taps.txt
 
 [output]
 ; choose output: possible values: uhd, file, zmq
diff --git a/src/DabMod.cpp b/src/DabMod.cpp
index 194c441..fc28218 100644
--- a/src/DabMod.cpp
+++ b/src/DabMod.cpp
@@ -423,14 +423,7 @@ int launch_modulator(int argc, char* argv[])
 
         // FIR Filter parameters:
         if (pt.get("firfilter.enabled", 0) == 1) {
-            try {
-                filterTapsFilename = pt.get<std::string>("firfilter.filtertapsfile");
-            }
-            catch (std::exception &e) {
-                std::cerr << "Error: " << e.what() << "\n";
-                std::cerr << "       Configuration enables firfilter, but does not specify filter taps file\n";
-                throw std::runtime_error("Configuration error");
-            }
+            filterTapsFilename = pt.get<std::string>("firfilter.filtertapsfile", "default");
         }
 
         // Output options
@@ -609,7 +602,7 @@ int launch_modulator(int argc, char* argv[])
 
     // When using the FIRFilter, increase the modulator offset pipelining delay
     // by the correct amount
-    if (filterTapsFilename != "") {
+    if (not filterTapsFilename.empty()) {
         tist_delay_stages += FIRFILTER_PIPELINE_DELAY;
     }
 
diff --git a/src/DabModulator.cpp b/src/DabModulator.cpp
index 927c7bd..6d22f2d 100644
--- a/src/DabModulator.cpp
+++ b/src/DabModulator.cpp
@@ -60,7 +60,7 @@ DabModulator::DabModulator(
         unsigned outputRate, unsigned clockRate,
         unsigned dabMode, GainMode gainMode,
         float& digGain, float normalise,
-        std::string& filterTapsFilename
+        const std::string& filterTapsFilename
         ) :
     ModCodec(ModFormat(1), ModFormat(0)),
     myOutputRate(outputRate),
@@ -214,7 +214,7 @@ int DabModulator::process(Buffer* const dataIn, Buffer* dataOut)
                 myNbSymbols, mySpacing, myNullSize, mySymSize);
 
         shared_ptr<FIRFilter> cifFilter;
-        if (myFilterTapsFilename != "") {
+        if (not myFilterTapsFilename.empty()) {
             cifFilter = make_shared<FIRFilter>(myFilterTapsFilename);
             rcs.enrol(cifFilter.get());
         }
diff --git a/src/DabModulator.h b/src/DabModulator.h
index fb2d758..41fa42d 100644
--- a/src/DabModulator.h
+++ b/src/DabModulator.h
@@ -55,7 +55,7 @@ public:
             unsigned outputRate, unsigned clockRate,
             unsigned dabMode, GainMode gainMode,
             float& digGain, float normalise,
-            std::string& filterTapsFilename);
+            const std::string& filterTapsFilename);
     DabModulator(const DabModulator& other) = delete;
     DabModulator& operator=(const DabModulator& other) = delete;
     virtual ~DabModulator();
@@ -78,7 +78,7 @@ protected:
     EtiReader myEtiReader;
     Flowgraph* myFlowgraph;
     OutputMemory* myOutput;
-    std::string& myFilterTapsFilename;
+    std::string myFilterTapsFilename;
     tii_config_t& myTiiConfig;
 
     size_t myNbSymbols;
diff --git a/src/FIRFilter.cpp b/src/FIRFilter.cpp
index 86f558b..7e6014c 100644
--- a/src/FIRFilter.cpp
+++ b/src/FIRFilter.cpp
@@ -2,8 +2,10 @@
    Copyright (C) 2007, 2008, 2009, 2010, 2011 Her Majesty the Queen in
    Right of Canada (Communications Research Center Canada)
 
-   Written by
-   2012, Matthias P. Braendli, matthias.braendli@mpb.li
+   Copyright (C) 2016
+   Matthias P. Braendli, matthias.braendli@mpb.li
+
+    http://opendigitalradio.org
 
    This block implements a FIR filter. The real filter taps are given
    as floats, and the block can take advantage of SSE.
@@ -34,6 +36,7 @@
 #include <stdio.h>
 #include <stdexcept>
 
+#include <array>
 #include <iostream>
 #include <fstream>
 #include <memory>
@@ -46,6 +49,29 @@ using namespace std;
 
 #include <sys/time.h>
 
+/* This is the FIR Filter calculated with the doc/fir-filter/generate-filter.py script
+ * with settings
+ *   gain = 1
+ *   sampling_freq = 2.048e6
+ *   cutoff = 810e3
+ *   transition_width = 250e3
+ *
+ * It is a good default filter for the common scenarios.
+ */
+static const std::array<float, 45> default_filter_taps({
+        -0.00110450468492, 0.00120703084394, -0.000840645749122, -0.000187368263141,
+        0.00184351124335, -0.00355578539893, 0.00419321097434, -0.00254214904271,
+        -0.00183473504148, 0.00781436730176, -0.0125957569107, 0.0126200336963,
+        -0.00537294941023, -0.00866683479398, 0.0249746385962, -0.0356550291181,
+        0.0319730602205, -0.00795613788068, -0.0363943465054, 0.0938014090061,
+        -0.151176810265, 0.193567320704, 0.791776955128, 0.193567320704,
+        -0.151176810265, 0.0938014090061, -0.0363943465054, -0.00795613788068,
+        0.0319730602205, -0.0356550291181, 0.0249746385962, -0.00866683479398,
+        -0.00537294941023, 0.0126200336963, -0.0125957569107, 0.00781436730176,
+        -0.00183473504148, -0.00254214904271, 0.00419321097434, -0.00355578539893,
+        0.00184351124335, -0.000187368263141, -0.000840645749122, 0.00120703084394,
+        -0.00110450468492});
+
 void FIRFilterWorker::process(struct FIRFilterWorkerData *fwd)
 {
     size_t i;
@@ -238,7 +264,7 @@ void FIRFilterWorker::process(struct FIRFilterWorkerData *fwd)
 }
 
 
-FIRFilter::FIRFilter(std::string& taps_file) :
+FIRFilter::FIRFilter(const std::string& taps_file) :
     ModCodec(ModFormat(sizeof(complexf)), ModFormat(sizeof(complexf))),
     RemoteControllable("firfilter"),
     myTapsFile(taps_file)
@@ -257,37 +283,44 @@ FIRFilter::FIRFilter(std::string& taps_file) :
     worker.start(&firwd);
 }
 
-void FIRFilter::load_filter_taps(std::string tapsFile)
+void FIRFilter::load_filter_taps(const std::string &tapsFile)
 {
-    std::ifstream taps_fstream(tapsFile.c_str());
-    if(!taps_fstream) { 
-        fprintf(stderr, "FIRFilter: file %s could not be opened !\n", tapsFile.c_str());
-        throw std::runtime_error("FIRFilter: Could not open file with taps! ");
+    std::vector<float> filter_taps;
+    if (tapsFile == "default") {
+        std::copy(default_filter_taps.begin(), default_filter_taps.end(),
+                std::back_inserter(filter_taps));
     }
-    int n_taps;
-    taps_fstream >> n_taps;
+    else {
+        std::ifstream taps_fstream(tapsFile.c_str());
+        if(!taps_fstream) {
+            fprintf(stderr, "FIRFilter: file %s could not be opened !\n", tapsFile.c_str());
+            throw std::runtime_error("FIRFilter: Could not open file with taps! ");
+        }
+        int n_taps;
+        taps_fstream >> n_taps;
 
-    if (n_taps <= 0) {
-        fprintf(stderr, "FIRFilter: warning: taps file has invalid format\n");
-        throw std::runtime_error("FIRFilter: taps file has invalid format.");
-    }
+        if (n_taps <= 0) {
+            fprintf(stderr, "FIRFilter: warning: taps file has invalid format\n");
+            throw std::runtime_error("FIRFilter: taps file has invalid format.");
+        }
 
-    if (n_taps > 100) {
-        fprintf(stderr, "FIRFilter: warning: taps file has more than 100 taps\n");
-    }
+        if (n_taps > 100) {
+            fprintf(stderr, "FIRFilter: warning: taps file has more than 100 taps\n");
+        }
 
-    fprintf(stderr, "FIRFilter: Reading %d taps...\n", n_taps);
+        fprintf(stderr, "FIRFilter: Reading %d taps...\n", n_taps);
 
-    std::vector<float> filter_taps(n_taps);
+        filter_taps.resize(n_taps);
 
-    int n;
-    for (n = 0; n < n_taps; n++) {
-        taps_fstream >> filter_taps[n];
-        PDEBUG("FIRFilter: tap: %f\n",  filter_taps[n] );
-        if (taps_fstream.eof()) {
-            fprintf(stderr, "FIRFilter: file %s should contains %d taps, but EOF reached "\
-                    "after %d taps !\n", tapsFile.c_str(), n_taps, n);
-            throw std::runtime_error("FIRFilter: filtertaps file invalid ! ");
+        int n;
+        for (n = 0; n < n_taps; n++) {
+            taps_fstream >> filter_taps[n];
+            PDEBUG("FIRFilter: tap: %f\n",  filter_taps[n] );
+            if (taps_fstream.eof()) {
+                fprintf(stderr, "FIRFilter: file %s should contains %d taps, but EOF reached "\
+                        "after %d taps !\n", tapsFile.c_str(), n_taps, n);
+                throw std::runtime_error("FIRFilter: filtertaps file invalid ! ");
+            }
         }
     }
 
diff --git a/src/FIRFilter.h b/src/FIRFilter.h
index 2dd7354..ceac4cd 100644
--- a/src/FIRFilter.h
+++ b/src/FIRFilter.h
@@ -22,8 +22,7 @@
    along with ODR-DabMod.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef FIRFILTER_H
-#define FIRFILTER_H
+#pragma once
 
 #ifdef HAVE_CONFIG_H
 #   include <config.h>
@@ -98,7 +97,7 @@ class FIRFilterWorker {
 class FIRFilter : public ModCodec, public RemoteControllable
 {
 public:
-    FIRFilter(std::string& taps_file);
+    FIRFilter(const std::string& taps_file);
     virtual ~FIRFilter();
     FIRFilter(const FIRFilter&);
     FIRFilter& operator=(const FIRFilter&);
@@ -115,14 +114,12 @@ public:
 
 
 protected:
-    void load_filter_taps(std::string tapsFile);
+    void load_filter_taps(const std::string &tapsFile);
 
-    std::string& myTapsFile;
+    std::string myTapsFile;
 
     FIRFilterWorker worker;
     int number_of_runs;
     struct FIRFilterWorkerData firwd;
 };
 
-#endif //FIRFILTER_H
-
diff --git a/src/Utils.cpp b/src/Utils.cpp
index 54a4161..a91077c 100644
--- a/src/Utils.cpp
+++ b/src/Utils.cpp
@@ -73,6 +73,7 @@ void printUsage(char* progName)
                  "                  requiring an external REFCLK and PPS signal and frames that do not contain a valid timestamp\n"
                  "                  get muted.\n\n");
     fprintf(out, "-T taps_file:  Enable filtering before the output, using the specified file containing the filter taps.\n");
+    fprintf(out, "               Use 'default' as taps_file to use the internal taps.\n");
     fprintf(out, "-a gain:       Apply digital amplitude gain.\n");
     fprintf(out, "-c rate:       Set the DAC clock rate and enable Cic Equalisation.\n");
     fprintf(out, "-g gainmode:   Set computation gain mode: fix, max or var\n");