CMakeLists.txt

@@ -8,7 +8,6 @@ add_subdirectory(external/magic_enum)
 add_subdirectory(external/argparse)
 add_subdirectory(external/log4cxx)
 
-
 file(GLOB_RECURSE sources src/*.cpp src/*.h)
 file(GLOB_RECURSE data resources/*)
 

scripts/raw-to-wav.sh

@@ -1,13 +0,0 @@
-#! /bin/sh
-
-set -eux
-
-input_file="$1"
-output_file="$2"
-tempfile=$(mktemp /tmp/stereoXXXXXX.wav)
-
-# Two step process:
-#   1. Convert s16 PCM to a stereo wav file
-#   2. Convert stereo wav file to mono
-sox -r 44100 -e signed-integer -b 16 -c 2 ${input_file} ${tempfile}
-sox ${tempfile} -c 1 ${output_file}

scripts/samples.py

@@ -1,6 +1,6 @@
 #! /usr/bin/env python3
 
-from tones import SQUARE_WAVE, SINE_WAVE
+from tones import SQUARE_WAVE
 from tones.mixer import Mixer
 import csv
 import math
@@ -14,8 +14,7 @@ def frequency_to_midi(frequency):
     f = 440 * 2 ^ (n - 69)/12
     '''
     note = 12 * (math.log(frequency/220)/math.log(2)) + 57
-    #return round(note)
-    return note
+    return round(note)
 
 tones = {}
 with open('tones.csv', newline='') as csvfile:
@@ -27,27 +26,6 @@ for tone in tones:
     print(f"{tone} is MIDI #{frequency_to_midi(tones[tone])}")
 
     mixer = Mixer(44100, 1)
-    mixer.create_track(0, SINE_WAVE)
+    mixer.create_track(0, SQUARE_WAVE)
     mixer.add_tone(0, frequency=tones[tone], duration=1.0)
     mixer.write_wav(f'samples/{tone}.wav')
-
-
-mixer = Mixer(44100, 1)
-mixer.create_track(0, SQUARE_WAVE)
-mixer.add_tone(0, frequency=440, duration=1.0)
-mixer.write_wav(f'samples/MIDI-69-square.wav')
-
-mixer = Mixer(44100, 1)
-mixer.create_track(0, SINE_WAVE)
-mixer.add_tone(0, frequency=440, duration=1.0)
-mixer.write_wav(f'samples/MIDI-69-sine.wav')
-
-mixer = Mixer(44100, 1)
-mixer.create_track(0, SQUARE_WAVE)
-mixer.add_tone(0, frequency=261.6256, duration=1.0)
-mixer.write_wav(f'samples/MIDI-60-square.wav')
-
-mixer = Mixer(44100, 1)
-mixer.create_track(0, SINE_WAVE)
-mixer.add_tone(0, frequency=261.6256, duration=1.0)
-mixer.write_wav(f'samples/MIDI-60-sine.wav')

scripts/selcal-detect.py

@@ -1,124 +0,0 @@
-#! /usr/bin/env python3
-
-import csv
-import sys
-import numpy as np
-from scipy import signal
-from scipy.io import wavfile
-from scipy.signal import butter, lfilter
-
-
-tones = {}
-with open('tones.csv', newline='') as csvfile:
-    reader = csv.DictReader(csvfile)
-    for row in reader:
-        tones[row['designator']] = float(row['frequency'])
-
-'''
-def freq_of_key(midi_key):
-    return 440.0 * (2 ** ((midi_key - 69)/12))
-
-tones = {}
-for c in range(65, 90):
-    tones[c] = freq_of_key(c)
-'''
-
-# Shamelessly lifted from
-# https://scipy.github.io/old-wiki/pages/Cookbook/ButterworthBandpass
-def butter_bandpass(lowcut, highcut, fs, order=5):
-    nyq = 0.5 * fs
-    low = lowcut / nyq
-    high = highcut / nyq
-    b, a = butter(order, [low, high], btype='band')
-    return b, a
-
-def butter_bandpass_filter(data, lowcut, highcut, fs, order=5):
-    b, a = butter_bandpass(lowcut, highcut, fs, order=order)
-    y = lfilter(b, a, data)
-    return y
-
-# tone synthesis
-def note(freq, cycles, amp=32767.0, rate=44100):
-    len = cycles * (1.0/rate)
-    t = np.linspace(0, len, int(len * rate))
-    if freq == 0:
-        data = np.zeros(int(len * rate))
-    else:
-        data = np.sin(2 * np.pi * freq * t) * amp
-    return data.astype(int)
-
-def decimate_from_sample_rate(sample_rate):
-    if sample_rate == 44100:
-        return 4  # rate = 11025, Fmax = 5512.5 Hz
-    elif sample_rate == 48000:
-        return 5  # rate = 9600, Fmax = 4800 Hz
-    elif sample_rate == 22050:
-        return 2  # rate = 11025, Fmax = 5512.5 Hz
-    elif sample_rate == 11025:
-        return 1  # rate = 11025, Fmax = 5512.5 Hz
-    else:
-        raise ValueError("Sample rate not supported")
-
-
-if __name__ == '__main__':
-    # TODO JMT: What is this?
-    FLT_LEN = 2000
-
-    file_name = sys.argv[1]
-    sample_rate, data = wavfile.read(file_name)
-
-    print(f"{file_name}: {len(data)} samples @ {sample_rate} Hz")
-
-    decimate = decimate_from_sample_rate(sample_rate)
-    if decimate > 1:
-        data = signal.decimate(data, decimate)
-        sample_rate = sample_rate / decimate
-
-    print(f'Length after decimation: {len(data)} samples')
-
-    data = butter_bandpass_filter(data, 270, 1700, sample_rate, order=8)
-
-    pure_signals = {tone:note(freq, FLT_LEN, rate=sample_rate) for tone,freq in tones.items()}
-    correlations = {tone:np.abs(signal.correlate(data, pure, mode='same')) for tone,pure in pure_signals.items()}
-
-    N = FLT_LEN # Rolling average length
-    cumsum_convolution = np.ones(N)/N
-    massaged = {tone:np.convolve(correlation, cumsum_convolution, mode='valid') for tone,correlation in correlations.items()}
-
-    # Only import if we're actually plotting, these imports are pretty heavy.
-    import pyqtgraph as pg
-    from PyQt5 import QtWidgets
-
-    app = QtWidgets.QApplication([])
-    layout = pg.GraphicsLayoutWidget(show=True, title="SELCAL Tone Correlation")
-    layout.setGeometry(0, 0, 1600, 960)
-
-    plot = layout.addPlot(title=file_name)
-    legend_view = layout.addViewBox()
-
-    legend = pg.LegendItem(offset=(0, 0))
-    legend.setParentItem(legend_view)
-
-    color_map = pg.colormap.get('CET-C6s')
-    colors = color_map.getLookupTable(nPts=len(tones))
-
-    for (tone, correlation), color in zip(massaged.items(), colors):
-        line = plot.plot(correlation, pen=pg.mkPen(color=color), fillLevel=0.1, name=tone)
-        legend.addItem(line, tone)
-
-        y_max = max(line.getData()[1])  # Maximum y-value
-        x_max = line.getData()[0][np.argmax(line.getData()[1])]  # Corresponding x-coordinate
-
-        label = pg.TextItem(html=f'<div style="text-align: center"><span style="color: #FFFFFF; font-size: 12pt;">{line.opts["name"]}</span></div>', anchor=(0.5, 0.5))
-        plot.addItem(label)
-        label.setPos(x_max, y_max)
-        label.setZValue(100)  # Ensure label is above other items
-
-    plot.setLabel('left', 'Signal Correlation')
-    plot.setLabel('bottom', 'Time (samples)')
-    plot.showGrid(x=True, y=True)
-
-    legend_view.setFixedWidth(80)
-    layout.ci.layout.setColumnFixedWidth(1, 80)
-
-    app.exec_()

src/main.cpp

@@ -7,12 +7,10 @@
 #include <argparse/argparse.hpp>
 #include <log4cxx/logger.h>
 #include <log4cxx/basicconfigurator.h>
-#include <sstream>
 
 #include <thread>
 #include <chrono>
 
-namespace {
 // TODO JMT: Does fluidsynth define this itself?
 constexpr int ALL_CHANNELS = -1;
 constexpr double DEFAULT_TONE_DURATION = 1.0;
@@ -26,27 +24,24 @@ static auto logger = log4cxx::Logger::getLogger("tone-generator");
  * to exactly play the the SELCAL tones. Worse again, using the nearest standard MIDI note available
  * results in collisions for SELCAL tones.
  * The way around this is to define a custom MIDI tuning. We're still limited to 128 frequencies,
- * but we can make those frequencies anything we want.
+ * but we can make those frequencies anything we want. This method generates a tuning in the format
+ * that fluidsynth accepts which _only_ contains the SELCAL tones.
  */
-TuningFrequencies getSelcalFrequencies() {
-    TuningFrequencies tunings;
-    tunings.fill(0.0);
+Tuning getSelcalTunings() {
+    Tuning tunings;
+    tunings.fill(0);
 
+    for (auto pair : SELCAL::KeyFrequencies) {
+        // fluidsynth wants tunings in MIDI cents, which effectively means MIDI key * 100.
         // As we only care about the SELCAL 32 tones, only tune those specific keys. We don't
         // need to tune the full 128-key keyboard.
-    std::stringstream ss;
-    for (auto pair : SELCAL::KeyFrequencies) {
-        auto value = static_cast<int>(pair.first);
-        tunings[value] = pair.second;
-        ss << value << ":" << pair.second << ", ";
+        constexpr double MIDI_CENT_SCALE = 100.0;
+        const int keyIndex = static_cast<int>(pair.first);
+        tunings[keyIndex] = frequencyToMidi(pair.second) * MIDI_CENT_SCALE;
     }
 
-    LOG4CXX_DEBUG(logger, "SELCAL freqs {" << ss.str() << "}");
-
     return tunings;
 }
-} // anonymous
-
 
 
 int main(int argc, char** argv) {
@@ -94,13 +89,11 @@ int main(int argc, char** argv) {
         return 1;
     }
 
-    // Handle fluidsynth log messages before touching anything else in the lib
-    redirect_fluid_logs();
+
     Synth synth;
 
-
-    auto tuning = getSelcalFrequencies();
-    if (!synth.setTuning(tuning)) {
+    auto tunings = getSelcalTunings();
+    if (!synth.setTuning(tunings)) {
         LOG4CXX_ERROR(logger, "Failed to set SELCAL tuning on synth");
         return 1;
     }
@@ -134,11 +127,9 @@ int main(int argc, char** argv) {
 
     SELCAL::Code code{parser.get<std::string>("code")};
 
-
     for (auto& group : code.getGroups()) {
-        LOG4CXX_INFO(logger, "Playing MIDI " << static_cast<int>(group[0]) << " & " << static_cast<int>(group[1]));
-        fluid_synth_noteon(raw_synth, 0, static_cast<int>(group[0]), 80);
-        fluid_synth_noteon(raw_synth, 1, static_cast<int>(group[1]), 80);
+        fluid_synth_noteon(raw_synth, 0, static_cast<int>(group[0]), 127);
+        fluid_synth_noteon(raw_synth, 1, static_cast<int>(group[1]), 127);
         std::this_thread::sleep_for(std::chrono::duration<double>(toneDuration));
 
         // Silence between tone groups
@@ -148,5 +139,5 @@ int main(int argc, char** argv) {
 
     // Wait long enough for the full tone to play before tearing down.
     using namespace std::chrono_literals;
-    //std::this_thread::sleep_for(500ms);
+    std::this_thread::sleep_for(500ms);
 }

src/midi.h

@@ -1,26 +1,11 @@
 #pragma once
 
 #include <cmath>
-#include <algorithm>
 
-// Applicable for standard (even temperament) MIDI tuning only.
-// The formula connecting the MIDI note number and the base frequency assume equal tuning based
-// on A4 = 440 Hz.
-constexpr int NUM_MIDI_KEYS = 128;  // Also inclusive of 0 & 128, apparently.
-constexpr double A4_FREQUENCY = 440.0; // Hz
-constexpr int A4_MIDI_KEY = 69; // Hehe
-constexpr int KEYS_PER_OCTAVE = 12;
-
-// Template parameter allows for (non-standard) fractional keys.
-template <typename T>
-constexpr double MidiKeyToFrequency(T key) {
-    return A4_FREQUENCY * std::pow(2, (key - A4_MIDI_KEY) / KEYS_PER_OCTAVE);
+double frequencyToMidi(double f) {
+    return ((12 * std::log(f / 220.0) / std::log(2.0)) + 57.01);
 }
 
-constexpr double frequencyToMidiKey(double f) {
-    return ((KEYS_PER_OCTAVE * std::log2(f / A4_FREQUENCY)) + A4_MIDI_KEY);
-}
-
-constexpr int frequencyToNearestMidiKey(double f) {
-    return std::clamp(static_cast<int>(std::round(frequencyToMidiKey(f))), 0, NUM_MIDI_KEYS);
+int frequencyToNearestMidi(double f) {
+    return (int) frequencyToMidi(f);
 }

src/synth.cpp

@@ -1,18 +1,6 @@
 #include "synth.h"
 
 #include <stdexcept>
-#include <sstream>
-#include <log4cxx/logger.h>
-
-namespace {
-// Helpers for the C API stuff
-constexpr int TRUE = 1;
-constexpr int FALSE = 0;
-
-static auto logger = log4cxx::Logger::getLogger("synth");
-static auto fluidLogger = log4cxx::Logger::getLogger("synth.fluid");
-}
-
 
 Synth::Synth() {
     try {
@@ -26,15 +14,6 @@ Synth::Synth() {
             throw new std::runtime_error("Unable to create fluid synth");
         }
 
-        fluid_settings_setstr(settings, "audio.driver", "file");
-        fluid_settings_setstr(settings, "audio.file.name", "output.raw");
-        fluid_settings_setstr(settings, "audio.file.format", "s16");
-        fluid_settings_setstr(settings, "audio.file.type", "raw");
-        fluid_settings_setnum(settings, "synth.sample-rate", 44100);
-        fluid_settings_setnum(settings, "synth.gain", 1.0);
-        //fluid_settings_setint(settings, "synth.chorus.active", 0);
-        //fluid_settings_setint(settings, "synth.reverb.active", 0);
-
         adriver = new_fluid_audio_driver(settings, synth);
         if (adriver == nullptr) {
             throw new std::runtime_error("Unable to create audio driver");
@@ -90,35 +69,33 @@ bool Synth::loadProgram(const Program& program) {
     return true;
 }
 
-bool Synth::setTuning(const TuningFrequencies& frequencies) {
-    // fluidsynth wants tunings in MIDI cents, which effectively means MIDI key * 100.
-    // For example: normally note 0 is 0.0, 1 is 100.0, 60 is 6000.0, etc.
-    constexpr double MIDI_CENT_SCALE = 100.0;
-    std::array<double, NUM_MIDI_KEYS> pitchCents;
-    std::transform(
-        frequencies.begin(),
-        frequencies.end(),
-        pitchCents.begin(),
-        [] (double frequency) {
-            // Remap 0 Hz to MIDI 0, otherwise we get -inf which causes some interpolations between
-            // notes to result in zero sound.
-            return frequency == 0.0 ? 0.0 : frequencyToMidiKey(frequency) * MIDI_CENT_SCALE;
-        }
+bool Synth::setTuning(const std::array<double, NUM_MIDI_NOTES>& pitches) {
+    int result = fluid_synth_activate_key_tuning(
+        synth,
+        0, 0,
+        "default",
+        pitches.data(),
+        1
     );
 
-    std::stringstream ss;
-    for (auto p : pitchCents) {
-        ss << p << ", ";
+    if (result == FLUID_OK) {
+        result = fluid_synth_activate_tuning(synth, 0, 0, 0, 1);
+        result = fluid_synth_activate_tuning(synth, 1, 0, 0, 1);
     }
-    LOG4CXX_DEBUG(logger, "Tuning pitches [" << ss.str() << "]");
 
-    auto result = fluid_synth_activate_key_tuning(synth, 0, 0, "default", pitchCents.data(), FALSE);
-    return (result == FLUID_OK) ? activateTuning() : false;
+    return result == FLUID_OK;
 }
 
 bool Synth::resetTuning() {
-    auto result = fluid_synth_activate_key_tuning(synth, 0, 0, "default", nullptr, 1);
-    return (result == FLUID_OK) ? activateTuning() : false;
+    int result = fluid_synth_activate_key_tuning(
+        synth,
+        0, 0,
+        "default",
+        nullptr,
+        1
+    );
+
+    return result == FLUID_OK;
 }
 
 const std::vector<Synth::Program>& Synth::getPrograms() const {
@@ -128,46 +105,3 @@ const std::vector<Synth::Program>& Synth::getPrograms() const {
 fluid_synth_t* Synth::getSynth() {
     return synth;
 }
-
-
-bool Synth::activateTuning() {
-    int channelIndex = 0;
-    int result;
-
-    do {
-        result = fluid_synth_activate_tuning(synth, channelIndex++, 0, 0, TRUE);
-    } while (result == FLUID_OK && channelIndex < NUM_MIDI_CHANNELS);
-
-    LOG4CXX_DEBUG(logger, "Tuning activation result: " << result);
-
-    return result == FLUID_OK;
-}
-
-// Fluid logging redirector.
-void fluid_log_function(int level, const char* message, void* data) {
-    switch (level) {
-        case FLUID_PANIC:
-            LOG4CXX_FATAL(fluidLogger, message);
-            break;
-        case FLUID_ERR:
-            LOG4CXX_ERROR(fluidLogger, message);
-            break;
-        case FLUID_WARN:
-            LOG4CXX_WARN(fluidLogger, message);
-            break;
-        case FLUID_INFO:
-            LOG4CXX_INFO(fluidLogger, message);
-            break;
-        case FLUID_DBG:
-            LOG4CXX_DEBUG(fluidLogger, message);
-            break;
-    }
-}
-
-void redirect_fluid_logs() {
-    fluid_set_log_function(FLUID_PANIC, fluid_log_function, NULL);
-    fluid_set_log_function(FLUID_ERR, fluid_log_function, NULL);
-    fluid_set_log_function(FLUID_WARN, fluid_log_function, NULL);
-    fluid_set_log_function(FLUID_INFO, fluid_log_function, NULL);
-    fluid_set_log_function(FLUID_DBG, fluid_log_function, NULL);
-}

src/synth.h

@@ -5,13 +5,9 @@
 #include <string>
 #include <array>
 
-#include "midi.h"
+constexpr int NUM_MIDI_NOTES = 128;
 
-namespace {
-constexpr int NUM_MIDI_CHANNELS = 2;
-}
-
-typedef std::array<double, NUM_MIDI_KEYS> TuningFrequencies;
+typedef std::array<double, NUM_MIDI_NOTES> Tuning;
 
 /**
  * C++ wrapper around the fluidsynth API.
@@ -36,7 +32,7 @@ public:
     bool loadSoundfont(const std::string& filepath);
     bool loadProgram(const Program& program);
 
-    bool setTuning(const TuningFrequencies& frequencies);
+    bool setTuning(const Tuning& pitches);
     bool resetTuning();
 
     const std::vector<Program>& getPrograms() const;
@@ -45,7 +41,7 @@ public:
     fluid_synth_t* getSynth();
 
 private:
-    bool activateTuning();
+
 
     std::vector<Soundfont> soundfonts;
     std::vector<Program> programs;
@@ -54,8 +50,3 @@ private:
     fluid_synth_t* synth = NULL;
     fluid_audio_driver_t* adriver = NULL;
 };
-
-
-// Fluid logging redirector.
-void fluid_log_function(int level, const char* message, void* data);
-void redirect_fluid_logs();