From bafb694b74aa28cfbcf8a2b19cfd3e0032028a38 Mon Sep 17 00:00:00 2001
From: f4exb <f4exb06@gmail.com>
Date: Sun, 22 Nov 2020 12:34:12 +0100
Subject: [PATCH] AM mod: reworked input audio. Implements #495

---
 plugins/channeltx/modam/ammodsource.cpp | 40 ++++++++++++++++++++++---
 plugins/channeltx/modam/ammodsource.h   | 13 ++++++--
 2 files changed, 47 insertions(+), 6 deletions(-)

diff --git a/plugins/channeltx/modam/ammodsource.cpp b/plugins/channeltx/modam/ammodsource.cpp
index dd8e80204..ef7912f92 100644
--- a/plugins/channeltx/modam/ammodsource.cpp
+++ b/plugins/channeltx/modam/ammodsource.cpp
@@ -25,15 +25,18 @@ AMModSource::AMModSource() :
     m_channelSampleRate(48000),
     m_channelFrequencyOffset(0),
     m_audioSampleRate(48000),
-    m_audioFifo(4800),
+    m_audioFifo(12000),
     m_feedbackAudioFifo(48000),
 	m_levelCalcCount(0),
 	m_peakLevel(0.0f),
 	m_levelSum(0.0f),
-    m_ifstream(nullptr)
+    m_ifstream(nullptr),
+    m_mutex(QMutex::Recursive)
 {
-	m_audioBuffer.resize(1<<14);
+	m_audioBuffer.resize(24000);
 	m_audioBufferFill = 0;
+	m_audioReadBuffer.resize(24000);
+	m_audioReadBufferFill = 0;
 
 	m_feedbackAudioBuffer.resize(1<<14);
 	m_feedbackAudioBufferFill = 0;
@@ -107,13 +110,20 @@ void AMModSource::prefetch(unsigned int nbSamples)
 
 void AMModSource::pullAudio(unsigned int nbSamples)
 {
+    QMutexLocker mlock(&m_mutex);
 
     if (nbSamples > m_audioBuffer.size()) {
         m_audioBuffer.resize(nbSamples);
     }
 
-    m_audioFifo.read(reinterpret_cast<quint8*>(&m_audioBuffer[0]), nbSamples);
+    std::copy(&m_audioReadBuffer[0], &m_audioReadBuffer[nbSamples], &m_audioBuffer[0]);
     m_audioBufferFill = 0;
+
+    if (m_audioReadBufferFill > nbSamples) // copy back remaining samples at the start of the read buffer
+    {
+        std::copy(&m_audioReadBuffer[nbSamples], &m_audioReadBuffer[m_audioReadBufferFill], &m_audioReadBuffer[0]);
+        m_audioReadBufferFill = m_audioReadBufferFill - nbSamples; // adjust current read buffer fill pointer
+    }
 }
 
 void AMModSource::modulateSample()
@@ -314,6 +324,15 @@ void AMModSource::applySettings(const AMModSettings& settings, bool force)
         m_toneNco.setFreq(settings.m_toneFrequency, m_audioSampleRate);
     }
 
+    if ((settings.m_modAFInput != m_settings.m_modAFInput) || force)
+    {
+        if (settings.m_modAFInput == AMModSettings::AMModInputAudio) {
+            connect(&m_audioFifo, SIGNAL(dataReady()), this, SLOT(handleAudio()));
+        } else {
+            disconnect(&m_audioFifo, SIGNAL(dataReady()), this, SLOT(handleAudio()));
+        }
+    }
+
     m_settings = settings;
 }
 
@@ -340,3 +359,16 @@ void AMModSource::applyChannelSettings(int channelSampleRate, int channelFrequen
     m_channelSampleRate = channelSampleRate;
     m_channelFrequencyOffset = channelFrequencyOffset;
 }
+
+void AMModSource::handleAudio()
+{
+    QMutexLocker mlock(&m_mutex);
+    unsigned int nbRead;
+
+    while ((nbRead = m_audioFifo.read(reinterpret_cast<quint8*>(&m_audioReadBuffer[m_audioReadBufferFill]), 4096)) != 0)
+    {
+        if (m_audioReadBufferFill + nbRead + 4096 < m_audioReadBuffer.size()) {
+            m_audioReadBufferFill += nbRead;
+        }
+    }
+}
diff --git a/plugins/channeltx/modam/ammodsource.h b/plugins/channeltx/modam/ammodsource.h
index 63d1ddd13..3ff5bb14d 100644
--- a/plugins/channeltx/modam/ammodsource.h
+++ b/plugins/channeltx/modam/ammodsource.h
@@ -18,6 +18,7 @@
 #ifndef INCLUDE_AMMODSOURCE_H
 #define INCLUDE_AMMODSOURCE_H
 
+#include <QObject>
 #include <QMutex>
 
 #include <iostream>
@@ -33,8 +34,9 @@
 
 #include "ammodsettings.h"
 
-class AMModSource : public ChannelSampleSource
+class AMModSource : public QObject,  public ChannelSampleSource
 {
+    Q_OBJECT
 public:
     AMModSource();
     virtual ~AMModSource();
@@ -85,7 +87,9 @@ private:
 
     int m_audioSampleRate;
     AudioVector m_audioBuffer;
-    uint m_audioBufferFill;
+    unsigned int m_audioBufferFill;
+    AudioVector m_audioReadBuffer;
+    unsigned int m_audioReadBufferFill;
     AudioFifo m_audioFifo;
 
     int m_feedbackAudioSampleRate;
@@ -102,6 +106,8 @@ private:
     std::ifstream *m_ifstream;
     CWKeyer m_cwKeyer;
 
+    QMutex m_mutex;
+
     static const int m_levelNbSamples;
 
     void processOneSample(Complex& ci);
@@ -110,6 +116,9 @@ private:
     void pushFeedback(Real sample);
     void calculateLevel(Real& sample);
     void modulateSample();
+
+private slots:
+    void handleAudio();
 };