Allow the FM network sample rate to be specified.

Conf.cpp

@@ -268,6 +268,7 @@ m_fmGatewayAddress(),
 m_fmGatewayPort(0U),
 m_fmLocalAddress(),
 m_fmLocalPort(0U),
+m_fmSampleRate(8000U),
 m_fmNetworkModeHang(3U),
 m_fmNetworkDebug(false),
 m_ax25NetworkEnabled(false),
@@ -933,6 +934,8 @@ bool CConf::read()
 				m_fmGatewayAddress = value;
 			else if (::strcmp(key, "GatewayPort") == 0)
 				m_fmGatewayPort = (unsigned int)::atoi(value);
+			else if (::strcmp(key, "SampleRate") == 0)
+				m_fmSampleRate = (unsigned int)::atoi(value);
 			else if (::strcmp(key, "ModeHang") == 0)
 				m_fmNetworkModeHang = (unsigned int)::atoi(value);
 			else if (::strcmp(key, "Debug") == 0)
@@ -2054,6 +2057,11 @@ unsigned int CConf::getFMLocalPort() const
 	return m_fmLocalPort;
 }
 
+unsigned int CConf::getFMSampleRate() const
+{
+	return m_fmSampleRate;
+}
+
 unsigned int CConf::getFMNetworkModeHang() const
 {
 	return m_fmNetworkModeHang;

Conf.h

@@ -279,6 +279,7 @@ public:
   unsigned int getFMGatewayPort() const;
   std::string  getFMLocalAddress() const;
   unsigned int getFMLocalPort() const;
+  unsigned int getFMSampleRate() const;
   unsigned int getFMNetworkModeHang() const;
   bool         getFMNetworkDebug() const;
 
@@ -569,6 +570,7 @@ private:
   unsigned int m_fmGatewayPort;
   std::string  m_fmLocalAddress;
   unsigned int m_fmLocalPort;
+  unsigned int m_fmSampleRate;
   unsigned int m_fmNetworkModeHang;
   bool         m_fmNetworkDebug;
 

FMControl.cpp

@@ -89,7 +89,7 @@ bool CFMControl::writeModem(const unsigned char* data, unsigned int length)
 
         unsigned int pack = 0U;
         unsigned char* packPointer = (unsigned char*)&pack;
-        unsigned short out[168U];
+        float out[168U];
         unsigned int nOut = 0U;
         short unpackedSamples[2U];
 
@@ -102,28 +102,24 @@ bool CFMControl::writeModem(const unsigned char* data, unsigned int length)
             unpackedSamples[0U] = short(int(pack >> 12) - 2048);
 
             //process unpacked sample pair
-            for(unsigned char j = 0U; j < 2U; j++) {
+            for (unsigned char j = 0U; j < 2U; j++) {
-                //Convert to float (-1.0 to +1.0)
+                // Convert to float (-1.0 to +1.0)
                 float sampleFloat = float(unpackedSamples[j]) / 2048.0F;
 
-                //De-emphasise and remove CTCSS
+                // De-emphasise and remove CTCSS
                 sampleFloat = m_deemphasis->filter(sampleFloat);
-                sampleFloat = m_filterStage3->filter(m_filterStage2->filter(m_filterStage1->filter(sampleFloat)));
+                out[nOut++] = m_filterStage3->filter(m_filterStage2->filter(m_filterStage1->filter(sampleFloat)));
-
-                // Repack the float data to 16 bit unsigned
-                unsigned short sampleUShort = (unsigned short)((sampleFloat + 1.0F) * 32767.0F + 0.5F);
-                out[nOut++] = SWAP_BYTES_16(sampleUShort);
             }
         }
 
 #if defined(DUMP_RF_AUDIO)
         FILE * audiofile = fopen("./audiodump.bin", "ab");
         if(audiofile != NULL) {
-            fwrite(out, sizeof(unsigned short), nOut, audiofile);
+            fwrite(out, sizeof(float), nOut, audiofile);
             fclose(audiofile);
         }
 #endif
-        return m_network->writeData((unsigned char*)out, nOut * sizeof(unsigned short));
+        return m_network->writeData(out, nOut);
     }
 
     return true;
@@ -140,7 +136,7 @@ unsigned int CFMControl::readModem(unsigned char* data, unsigned int space)
     if (space > 252U)
         space = 252U;
 
-    unsigned short netData[168U];//modem can handle up to 168 samples at a time
+    unsigned short netData[168U]; // Modem can handle up to 168 samples at a time
     unsigned int length = m_network->read((unsigned char*)netData, 168U * sizeof(unsigned short));
     length /= sizeof(unsigned short);
     if (length == 0U)
@@ -150,7 +146,7 @@ unsigned int CFMControl::readModem(unsigned char* data, unsigned int space)
     unsigned char* packPointer = (unsigned char*)&pack;
     unsigned int nData = 0U;
 
-    for(unsigned int i = 0; i < length; i++) {
+    for (unsigned int i = 0; i < length; i++) {
         unsigned short netSample = SWAP_BYTES_16(netData[i]);
         
         // Convert the unsigned 16-bit data (+65535 - 0) to float (+1.0 - -1.0)

FMControl.h

@@ -45,11 +45,11 @@ private:
 	CFMNetwork* m_network;
     bool        m_enabled;
 	CRingBuffer<unsigned char> m_incomingRFAudio;
-	CIIRDirectForm1Filter * m_preemphasis;
+	CIIRDirectForm1Filter* m_preemphasis;
-	CIIRDirectForm1Filter * m_deemphasis;
+	CIIRDirectForm1Filter* m_deemphasis;
-	CIIRDirectForm1Filter * m_filterStage1;
+	CIIRDirectForm1Filter* m_filterStage1;
-	CIIRDirectForm1Filter * m_filterStage2;
+	CIIRDirectForm1Filter* m_filterStage2;
-	CIIRDirectForm1Filter * m_filterStage3;
+	CIIRDirectForm1Filter* m_filterStage3;
 };
 
 #endif

FMNetwork.cpp

@@ -27,10 +27,11 @@
 
 const unsigned int BUFFER_LENGTH = 500U;
 
-CFMNetwork::CFMNetwork(const std::string& localAddress, unsigned int localPort, const std::string& gatewayAddress, unsigned int gatewayPort, bool debug) :
+CFMNetwork::CFMNetwork(const std::string& localAddress, unsigned int localPort, const std::string& gatewayAddress, unsigned int gatewayPort, unsigned int sampleRate, bool debug) :
 m_socket(localAddress, localPort),
 m_address(),
 m_port(gatewayPort),
+m_sampleRate(sampleRate),
 m_debug(debug),
 m_enabled(false),
 m_buffer(2000U, "FM Network"),
@@ -38,12 +39,22 @@ m_pollTimer(1000U, 5U)
 {
 	assert(gatewayPort > 0U);
 	assert(!gatewayAddress.empty());
+	assert(sampleRate > 0U);
 
 	m_address = CUDPSocket::lookup(gatewayAddress);
+
+	int error;
+	m_incoming = ::src_new(SRC_SINC_FASTEST, 1, &error);
+	m_outgoing = ::src_new(SRC_SINC_FASTEST, 1, &error);
+
+	assert(m_incoming != NULL);
+	assert(m_outgoing != NULL);
 }
 
 CFMNetwork::~CFMNetwork()
 {
+	::src_delete(m_incoming);
+	::src_delete(m_outgoing);
 }
 
 bool CFMNetwork::open()
@@ -58,23 +69,53 @@ bool CFMNetwork::open()
 	return m_socket.open();
 }
 
-bool CFMNetwork::writeData(const unsigned char* data, unsigned int length)
+bool CFMNetwork::writeData(const float* data, unsigned int nSamples)
 {
+	assert(m_outgoing != NULL);
 	assert(data != NULL);
+	assert(nSamples > 0U);
 
-	unsigned char buffer[500U];
+	float out[1000U];
-	::memset(buffer, 0x00U, 500U);
+	SRC_DATA src;
+
+	if (m_sampleRate != 8000U) {
+		src.data_in = data;
+		src.data_out = out;
+		src.input_frames = nSamples;
+		src.output_frames = 1000;
+		src.end_of_input = 0;
+		src.src_ratio = double(m_sampleRate) / 8000.0;
+
+		int ret = ::src_process(m_outgoing, &src);
+		if (ret != 0) {
+			LogError("Error up/downsampling of the output audio has an error - %s", src_strerror(ret));
+			return false;
+		}
+	} else {
+		src.data_out = data;
+		src.output_frames_gen = nSamples;
+	}
+
+	unsigned int length = 3U;
+
+	unsigned char buffer[1500U];
+	::memset(buffer, 0x00U, 1500U);
 
 	buffer[0U] = 'F';
 	buffer[1U] = 'M';
 	buffer[2U] = 'D';
 
-	::memcpy(buffer + 3U, data, length);
+	for (long i = 0L; i < src.output_frames_gen; i++) {
+		unsigned short val = (unsigned short)((src.data_out[i] + 1.0F) * 32767.0F + 0.5F);
+
+		buffer[length++] = (val >> 8) & 0xFFU;
+		buffer[length++] = (val >> 0) & 0xFFU;
+	}
 
 	if (m_debug)
-		CUtils::dump(1U, "FM Network Data Sent", buffer, length + 3U);
+		CUtils::dump(1U, "FM Network Data Sent", buffer, length);
 
-	return m_socket.write(buffer, length + 3U, m_address, m_port);
+	return m_socket.write(buffer, length, m_address, m_port);
 }
 
 bool CFMNetwork::writeEOT()
@@ -131,29 +172,67 @@ void CFMNetwork::clock(unsigned int ms)
 	m_buffer.addData(buffer + 3U, length - 3U);
 }
 
-unsigned int CFMNetwork::read(unsigned char* data, unsigned int space)
+unsigned int CFMNetwork::read(float* data, unsigned int nSamples)
 {
+	assert(m_incoming != NULL);
 	assert(data != NULL);
+	assert(nSamples > 0U);
 
-
+	unsigned int bytes = m_buffer.dataSize() / sizeof(unsigned short);
-	unsigned int bytes = m_buffer.dataSize();
 	if (bytes == 0U)
 		return 0U;
 
-	if (bytes < space)
+	if (bytes < nSamples)
-		space = bytes;
+		nSamples = bytes;
 
-	//we store usignedshorts, therefore ensure we always return and even number of data
+	unsigned char buffer[1500U];
-	if(space > 0 && space % 2 != 0)
+	m_buffer.getData(buffer, nSamples * sizeof(unsigned short));
-		space--;//round down to multiple of 2
 
-	m_buffer.getData(data, space);
+	SRC_DATA src;
 
-	return space;
+	if (m_sampleRate != 8000U) {
+		float in[750U];
+
+		unsigned int j = 0U;
+		for (unsigned int i = 0U; i < nSamples; i++) {
+			unsigned short val = ((buffer[j++] & 0xFFU) << 8) + ((buffer[j++] & 0xFFU) << 0);
+			in[i] = (float(val) - 32768.0F) / 32768.0F;
+		}
+
+		src.data_in = in;
+		src.data_out = data;
+		src.input_frames = nSamples;
+		src.output_frames = 750;
+		src.end_of_input = 0;
+		src.src_ratio = 8000.0 / double(m_sampleRate);
+
+		int ret = ::src_process(m_incoming, &src);
+		if (ret != 0) {
+			LogError("Error up/downsampling of the input audio has an error - %s", src_strerror(ret));
+			return 0U;
+		}
+
+		return src.output_frames_gen;
+	} else {
+		unsigned int j = 0U;
+		for (unsigned int i = 0U; i < nSamples; i++) {
+			unsigned short val = ((buffer[j++] & 0xFFU) << 8) + ((buffer[j++] & 0xFFU) << 0);
+			data[i] = (float(val) - 32768.0F) / 32768.0F;
+		}
+
+		return nSamples;
+	}
 }
 
 void CFMNetwork::reset()
 {
+	assert(m_incoming != NULL);
+	assert(m_outgoing != NULL);
+
+	m_buffer.clear();
+
+	::src_reset(m_incoming);
+	::src_reset(m_outgoing);
 }
 
 void CFMNetwork::close()
@@ -168,7 +247,7 @@ void CFMNetwork::enable(bool enabled)
 	if (enabled && !m_enabled)
 		reset();
 	else if (!enabled && m_enabled)
-		m_buffer.clear();
+		reset();
 
 	m_enabled = enabled;
 }

FMNetwork.h

@@ -23,23 +23,25 @@
 #include "UDPSocket.h"
 #include "Timer.h"
 
+#include <samplerate.h>
+
 #include <cstdint>
 #include <string>
 
 class CFMNetwork {
 public:
-	CFMNetwork(const std::string& myAddress, unsigned int myPort, const std::string& gatewayAddress, unsigned int gatewayPort, bool debug);
+	CFMNetwork(const std::string& myAddress, unsigned int myPort, const std::string& gatewayAddress, unsigned int gatewayPort, unsigned int sampleRate, bool debug);
 	~CFMNetwork();
 
 	bool open();
 
 	void enable(bool enabled);
 
-    bool writeData(const unsigned char* data, unsigned int length);
+    bool writeData(const float* data, unsigned int nSamples);
 
     bool writeEOT();
 
-    unsigned int read(unsigned char* data, unsigned int space);
+    unsigned int read(float* data, unsigned int nSamples);
 
 	void reset();
 
@@ -51,10 +53,13 @@ private:
 	CUDPSocket     m_socket;
 	in_addr        m_address;
 	unsigned int   m_port;
+	unsigned int   m_sampleRate;
 	bool           m_debug;
 	bool           m_enabled;
 	CRingBuffer<unsigned char> m_buffer;
 	CTimer         m_pollTimer;
+	SRC_STATE*     m_incoming;
+	SRC_STATE*     m_outgoing;
 
 	bool writePoll();
 };

MMDVM.ini

@@ -250,6 +250,7 @@ LocalAddress=127.0.0.1
 LocalPort=3810
 GatewayAddress=127.0.0.1
 GatewayPort=4810
+SampleRate=8000
 # ModeHang=3
 Debug=0
 

MMDVMHost.cpp

@@ -1690,6 +1690,7 @@ bool CMMDVMHost::createFMNetwork()
 	unsigned int gatewayPort   = m_conf.getFMGatewayPort();
 	std::string localAddress   = m_conf.getFMLocalAddress();
 	unsigned int localPort     = m_conf.getFMLocalPort();
+	unsigned int sampleRate    = m_conf.getFMSampleRate();
 	m_fmNetModeHang            = m_conf.getFMNetworkModeHang();
 	bool debug                 = m_conf.getFMNetworkDebug();
 
@@ -1698,9 +1699,10 @@ bool CMMDVMHost::createFMNetwork()
 	LogInfo("    Gateway Port: %u", gatewayPort);
 	LogInfo("    Local Address: %s", localAddress.c_str());
 	LogInfo("    Local Port: %u", localPort);
+	LogInfo("    Sample Rate: %u", sampleRate);
 	LogInfo("    Mode Hang: %us", m_fmNetModeHang);
 
-	m_fmNetwork = new CFMNetwork(localAddress, localPort, gatewayAddress, gatewayPort, debug);
+	m_fmNetwork = new CFMNetwork(localAddress, localPort, gatewayAddress, gatewayPort, sampleRate, debug);
 
 	bool ret = m_fmNetwork->open();
 	if (!ret) {

Version.h

@@ -19,6 +19,6 @@
 #if !defined(VERSION_H)
 #define	VERSION_H
 
-const char* VERSION = "20200713";
+const char* VERSION = "20200727";
 
 #endif