DSD demod: allow use of audio rates that are integer multiples of 8k other than 48k (x2,3,4,5)

plugins/channelrx/demoddsd/dsddecoder.cpp

@@ -41,6 +41,11 @@ void DSDDecoder::set48k(bool to48k)
     m_decoder.setUpsampling(to48k ? 6 : 0);
 }
 
+void DSDDecoder::setUpsampling(int upsampling)
+{
+    m_decoder.setUpsampling(upsampling);
+}
+
 void DSDDecoder::setBaudRate(int baudRate)
 {
     if (baudRate == 2400)

plugins/channelrx/demoddsd/dsddecoder.h

@@ -72,6 +72,7 @@ public:
     void setSymbolPLLLock(bool pllLock) { m_decoder.setSymbolPLLLock(pllLock); }
     void useHPMbelib(bool useHP) { m_decoder.useHPMbelib(useHP); }
     void set48k(bool to48k);
+    void setUpsampling(int upsampling);
 
 private:
     DSDcc::DSDDecoder m_decoder;

plugins/channelrx/demoddsd/dsddemod.cpp

@@ -238,7 +238,7 @@ void DSDDemod::feed(const SampleVector::const_iterator& begin, const SampleVecto
                                 m_settings.m_volume * 10.0,
                                 m_settings.m_tdmaStereo ? 1 : 3, // left or both channels
                                 m_settings.m_highPassFilter,
-                                m_audioSampleRate != 8000, // upsample to 48k unless native 8k
+                                m_audioSampleRate/8000, // upsample from native 8k
                                 &m_audioFifo1);
                     }
 
@@ -255,7 +255,7 @@ void DSDDemod::feed(const SampleVector::const_iterator& begin, const SampleVecto
                                 m_settings.m_volume * 10.0,
                                 m_settings.m_tdmaStereo ? 2 : 3, // right or both channels
                                 m_settings.m_highPassFilter,
-                                m_audioSampleRate != 8000, // upsample to 48k unless native 8k
+                                m_audioSampleRate/8000, // upsample from native 8k
                                 &m_audioFifo2);
                     }
 
@@ -412,14 +412,15 @@ bool DSDDemod::handleMessage(const Message& cmd)
 
 void DSDDemod::applyAudioSampleRate(int sampleRate)
 {
-    qDebug("DSDDemod::applyAudioSampleRate: %d", sampleRate);
+    int upsampling = sampleRate / 8000;
 
-    if ((sampleRate != 48000) && (sampleRate != 8000)) {
-        qWarning("DSDDemod::applyAudioSampleRate: audio does not work properly with sample rates other than 48 or 8 kS/s");
+    qDebug("DSDDemod::applyAudioSampleRate: audio rate: %d upsample by %d", sampleRate, upsampling);
+
+    if (sampleRate % 8000 != 0) {
+        qDebug("DSDDemod::applyAudioSampleRate: audio will sound best with sample rates that are integer multiples of 8 kS/s");
     }
 
-    m_dsdDecoder.set48k(sampleRate != 8000);
-
+    m_dsdDecoder.setUpsampling(upsampling);
     m_audioSampleRate = sampleRate;
 }
 

plugins/channelrx/demoddsd/dsddemodplugin.cpp

@@ -25,7 +25,7 @@
 
 const PluginDescriptor DSDDemodPlugin::m_pluginDescriptor = {
 	QString("DSD Demodulator"),
-	QString("3.14.4"),
+	QString("3.14.5"),
 	QString("(c) Edouard Griffiths, F4EXB"),
 	QString("https://github.com/f4exb/sdrangel"),
 	true,