Tuning.

src/common/SoundSDL2.cxx

@@ -219,6 +219,18 @@ void SoundSDL2::adjustVolume(Int8 direction)
   myOSystem.frameBuffer().showMessage(message);
 }
 
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+uInt32 SoundSDL2::getFragmentSize() const
+{
+  return myHardwareSpec.size;
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+uInt32 SoundSDL2::getSampleRate() const
+{
+  return myHardwareSpec.freq;
+}
+
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void SoundSDL2::processFragment(Int16* stream, uInt32 length)
 {

src/common/SoundSDL2.hxx

@@ -96,6 +96,10 @@ class SoundSDL2 : public Sound
     */
     void adjustVolume(Int8 direction) override;
 
+    uInt32 getFragmentSize() const override;
+
+    uInt32 getSampleRate() const override;
+
   protected:
     /**
       Invoked by the sound callback to process the next sound fragment.

src/emucore/Console.cxx

@@ -72,7 +72,6 @@
 
 namespace {
   constexpr uInt8 YSTART_EXTRA = 2;
-  constexpr uInt8 AUDIO_QUEUE_CAPACITY_FRAGMENTS = 30;
   constexpr uInt8 AUDIO_QUEUE_HALF_FRAMES_PER_FRAGMENT = 1;
 }
 
@@ -722,9 +721,11 @@ void Console::createAudioQueue()
       throw runtime_error("invalid console timing");
   }
 
+  uInt32 queueSize = (2 * myOSystem.sound().getFragmentSize() * sampleRate) / (myOSystem.sound().getSampleRate() * fragmentSize);
+
   myAudioQueue = make_shared<AudioQueue>(
     fragmentSize,
-    AUDIO_QUEUE_CAPACITY_FRAGMENTS,
+    queueSize > 0 ? queueSize : 1,
     myProperties.get(Cartridge_Sound) == "STEREO",
     sampleRate
   );

src/emucore/OSystem.cxx

@@ -600,7 +600,7 @@ void OSystem::mainLoop()
     virtualTime += duration_cast<high_resolution_clock::duration>(timeslice);
     time_point<high_resolution_clock> now = high_resolution_clock::now();
 
-    if (duration_cast<duration<double>>(now - virtualTime).count() > 0.5)
+    if (duration_cast<duration<double>>(now - virtualTime).count() > 0)
       virtualTime = now;
     else if (virtualTime > now) {
       if (busyWait && cycles >= 0) {

src/emucore/Sound.hxx

@@ -66,6 +66,16 @@ class Sound
     */
     virtual void mute(bool state) = 0;
 
+    /**
+      Get the fragment size.
+    */
+    virtual uInt32 getFragmentSize() const = 0;
+
+    /**
+      Get the sample rate.
+    */
+    virtual uInt32 getSampleRate() const = 0;
+
     /**
       Reset the sound device.
     */