@@ -31,6 +31,7 @@ - Libretro now supports BIOS, rumble and solar sensor
  - Implement BIOS call Stop, for sleep mode
  - Automatically load patches, if found
  - Improved video synchronization
+ - Configurable audio output sample rate
 Bugfixes:
  - ARM7: Fix SWI and IRQ timings
  - GBA Audio: Force audio FIFOs to 32-bit

@@ -247,6 +247,7 @@ unsigned audioBuffers;
 	if (_lookupUIntValue(config, "audioBuffers", &audioBuffers)) {
 		opts->audioBuffers = audioBuffers;
 	}
+	_lookupUIntValue(config, "sampleRate", &opts->sampleRate);
 
 	int fakeBool;
 	if (_lookupIntValue(config, "useBios", &fakeBool)) {
@@ -305,6 +306,7 @@ ConfigurationSetIntValue(&config->defaultsTable, 0, "rewindBufferCapacity", opts->rewindBufferCapacity);
 	ConfigurationSetIntValue(&config->defaultsTable, 0, "rewindBufferInterval", opts->rewindBufferInterval);
 	ConfigurationSetFloatValue(&config->defaultsTable, 0, "fpsTarget", opts->fpsTarget);
 	ConfigurationSetUIntValue(&config->defaultsTable, 0, "audioBuffers", opts->audioBuffers);
+	ConfigurationSetUIntValue(&config->defaultsTable, 0, "sampleRate", opts->sampleRate);
 	ConfigurationSetIntValue(&config->defaultsTable, 0, "audioSync", opts->audioSync);
 	ConfigurationSetIntValue(&config->defaultsTable, 0, "videoSync", opts->videoSync);
 	ConfigurationSetIntValue(&config->defaultsTable, 0, "fullscreen", opts->fullscreen);

@@ -29,6 +29,7 @@ int rewindBufferCapacity;
 	int rewindBufferInterval;
 	float fpsTarget;
 	size_t audioBuffers;
+	unsigned sampleRate;
 
 	int fullscreen;
 	int width;

@@ -31,6 +31,7 @@ AudioProcessor(QObject* parent = nullptr);
 
 	virtual void setInput(GBAThread* input);
 	int getBufferSamples() const { return m_samples; }
+	virtual unsigned sampleRate() const = 0;
 
 public slots:
 	virtual void start() = 0;
@@ -39,7 +40,7 @@
 	virtual void setBufferSamples(int samples) = 0;
 	virtual void inputParametersChanged() = 0;
 
-	virtual unsigned sampleRate() const = 0;
+	virtual void requestSampleRate(unsigned) = 0;
 
 protected:
 	GBAThread* input() { return m_context; }

@@ -20,6 +20,7 @@ AudioProcessorQt::AudioProcessorQt(QObject* parent)
 	: AudioProcessor(parent)
 	, m_audioOutput(nullptr)
 	, m_device(nullptr)
+	, m_sampleRate(44100)
 {
 }
 
@@ -45,7 +46,7 @@ }
 
 	if (!m_audioOutput) {
 		QAudioFormat format;
-		format.setSampleRate(44100);
+		format.setSampleRate(m_sampleRate);
 		format.setChannelCount(2);
 		format.setSampleSize(16);
 		format.setCodec("audio/pcm");
@@ -81,6 +82,15 @@
 void AudioProcessorQt::inputParametersChanged() {
 	if (m_device) {
 		m_device->setFormat(m_audioOutput->format());
+	}
+}
+
+void AudioProcessorQt::requestSampleRate(unsigned rate) {
+	m_sampleRate = rate;
+	if (m_device) {
+		QAudioFormat format(m_audioOutput->format());
+		format.setSampleRate(rate);
+		m_device->setFormat(format);
 	}
 }
 

@@ -20,6 +20,7 @@ public:
 	AudioProcessorQt(QObject* parent = nullptr);
 
 	virtual void setInput(GBAThread* input);
+	virtual unsigned sampleRate() const override;
 
 public slots:
 	virtual void start();
@@ -28,11 +29,12 @@
 	virtual void setBufferSamples(int samples);
 	virtual void inputParametersChanged();
 
-	virtual unsigned sampleRate() const override;
+	virtual void requestSampleRate(unsigned) override;
 
 private:
 	QAudioOutput* m_audioOutput;
 	AudioDevice* m_device;
+	unsigned m_sampleRate;
 };
 
 }

@@ -15,7 +15,7 @@ using namespace QGBA;
 
 AudioProcessorSDL::AudioProcessorSDL(QObject* parent)
 	: AudioProcessor(parent)
-	, m_audio()
+	, m_audio{ 2048, 44100 }
 {
 }
 
@@ -55,6 +55,18 @@
 void AudioProcessorSDL::inputParametersChanged() {
 }
 
+void AudioProcessorSDL::requestSampleRate(unsigned rate) {
+	m_audio.sampleRate = rate;
+	if (m_audio.thread) {
+		GBASDLDeinitAudio(&m_audio);
+		GBASDLInitAudio(&m_audio, input());
+	}
+}
+
 unsigned AudioProcessorSDL::sampleRate() const {
-	return m_audio.obtainedSpec.freq;
+	if (m_audio.thread) {
+		return m_audio.obtainedSpec.freq;
+	} else {
+		return 0;
+	}
 }

@@ -22,6 +22,8 @@ public:
 	AudioProcessorSDL(QObject* parent = nullptr);
 	~AudioProcessorSDL();
 
+	virtual unsigned sampleRate() const override;
+
 public slots:
 	virtual void start();
 	virtual void pause();
@@ -29,7 +31,7 @@
 	virtual void setBufferSamples(int samples);
 	virtual void inputParametersChanged();
 
-	virtual unsigned sampleRate() const override;
+	virtual void requestSampleRate(unsigned) override;
 
 private:
 	GBASDLAudio m_audio;

@@ -53,6 +53,7 @@ ::exit(0);
 		return;
 	}
 
+	AudioProcessor::setDriver(static_cast<AudioProcessor::Driver>(m_configController.getQtOption("audioDriver").toInt()));
 	Window* w = new Window(&m_configController);
 	connect(w, &Window::destroyed, [this]() {
 		m_windows[0] = nullptr;
@@ -66,9 +67,6 @@ w->loadConfig();
 	}
 	freeArguments(&args);
 	w->show();
-
-	AudioProcessor::setDriver(static_cast<AudioProcessor::Driver>(m_configController.getQtOption("audioDriver").toInt()));
-	w->controller()->reloadAudioDriver();
 
 	w->controller()->setMultiplayerController(&m_multiplayer);
 }

@@ -87,7 +87,9 @@ setLuminanceLevel(0);
 
 	m_threadContext.startCallback = [](GBAThread* context) {
 		GameController* controller = static_cast<GameController*>(context->userData);
-		controller->m_audioProcessor->setInput(context);
+		if (controller->m_audioProcessor) {
+			controller->m_audioProcessor->setInput(context);
+		}
 		context->gba->luminanceSource = &controller->m_lux;
 		GBARTCGenericSourceInit(&controller->m_rtc, context->gba);
 		context->gba->rtcSource = &controller->m_rtc.d;
@@ -588,10 +590,21 @@ updateKeys();
 }
 
 void GameController::setAudioBufferSamples(int samples) {
-	threadInterrupt();
-	redoSamples(samples);
-	threadContinue();
-	QMetaObject::invokeMethod(m_audioProcessor, "setBufferSamples", Q_ARG(int, samples));
+	if (m_audioProcessor) {
+		threadInterrupt();
+		redoSamples(samples);
+		threadContinue();
+		QMetaObject::invokeMethod(m_audioProcessor, "setBufferSamples", Q_ARG(int, samples));
+	}
+}
+
+void GameController::setAudioSampleRate(unsigned rate) {
+	if (m_audioProcessor) {
+		threadInterrupt();
+		redoSamples(m_audioProcessor->getBufferSamples());
+		threadContinue();
+		QMetaObject::invokeMethod(m_audioProcessor, "requestSampleRate", Q_ARG(unsigned, rate));
+	}
 }
 
 void GameController::setAudioChannelEnabled(int channel, bool enable) {
@@ -644,7 +657,9 @@ m_threadContext.fpsTarget = fps;
 	if (m_turbo && m_turboSpeed > 0) {
 		m_threadContext.fpsTarget *= m_turboSpeed;
 	}
-	redoSamples(m_audioProcessor->getBufferSamples());
+	if (m_audioProcessor) {
+		redoSamples(m_audioProcessor->getBufferSamples());
+	}
 	threadContinue();
 }
 
@@ -801,7 +816,9 @@ m_threadContext.fpsTarget = m_fpsTarget * m_turboSpeed;
 		m_threadContext.sync.audioWait = true;
 		m_threadContext.sync.videoFrameWait = false;
 	}
-	redoSamples(m_audioProcessor->getBufferSamples());
+	if (m_audioProcessor) {
+		redoSamples(m_audioProcessor->getBufferSamples());
+	}
 	threadContinue();
 }
 
@@ -830,11 +847,21 @@ }
 #endif
 
 void GameController::reloadAudioDriver() {
-	QMetaObject::invokeMethod(m_audioProcessor, "pause", Qt::BlockingQueuedConnection);
-	int samples = m_audioProcessor->getBufferSamples();
-	delete m_audioProcessor;
+	int samples = 0;
+	unsigned sampleRate = 0;
+	if (m_audioProcessor) {
+		QMetaObject::invokeMethod(m_audioProcessor, "pause", Qt::BlockingQueuedConnection);
+		samples = m_audioProcessor->getBufferSamples();
+		sampleRate = m_audioProcessor->sampleRate();
+		delete m_audioProcessor;
+	}
 	m_audioProcessor = AudioProcessor::create();
-	m_audioProcessor->setBufferSamples(samples);
+	if (samples) {
+		m_audioProcessor->setBufferSamples(samples);
+	}
+	if (sampleRate) {
+		m_audioProcessor->requestSampleRate(sampleRate);
+	}
 	m_audioProcessor->moveToThread(m_audioThread);
 	connect(this, SIGNAL(gameStarted(GBAThread*)), m_audioProcessor, SLOT(start()));
 	connect(this, SIGNAL(gameStopped(GBAThread*)), m_audioProcessor, SLOT(pause()));

@@ -119,6 +119,7 @@ void keyPressed(int key);
 	void keyReleased(int key);
 	void clearKeys();
 	void setAudioBufferSamples(int samples);
+	void setAudioSampleRate(unsigned rate);
 	void setAudioChannelEnabled(int channel, bool enable = true);
 	void setVideoLayerEnabled(int layer, bool enable = true);
 	void setFPSTarget(float fps);

@@ -127,6 +127,7 @@ connect(this, SIGNAL(shutdown()), m_display, SLOT(stopDrawing()));
 	connect(this, SIGNAL(shutdown()), m_controller, SLOT(closeGame()));
 	connect(this, SIGNAL(shutdown()), m_logView, SLOT(hide()));
 	connect(this, SIGNAL(audioBufferSamplesChanged(int)), m_controller, SLOT(setAudioBufferSamples(int)));
+	connect(this, SIGNAL(sampleRateChanged(unsigned)), m_controller, SLOT(setAudioSampleRate(unsigned)));
 	connect(this, SIGNAL(fpsTargetChanged(float)), m_controller, SLOT(setFPSTarget(float)));
 	connect(&m_fpsTimer, SIGNAL(timeout()), this, SLOT(showFPS()));
 	connect(m_display, &Display::hideCursor, [this]() {
@@ -195,12 +196,17 @@ if (opts->bios) {
 		m_controller->loadBIOS(opts->bios);
 	}
 
+	// TODO: Move these to ConfigController
 	if (opts->fpsTarget) {
 		emit fpsTargetChanged(opts->fpsTarget);
 	}
 
 	if (opts->audioBuffers) {
 		emit audioBufferSamplesChanged(opts->audioBuffers);
+	}
+
+	if (opts->sampleRate) {
+		emit sampleRateChanged(opts->sampleRate);
 	}
 
 	if (opts->width && opts->height) {

@@ -54,6 +54,7 @@ signals:
 	void startDrawing(GBAThread*);
 	void shutdown();
 	void audioBufferSamplesChanged(int samples);
+	void sampleRateChanged(unsigned samples);
 	void fpsTargetChanged(float target);
 
 public slots:

@@ -112,6 +112,10 @@
 	bool didFail = false;
 
 	renderer.audio.samples = context.audioBuffers;
+	renderer.audio.sampleRate = 44100;
+	if (opts.sampleRate) {
+		renderer.audio.sampleRate = opts.sampleRate;
+	}
 	if (!GBASDLInitAudio(&renderer.audio, &context)) {
 		didFail = true;
 	}

@@ -22,7 +22,7 @@ GBALog(0, GBA_LOG_ERROR, "Could not initialize SDL sound system: %s", SDL_GetError());
 		return false;
 	}
 
-	context->desiredSpec.freq = 44100;
+	context->desiredSpec.freq = context->sampleRate;
 	context->desiredSpec.format = AUDIO_S16SYS;
 	context->desiredSpec.channels = 2;
 	context->desiredSpec.samples = context->samples;

@@ -15,6 +15,7 @@
 struct GBASDLAudio {
 	// Input
 	size_t samples;
+	unsigned sampleRate;
 
 	// State
 	SDL_AudioSpec desiredSpec;