WASAPI: Survive switching to a mono device. Fixes #14591

It's a little flaky whether it tries to switch or not, but you can at
least use Windows' device selector to switch back and forth.

Should maybe also add an option to not follow the default device... Not
sure.

Windows/WASAPIStream.cpp

@@ -5,6 +5,7 @@
 #include "Common/Log.h"
 #include "Core/Reporting.h"
 #include "Core/Util/AudioFormat.h"
+#include "Common/Data/Encoding/Utf8.h"
 
 #include "Common/Thread/ThreadUtil.h"
 
@@ -50,6 +51,11 @@ public:
 		if (!device || FAILED(device->GetId(&currentDevice_))) {
 			currentDevice_ = nullptr;
 		}
+
+		if (currentDevice_) {
+			INFO_LOG(SCEAUDIO, "Switching to WASAPI audio device: '%s'", GetDeviceName(currentDevice_).c_str());
+		}
+
 		deviceChanged_ = false;
 	}
 
@@ -89,7 +95,7 @@ public:
 	HRESULT STDMETHODCALLTYPE OnDefaultDeviceChanged(EDataFlow flow, ERole role, LPCWSTR pwstrDeviceId) override {
 		std::lock_guard<std::mutex> guard(lock_);
 
-		if (flow != eRender || role != eMultimedia) {
+		if (flow != eRender || role != eConsole) {
 			// Not relevant to us.
 			return S_OK;
 		}
@@ -105,7 +111,7 @@ public:
 		}
 
 		deviceChanged_ = true;
-		INFO_LOG(SCEAUDIO, "New default WASAPI audio device detected");
+		INFO_LOG(SCEAUDIO, "New default eRender/eConsole WASAPI audio device detected: '%s'", GetDeviceName(pwstrDeviceId).c_str());
 		return S_OK;
 	}
 
@@ -136,6 +142,45 @@ public:
 		return S_OK;
 	}
 
+	std::string GetDeviceName(LPCWSTR pwstrId)
+	{
+		HRESULT hr = S_OK;
+		IMMDevice *pDevice = NULL;
+		IPropertyStore *pProps = NULL;
+		PROPVARIANT varString;
+		PropVariantInit(&varString);
+
+		if (_pEnumerator == NULL)
+		{
+			// Get enumerator for audio endpoint devices.
+			hr = CoCreateInstance(__uuidof(MMDeviceEnumerator),
+				NULL, CLSCTX_INPROC_SERVER,
+				__uuidof(IMMDeviceEnumerator),
+				(void**)&_pEnumerator);
+		}
+		if (hr == S_OK)
+		{
+			hr = _pEnumerator->GetDevice(pwstrId, &pDevice);
+		}
+		if (hr == S_OK)
+		{
+			hr = pDevice->OpenPropertyStore(STGM_READ, &pProps);
+		}
+		if (hr == S_OK)
+		{
+			// Get the endpoint device's friendly-name property.
+			hr = pProps->GetValue(PKEY_Device_FriendlyName, &varString);
+		}
+
+		std::string name = ConvertWStringToUTF8((hr == S_OK) ? varString.pwszVal : L"null device");
+
+		PropVariantClear(&varString);
+
+		SAFE_RELEASE(pProps)
+		SAFE_RELEASE(pDevice)
+		return name;
+	}
+
 private:
 	std::mutex lock_;
 	LONG _cRef = 1;
@@ -236,7 +281,7 @@ WASAPIAudioThread::~WASAPIAudioThread() {
 
 bool WASAPIAudioThread::ActivateDefaultDevice() {
 	_assert_(device_ == nullptr);
-	HRESULT hresult = deviceEnumerator_->GetDefaultAudioEndpoint(eRender, eMultimedia, &device_);
+	HRESULT hresult = deviceEnumerator_->GetDefaultAudioEndpoint(eRender, eConsole, &device_);
 	if (FAILED(hresult) || device_ == nullptr)
 		return false;
 
@@ -341,7 +386,7 @@ bool WASAPIAudioThread::ValidateFormat(const WAVEFORMATEXTENSIBLE *fmt) {
 
 	if (fmt->Format.wFormatTag == WAVE_FORMAT_EXTENSIBLE) {
 		if (!memcmp(&fmt->SubFormat, &KSDATAFORMAT_SUBTYPE_IEEE_FLOAT, sizeof(fmt->SubFormat))) {
-			if (fmt->Format.nChannels >= 2)
+			if (fmt->Format.nChannels >= 1)
 				format_ = Format::IEEE_FLOAT;
 		} else {
 			ERROR_LOG_REPORT_ONCE(unexpectedformat, SCEAUDIO, "Got unexpected WASAPI 0xFFFE stream format, expected float!");
@@ -350,7 +395,7 @@ bool WASAPIAudioThread::ValidateFormat(const WAVEFORMATEXTENSIBLE *fmt) {
 			}
 		}
 	} else if (fmt->Format.wFormatTag == WAVE_FORMAT_IEEE_FLOAT) {
-		if (fmt->Format.nChannels >= 2)
+		if (fmt->Format.nChannels >= 1)
 			format_ = Format::IEEE_FLOAT;
 	} else {
 		ERROR_LOG_REPORT_ONCE(unexpectedformat2, SCEAUDIO, "Got unexpected non-extensible WASAPI stream format, expected extensible float!");
@@ -374,7 +419,8 @@ bool WASAPIAudioThread::PrepareFormat() {
 	const int numSamples = numBufferFrames * deviceFormat_->Format.nChannels;
 	if (format_ == Format::IEEE_FLOAT) {
 		memset(pData, 0, sizeof(float) * numSamples);
-		shortBuf_ = new short[numSamples];
+		// This buffer is always stereo - PPSSPP writes to it.
+		shortBuf_ = new short[numBufferFrames * 2];
 	} else if (format_ == Format::PCM16) {
 		memset(pData, 0, sizeof(short) * numSamples);
 	}
@@ -394,6 +440,7 @@ void WASAPIAudioThread::Run() {
 	HRESULT hresult = CoCreateInstance(CLSID_MMDeviceEnumerator,
 		nullptr, /* Object is not created as the part of the aggregate */
 		CLSCTX_ALL, IID_IMMDeviceEnumerator, (void **)&deviceEnumerator_);
+
 	if (FAILED(hresult) || deviceEnumerator_ == nullptr)
 		return;
 
@@ -446,8 +493,14 @@ void WASAPIAudioThread::Run() {
 			int chans = deviceFormat_->Format.nChannels;
 			switch (format_) {
 			case Format::IEEE_FLOAT:
-				callback_(shortBuf_, pNumAvFrames, 16, sampleRate_, chans);
-				if (chans == 2) {
+				callback_(shortBuf_, pNumAvFrames, 16, sampleRate_);
+				if (chans == 1) {
+					float *ptr = (float *)pData;
+					memset(ptr, 0, pNumAvFrames * chans * sizeof(float));
+					for (UINT32 i = 0; i < pNumAvFrames; i++) {
+						ptr[i * chans + 0] = 0.5f * ((float)shortBuf_[i * 2] + (float)shortBuf_[i * 2 + 1]) * (1.0f / 32768.0f);
+					}
+				} else if (chans == 2) {
 					ConvertS16ToF32((float *)pData, shortBuf_, pNumAvFrames * chans);
 				} else if (chans > 2) {
 					float *ptr = (float *)pData;
@@ -459,7 +512,7 @@ void WASAPIAudioThread::Run() {
 				}
 				break;
 			case Format::PCM16:
-				callback_((short *)pData, pNumAvFrames, 16, sampleRate_, chans);
+				callback_((short *)pData, pNumAvFrames, 16, sampleRate_);
 				break;
 			}
 		}
@@ -482,6 +535,7 @@ void WASAPIAudioThread::Run() {
 
 			if (!ActivateDefaultDevice()) {
 				ERROR_LOG(SCEAUDIO, "WASAPI: Could not activate default device");
+				// TODO: Return to the old device here?
 				return;
 			}
 			notificationClient_->SetCurrentDevice(device_);