Merge pull request #20534 from hrydgard/refactor-audio

Add internal AudioBackend interface

CMakeLists.txt

@@ -842,6 +842,7 @@ add_library(Common STATIC
 	Common/Render/Text/draw_text_win.h
 	Common/Render/Text/draw_text_uwp.cpp
 	Common/Render/Text/draw_text_uwp.h
+	Common/Audio/AudioBackend.h
 	Common/System/Display.cpp
 	Common/System/Display.h
 	Common/System/System.h
@@ -2625,8 +2626,8 @@ add_dependencies(${CoreLibName} GitVersion)
 set(WindowsFiles
 	Windows/WindowsAudio.cpp
 	Windows/WindowsAudio.h
-	Windows/WASAPIStream.cpp
-	Windows/WASAPIStream.h
+	Windows/WASAPIContext.cpp
+	Windows/WASAPIContext.h
 	Windows/Debugger/BreakpointWindow.cpp
 	Windows/Debugger/BreakpointWindow.h
 	Windows/Debugger/DumpMemoryWindow.cpp

Common/Audio/AudioBackend.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include <string>
+#include <string_view>
+#include <vector>
+
+// Always 2 channels, 16-bit audio.
+typedef int (*StreamCallback)(short *buffer, int numSamples, int rate, void *userdata);
+
+// Note that the backend may override the passed in sample rate. The actual sample rate
+// should be returned by SampleRate though.
+class AudioBackend {
+public:
+	virtual ~AudioBackend() {}
+	virtual bool Init(StreamCallback _callback, void *userdata = nullptr) = 0;
+	virtual int SampleRate() const = 0;
+	virtual int PeriodFrames() const = 0;
+	virtual void FrameUpdate() {}
+};

Common/Common.vcxproj

@@ -361,6 +361,7 @@
     <ClInclude Include="Arm64Emitter.h" />
     <ClInclude Include="ArmCommon.h" />
     <ClInclude Include="ArmEmitter.h" />
+    <ClInclude Include="Audio\AudioBackend.h" />
     <ClInclude Include="BitScan.h" />
     <ClInclude Include="BitSet.h" />
     <ClInclude Include="Buffer.h" />

Common/Common.vcxproj.filters

@@ -685,6 +685,9 @@
     <ClInclude Include="..\ext\imgui\imgui_extras.h">
       <Filter>ext\imgui</Filter>
     </ClInclude>
+    <ClInclude Include="Audio\AudioBackend.h">
+      <Filter>Audio</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="ABI.cpp" />
@@ -1410,6 +1413,9 @@
     <Filter Include="ext\sol">
       <UniqueIdentifier>{ec7d8691-bb7f-4689-b66a-cb60c1f48afd}</UniqueIdentifier>
     </Filter>
+    <Filter Include="Audio">
+      <UniqueIdentifier>{92746a51-33a9-4a00-af10-3538322f04f0}</UniqueIdentifier>
+    </Filter>
   </ItemGroup>
   <ItemGroup>
     <Text Include="..\ext\libpng17\CMakeLists.txt">

Common/Log/LogManager.cpp

@@ -164,16 +164,17 @@ LogManager::LogManager() {
 	stdioUseColor_ = isatty(fileno(stdout));
 #endif
 
-#if PPSSPP_PLATFORM(WINDOWS) && !PPSSPP_PLATFORM(UWP)
+#if PPSSPP_PLATFORM(WINDOWS)
 	if (IsDebuggerPresent()) {
 		outputs_ |= LogOutput::DebugString;
 	}
-
+#if !PPSSPP_PLATFORM(UWP)
 	if (!consoleLog_) {
 		consoleLog_ = new ConsoleListener();
 	}
 	outputs_ |= LogOutput::WinConsole;
 #endif
+#endif
 }
 
 LogManager::~LogManager() {

Common/System/NativeApp.h

@@ -15,6 +15,7 @@ struct KeyInput;
 struct AxisInput;
 
 class GraphicsContext;
+class AudioBackend;
 
 // The first function to get called, just write strings to the two pointers.
 // This might get called multiple times in some implementations, you must be able to handle that.
@@ -64,7 +65,7 @@ void NativeFrame(GraphicsContext *graphicsContext);
 // the rest of the game, so be careful with synchronization.
 // Returns the number of samples actually output. The app should do everything it can
 // to fill the buffer completely.
-int NativeMix(short *audio, int num_samples, int sampleRateHz);
+int NativeMix(short *audio, int num_samples, int sampleRateHz, void *userdata);
 
 // Called when it's time to shutdown. After this has been called,
 // no more calls to any other function will be made from the framework
@@ -92,3 +93,4 @@ bool Native_IsWindowHidden();
 // TODO: Feels like this belongs elsewhere.
 bool Native_UpdateScreenScale(int width, int height, float customScale);
 
+AudioBackend *System_CreateAudioBackend();

Core/Config.cpp

@@ -771,7 +771,6 @@ static int DefaultAchievementVolume() {
 
 static const ConfigSetting soundSettings[] = {
 	ConfigSetting("Enable", &g_Config.bEnableSound, true, CfgFlag::PER_GAME),
-	ConfigSetting("AudioBackend", &g_Config.iAudioBackend, 0, CfgFlag::PER_GAME),
 	ConfigSetting("ExtraAudioBuffering", &g_Config.bExtraAudioBuffering, false, CfgFlag::DEFAULT),
 	ConfigSetting("AudioBufferSize", &g_Config.iSDLAudioBufferSize, 256, CfgFlag::DEFAULT),
 

Core/Config.h

@@ -287,7 +287,6 @@ public:
 
 	// Sound
 	bool bEnableSound;
-	int iAudioBackend;
 	int iSDLAudioBufferSize;
 
 	// Legacy volume settings, 0-10. These get auto-upgraded and should not be used.

Core/ConfigValues.h

@@ -142,12 +142,6 @@ ENUM_CLASS_BITOPS(DisableHLEFlags);
 std::string GPUBackendToString(GPUBackend backend);
 GPUBackend GPUBackendFromString(std::string_view backend);
 
-enum AudioBackendType {
-	AUDIO_BACKEND_AUTO,
-	AUDIO_BACKEND_DSOUND,
-	AUDIO_BACKEND_WASAPI,
-};
-
 // For iIOTimingMethod.
 enum IOTimingMethods {
 	IOTIMING_FAST = 0,

Core/HLE/sceSas.cpp

@@ -344,7 +344,7 @@ static u32 sceSasSetVoice(u32 core, int voiceNum, u32 vagAddr, int size, int loo
 
 	u32 prevVagAddr = v.vagAddr;
 	bool reset = false;
-	if (v.type != VOICETYPE_VAG || v.vagAddr != vagAddr || v.vagSize != size || v.loop != loop) {
+	if (v.type != VOICETYPE_VAG || v.vagAddr != vagAddr || v.vagSize != size || v.loop != (loop != 0)) {
 		v.type = VOICETYPE_VAG;
 		reset = true;
 	}

Qt/QtMain.cpp

@@ -33,6 +33,7 @@
 #include "SDL_keyboard.h"
 #endif
 
+#include "Common/Audio/AudioBackend.h"
 #include "Common/System/NativeApp.h"
 #include "Common/System/Request.h"
 #include "Common/GPU/OpenGL/GLFeatures.h"
@@ -78,7 +79,7 @@ SDL_AudioSpec g_retFmt;
 static SDL_AudioDeviceID audioDev = 0;
 
 extern void mixaudio(void *userdata, Uint8 *stream, int len) {
-	NativeMix((short *)stream, len / 4, AUDIO_FREQ);
+	NativeMix((short *)stream, len / 4, AUDIO_FREQ, userdata);
 }
 
 static void InitSDLAudioDevice() {
@@ -444,6 +445,11 @@ void System_LaunchUrl(LaunchUrlType urlType, const char *url)
 	QDesktopServices::openUrl(QUrl(url));
 }
 
+AudioBackend *System_CreateAudioBackend() {
+	// Use legacy mechanisms.
+	return nullptr;
+}
+
 static int mainInternal(QApplication &a) {
 #ifdef MOBILE_DEVICE
 	emugl = new MainUI();

SDL/SDLMain.cpp

@@ -34,6 +34,7 @@ SDLJoystick *joystick = NULL;
 #include "Common/System/System.h"
 #include "Common/System/Request.h"
 #include "Common/System/NativeApp.h"
+#include "Common/Audio/AudioBackend.h"
 #include "ext/glslang/glslang/Public/ShaderLang.h"
 #include "Common/Data/Format/PNGLoad.h"
 #include "Common/Net/Resolve.h"
@@ -134,7 +135,7 @@ int getDisplayNumber(void) {
 }
 
 void sdl_mixaudio_callback(void *userdata, Uint8 *stream, int len) {
-	NativeMix((short *)stream, len / (2 * 2), g_sampleRate);
+	NativeMix((short *)stream, len / (2 * 2), g_sampleRate, userdata);
 }
 
 static SDL_AudioDeviceID audioDev = 0;
@@ -244,6 +245,11 @@ void System_Vibrate(int length_ms) {
 	// Ignore on PC
 }
 
+AudioBackend *System_CreateAudioBackend() {
+	// Use legacy mechanisms.
+	return nullptr;
+}
+
 static void InitializeFilters(std::vector<std::string> &filters, BrowseFileType type) {
 	switch (type) {
 	case BrowseFileType::BOOTABLE:

UI/AudioCommon.cpp

@@ -7,7 +7,7 @@ StereoResampler g_resampler;
 
 // numFrames is number of stereo frames.
 // This is called from *outside* the emulator thread.
-int NativeMix(int16_t *outStereo, int numFrames, int sampleRateHz) {
+int NativeMix(int16_t *outStereo, int numFrames, int sampleRateHz, void *userdata) {
 	int validFrames = g_resampler.Mix(outStereo, numFrames, false, sampleRateHz);
 
 	// Mix sound effects on top.

UI/GameSettingsScreen.cpp

@@ -694,7 +694,13 @@ void GameSettingsScreen::CreateAudioSettings(UI::ViewGroup *audioSettings) {
 	});
 #endif
 
-	if (sdlAudio || g_Config.iAudioBackend == AUDIO_BACKEND_WASAPI) {
+#if PPSSPP_PLATFORM(WINDOWS) && !PPSSPP_PLATFORM(UWP)
+	const bool isWindows = true;
+#else
+	const bool isWindows = false;
+#endif
+
+	if (sdlAudio || isWindows) {
 		audioSettings->Add(new CheckBox(&g_Config.bAutoAudioDevice, a->T("Use new audio devices automatically")));
 	}
 

UI/NativeApp.cpp

@@ -86,6 +86,7 @@
 #include "Common/GPU/ShaderTranslation.h"
 #include "Common/VR/PPSSPPVR.h"
 #include "Common/Thread/ThreadManager.h"
+#include "Common/Audio/AudioBackend.h"
 
 #include "Core/ControlMapper.h"
 #include "Core/Config.h"
@@ -193,9 +194,7 @@ static int g_restartGraphics;
 static bool g_windowHidden = false;
 std::vector<std::function<void()>> g_pendingClosures;
 
-#ifdef _WIN32
-WindowsAudioBackend *winAudioBackend;
-#endif
+AudioBackend *g_audioBackend = nullptr;
 
 std::thread *graphicsLoadThread;
 
@@ -839,14 +838,10 @@ bool NativeInitGraphics(GraphicsContext *graphicsContext) {
 	g_screenManager->setPostRenderCallback(&CallbackPostRender, nullptr);
 	g_screenManager->deviceRestored(g_draw);
 
-#ifdef _WIN32
-	winAudioBackend = CreateAudioBackend((AudioBackendType)g_Config.iAudioBackend);
-#if PPSSPP_PLATFORM(UWP)
-	winAudioBackend->Init(0, &NativeMix, 44100);
-#else
-	winAudioBackend->Init(MainWindow::GetHWND(), &NativeMix, 44100);
-#endif
-#endif
+	g_audioBackend = System_CreateAudioBackend();
+	if (g_audioBackend) {
+		g_audioBackend->Init(&NativeMix);
+	}
 
 #if defined(_WIN32) && !PPSSPP_PLATFORM(UWP)
 	if (IsWin7OrHigher()) {
@@ -932,11 +927,6 @@ void NativeShutdownGraphics() {
 	if (gpu)
 		gpu->DeviceLost();
 
-#if PPSSPP_PLATFORM(WINDOWS)
-	delete winAudioBackend;
-	winAudioBackend = nullptr;
-#endif
-
 #if PPSSPP_PLATFORM(WINDOWS) && !PPSSPP_PLATFORM(UWP)
 	if (winCamera) {
 		winCamera->waitShutDown();
@@ -950,6 +940,11 @@ void NativeShutdownGraphics() {
 	}
 #endif
 
+	if (g_audioBackend) {
+		delete g_audioBackend;
+		g_audioBackend = nullptr;
+	}
+
 	UIBackgroundShutdown();
 
 	delete g_gameInfoCache;
@@ -1097,6 +1092,10 @@ void NativeFrame(GraphicsContext *graphicsContext) {
 
 	g_screenManager->update();
 
+	if (g_audioBackend) {
+		g_audioBackend->FrameUpdate();
+	}
+
 	// Do this after g_screenManager.update() so we can receive setting changes before rendering.
 	{
 		std::vector<PendingMessage> toProcess;
@@ -1534,8 +1533,9 @@ void NativeShutdown() {
 	ShaderTranslationShutdown();
 
 	// Avoid shutting this down when restarting core.
-	if (!restarting)
+	if (!restarting) {
 		g_logManager.Shutdown();
+	}
 
 	g_threadManager.Teardown();
 

UWP/PPSSPP_UWPMain.cpp

@@ -11,6 +11,7 @@
 #include "Common/GPU/thin3d_create.h"
 
 #include "Common/Common.h"
+#include "Common/Audio/AudioBackend.h"
 #include "Common/Input/InputState.h"
 #include "Common/File/VFS/VFS.h"
 #include "Common/Thread/ThreadUtil.h"
@@ -51,8 +52,6 @@ using namespace Windows::ApplicationModel::DataTransfer;
 using namespace Windows::Devices::Enumeration;
 using namespace Concurrency;
 
-// UGLY!
-extern WindowsAudioBackend *winAudioBackend;
 std::list<std::unique_ptr<InputDevice>> g_input;
 
 // TODO: Use Microsoft::WRL::ComPtr<> for D3D11 objects?
@@ -362,10 +361,12 @@ std::vector<std::string> System_GetPropertyStringVec(SystemProperty prop) {
 	}
 }
 
+extern AudioBackend *g_audioBackend;
+
 int64_t System_GetPropertyInt(SystemProperty prop) {
 	switch (prop) {
 	case SYSPROP_AUDIO_SAMPLE_RATE:
-		return winAudioBackend ? winAudioBackend->GetSampleRate() : -1;
+		return g_audioBackend ? g_audioBackend->SampleRate() : -1;
 
 	case SYSPROP_DEVICE_TYPE:
 	{

UWP/XAudioSoundStream.cpp

@@ -7,19 +7,20 @@
 
 #include "Common/Log.h"
 #include "Common/Thread/ThreadUtil.h"
+#include "Common/Audio/AudioBackend.h"
 #include "XAudioSoundStream.h"
-
 #include <process.h>
 
 const size_t BUFSIZE = 32 * 1024;
 
-class XAudioBackend : public WindowsAudioBackend {
+class XAudioBackend : public AudioBackend {
 public:
 	XAudioBackend();
 	~XAudioBackend() override;
 
-	bool Init(HWND window, StreamCallback callback, int sampleRate) override;  // If fails, can safely delete the object
-	int GetSampleRate() const override { return sampleRate_; }
+	bool Init(StreamCallback callback, void *userdata = nullptr) override;  // If fails, can safely delete the object
+	int SampleRate() const override { return sampleRate_; }
+	int PeriodFrames() const override { return 0; }
 
 private:
 	bool RunSound();
@@ -32,7 +33,10 @@ private:
 	IXAudio2MasteringVoice *xaudioMaster = nullptr;
 	IXAudio2SourceVoice *xaudioVoice = nullptr;
 
-	int sampleRate_ = 0;
+	void *userdata_ = nullptr;
+
+	int sampleRate_ = 44100;
+	int periodFrames_ = 0;
 
 	char realtimeBuffer_[BUFSIZE]{};
 	uint32_t cursor_ = 0;
@@ -126,9 +130,9 @@ XAudioBackend::~XAudioBackend() {
 	xaudioDevice->Release();
 }
 
-bool XAudioBackend::Init(HWND window, StreamCallback _callback, int sampleRate) {
+bool XAudioBackend::Init(StreamCallback _callback, void *userdata) {
 	callback_ = _callback;
-	sampleRate_ = sampleRate;
+	userdata_ = userdata;
 	return RunSound();
 }
 
@@ -155,7 +159,7 @@ void XAudioBackend::PollLoop() {
 		// take ownership of the data. It needs to be big enough to fit the max number of buffers we check for
 		// above, which it is, easily.
 
-		int stereoSamplesRendered = (*callback_)((short*)&realtimeBuffer_[cursor_], readCount / 4, sampleRate_);
+		int stereoSamplesRendered = (*callback_)((short*)&realtimeBuffer_[cursor_], readCount / 4, sampleRate_, userdata_);
 		int numBytesRendered = 2 * sizeof(short) * stereoSamplesRendered;
 
 		XAUDIO2_BUFFER xaudioBuffer{};
@@ -170,12 +174,13 @@ void XAudioBackend::PollLoop() {
 			cursor_ = 0;
 			bytesLeftInBuffer = BUFSIZE;
 		}
+		periodFrames_ = stereoSamplesRendered;
 	}
 
 	SetEvent(exitEvent_);
 }
 
-WindowsAudioBackend *CreateAudioBackend(AudioBackendType type) {
+AudioBackend *System_CreateAudioBackend() {
 	// Only one type available on UWP.
 	return new XAudioBackend();
 }

UWP/XAudioSoundStream.h

@@ -1,9 +1 @@
 #pragma once
-
-#include "Common/CommonWindows.h"
-#include "Core/Config.h"
-
-#include "Windows/WindowsAudio.h"
-
-// Factory
-WindowsAudioBackend *CreateAudioBackend(AudioBackendType type);

Windows/PPSSPP.vcxproj

@@ -718,7 +718,7 @@
       <ExcludedFromBuild Condition="'$(Configuration)|$(Platform)'=='Release|ARM64'">true</ExcludedFromBuild>
     </ClCompile>
     <ClCompile Include="W32Util\UAHMenuBar.cpp" />
-    <ClCompile Include="WASAPIStream.cpp" />
+    <ClCompile Include="WASAPIContext.cpp" />
     <ClCompile Include="WindowsAudio.cpp" />
     <ClCompile Include="WindowsHost.cpp" />
     <ClCompile Include="main.cpp" />
@@ -1166,7 +1166,7 @@
     <ClInclude Include="MainWindow.h" />
     <ClInclude Include="GPU\WindowsGLContext.h" />
     <ClInclude Include="W32Util\UAHMenuBar.h" />
-    <ClInclude Include="WASAPIStream.h" />
+    <ClInclude Include="WASAPIContext.h" />
     <ClInclude Include="WindowsAudio.h" />
     <ClInclude Include="WindowsHost.h" />
     <ClInclude Include="main.h" />
@@ -1434,4 +1434,4 @@
       <UserProperties RESOURCE_FILE="DaSh.rc" />
     </VisualStudio>
   </ProjectExtensions>
-</Project>
+</Project>

Windows/PPSSPP.vcxproj.filters

@@ -181,7 +181,7 @@
     <ClCompile Include="WindowsAudio.cpp">
       <Filter>Windows\System</Filter>
     </ClCompile>
-    <ClCompile Include="WASAPIStream.cpp">
+    <ClCompile Include="WASAPIContext.cpp">
       <Filter>Windows\System</Filter>
     </ClCompile>
     <ClCompile Include="CaptureDevice.cpp">
@@ -390,7 +390,7 @@
     <ClInclude Include="WindowsAudio.h">
       <Filter>Windows\System</Filter>
     </ClInclude>
-    <ClInclude Include="WASAPIStream.h">
+    <ClInclude Include="WASAPIContext.h">
       <Filter>Windows\System</Filter>
     </ClInclude>
     <ClInclude Include="..\ppsspp_config.h" />

Windows/WASAPIContext.cpp

@@ -2,7 +2,7 @@
 
 #include <initguid.h>
 #include "WindowsAudio.h"
-#include "WASAPIStream.h"
+#include "WASAPIContext.h"
 #include "Common/Log.h"
 #include "Common/LogReporting.h"
 #include "Core/Config.h"
@@ -186,8 +186,7 @@ private:
 #define REFTIMES_PER_SEC  (10000000/200)
 #define REFTIMES_PER_MILLISEC  (REFTIMES_PER_SEC / 1000)
 
-WASAPIAudioBackend::WASAPIAudioBackend() : threadData_(0) {
-}
+WASAPIAudioBackend::WASAPIAudioBackend() : threadData_(0) { }
 
 WASAPIAudioBackend::~WASAPIAudioBackend() {
 	if (threadData_ == 0) {
@@ -210,10 +209,10 @@ unsigned int WINAPI WASAPIAudioBackend::soundThread(void *param) {
 	return backend->RunThread();
 }
 
-bool WASAPIAudioBackend::Init(HWND window, StreamCallback callback, int sampleRate) {
+bool WASAPIAudioBackend::Init(StreamCallback callback, void *userdata) {
 	threadData_ = 0;
+	userdata_ = userdata;
 	callback_ = callback;
-	sampleRate_ = sampleRate;
 	hThread_ = (HANDLE)_beginthreadex(0, 0, soundThread, (void *)this, 0, 0);
 	if (!hThread_)
 		return false;
@@ -493,7 +492,7 @@ void WASAPIAudioThread::Run() {
 			int chans = deviceFormat_->Format.nChannels;
 			switch (format_) {
 			case Format::IEEE_FLOAT:
-				callback_(shortBuf_, pNumAvFrames, sampleRate_);
+				callback_(shortBuf_, pNumAvFrames, sampleRate_, nullptr);
 				if (chans == 1) {
 					float *ptr = (float *)pData;
 					memset(ptr, 0, pNumAvFrames * chans * sizeof(float));
@@ -512,7 +511,7 @@ void WASAPIAudioThread::Run() {
 				}
 				break;
 			case Format::PCM16:
-				callback_((short *)pData, pNumAvFrames, sampleRate_);
+				callback_((short *)pData, pNumAvFrames, sampleRate_, nullptr);
 				break;
 			case Format::UNKNOWN:
 				break;

Windows/WASAPIContext.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include <atomic>
+#include "WindowsAudio.h"
+
+// This should only be included from WindowsAudio.cpp and WASAPIStream.cpp.
+
+class WASAPIAudioBackend : public AudioBackend {
+public:
+	WASAPIAudioBackend();
+	~WASAPIAudioBackend();
+
+	bool Init(StreamCallback callback, void *userdata) override;  // If fails, can safely delete the object
+	int SampleRate() const override { return sampleRate_; }
+	int PeriodFrames() const override { return periodFrames_; }  // amount of frames normally requested
+	void FrameUpdate() override {}
+
+private:
+	int RunThread();
+	static unsigned int WINAPI soundThread(void *param);
+
+	HANDLE hThread_ = nullptr;
+	StreamCallback callback_ = nullptr;
+	int sampleRate_ = 0;
+	int periodFrames_ = 0;
+	void *userdata_ = 0;
+	std::atomic<int> threadData_{};
+};

Windows/WASAPIStream.h

@@ -1,24 +0,0 @@
-#pragma once
-
-#include <atomic>
-#include "WindowsAudio.h"
-
-// This should only be included from WindowsAudio.cpp and WASAPIStream.cpp.
-
-class WASAPIAudioBackend : public WindowsAudioBackend {
-public:
-	WASAPIAudioBackend();
-	~WASAPIAudioBackend();
-
-	bool Init(HWND window, StreamCallback callback, int sampleRate) override;  // If fails, can safely delete the object
-	int GetSampleRate() const override { return sampleRate_; }
-
-private:
-	int RunThread();
-	static unsigned int WINAPI soundThread(void *param);
-
-	HANDLE hThread_ = nullptr;
-	StreamCallback callback_ = nullptr;
-	int sampleRate_ = 0;
-	std::atomic<int> threadData_;
-};

Windows/WindowsAudio.cpp

@@ -1,7 +1,7 @@
 #include "Common/OSVersion.h"
 #include "WindowsAudio.h"
-#include "WASAPIStream.h"
+#include "WASAPIContext.h"
 
-WindowsAudioBackend *CreateAudioBackend(AudioBackendType type) {
+AudioBackend *System_CreateAudioBackend() {
 	return new WASAPIAudioBackend();
 }

Windows/WindowsAudio.h

@@ -1,19 +1,5 @@
 #pragma once
 
 #include "Common/CommonWindows.h"
+#include "Common/Audio/AudioBackend.h"
 #include "Core/ConfigValues.h"
-
-// Always 2 channels, 16-bit audio.
-typedef int (*StreamCallback)(short *buffer, int numSamples, int rate);
-
-// Note that the backend may override the passed in sample rate. The actual sample rate
-// should be returned by GetSampleRate though.
-class WindowsAudioBackend {
-public:
-	virtual ~WindowsAudioBackend() {}
-	virtual bool Init(HWND window, StreamCallback _callback, int sampleRate) = 0;
-	virtual int GetSampleRate() const = 0;
-};
-
-// Factory
-WindowsAudioBackend *CreateAudioBackend(AudioBackendType type);

Windows/main.cpp

@@ -277,7 +277,7 @@ std::vector<std::string> System_GetPropertyStringVec(SystemProperty prop) {
 }
 
 // Ugly!
-extern WindowsAudioBackend *winAudioBackend;
+extern AudioBackend *winAudioBackend;
 
 #ifdef _WIN32
 #if PPSSPP_PLATFORM(UWP)
@@ -319,12 +319,16 @@ static float ScreenRefreshRateHz() {
 	return rate;
 }
 
+extern AudioBackend *g_audioBackend;
+
 int64_t System_GetPropertyInt(SystemProperty prop) {
 	switch (prop) {
 	case SYSPROP_MAIN_WINDOW_HANDLE:
 		return (int64_t)MainWindow::GetHWND();
 	case SYSPROP_AUDIO_SAMPLE_RATE:
-		return winAudioBackend ? winAudioBackend->GetSampleRate() : -1;
+		return g_audioBackend ? g_audioBackend->SampleRate() : -1;
+	case SYSPROP_AUDIO_FRAMES_PER_BUFFER:
+		return g_audioBackend ? g_audioBackend->PeriodFrames() : -1;
 	case SYSPROP_DEVICE_TYPE:
 		return DEVICE_TYPE_DESKTOP;
 	case SYSPROP_DISPLAY_COUNT:
@@ -485,6 +489,7 @@ void System_Notify(SystemNotification notification) {
 
 	case SystemNotification::POLL_CONTROLLERS:
 		g_inputManager.PollControllers();
+		// Also poll the audio backend for changes.
 		break;
 
 	case SystemNotification::TOGGLE_DEBUG_CONSOLE:

android/jni/AndroidAudio.h

@@ -3,7 +3,7 @@
 #include <string>
 #include <mutex>
 
-typedef int (*AndroidAudioCallback)(short *buffer, int numSamples, int sampleRateHz);
+typedef int (*AndroidAudioCallback)(short *buffer, int numSamples, int sampleRateHz, void *userdata);
 
 class AudioContext {
 public:

android/jni/OpenSLContext.cpp

@@ -49,7 +49,7 @@ void OpenSLContext::BqPlayerCallback(SLAndroidSimpleBufferQueueItf bq) {
 		return;
 	}
 
-	int renderedFrames = audioCallback(buffer[curBuffer], framesPerBuffer, SampleRate());
+	int renderedFrames = audioCallback(buffer[curBuffer], framesPerBuffer, SampleRate(), nullptr);
 
 	int sizeInBytes = framesPerBuffer * 2 * sizeof(short);
 	int byteCount = (framesPerBuffer - renderedFrames) * 4;

android/jni/app-android.cpp

@@ -820,6 +820,11 @@ retry:
 	}
 }
 
+AudioBackend *System_CreateAudioBackend() {
+	// Use legacy mechanisms.
+	return nullptr;
+}
+
 extern "C" void Java_org_ppsspp_ppsspp_NativeApp_audioInit(JNIEnv *, jclass) {
 	sampleRate = optimalSampleRate;
 	if (optimalSampleRate == 0) {

ios/AudioEngine.mm

@@ -19,7 +19,7 @@ static volatile BOOL done = 0;
 #define SAMPLE_SIZE 44100
 static short stream[SAMPLE_SIZE];
 
-int NativeMix(short *audio, int numSamples, int sampleRateHz);
+int NativeMix(short *audio, int numSamples, int sampleRateHz, void *userdata);
 
 @interface AudioEngine ()
 
@@ -125,7 +125,7 @@ int NativeMix(short *audio, int numSamples, int sampleRateHz);
         {
             size_t frames_ready;
             if (![self playing])
-                frames_ready = NativeMix(stream, SAMPLE_SIZE / 2, sampleRateHz);
+                frames_ready = NativeMix(stream, SAMPLE_SIZE / 2, sampleRateHz, 0);
             else
                 frames_ready = 0;
 

ios/iOSCoreAudio.mm

@@ -74,7 +74,7 @@ void iOSCoreAudioSetDisplayConnected(bool connected) {
 	iOSCoreAudioUpdateSession();
 }
 
-int NativeMix(short *audio, int numSamples, int sampleRate);
+int NativeMix(short *audio, int numSamples, int sampleRate, void *userdata);
 
 OSStatus iOSCoreAudioCallback(void *inRefCon,
 							  AudioUnitRenderActionFlags *ioActionFlags,
@@ -85,7 +85,7 @@ OSStatus iOSCoreAudioCallback(void *inRefCon,
 {
 	// see if we have any sound to play
 	short *output = (short *)ioData->mBuffers[0].mData;
-	UInt32 framesReady = NativeMix(output, inNumberFrames, SAMPLE_RATE);
+	UInt32 framesReady = NativeMix(output, inNumberFrames, SAMPLE_RATE, nullptr);
 	
 	if (framesReady == 0) {
 		// oops, we don't currently have any sound, so return silence

ios/main.mm

@@ -28,6 +28,7 @@
 #import "IAPManager.h"
 
 #include "Common/MemoryUtil.h"
+#include "Common/Audio/AudioBackend.h"
 #include "Common/System/NativeApp.h"
 #include "Common/System/System.h"
 #include "Common/System/Request.h"
@@ -612,6 +613,11 @@ void System_Vibrate(int mode) {
 	}
 }
 
+AudioBackend *System_CreateAudioBackend() {
+	// Use legacy mechanisms.
+	return nullptr;
+}
+
 int main(int argc, char *argv[])
 {
 	// SetCurrentThreadName("MainThread");