AudioMixerWasapi.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "AudioMixer.h" 
#include "AudioMixerWasapiRenderStream.h"
#include "IAudioMixerWasapiDeviceManager.h"
#include "Templates/SharedPointer.h"
#include "Templates/UniquePtr.h"
 
#include "Windows/AllowWindowsPlatformTypes.h"
#include "Windows/AllowWindowsPlatformAtomics.h"
 
#include "Microsoft/COMPointer.h"
 
THIRD_PARTY_INCLUDES_START
#include <mmdeviceapi.h>            // IMMNotificationClient
#include <audiopolicy.h>            // IAudioSessionEvents
THIRD_PARTY_INCLUDES_END
 
#include "Windows/HideWindowsPlatformAtomics.h"
#include "Windows/HideWindowsPlatformTypes.h"
 
namespace Audio
{
    class FWasapiDefaultRenderStream;
 
    struct FWasapiDeviceSwapContext : public FDeviceSwapContext
    {
        FWasapiDeviceSwapContext() = delete;
        FWasapiDeviceSwapContext(const FString& InRequestedDeviceID, const FString& InReason) :
            FDeviceSwapContext(InRequestedDeviceID, InReason)
        {}
        
        FAudioPlatformSettings PlatformSettings;
        TArray<FWasapiRenderStreamParams> StreamParams;
        TFunction<void()> ReadNextBufferCallback;
        TUniquePtr<IAudioMixerWasapiDeviceManager> OldDeviceManager;
        bool bIsAggregateDevice = false;
    };
 
    struct FWasapiDeviceSwapResult : public FDeviceSwapResult
    {
        virtual bool IsNewDeviceReady() const override
        {
            return NewDeviceManager.IsValid();
        }
 
        TUniquePtr<IAudioMixerWasapiDeviceManager> NewDeviceManager;
        bool bIsAggregateDevice = false;
    };
 
    class FAudioMixerWasapi : public FAudioMixerPlatformSwappable
    {
    public:
 
        FAudioMixerWasapi();
        virtual ~FAudioMixerWasapi() override;
 
        //~ Begin IAudioMixerPlatformInterface
        virtual FString GetPlatformApi() const override { return TEXT("WASAPIMixer"); }
        virtual bool InitializeHardware() override;
        virtual bool TeardownHardware() override;
        virtual bool IsInitialized() const override;
        virtual int32 GetNumFrames(const int32 InNumRequestedFrames) override;
        virtual bool GetNumOutputDevices(uint32& OutNumOutputDevices) override;
        virtual bool GetOutputDeviceInfo(const uint32 InDeviceIndex, FAudioPlatformDeviceInfo& OutInfo) override;
        virtual bool GetDefaultOutputDeviceIndex(uint32& OutDefaultDeviceIndex) const override;
        virtual bool OpenAudioStream(const FAudioMixerOpenStreamParams& Params) override;
        virtual bool CloseAudioStream() override;
        virtual bool StartAudioStream() override;
        virtual bool StopAudioStream() override;
        virtual FAudioPlatformDeviceInfo GetPlatformDeviceInfo() const override;
        virtual void SubmitBuffer(const uint8* Buffer) override;
        virtual void SubmitDirectOutBuffer(const int32 InDirectOutIndex, const FAlignedFloatBuffer& InBuffer) override;
        virtual FString GetDefaultDeviceName() override;
        virtual FAudioPlatformSettings GetPlatformSettings() const override;
        virtual IAudioPlatformDeviceInfoCache* GetDeviceInfoCache() const override;
        virtual bool IsDeviceInfoValid(const FAudioPlatformDeviceInfo& InDeviceInfo) const override;
        virtual bool ShouldUseDeviceInfoCache() const override { return true; }
        //~ End IAudioMixerPlatformInterface
 
        //~ Begin IAudioMixerDeviceChangedListener
        virtual void RegisterDeviceChangedListener() override;
        virtual void UnregisterDeviceChangedListener() override;
        virtual void OnDefaultCaptureDeviceChanged(const EAudioDeviceRole InAudioDeviceRole, const FString& DeviceId) override;
        virtual void OnDefaultRenderDeviceChanged(const EAudioDeviceRole InAudioDeviceRole, const FString& DeviceId) override;
        virtual void OnDeviceAdded(const FString& DeviceId, bool bIsRenderDevice) override;
        virtual void OnDeviceRemoved(const FString& DeviceId, bool bIsRenderDevice) override;
        virtual void OnDeviceStateChanged(const FString& DeviceId, const EAudioDeviceState InState, bool bIsRenderDevice) override;
        virtual void OnFormatChanged(const FString& InDeviceId, const FFormatChangedData& InFormat) override;
        virtual void OnSessionDisconnect(Audio::IAudioMixerDeviceChangedListener::EDisconnectReason InReason) override;
        virtual FString GetDeviceId() const override;
        //~ End IAudioMixerDeviceChangedListener
 
        //~ Begin FAudioMixerPlatformSwappable
        virtual bool InitializeDeviceSwapContext(const FString& InRequestedDeviceID, const TCHAR* InReason) override;
        virtual bool CheckThreadedDeviceSwap() override;
        virtual bool PreDeviceSwap() override;
        virtual void EnqueueAsyncDeviceSwap() override;
        virtual void SynchronousDeviceSwap() override;
        virtual bool PostDeviceSwap() override;
        //~ End FAudioMixerPlatformSwappable
 
    protected:
        bool InitDeviceSwapContextInternal(const FString& InRequestedDeviceID, const TCHAR* InReason, const TOptional<FAudioPlatformDeviceInfo>& InDeviceInfo);
        
    private:
 
        TUniquePtr<IAudioPlatformDeviceInfoCache> DeviceInfoCache;
        
        TUniquePtr<IAudioMixerWasapiDeviceManager> DeviceManager;
 
        bool bIsInitialized = false;
 
        TUniquePtr<FWasapiDeviceSwapContext> DeviceSwapContext;
        
        TComPtr<IMMDevice> GetMMDevice(const FString& InDeviceID) const;
 
        FString ExtractAggregateDeviceName(const FString& InDeviceID) const;
        
        static void CreateDeviceManager(const bool bInUseAggregateDevice, TUniquePtr<IAudioMixerWasapiDeviceManager>& InDeviceManager);
        
        bool InitStreamParams(const uint32 InDeviceIndex, const int32 InNumBufferFrames, const int32 InNumBuffers, const int32 InSampleRate, TArray<FWasapiRenderStreamParams>& OutParams);
        bool InitStreamParams(const FAudioPlatformDeviceInfo& InDeviceInfo, const int32 InNumBufferFrames, const int32 InNumBuffers, const int32 InSampleRate, TArray<FWasapiRenderStreamParams>& OutParams) const;
        
        static TUniquePtr<FDeviceSwapResult> PerformDeviceSwap(TUniquePtr<FWasapiDeviceSwapContext>&& InDeviceContext);
 
#if PLATFORM_WINDOWS
        static void RegisterForSessionEvents(const FString& InDeviceId);
        static void UnregisterForSessionEvents();
#endif //PLATFORM_WINDOWS
 
 
    };
 
 }