file
class        class AWorldSettings : public AInfo, public IInterface_AssetUserData

	/** Default Base SoundMix.																			*/
	UPROPERTY(EditAnywhere, Category=Audio)
	TObjectPtr<class USoundMix> DefaultBaseSoundMix;

#if WITH_EDITORONLY_DATA
	/** If set overrides the level settings and global project settings */
	UPROPERTY(EditAnywhere, config, Category = HLODSystem, meta=(EditConditionHides, EditCondition = "WorldPartition == nullptr"))
	TSoftClassPtr<class UHierarchicalLODSetup> HLODSetupAsset;

file
class        class UAudioSettings : public UDeveloperSettings

	/** The SoundMix to use as base when no other system has specified a Base SoundMix */
	UPROPERTY(config, EditAnywhere, Category="Audio", meta=(AllowedClasses="/Script/Engine.SoundMix"))
	FSoftObjectPath DefaultBaseSoundMix;

	/** Sound class to be used for the VOIP audio component */
	UPROPERTY(config, EditAnywhere, Category="Audio", meta=(AllowedClasses="/Script/Engine.SoundClass", DisplayName = "VOIP Sound Class"))
	FSoftObjectPath VoiPSoundClass;

	/** The default submix through which all sounds are routed to. The root submix that outputs to audio hardware. */

file
function     FAudioDevice::FAudioDevice

	, NextResourceID(1)
	, BaseSoundMix(nullptr)
	, DefaultBaseSoundMix(nullptr)
	, Effects(nullptr)
	, CurrentReverbEffect(nullptr)
	, PlatformAudioHeadroom(1.0f)
	, DefaultReverbSendLevel(0.0f)
	, bHRTFEnabledForAll_OnGameThread(false)
	, bHRTFDisabled_OnGameThread(false)

file
function     bool FAudioDevice::Init

	DefaultReverbSendLevel = AudioSettings->DefaultReverbSendLevel_DEPRECATED;

	const FSoftObjectPath DefaultBaseSoundMixName = GetDefault<UAudioSettings>()->DefaultBaseSoundMix;
	if (DefaultBaseSoundMixName.IsValid())
	{
		DefaultBaseSoundMix = LoadObject<USoundMix>(nullptr, *DefaultBaseSoundMixName.ToString());
	}

	GetDefault<USoundGroups>()->Initialize();

	// Parses sound classes.
	InitSoundClasses();

file
function     void FAudioDevice::AddReferencedObjects

void FAudioDevice::AddReferencedObjects(FReferenceCollector& Collector)
{
	Collector.AddReferencedObject(DefaultBaseSoundMix);
	Collector.AddReferencedObjects(PrevPassiveSoundMixModifiers);
	Collector.AddReferencedObjects(SoundMixModifiers);

	for (TPair<FName, FActivatedReverb>& ActivatedReverbPair : ActivatedReverbs)
	{
		Collector.AddReferencedObject(ActivatedReverbPair.Value.ReverbSettings.ReverbEffect);

file
function     void FAudioDevice::SetDefaultBaseSoundMix

	if (IsInGameThread() && SoundMix == nullptr)
	{
		const FSoftObjectPath DefaultBaseSoundMixName = GetDefault<UAudioSettings>()->DefaultBaseSoundMix;
		if (DefaultBaseSoundMixName.IsValid())
		{
			SoundMix = LoadObject<USoundMix>(nullptr, *DefaultBaseSoundMixName.ToString());
		}
	}

file
function     void FAudioDevice::SetDefaultBaseSoundMix

	}

	DefaultBaseSoundMix = SoundMix;
	SetBaseSoundMix(SoundMix);
}

void FAudioDevice::RemoveSoundMix(USoundMix* SoundMix)
{
	check(IsInAudioThread());

file
function     void FAudioDevice::RemoveSoundMix

	{
		// Not sure if we will ever destroy the default base SoundMix
		if (SoundMix == DefaultBaseSoundMix)
		{
			DefaultBaseSoundMix = nullptr;
		}

		ClearSoundMix(SoundMix);

		// Try setting to global default if base SoundMix has been cleared
		if (BaseSoundMix == nullptr)
		{
			SetBaseSoundMix(DefaultBaseSoundMix);
		}
	}
}

void FAudioDevice::RecurseIntoSoundClasses(USoundClass* CurrentClass, FSoundClassProperties& ParentProperties)
{

file
function     void UGameViewportClient::Init

				if (World)
				{
					AudioDevice.GetAudioDevice()->SetDefaultBaseSoundMix(World->GetWorldSettings()->DefaultBaseSoundMix);

					// Set the world's audio device handle to use so that sounds which play in that world will use the correct audio device
					World->SetAudioDevice(AudioDevice);
				}

				// Set this audio device handle on the world context so future world's set onto the world context

file
function     bool UEngine::LoadMap

		if (AWorldSettings* WorldSettings = WorldContext.World()->GetWorldSettings())
		{
			AudioDevice->SetDefaultBaseSoundMix(WorldSettings->DefaultBaseSoundMix);
		}
		else
		{
			UE_LOG(LogInit, Warning, TEXT("Unable to get world settings. Can't initialize default base soundmix."));
		}
	}

file
function     UWorld* FSeamlessTravelHandler::Tick

				if (FAudioDevice* AudioDevice = LoadedWorld->GetAudioDeviceRaw())
				{
					AudioDevice->SetDefaultBaseSoundMix(LoadedWorld->GetWorldSettings()->DefaultBaseSoundMix);
				}

				// Copy cheat flags if the game info is present
				// @todo FIXMELH - see if this exists, it should not since it's created in GameMode or it's garbage info
				if (LoadedWorld->NetworkManager != nullptr)
				{

file
class        class FAudioDevice : public FExec
function     USoundMix* GetDefaultBaseSoundMixModifier

	USoundMix* GetDefaultBaseSoundMixModifier()
	{
		return DefaultBaseSoundMix;
	}

	void SetSoundMixModifiers(const TMap<USoundMix*, FSoundMixState>& InSoundMixModifiers, const TArray<USoundMix*>& InPrevPassiveSoundMixModifiers, USoundMix* InDefaultBaseSoundMix)
	{
		SoundMixModifiers = ObjectPtrWrap(InSoundMixModifiers);
		PrevPassiveSoundMixModifiers = ObjectPtrWrap(InPrevPassiveSoundMixModifiers);
		DefaultBaseSoundMix = InDefaultBaseSoundMix;
	}

	ENGINE_API FDelegateHandle AddPreRenderDelegate(const FOnAudioDevicePreRender::FDelegate& InDelegate);

	ENGINE_API bool RemovePreRenderDelegate(const FDelegateHandle& InHandle);

file
class        class FAudioDevice : public FExec

	/** The Base SoundMix that should be applied by default */
	TObjectPtr<USoundMix> DefaultBaseSoundMix;

	/** Map of sound mixes currently affecting audio properties */
	TMap<TObjectPtr<USoundMix>, FSoundMixState> SoundMixModifiers;

	/** Map of sound mix sound class overrides. Will override any sound class effects for any sound mixes */
	TMap<USoundMix*, FSoundMixClassOverrideMap> SoundMixClassEffectOverrides;