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  3. IAudioMixerPlatformInterface

IAudioMixerPlatformInterface

Abstract interface for mixer platform.

API > API/Runtime > API/Runtime/AudioMixerCore

Inheritance Hierarchy

References

   
Module AudioMixerCore
Header /Engine/Source/Runtime/AudioMixerCore/Public/AudioMixer.h
Include #include "AudioMixer.h"

Syntax

class IAudioMixerPlatformInterface :  
    public FRunnable ,  
    public FSingleThreadRunnable ,  
    public Audio::IAudioMixerDeviceChangedListener

Remarks

Abstract interface for mixer platform.

Variables

  Type Name Description
Protected variable FEvent * AudioFadeEvent Event allows you to block until fadeout is complete.
Protected variable FEvent * AudioRenderEvent The render thread sync event.
Protected variable TUniquePtr< FRunnableThread > AudioRenderThread FRunnableThread* AudioRenderThread;.
Protected variable FAudioOutputStreamInfo AudioStreamInfo The audio device stream info.
Protected variable FThreadSafeBool bFadedOut  
Protected variable FThreadSafeBool bIsDeviceInitialized  
Protected variable FThreadSafeBool bIsGeneratingAudio  
Protected variable FThreadSafeBool bIsInDeviceSwap This is used if we are attempting to TryLock on DeviceSwapCriticalSection, but a buffer callback is being called in the current thread.
Protected variable FThreadSafeBool bIsUsingNullDevice  
Protected variable FThreadSafeBool bMoveAudioStreamToNewAudioDevice  
Protected variable FThreadSafeBool bPerformingFade  
Protected variable bool bWarnedBufferUnderrun Whether or not we warned of buffer underrun.
Protected variable int32 CallCounterApplyAttenuationInternal  
Protected variable int32 CallCounterReadNextBuffer  
Protected variable FString CurrentDeviceName This device name can be used to override the default device being used on platforms that use strings to identify audio devices.
Protected variable FCriticalSection DeviceSwapCriticalSection Critical Section used for times when we need the render loop to halt for the device swap.
Protected variable FParam FadeParam Source param used to fade in and out audio device.
Protected variable float FadeVolume The fade value. Used for fading in/out primary audio.
Protected variable const int32 InstanceID A Unique ID Identifying this instance. Mostly used for logging.
Protected variable FString LastError String containing the last generated error.
Protected variable int32 NumOutputBuffers The number of mixer buffers to queue on the output source voice.
Protected variable FAudioMixerOpenStreamParams OpenStreamParams  
Protected variable Audio::FOutputBuffer OutputBuffer List of generated output buffers.

Constructors

  Type Name Description
Public function   Constructor.

Destructors

  Type Name Description
Public function Virtual   Virtual destructor.

Functions

  Type Name Description
Protected function void

ApplyAttenuationInternal ( TArrayView< BufferType >& InOutBuffer
)

  
Protected function void

ApplyMasterAttenuation ( TArrayView< const uint8 >& InOutPoppedAudio
)

 Deprecated - use ApplyPrimaryAttenuation
Protected function void

ApplyPrimaryAttenuation ( TArrayView< const uint8 >& InOutPoppedAudio
)

 Performs buffer fades for shutdown/startup of audio mixer.
Protected function void

AudioMixerPlatformLogOnce ( const FString& LogDetails,
const FString& FileName,
int32 LineNumber,
ELogVerbosity::Type InVerbosity
)

 Is called when an error, warning or log is generated.
Protected function void Start generating audio from our mixer.
Public function Virtual bool Check if audio device changed if applicable. Return true if audio device changed.
Public function bool Closes the audio stream (if it's open).
Protected function void

CreateNullDeviceThread ( const TFunction< void()> InCallback,
float InBufferDuration,
bool bShouldPauseOnStart
)

 Called by platform specific logic to pre-create or create the null renderer thread
Public function Virtual Const bool Whether or not the platform disables caching of decompressed PCM data (i.e. to save memory on fixed memory platforms)
Public function Virtual void

FadeIn ()

 Reset the fade state (use if reusing audio platform interface, e.g. in main audio device.
Public function Virtual void

FadeOut ()

 Start a fadeout. Prevents pops during shutdown.
Public function Static bool Helper function to gets the channel map type at the given index.
Public function Virtual Const FString Returns the name of the currently used audio device.
Public function FString Return any optional device name defined in platform configuratio.
Public function Virtual Const bool

GetDefaultOutputDeviceIndex ( uint32& OutDefaultDeviceIndex
)

 Returns the default device index.
Public function Virtual Const IAudioPlatformDeviceInfoCache * Get the DeviceInfo Cache if one exists.
Public function Virtual int32

GetIndexForDevice ( const FString& InDeviceName
)

 Can be used to look up the current index for a given device name.
Public function Const FString Returns the last error generated.
Public function Virtual int32

GetNumFrames ( const int32 InNumReqestedFrames
)

 Allows platforms to filter the requested number of frames to render.
Public function Virtual bool

GetNumOutputDevices ( uint32& OutNumOutputDevices
)

 Returns the number of output devices.
Public function bool

GetOutputDeviceInfo ( const uint32 InDeviceIndex,
FAudioPlatformDeviceInfo& OutInfo
)

 Gets the device information of the given device index.
Public function Const FString Returns the platform API name.
Public function Const FAudioPlatformDeviceInfo Returns the platform device info of the currently open audio stream.
Public function Const FAudioPlatformSettings Gets the platform specific audio settings.
Public function bool Initialize the hardware.
Public function Const bool Is the hardware initialized.
Public function Virtual Const bool Whether this is an interface for a non-realtime renderer.
Protected function uint32 Run the "main" audio device.
Public function Virtual bool

MoveAudioStreamToNewAudioDevice ( const FString& InNewDeviceId
)

 Resets the audio stream to use a new audio device with the given device ID (empty string means default).
Public function Virtual void Function called at the beginning of every call of UpdateHardware on the audio thread.
Public function bool Opens up a new audio stream with the given parameters.
Public function void This is called after InitializeHardware() is called.
Public function void Retrieves the next generated buffer and feeds it to the platform mixer output stream.
Public function Virtual bool

RequestDeviceSwap ( const FString& DeviceID,
bool bInForce,
const TCHAR* InReason
)

 Sends a command to swap which output device is being used
Public function Virtual void Function to resume audio rendering. Used on mobile platforms which can suspend the application.
Public function Virtual void Resumes playback on new audio device after device change.
Protected function Virtual uint32 Wrapper around the thread Run. This is virtualized so a platform can fundamentally override the render function.
Public function bool Starts the audio stream processing and generating audio.
Protected function void When called, spins up a thread to start consuming output when no audio device is available.
Public function bool Stops the audio stream (but keeps the audio stream open).
Protected function void Stops the render thread from generating audio.
Protected function void When called, terminates the null device.
Public function Virtual void

SubmitBuffer ( const uint8* Buffer
)

 Submit the given buffer to the platform's output audio device.
Public function Virtual void

SubmitDirectOutBuffer ( const int32 InDirectOutIndex,
const Audio::FAlignedFloatBuffer& InBuffer
)

 Submit a buffer that is to be output directly through a discreet device channel.
Public function Virtual Const bool Whether or not this platform has hardware decompression.
Public function Virtual void Function to stop all audio from rendering. Used on mobile platforms which can suspend the application.
Public function bool Teardown the hardware.

Overridden from FRunnable

  Type Name Description
Public function Virtual FSingleThreadRunnable * FSingleThreadRunnable accessor for ticking this FRunnable when multi-threading is disabled.
Public function Virtual uint32

Run ()

 Runs the runnable object.

Overridden from FSingleThreadRunnable

  Type Name Description
Public function Virtual void

Tick ()

 Tick function.

Constants

Name Description
NextInstanceID A Counter to provide the next unique id.

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