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  3. FSpectrumAnalyzer

FSpectrumAnalyzer

Class built to be a rolling spectrum analyzer for arbitrary, monaural audio data.

API > API/Runtime > API/Runtime/SignalProcessing

Class built to be a rolling spectrum analyzer for arbitrary, monaural audio data. Class is meant to scale accuracy with CPU and memory budgets. Typical usage is to either call PushAudio() and then PerformAnalysisIfPossible immediately afterwards, or have a seperate thread call PerformAnalysisIfPossible().

   
Name FSpectrumAnalyzer
Type class
Header File /Engine/Source/Runtime/SignalProcessing/Public/DSP/SpectrumAnalyzer.h
Include Path #include "DSP/SpectrumAnalyzer.h"

Syntax

class FSpectrumAnalyzer

Constructors

Name Remarks Include Path Unreal Specifiers

FSpectrumAnalyzer ( const FSpectrumAnalyzerSettings& InSettings,
float InSampleRate
)

   DSP/SpectrumAnalyzer.h  

FSpectrumAnalyzer ( float InSampleRate
)

 If an instance is created using either of these constructors, Init() is not neccessary. DSP/SpectrumAnalyzer.h  
If an instance is created using the default constructor, Init() must be called before it is used. DSP/SpectrumAnalyzer.h  

Destructors

Name Remarks Include Path Unreal Specifiers

virtual ~FSpectrumAnalyzer()

   DSP/SpectrumAnalyzer.h  

Enums

Public

Name Remarks
EPeakInterpolationMethod Peak interpolation method.

Variables

Protected

Name Type Remarks Include Path Unreal Specifiers
AnalysisTimeDomainBuffer FAlignedFloatBuffer   DSP/SpectrumAnalyzer.h  
bIsInitialized volatile bool   DSP/SpectrumAnalyzer.h  
bSettingsWereUpdated volatile bool   DSP/SpectrumAnalyzer.h  
CurrentSettings FSpectrumAnalyzerSettings Cached current settings. Only actually used in ResetSettings(). DSP/SpectrumAnalyzer.h  
FFT TUniquePtr< IFFTAlgorithm >   DSP/SpectrumAnalyzer.h  
FFTScaling EFFTScaling   DSP/SpectrumAnalyzer.h  
FFTSize int32   DSP/SpectrumAnalyzer.h  
FrequencyBuffer FSpectrumAnalyzerBuffer   DSP/SpectrumAnalyzer.h  
HopInSamples int32   DSP/SpectrumAnalyzer.h  
InputQueue TCircularAudioBuffer< float >   DSP/SpectrumAnalyzer.h  
LockedBufferTimestamp double If non-null, owns pointer to locked frequency vector we're using. DSP/SpectrumAnalyzer.h  
LockedFrequencyVector const FAlignedFloatBuffer *   DSP/SpectrumAnalyzer.h  
SampleCounter FThreadSafeCounter   DSP/SpectrumAnalyzer.h  
SampleRate float   DSP/SpectrumAnalyzer.h  
Window FWindow Cached window that is applied prior to running the FFT. DSP/SpectrumAnalyzer.h  

Functions

Public

Name Remarks Include Path Unreal Specifiers

void GetBands ( ISpectrumBandExtractor& InExtractor,
TArray< float >& OutValues
)

 Return array of bands using spectrum band extractor. DSP/SpectrumAnalyzer.h  

float GetMagnitudeForFrequency ( float InFrequency,
EPeakInterpolationMethod InMethod
)

 Samples magnitude (linearly) for a given frequency, in Hz. DSP/SpectrumAnalyzer.h  

float GetNormalizedMagnitudeForFrequency ( float InFrequency,
EPeakInterpolationMethod InMethod
)

   DSP/SpectrumAnalyzer.h  

float GetPhaseForFrequency ( float InFrequency,
EPeakInterpolationMethod InMethod
)

 Samples phase for a given frequency, in Hz. DSP/SpectrumAnalyzer.h  

void GetSettings ( FSpectrumAnalyzerSettings& OutSettings
)

 Get the current settings used by this Spectrum Analyzer. DSP/SpectrumAnalyzer.h  

void Init ( const FSpectrumAnalyzerSettings& InSettings,
float InSampleRate
)

   DSP/SpectrumAnalyzer.h  

void Init ( float InSampleRate
)

 Initialize sample rate of analyzer if not known at time of construction. DSP/SpectrumAnalyzer.h  

bool IsInitialized()

 Returns false if this instance of FSpectrumAnalyzer was constructed with the default constructor and Init() has not been called yet. DSP/SpectrumAnalyzer.h  
You can call this function to ensure that you're sampling the same window of frequency data, Then call UnlockOutputBuffer when you're done. DSP/SpectrumAnalyzer.h  

bool PerformAnalysisIfPossible ( bool bUseLatestAudio
)

 Thread safe call to perform actual FFT. DSP/SpectrumAnalyzer.h  

bool PushAudio ( const TSampleBuffer< float >& InBuffer
)

 Push audio to queue. Returns false if the queue is already full. DSP/SpectrumAnalyzer.h  

bool PushAudio ( const float* InBuffer,
int32 NumSamples
)

   DSP/SpectrumAnalyzer.h  

void SetSettings ( const FSpectrumAnalyzerSettings& InSettings
)

 Update the settings used by this Spectrum Analyzer. Safe to call on any thread, but should not be called every tick. DSP/SpectrumAnalyzer.h  

void UnlockOutputBuffer()

   DSP/SpectrumAnalyzer.h  

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