FOnsetStrengthAnalyzer | Unreal Engine 5.7 Documentation

API > API/Plugins > API/Plugins/AudioSynesthesiaCore

FOnsetStrengthAnalyzer calculates the onset strength from audio.

Onset strength is calculated as the half wave rectificed difference between two spectral frames. This onset strength onset analyzer uses the following approach.

[audio]->[fft]->[mel spectrum]->[diff]->[half wave rectify]->[mean]->[onset strength] | | >-[lag]--|


Name	FOnsetStrengthAnalyzer
Type	class
Header File	/Engine/Plugins/Runtime/AudioSynesthesia/Source/AudioSynesthesiaCore/Public/OnsetAnalyzer.h
Include Path	#include "OnsetAnalyzer.h"

Syntax

class FOnsetStrengthAnalyzer

Constructors

Name	Remarks	Include Path	Unreal Specifiers
FOnsetStrengthAnalyzer ( const FOnsetStrengthSettings& InSettings, float InSampleRate )		OnsetAnalyzer.h

Variables

Protected

Name	Type	Remarks	Include Path
ActualFFTSize	int32		OnsetAnalyzer.h
ComplexSpectrum	FAlignedFloatBuffer		OnsetAnalyzer.h
FFT	TUniquePtr< IFFTAlgorithm >		OnsetAnalyzer.h
LagSpectraIndex	int32		OnsetAnalyzer.h
MelSpectrum	TArray< float >		OnsetAnalyzer.h
MelSpectrumDifference	TArray< float >		OnsetAnalyzer.h
MelTransform	TUniquePtr< FContiguousSparse2DKernelTransform >		OnsetAnalyzer.h
PreviousMelSpectra	TArray< FAlignedFloatBuffer >	Array of arrays to hold lag spectra.	OnsetAnalyzer.h
RealSpectrum	FAlignedFloatBuffer		OnsetAnalyzer.h
Settings	FOnsetStrengthSettings		OnsetAnalyzer.h
SlidingBuffer	TSlidingBuffer< float >		OnsetAnalyzer.h
Window	FWindow		OnsetAnalyzer.h
WindowedSamples	FAlignedFloatBuffer		OnsetAnalyzer.h
WorkingBuffer	FAlignedFloatBuffer		OnsetAnalyzer.h

Functions

Public

Name	Remarks	Include Path
void CalculateOnsetStrengths ( TArrayView< const float > InSamples, TArray< float >& OutOnsetStrengths )	Calculates onset strengths from audio and fills OutOnsetStrengths with generated onset strengths	OnsetAnalyzer.h
void FlushAudio ( TArray< float >& OutEnvelopeStrengths )	Call when done processing audio for an audio analyzer	OnsetAnalyzer.h
void Reset()	Call to reset internal counters and lag spectra.	OnsetAnalyzer.h

Static

Name	Remarks	Include Path	Unreal Specifiers
static float GetTimestampForIndex ( const FOnsetStrengthSettings& InSettings, float InSampleRate, int32 InIndex )	Converts an onset strength index into a timestamp.	OnsetAnalyzer.h

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