MultichannelLinearResampler.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "DSP/BufferVectorOperations.h"
#include "DSP/Dsp.h"
#include "DSP/MultichannelBuffer.h"
 
namespace Audio
{
    class FMultichannelLinearResampler
    {
        static constexpr float MinFrameRatioFrameDelta = 0.001f;
    public:
 
        SIGNALPROCESSING_API static const float MaxFrameRatio;
        SIGNALPROCESSING_API static const float MinFrameRatio;
 
        SIGNALPROCESSING_API FMultichannelLinearResampler(int32 InNumChannels);
 
        SIGNALPROCESSING_API void SetFrameRatio(float InRatio, int32 InNumFramesToInterpolate=0);
 
        SIGNALPROCESSING_API float MapInputFrameToOutputFrame(float InInputFrameIndex) const;
 
        SIGNALPROCESSING_API float MapOutputFrameToInputFrame(float InOutputFrameIndex) const;
 
        SIGNALPROCESSING_API int32 GetNumInputFramesNeededToProduceOutputFrames(int32 InNumOutputFrames) const;
 
        SIGNALPROCESSING_API int32 ProcessAndConsumeAudio(FMultichannelCircularBuffer& InAudio, FMultichannelBuffer& OutAudio);
        SIGNALPROCESSING_API int32 ProcessAndConsumeAudio(FMultichannelCircularBuffer& InAudio, FMultichannelBufferView& OutAudio);
 
    private:
 
        template<typename OutputMultichannelBufferType>
        int32 ProcessAndConsumeAudioInternal(FMultichannelCircularBuffer& InAudio, OutputMultichannelBufferType& OutAudio);
 
 
        float ProcessChannelAudioInternal(TArrayView<const float> InAudio, TArrayView<float> OutAudio);
        int32 GetNumBufferFramesToProduceOutputFrames(int32 InNumOutputFrames) const;
 
        Audio::FAlignedFloatBuffer WorkBuffer;
        float CurrentInputFrameIndex = 0.f;
        float CurrentFrameRatio = 1.f;
        float TargetFrameRatio = 1.f;
        float FrameRatioFrameDelta = 0.f;
        int32 NumFramesToInterpolate = 0;
        int32 NumChannels = 0;
    };
}