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/*############################################################################*/
/*# #*/
/*# Ambisonic C++ Library #*/
/*# CAmbisonicProcessor - Ambisonic Processor #*/
/*# Copyright © 2007 Aristotel Digenis #*/
/*# Copyright © 2017 Videolabs #*/
/*# #*/
/*# Filename: AmbisonicProcessor.cpp #*/
/*# Version: 0.2 #*/
/*# Date: 19/05/2007 #*/
/*# Author(s): Aristotel Digenis, Peter Stitt #*/
/*# Licence: LGPL #*/
/*# #*/
/*############################################################################*/
#include "AmbisonicProcessor.h"
#include <iostream>
CAmbisonicProcessor::CAmbisonicProcessor()
: m_orientation(0, 0, 0)
{
m_pfTempSample = nullptr;
m_pfScratchBufferA = nullptr;
m_pFFT_psych_cfg = nullptr;
m_pIFFT_psych_cfg = nullptr;
m_ppcpPsychFilters = nullptr;
m_pcpScratch = nullptr;
m_pfOverlap = nullptr;
}
CAmbisonicProcessor::~CAmbisonicProcessor()
{
if(m_pfTempSample)
delete [] m_pfTempSample;
if(m_pfScratchBufferA)
delete [] m_pfScratchBufferA;
if(m_pFFT_psych_cfg)
kiss_fftr_free(m_pFFT_psych_cfg);
if(m_pIFFT_psych_cfg)
kiss_fftr_free(m_pIFFT_psych_cfg);
if (m_ppcpPsychFilters)
{
for(unsigned i=0; i<=m_nOrder; i++)
if(m_ppcpPsychFilters[i])
delete [] m_ppcpPsychFilters[i];
delete [] m_ppcpPsychFilters;
}
if(m_pcpScratch)
delete [] m_pcpScratch;
if(m_pfOverlap){
for(unsigned i=0; i<m_nChannelCount; i++)
if(m_pfOverlap[i])
delete [] m_pfOverlap[i];
delete [] m_pfOverlap;
}
}
bool CAmbisonicProcessor::Configure(unsigned nOrder, bool b3D, unsigned nBlockSize, unsigned nMisc)
{
bool success = CAmbisonicBase::Configure(nOrder, b3D, nMisc);
if(!success)
return false;
if(m_pfTempSample)
delete [] m_pfTempSample;
m_pfTempSample = new float[m_nChannelCount];
memset(m_pfTempSample, 0, m_nChannelCount * sizeof(float));
/* This bool should be set as a user option to turn optimisation on and off*/
m_bOpt = true;
// All optimisation filters have the same number of taps so take from the first order 3D impulse response arbitrarily
unsigned nbTaps = sizeof(first_order_3D[0]) / sizeof(int16_t);
m_nBlockSize = nBlockSize;
m_nTaps = nbTaps;
//What will the overlap size be?
m_nOverlapLength = m_nBlockSize < m_nTaps ? m_nBlockSize - 1 : m_nTaps - 1;
//How large does the FFT need to be
m_nFFTSize = 1;
while(m_nFFTSize < (m_nBlockSize + m_nTaps + m_nOverlapLength))
m_nFFTSize <<= 1;
//How many bins is that
m_nFFTBins = m_nFFTSize / 2 + 1;
//What do we need to scale the result of the iFFT by
m_fFFTScaler = 1.f / m_nFFTSize;
//Allocate buffers
m_pfOverlap = new float*[m_nChannelCount];
for(unsigned i=0; i<m_nChannelCount; i++)
m_pfOverlap[i] = new float[m_nOverlapLength];
m_pfScratchBufferA = new float[m_nFFTSize];
m_ppcpPsychFilters = new kiss_fft_cpx*[m_nOrder+1];
for(unsigned i = 0; i <= m_nOrder; i++)
m_ppcpPsychFilters[i] = new kiss_fft_cpx[m_nFFTBins];
m_pcpScratch = new kiss_fft_cpx[m_nFFTBins];
//Allocate temporary buffers for retrieving taps of psychoacoustic opimisation filters
std::vector<std::unique_ptr<float[]>> pfPsychIR;
for(unsigned i = 0; i <= m_nOrder; i++)
{
pfPsychIR.emplace_back(new float[m_nTaps]);
}
Reset();
//Allocate FFT and iFFT for new size
m_pFFT_psych_cfg = kiss_fftr_alloc(m_nFFTSize, 0, 0, 0);
m_pIFFT_psych_cfg = kiss_fftr_alloc(m_nFFTSize, 1, 0, 0);
// get impulse responses for psychoacoustic optimisation based on playback system (2D or 3D) and playback order (1 to 3)
//Convert from short to float representation
for (unsigned i_m = 0; i_m <= m_nOrder; i_m++){
for(unsigned i = 0; i < m_nTaps; i++)
if(m_b3D){
switch(m_nOrder){
case 1: pfPsychIR[i_m][i] = 2.f*first_order_3D[i_m][i] / 32767.f; break;
case 2: pfPsychIR[i_m][i] = 2.f*second_order_3D[i_m][i] / 32767.f; break;
case 3: pfPsychIR[i_m][i] = 2.f*third_order_3D[i_m][i] / 32767.f; break;
}
}
else{
switch(m_nOrder){
case 1: pfPsychIR[i_m][i] = 2.f*first_order_2D[i_m][i] / 32767.f; break;
case 2: pfPsychIR[i_m][i] = 2.f*second_order_2D[i_m][i] / 32767.f; break;
case 3: pfPsychIR[i_m][i] = 2.f*third_order_2D[i_m][i] / 32767.f; break;
}
}
// Convert the impulse responses to the frequency domain
memcpy(m_pfScratchBufferA, pfPsychIR[i_m].get(), m_nTaps * sizeof(float));
memset(&m_pfScratchBufferA[m_nTaps], 0, (m_nFFTSize - m_nTaps) * sizeof(float));
kiss_fftr(m_pFFT_psych_cfg, m_pfScratchBufferA, m_ppcpPsychFilters[i_m]);
}
return true;
}
void CAmbisonicProcessor::Reset()
{
for(unsigned i=0; i<m_nChannelCount; i++)
memset(m_pfOverlap[i], 0, m_nOverlapLength * sizeof(float));
}
void CAmbisonicProcessor::Refresh()
{
// Trig terms used multiple times in rotation equations
m_fCosAlpha = cosf(m_orientation.fAlpha);
m_fSinAlpha = sinf(m_orientation.fAlpha);
m_fCosBeta = cosf(m_orientation.fBeta);
m_fSinBeta = sinf(m_orientation.fBeta);
m_fCosGamma = cosf(m_orientation.fGamma);
m_fSinGamma = sinf(m_orientation.fGamma);
m_fCos2Alpha = cosf(2.f * m_orientation.fAlpha);
m_fSin2Alpha = sinf(2.f * m_orientation.fAlpha);
m_fCos2Beta = cosf(2.f * m_orientation.fBeta);
m_fSin2Beta = sinf(2.f * m_orientation.fBeta);
m_fCos2Gamma = cosf(2.f * m_orientation.fGamma);
m_fSin2Gamma = sinf(2.f * m_orientation.fGamma);
m_fCos3Alpha = cosf(3.f * m_orientation.fAlpha);
m_fSin3Alpha = sinf(3.f * m_orientation.fAlpha);
m_fCos3Beta = cosf(3.f * m_orientation.fBeta);
m_fSin3Beta = sinf(3.f * m_orientation.fBeta);
m_fCos3Gamma = cosf(3.f * m_orientation.fGamma);
m_fSin3Gamma = sinf(3.f * m_orientation.fGamma);
}
void CAmbisonicProcessor::SetOrientation(Orientation orientation)
{
m_orientation = orientation;
}
Orientation CAmbisonicProcessor::GetOrientation()
{
return m_orientation;
}
void CAmbisonicProcessor::Process(CBFormat* pBFSrcDst, unsigned nSamples)
{
/* Rotate the sound scene based on the rotation angle from the 360 video*/
/* Before the rotation we apply the psychoacoustic optimisation filters */
if(m_bOpt)
{
ShelfFilterOrder(pBFSrcDst, nSamples);
}
else
{
// No filtering required
}
/* 3D Ambisonics input expected so perform 3D rotations */
if(m_nOrder >= 1)
ProcessOrder1_3D(pBFSrcDst, nSamples);
if(m_nOrder >= 2)
ProcessOrder2_3D(pBFSrcDst, nSamples);
if(m_nOrder >= 3)
ProcessOrder3_3D(pBFSrcDst, nSamples);
}
void CAmbisonicProcessor::ProcessOrder1_3D(CBFormat* pBFSrcDst, unsigned nSamples)
{
/* Rotations are performed in the following order:
1 - rotation around the z-axis
2 - rotation around the *new* y-axis (y')
3 - rotation around the new z-axis (z'')
This is different to the rotations obtained from the video, which are around z, y' then x''.
The rotation equations used here work for third order. However, for higher orders a recursive algorithm
should be considered.*/
for(unsigned niSample = 0; niSample < nSamples; niSample++)
{
// Alpha rotation
m_pfTempSample[kY] = -pBFSrcDst->m_ppfChannels[kX][niSample] * m_fSinAlpha
+ pBFSrcDst->m_ppfChannels[kY][niSample] * m_fCosAlpha;
m_pfTempSample[kZ] = pBFSrcDst->m_ppfChannels[kZ][niSample];
m_pfTempSample[kX] = pBFSrcDst->m_ppfChannels[kX][niSample] * m_fCosAlpha
+ pBFSrcDst->m_ppfChannels[kY][niSample] * m_fSinAlpha;
// Beta rotation
pBFSrcDst->m_ppfChannels[kY][niSample] = m_pfTempSample[kY];
pBFSrcDst->m_ppfChannels[kZ][niSample] = m_pfTempSample[kZ] * m_fCosBeta
+ m_pfTempSample[kX] * m_fSinBeta;
pBFSrcDst->m_ppfChannels[kX][niSample] = m_pfTempSample[kX] * m_fCosBeta
- m_pfTempSample[kZ] * m_fSinBeta;
// Gamma rotation
m_pfTempSample[kY] = -pBFSrcDst->m_ppfChannels[kX][niSample] * m_fSinGamma
+ pBFSrcDst->m_ppfChannels[kY][niSample] * m_fCosGamma;
m_pfTempSample[kZ] = pBFSrcDst->m_ppfChannels[kZ][niSample];
m_pfTempSample[kX] = pBFSrcDst->m_ppfChannels[kX][niSample] * m_fCosGamma
+ pBFSrcDst->m_ppfChannels[kY][niSample] * m_fSinGamma;
pBFSrcDst->m_ppfChannels[kX][niSample] = m_pfTempSample[kX];
pBFSrcDst->m_ppfChannels[kY][niSample] = m_pfTempSample[kY];
pBFSrcDst->m_ppfChannels[kZ][niSample] = m_pfTempSample[kZ];
}
}
void CAmbisonicProcessor::ProcessOrder2_3D(CBFormat* pBFSrcDst, unsigned nSamples)
{
float fSqrt3 = sqrt(3.f);
for(unsigned niSample = 0; niSample < nSamples; niSample++)
{
// Alpha rotation
m_pfTempSample[kV] = - pBFSrcDst->m_ppfChannels[kU][niSample] * m_fSin2Alpha
+ pBFSrcDst->m_ppfChannels[kV][niSample] * m_fCos2Alpha;
m_pfTempSample[kT] = - pBFSrcDst->m_ppfChannels[kS][niSample] * m_fSinAlpha
+ pBFSrcDst->m_ppfChannels[kT][niSample] * m_fCosAlpha;
m_pfTempSample[kR] = pBFSrcDst->m_ppfChannels[kR][niSample];
m_pfTempSample[kS] = pBFSrcDst->m_ppfChannels[kS][niSample] * m_fCosAlpha
+ pBFSrcDst->m_ppfChannels[kT][niSample] * m_fSinAlpha;
m_pfTempSample[kU] = pBFSrcDst->m_ppfChannels[kU][niSample] * m_fCos2Alpha
+ pBFSrcDst->m_ppfChannels[kV][niSample] * m_fSin2Alpha;
// Beta rotation
pBFSrcDst->m_ppfChannels[kV][niSample] = -m_fSinBeta * m_pfTempSample[kT]
+ m_fCosBeta * m_pfTempSample[kV];
pBFSrcDst->m_ppfChannels[kT][niSample] = -m_fCosBeta * m_pfTempSample[kT]
+ m_fSinBeta * m_pfTempSample[kV];
pBFSrcDst->m_ppfChannels[kR][niSample] = (0.75f * m_fCos2Beta + 0.25f) * m_pfTempSample[kR]
+ (0.5 * fSqrt3 * pow(m_fSinBeta,2.0) ) * m_pfTempSample[kU]
+ (fSqrt3 * m_fSinBeta * m_fCosBeta) * m_pfTempSample[kS];
pBFSrcDst->m_ppfChannels[kS][niSample] = m_fCos2Beta * m_pfTempSample[kS]
- fSqrt3 * m_fCosBeta * m_fSinBeta * m_pfTempSample[kR]
+ m_fCosBeta * m_fSinBeta * m_pfTempSample[kU];
pBFSrcDst->m_ppfChannels[kU][niSample] = (0.25f * m_fCos2Beta + 0.75f) * m_pfTempSample[kU]
- m_fCosBeta * m_fSinBeta * m_pfTempSample[kS]
+0.5 * fSqrt3 * pow(m_fSinBeta,2.0) * m_pfTempSample[kR];
// Gamma rotation
m_pfTempSample[kV] = - pBFSrcDst->m_ppfChannels[kU][niSample] * m_fSin2Gamma
+ pBFSrcDst->m_ppfChannels[kV][niSample] * m_fCos2Gamma;
m_pfTempSample[kT] = - pBFSrcDst->m_ppfChannels[kS][niSample] * m_fSinGamma
+ pBFSrcDst->m_ppfChannels[kT][niSample] * m_fCosGamma;
m_pfTempSample[kR] = pBFSrcDst->m_ppfChannels[kR][niSample];
m_pfTempSample[kS] = pBFSrcDst->m_ppfChannels[kS][niSample] * m_fCosGamma
+ pBFSrcDst->m_ppfChannels[kT][niSample] * m_fSinGamma;
m_pfTempSample[kU] = pBFSrcDst->m_ppfChannels[kU][niSample] * m_fCos2Gamma
+ pBFSrcDst->m_ppfChannels[kV][niSample] * m_fSin2Gamma;
pBFSrcDst->m_ppfChannels[kR][niSample] = m_pfTempSample[kR];
pBFSrcDst->m_ppfChannels[kS][niSample] = m_pfTempSample[kS];
pBFSrcDst->m_ppfChannels[kT][niSample] = m_pfTempSample[kT];
pBFSrcDst->m_ppfChannels[kU][niSample] = m_pfTempSample[kU];
pBFSrcDst->m_ppfChannels[kV][niSample] = m_pfTempSample[kV];
}
}
void CAmbisonicProcessor::ProcessOrder3_3D(CBFormat* pBFSrcDst, unsigned nSamples)
{
/* (should move these somewhere that does recompute each time) */
float fSqrt3_2 = sqrt(3.f/2.f);
float fSqrt15 = sqrt(15.f);
float fSqrt5_2 = sqrt(5.f/2.f);
for(unsigned niSample = 0; niSample < nSamples; niSample++)
{
// Alpha rotation
m_pfTempSample[kQ] = - pBFSrcDst->m_ppfChannels[kP][niSample] * m_fSin3Alpha
+ pBFSrcDst->m_ppfChannels[kQ][niSample] * m_fCos3Alpha;
m_pfTempSample[kO] = - pBFSrcDst->m_ppfChannels[kN][niSample] * m_fSin2Alpha
+ pBFSrcDst->m_ppfChannels[kO][niSample] * m_fCos2Alpha;
m_pfTempSample[kM] = - pBFSrcDst->m_ppfChannels[kL][niSample] * m_fSinAlpha
+ pBFSrcDst->m_ppfChannels[kM][niSample] * m_fCosAlpha;
m_pfTempSample[kK] = pBFSrcDst->m_ppfChannels[kK][niSample];
m_pfTempSample[kL] = pBFSrcDst->m_ppfChannels[kL][niSample] * m_fCosAlpha
+ pBFSrcDst->m_ppfChannels[kM][niSample] * m_fSinAlpha;
m_pfTempSample[kN] = pBFSrcDst->m_ppfChannels[kN][niSample] * m_fCos2Alpha
+ pBFSrcDst->m_ppfChannels[kO][niSample] * m_fSin2Alpha;
m_pfTempSample[kP] = pBFSrcDst->m_ppfChannels[kP][niSample] * m_fCos3Alpha
+ pBFSrcDst->m_ppfChannels[kQ][niSample] * m_fSin3Alpha;
// Beta rotation
pBFSrcDst->m_ppfChannels[kQ][niSample] = 0.125f * m_pfTempSample[kQ] * (5.f + 3.f*m_fCos2Beta)
- fSqrt3_2 * m_pfTempSample[kO] *m_fCosBeta * m_fSinBeta
+ 0.25f * fSqrt15 * m_pfTempSample[kM] * pow(m_fSinBeta,2.0f);
pBFSrcDst->m_ppfChannels[kO][niSample] = m_pfTempSample[kO] * m_fCos2Beta
- fSqrt5_2 * m_pfTempSample[kM] * m_fCosBeta * m_fSinBeta
+ fSqrt3_2 * m_pfTempSample[kQ] * m_fCosBeta * m_fSinBeta;
pBFSrcDst->m_ppfChannels[kM][niSample] = 0.125f * m_pfTempSample[kM] * (3.f + 5.f*m_fCos2Beta)
- fSqrt5_2 * m_pfTempSample[kO] *m_fCosBeta * m_fSinBeta
+ 0.25f * fSqrt15 * m_pfTempSample[kQ] * pow(m_fSinBeta,2.0f);
pBFSrcDst->m_ppfChannels[kK][niSample] = 0.25f * m_pfTempSample[kK] * m_fCosBeta * (-1.f + 15.f*m_fCos2Beta)
+ 0.5f * fSqrt15 * m_pfTempSample[kN] * m_fCosBeta * pow(m_fSinBeta,2.f)
+ 0.5f * fSqrt5_2 * m_pfTempSample[kP] * pow(m_fSinBeta,3.f)
+ 0.125f * fSqrt3_2 * m_pfTempSample[kL] * (m_fSinBeta + 5.f * m_fSin3Beta);
pBFSrcDst->m_ppfChannels[kL][niSample] = 0.0625f * m_pfTempSample[kL] * (m_fCosBeta + 15.f * m_fCos3Beta)
+ 0.25f * fSqrt5_2 * m_pfTempSample[kN] * (1.f + 3.f * m_fCos2Beta) * m_fSinBeta
+ 0.25f * fSqrt15 * m_pfTempSample[kP] * m_fCosBeta * pow(m_fSinBeta,2.f)
- 0.125 * fSqrt3_2 * m_pfTempSample[kK] * (m_fSinBeta + 5.f * m_fSin3Beta);
pBFSrcDst->m_ppfChannels[kN][niSample] = 0.125f * m_pfTempSample[kN] * (5.f * m_fCosBeta + 3.f * m_fCos3Beta)
+ 0.25f * fSqrt3_2 * m_pfTempSample[kP] * (3.f + m_fCos2Beta) * m_fSinBeta
+ 0.5f * fSqrt15 * m_pfTempSample[kK] * m_fCosBeta * pow(m_fSinBeta,2.f)
+ 0.125 * fSqrt5_2 * m_pfTempSample[kL] * (m_fSinBeta - 3.f * m_fSin3Beta);
pBFSrcDst->m_ppfChannels[kP][niSample] = 0.0625f * m_pfTempSample[kP] * (15.f * m_fCosBeta + m_fCos3Beta)
- 0.25f * fSqrt3_2 * m_pfTempSample[kN] * (3.f + m_fCos2Beta) * m_fSinBeta
+ 0.25f * fSqrt15 * m_pfTempSample[kL] * m_fCosBeta * pow(m_fSinBeta,2.f)
- 0.5 * fSqrt5_2 * m_pfTempSample[kK] * pow(m_fSinBeta,3.f);
// Gamma rotation
m_pfTempSample[kQ] = - pBFSrcDst->m_ppfChannels[kP][niSample] * m_fSin3Gamma
+ pBFSrcDst->m_ppfChannels[kQ][niSample] * m_fCos3Gamma;
m_pfTempSample[kO] = - pBFSrcDst->m_ppfChannels[kN][niSample] * m_fSin2Gamma
+ pBFSrcDst->m_ppfChannels[kO][niSample] * m_fCos2Gamma;
m_pfTempSample[kM] = - pBFSrcDst->m_ppfChannels[kL][niSample] * m_fSinGamma
+ pBFSrcDst->m_ppfChannels[kM][niSample] * m_fCosGamma;
m_pfTempSample[kK] = pBFSrcDst->m_ppfChannels[kK][niSample];
m_pfTempSample[kL] = pBFSrcDst->m_ppfChannels[kL][niSample] * m_fCosGamma
+ pBFSrcDst->m_ppfChannels[kM][niSample] * m_fSinGamma;
m_pfTempSample[kN] = pBFSrcDst->m_ppfChannels[kN][niSample] * m_fCos2Gamma
+ pBFSrcDst->m_ppfChannels[kO][niSample] * m_fSin2Gamma;
m_pfTempSample[kP] = pBFSrcDst->m_ppfChannels[kP][niSample] * m_fCos3Gamma
+ pBFSrcDst->m_ppfChannels[kQ][niSample] * m_fSin3Gamma;
pBFSrcDst->m_ppfChannels[kQ][niSample] = m_pfTempSample[kQ];
pBFSrcDst->m_ppfChannels[kO][niSample] = m_pfTempSample[kO];
pBFSrcDst->m_ppfChannels[kM][niSample] = m_pfTempSample[kM];
pBFSrcDst->m_ppfChannels[kK][niSample] = m_pfTempSample[kK];
pBFSrcDst->m_ppfChannels[kL][niSample] = m_pfTempSample[kL];
pBFSrcDst->m_ppfChannels[kN][niSample] = m_pfTempSample[kN];
pBFSrcDst->m_ppfChannels[kP][niSample] = m_pfTempSample[kP];
}
}
// ACN/SN3D is generally only ever produced for 3D Ambisonics.
// If 2D Ambisonics is required then these equations need to be modified (they can be found in the 3D code for the first Z-rotation).
// Generally, 2D-only rotations do not make sense for use with 360 degree videos.
/*
void CAmbisonicProcessor::ProcessOrder1_2D(CBFormat* pBFSrcDst, unsigned nSamples)
{
for(unsigned niSample = 0; niSample < nSamples; niSample++)
{
//Yaw
m_pfTempSample[kX] = pBFSrcDst->m_ppfChannels[kX][niSample] * m_fCosYaw
- pBFSrcDst->m_ppfChannels[kY][niSample] * m_fSinYaw;
m_pfTempSample[kY] = pBFSrcDst->m_ppfChannels[kX][niSample] * m_fSinYaw
+ pBFSrcDst->m_ppfChannels[kY][niSample] * m_fCosYaw;
pBFSrcDst->m_ppfChannels[kX][niSample] = m_pfTempSample[kX];
pBFSrcDst->m_ppfChannels[kY][niSample] = m_pfTempSample[kY];
}
}
void CAmbisonicProcessor::ProcessOrder2_2D(CBFormat* pBFSrcDst, unsigned nSamples)
{
for(unsigned niSample = 0; niSample < nSamples; niSample++)
{
//Yaw
m_pfTempSample[kS] = pBFSrcDst->m_ppfChannels[kS][niSample] * m_fCosYaw
- pBFSrcDst->m_ppfChannels[kT][niSample] * m_fSinYaw;
m_pfTempSample[kT] = pBFSrcDst->m_ppfChannels[kS][niSample] * m_fSinYaw
+ pBFSrcDst->m_ppfChannels[kT][niSample] * m_fCosYaw;
m_pfTempSample[kU] = pBFSrcDst->m_ppfChannels[kU][niSample] * m_fCos2Yaw
- pBFSrcDst->m_ppfChannels[kV][niSample] * m_fSin2Yaw;
m_pfTempSample[kV] = pBFSrcDst->m_ppfChannels[kU][niSample] * m_fSin2Yaw
+ pBFSrcDst->m_ppfChannels[kV][niSample] * m_fCos2Yaw;
pBFSrcDst->m_ppfChannels[kS][niSample] = m_pfTempSample[kS];
pBFSrcDst->m_ppfChannels[kT][niSample] = m_pfTempSample[kT];
pBFSrcDst->m_ppfChannels[kU][niSample] = m_pfTempSample[kU];
pBFSrcDst->m_ppfChannels[kV][niSample] = m_pfTempSample[kV];
}
}
void CAmbisonicProcessor::ProcessOrder3_2D(CBFormat* pBFSrcDst, unsigned nSamples)
{
//TODO
}
*/
void CAmbisonicProcessor::ShelfFilterOrder(CBFormat* pBFSrcDst, unsigned nSamples)
{
kiss_fft_cpx cpTemp;
unsigned iChannelOrder = 0;
// Filter the Ambisonics channels
// All channels are filtered using linear phase FIR filters.
// In the case of the 0th order signal (W channel) this takes the form of a delay
// For all other channels shelf filters are used
memset(m_pfScratchBufferA, 0, m_nFFTSize * sizeof(float));
for(unsigned niChannel = 0; niChannel < m_nChannelCount; niChannel++)
{
iChannelOrder = int(sqrt(niChannel)); //get the order of the current channel
memcpy(m_pfScratchBufferA, pBFSrcDst->m_ppfChannels[niChannel], m_nBlockSize * sizeof(float));
memset(&m_pfScratchBufferA[m_nBlockSize], 0, (m_nFFTSize - m_nBlockSize) * sizeof(float));
kiss_fftr(m_pFFT_psych_cfg, m_pfScratchBufferA, m_pcpScratch);
// Perform the convolution in the frequency domain
for(unsigned ni = 0; ni < m_nFFTBins; ni++)
{
cpTemp.r = m_pcpScratch[ni].r * m_ppcpPsychFilters[iChannelOrder][ni].r
- m_pcpScratch[ni].i * m_ppcpPsychFilters[iChannelOrder][ni].i;
cpTemp.i = m_pcpScratch[ni].r * m_ppcpPsychFilters[iChannelOrder][ni].i
+ m_pcpScratch[ni].i * m_ppcpPsychFilters[iChannelOrder][ni].r;
m_pcpScratch[ni] = cpTemp;
}
// Convert from frequency domain back to time domain
kiss_fftri(m_pIFFT_psych_cfg, m_pcpScratch, m_pfScratchBufferA);
for(unsigned ni = 0; ni < m_nFFTSize; ni++)
m_pfScratchBufferA[ni] *= m_fFFTScaler;
memcpy(pBFSrcDst->m_ppfChannels[niChannel], m_pfScratchBufferA, m_nBlockSize * sizeof(float));
for(unsigned ni = 0; ni < m_nOverlapLength; ni++)
{
pBFSrcDst->m_ppfChannels[niChannel][ni] += m_pfOverlap[niChannel][ni];
}
memcpy(m_pfOverlap[niChannel], &m_pfScratchBufferA[m_nBlockSize], m_nOverlapLength * sizeof(float));
}
}
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