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winamp/Src/vlb/dolby_imdct.cpp

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/* $Header: /cvs/root/winamp/vlb/dolby_imdct.cpp,v 1.1 2009/04/28 20:21:09 audiodsp Exp $ */
/***************************************************************************\
*
* Copyright 2000-2002 Dolby Laboratories, Inc. All Rights
* Reserved. Do not copy. Do not distribute.
* Confidential information.
*
* filename: dolby_imdct.cpp
* project : MPEG-2 AAC Decoder
* contents/description: IMDCT transform routines
*
\***************************************************************************/
#include"dolby_imdct.h"
#ifdef INTERPOLATE_WINDOW
#include "window_tab.h"
#endif
/* #defines related to Izero and CalculateKBDWindowExact */
#define IzeroEPSILON 1E-21 /* Max error acceptable in Izero */
#define M_PI 3.14159265358979323846264338327950288f
/*------------------------ Window Functions ---------------------------*/
void Sine_Window(float*pfWindow,int iSize)
{
#ifdef INTERPOLATE_WINDOW
int count, j;
switch (iSize)
{
case 256:
for(j=0; j < iSize/2 ;j++)
{
pfWindow[j]=(float)(sin_short[j]);
}
break;
case 512:
count = 0;
for (j = 0; j < iSize/4-1; j++)
{
pfWindow[count++] = (float) sin_short[j];
pfWindow[count++] = (float) ((sin_short[j] + sin_short[j + 1]) * 0.5);
}
pfWindow[count++] = (float) sin_short[j];
pfWindow[count] = (float) 1.0;
break;
case 2048:
for(j=0; j < iSize/2 ;j++)
{
pfWindow[j]=(float)(sin_long[j]);
}
break;
case 4096:
count = 0;
for (j = 0; j < iSize/4-1; j++)
{
pfWindow[count++] = (float) sin_long[j];
pfWindow[count++] = (float) ((sin_long[j] + sin_long[j + 1]) * 0.5);
}
pfWindow[count++] = (float) sin_long[j];
pfWindow[count] = (float) 1.0;
break;
}
#else
int n;
for(n=0;n<iSize/2;n++){
pfWindow[n]=(float)(sin(pi*((float)n+0.5)/(float)iSize));
}
#endif
}
static float Izero(float x)
{
float sum,
u,
halfx,
temp;
int n;
sum = u = 1.0f;
n = 1;
halfx = x / 2.0f;
do
{
temp = halfx / (float) n;
n += 1;
temp *= temp;
u *= temp;
sum += u;
} while (u >= IzeroEPSILON * sum);
return (sum);
}
/*****************************************************************************
functionname: CalculateKBDWindowExact
description: calculates the window coefficients for the Kaiser-Bessel
derived window
returns:
input: window length, alpha
output: window coefficients
*****************************************************************************/
void CalculateKBDWindowExact(float * win, float alpha, int length)
{
int i;
float IBeta;
float tmp;
float sum = 0.0;
alpha *= M_PI;
IBeta = 1.0f / Izero(alpha);
/* calculate lower half of Kaiser Bessel window */
for (i = 0; i < (length >> 1); i++)
{
tmp = 4.0f * (float) i / (float) length - 1.0f;
win[i] = Izero(alpha * ((float) sqrt(1.0f - tmp * tmp))) * IBeta;
sum += win[i];
}
sum = 1.0f / sum;
tmp = 0.0;
/* calculate lower half of window */
for (i = 0; i < (length >> 1); i++)
{
tmp += win[i];
win[i] = (float) sqrt(tmp * sum);
}
}
void KBD_Window(float*pfWindow,int iSize)
{
#ifdef INTERPOLATE_WINDOW
int count, j;
switch (iSize)
{
case 256:
for(j=0; j < iSize/2 ;j++)
{
pfWindow[j]=(float)(KBD_short[j]);
}
break;
case 512:
count = 0;
for (j = 0; j < iSize/4-1; j++)
{
pfWindow[count++] = (float) KBD_short[j];
pfWindow[count++] = (float) ((KBD_short[j] + KBD_short[j + 1]) * 0.5);
}
pfWindow[count++] = (float) KBD_short[j];
pfWindow[count] = (float) 1.0;
break;
case 2048:
for(j=0; j < iSize/2 ;j++)
{
pfWindow[j]=(float)(KBD_long[j]);
}
break;
case 4096:
count = 0;
for (j = 0; j < iSize/4-1; j++)
{
pfWindow[count++] = (float) KBD_long[j];
pfWindow[count++] = (float) ((KBD_long[j] + KBD_long[j + 1]) * 0.5);
}
pfWindow[count++] = (float) KBD_long[j];
pfWindow[count] = (float) 1.0;
break;
}
#else
/* The stock AAC MP4 encoder calculates KBD windows with different alphas
depending on the blocklength. We must match those windows here. */
switch(iSize)
{
case 256:
case 512:
CalculateKBDWindowExact(pfWindow, 6.0, iSize);
break;
case 2048:
case 4096:
CalculateKBDWindowExact(pfWindow, 4.0, iSize);
break;
default:
CalculateKBDWindowExact(pfWindow, 4.0, iSize);
}
#endif
}
/*----------------------- DOLBY IMDCT ---------------------------------*/
IMDCTObject::IMDCTObject(int _iLongSize,
int _iOverlap)
:iLongSize(_iLongSize),
iHLongSize(_iLongSize/2),
iOverlap(_iOverlap),
iOldShape(0)
{
if(iLongSize==0){
return;
}
if(iOverlap==0){
return;
}
int n,k;
//Obtain memory for Short Windows:
//These arrays are larger than they need to be,
//but are made this large for convenience
iShortSize = iLongSize / 8;
iHShortSize = iHLongSize / 8;
pfShortWindowSin = new float[iHLongSize];
pfShortWindowKBD = new float[iHLongSize];
//Obtain memory for Longwindows:
pfLongWindowSin=new float[iHLongSize];
pfS2LWindowSin=new float[iHLongSize];
pfLongWindowKBD=new float[iHLongSize];
pfS2LWindowKBD=new float[iHLongSize];
//Obtain memory for temporary buffer:
pfTempBuffer=new float[iLongSize];
pfEightWindowsBuffer=new float[iLongSize];
pfSavedBuffer=new float[iHLongSize];
for(n=0;n<iHLongSize;n++) pfSavedBuffer[n]=0;
//Create Windows:
KBD_Window(pfLongWindowKBD,iLongSize);
Sine_Window(pfLongWindowSin,iLongSize);
//Create S2L Window:
KBD_Window(pfShortWindowKBD,iOverlap*2); // temporary
for(k=0,n=iHLongSize/2-iOverlap/2;k<iOverlap;k++,n++){
pfS2LWindowKBD[n]=pfShortWindowKBD[k];
}
for(n=0;n<iHLongSize/2-iOverlap/2;n++){
pfS2LWindowKBD[n]=0.0f;
}
for(n=iHLongSize/2+iOverlap/2;n<iHLongSize;n++){
pfS2LWindowKBD[n]=1.0f;
}
//Create correct length short window
KBD_Window(pfShortWindowKBD,iShortSize);
//Create S2L Window:
Sine_Window(pfShortWindowSin,iOverlap*2); // temporary
for(k=0,n=iHLongSize/2-iOverlap/2;k<iOverlap;k++,n++){
pfS2LWindowSin[n]=pfShortWindowSin[k];
}
for(n=0;n<iHLongSize/2-iOverlap/2;n++){
pfS2LWindowSin[n]=0.0f;
}
for(n=iHLongSize/2+iOverlap/2;n<iHLongSize;n++){
pfS2LWindowSin[n]=1.0f;
}
//Create correct length short window
Sine_Window(pfShortWindowSin,iShortSize);
// Compute Long Twiddles
iLongFFTSize=iLongSize/4;
pfReal=new float[iLongFFTSize];
pfImag=new float[iLongFFTSize];
pfRealLongTwiddle=new float[iLongFFTSize];
pfImagLongTwiddle=new float[iLongFFTSize];
pfRealLongTwiddle[0]=(float)(cos(0.125*2.0*pi/(float)iLongSize));
pfImagLongTwiddle[0]=(float)(sin(0.125*2.0*pi/(float)iLongSize));
for(n=1;n<iLongFFTSize;n++){
pfRealLongTwiddle[n]=(float)(cos(2.0*pi/(float)iLongSize))*pfRealLongTwiddle[n-1]-
(float)(sin(2.0*pi/(float)iLongSize))*pfImagLongTwiddle[n-1];
pfImagLongTwiddle[n]=(float)(cos(2.0*pi/(float)iLongSize))*pfImagLongTwiddle[n-1]+
(float)(sin(2.0*pi/(float)iLongSize))*pfRealLongTwiddle[n-1];
}
// Compute Short Twiddles
// these twiddles may be redundant - they may be able to be computed as a function
// of the long twiddles
iShortFFTSize=iShortSize/4;
pfRealShort=new float[iShortFFTSize];
pfImagShort=new float[iShortFFTSize];
pfRealShortTwiddle=new float[iShortFFTSize];
pfImagShortTwiddle=new float[iShortFFTSize];
pfRealShortTwiddle[0]=(float)(cos(0.125*2.0*pi/(float)iShortSize));
pfImagShortTwiddle[0]=(float)(sin(0.125*2.0*pi/(float)iShortSize));
for(n=1;n<iShortFFTSize;n++){
pfRealShortTwiddle[n]=(float)(cos(2.0*pi/(float)iShortSize))*pfRealShortTwiddle[n-1]-
(float)(sin(2.0*pi/(float)iShortSize))*pfImagShortTwiddle[n-1];
pfImagShortTwiddle[n]=(float)(cos(2.0*pi/(float)iShortSize))*pfImagShortTwiddle[n-1]+
(float)(sin(2.0*pi/(float)iShortSize))*pfRealShortTwiddle[n-1];
}
}
IMDCTObject::IMDCTObject()
:iLongSize(0),
iOverlap(0)
{
}
IMDCTObject::IMDCTObject(IMDCTObject&oCopy)
:iLongSize(oCopy.iLongSize),
iHLongSize(iLongSize/2),
iOverlap(oCopy.iOverlap),
iOldShape(oCopy.iOldShape)
{
if(iLongSize==0){
return;
}
if(iOverlap==0){
return;
}
int n,k;
//Obtain memory for Short Windows:
//These arrays are larger than they need to be,
//but are made this large for convenience
iShortSize = iLongSize / 8;
iHShortSize = iHLongSize / 8;
pfShortWindowSin = new float[iHLongSize];
pfShortWindowKBD = new float[iHLongSize];
//Obtain memory for windows:
pfLongWindowSin=new float[iHLongSize];
pfS2LWindowSin=new float[iHLongSize];
pfLongWindowKBD=new float[iHLongSize];
pfS2LWindowKBD=new float[iHLongSize];
//Obtain memory for temporary buffer:
pfTempBuffer=new float[iLongSize];
pfEightWindowsBuffer=new float[iLongSize];
pfSavedBuffer=new float[iHLongSize];
for(n=0;n<iHLongSize;n++) pfSavedBuffer[n]=0;
//Create Windows:
KBD_Window(pfLongWindowKBD,iLongSize);
Sine_Window(pfLongWindowSin,iLongSize);
//Create S2L Window:
KBD_Window(pfShortWindowKBD,iOverlap*2); // temporary
for(k=0,n=iHLongSize/2-iOverlap/2;k<iOverlap;k++,n++){
pfS2LWindowKBD[n]=pfShortWindowKBD[k];
}
for(n=0;n<iHLongSize/2-iOverlap/2;n++){
pfS2LWindowKBD[n]=0.0f;
}
for(n=iHLongSize/2+iOverlap/2;n<iHLongSize;n++){
pfS2LWindowKBD[n]=1.0f;
}
//Create correct length short window
KBD_Window(pfShortWindowKBD,iShortSize);
//Create S2L Window:
Sine_Window(pfShortWindowSin,iOverlap*2); // temporary
for(k=0,n=iHLongSize/2-iOverlap/2;k<iOverlap;k++,n++){
pfS2LWindowSin[n]=pfShortWindowSin[k];
}
for(n=0;n<iHLongSize/2-iOverlap/2;n++){
pfS2LWindowSin[n]=0.0f;
}
for(n=iHLongSize/2+iOverlap/2;n<iHLongSize;n++){
pfS2LWindowSin[n]=1.0f;
}
//Create correct length short window
Sine_Window(pfShortWindowSin,iShortSize);
// Compute Long Twiddles
iLongFFTSize=iLongSize/4;
pfReal=new float[iLongFFTSize];
pfImag=new float[iLongFFTSize];
pfRealLongTwiddle=new float[iLongFFTSize];
pfImagLongTwiddle=new float[iLongFFTSize];
pfRealLongTwiddle[0]=(float)(cos(0.125*2.0*pi/(float)iLongSize));
pfImagLongTwiddle[0]=(float)(sin(0.125*2.0*pi/(float)iLongSize));
for(n=1;n<iLongFFTSize;n++){
pfRealLongTwiddle[n]=(float)(cos(2.0*pi/(float)iLongSize))*pfRealLongTwiddle[n-1]-
(float)(sin(2.0*pi/(float)iLongSize))*pfImagLongTwiddle[n-1];
pfImagLongTwiddle[n]=(float)(cos(2.0*pi/(float)iLongSize))*pfImagLongTwiddle[n-1]+
(float)(sin(2.0*pi/(float)iLongSize))*pfRealLongTwiddle[n-1];
}
// Compute Short Twiddles
// these twiddles may be redundant - they may be able to be computed as a function
// of the long twiddles
iShortFFTSize=iShortSize/4;
pfRealShort=new float[iShortFFTSize];
pfImagShort=new float[iShortFFTSize];
pfRealShortTwiddle=new float[iShortFFTSize];
pfImagShortTwiddle=new float[iShortFFTSize];
pfRealShortTwiddle[0]=(float)(cos(0.125*2.0*pi/(float)iShortSize));
pfImagShortTwiddle[0]=(float)(sin(0.125*2.0*pi/(float)iShortSize));
for(n=1;n<iShortFFTSize;n++){
pfRealShortTwiddle[n]=(float)(cos(2.0*pi/(float)iShortSize))*pfRealShortTwiddle[n-1]-
(float)(sin(2.0*pi/(float)iShortSize))*pfImagShortTwiddle[n-1];
pfImagShortTwiddle[n]=(float)(cos(2.0*pi/(float)iShortSize))*pfImagShortTwiddle[n-1]+
(float)(sin(2.0*pi/(float)iShortSize))*pfRealShortTwiddle[n-1];
}
}
IMDCTObject& IMDCTObject::operator=(IMDCTObject&oCopy)
{
if(iLongSize!=0&&iOverlap!=0){
delete[] pfLongWindowKBD;
delete[] pfS2LWindowKBD;
delete[] pfLongWindowSin;
delete[] pfS2LWindowSin;
delete[] pfShortWindowSin;
delete[] pfShortWindowKBD;
delete[] pfSavedBuffer;
delete[] pfReal;
delete[] pfImag;
delete[] pfRealLongTwiddle;
delete[] pfImagLongTwiddle;
delete[] pfRealShort;
delete[] pfImagShort;
delete[] pfRealShortTwiddle;
delete[] pfImagShortTwiddle;
}
iLongSize=oCopy.iLongSize;
iHLongSize=iLongSize/2;
iShortSize=oCopy.iShortSize;
iHShortSize=iShortSize/2;
iOverlap=oCopy.iOverlap;
iOldShape=oCopy.iOldShape;
if(iLongSize==0){
return *this;
}
if(iOverlap==0){
return *this;
}
int n,k;
//Obtain memory for Short Windows:
//These arrays are larger than they need to be,
//but are made this large for convenience
iShortSize = iLongSize / 8;
iHShortSize = iHLongSize / 8;
pfShortWindowSin = new float[iHLongSize];
pfShortWindowKBD = new float[iHLongSize];
//Obtain memory for windows:
pfLongWindowSin=new float[iHLongSize];
pfS2LWindowSin=new float[iHLongSize];
pfLongWindowKBD=new float[iHLongSize];
pfS2LWindowKBD=new float[iHLongSize];
//Obtain memory for temporary buffer:
pfTempBuffer=new float[iLongSize];
pfEightWindowsBuffer=new float[iLongSize];
pfSavedBuffer=new float[iHLongSize];
for(n=0;n<iHLongSize;n++) pfSavedBuffer[n]=0;
//Create Windows:
KBD_Window(pfLongWindowKBD,iLongSize);
Sine_Window(pfLongWindowSin,iLongSize);
//Create S2L Window:
KBD_Window(pfShortWindowKBD,iOverlap*2); // temporary
for(k=0,n=iHLongSize/2-iOverlap/2;k<iOverlap;k++,n++){
pfS2LWindowKBD[n]=pfShortWindowKBD[k];
}
for(n=0;n<iHLongSize/2-iOverlap/2;n++){
pfS2LWindowKBD[n]=0.0f;
}
for(n=iHLongSize/2+iOverlap/2;n<iHLongSize;n++){
pfS2LWindowKBD[n]=1.0f;
}
//Create correct length short window
KBD_Window(pfShortWindowKBD,iShortSize);
//Create S2L Window:
Sine_Window(pfShortWindowSin,iOverlap*2); // temporary
for(k=0,n=iHLongSize/2-iOverlap/2;k<iOverlap;k++,n++){
pfS2LWindowSin[n]=pfShortWindowSin[k];
}
for(n=0;n<iHLongSize/2-iOverlap/2;n++){
pfS2LWindowSin[n]=0.0f;
}
for(n=iHLongSize/2+iOverlap/2;n<iHLongSize;n++){
pfS2LWindowSin[n]=1.0f;
}
//Create correct length short window
Sine_Window(pfShortWindowSin,iShortSize);
// Compute Long Twiddles
iLongFFTSize=iLongSize/4;
pfReal=new float[iLongFFTSize];
pfImag=new float[iLongFFTSize];
pfRealLongTwiddle=new float[iLongFFTSize];
pfImagLongTwiddle=new float[iLongFFTSize];
pfRealLongTwiddle[0]=(float)(cos(0.125*2.0*pi/(float)iLongSize));
pfImagLongTwiddle[0]=(float)(sin(0.125*2.0*pi/(float)iLongSize));
for(n=1;n<iLongFFTSize;n++){
pfRealLongTwiddle[n]=(float)(cos(2.0*pi/(float)iLongSize))*pfRealLongTwiddle[n-1]-
(float)(sin(2.0*pi/(float)iLongSize))*pfImagLongTwiddle[n-1];
pfImagLongTwiddle[n]=(float)(cos(2.0*pi/(float)iLongSize))*pfImagLongTwiddle[n-1]+
(float)(sin(2.0*pi/(float)iLongSize))*pfRealLongTwiddle[n-1];
}
// Compute Short Twiddles
// these twiddles may be redundant - they may be able to be computed as a function
// of the long twiddles
iShortFFTSize=iShortSize/4;
pfRealShort=new float[iShortFFTSize];
pfImagShort=new float[iShortFFTSize];
pfRealShortTwiddle=new float[iShortFFTSize];
pfImagShortTwiddle=new float[iShortFFTSize];
pfRealShortTwiddle[0]=(float)(cos(0.125*2.0*pi/(float)iShortSize));
pfImagShortTwiddle[0]=(float)(sin(0.125*2.0*pi/(float)iShortSize));
for(n=1;n<iShortFFTSize;n++){
pfRealShortTwiddle[n]=(float)(cos(2.0*pi/(float)iShortSize))*pfRealShortTwiddle[n-1]-
(float)(sin(2.0*pi/(float)iShortSize))*pfImagShortTwiddle[n-1];
pfImagShortTwiddle[n]=(float)(cos(2.0*pi/(float)iShortSize))*pfImagShortTwiddle[n-1]+
(float)(sin(2.0*pi/(float)iShortSize))*pfRealShortTwiddle[n-1];
}
return *this;
}
IMDCTObject::~IMDCTObject()
{
if(iLongSize!=0&&iOverlap!=0){
delete[] pfLongWindowKBD;
delete[] pfS2LWindowKBD;
delete[] pfLongWindowSin;
delete[] pfS2LWindowSin;
delete[] pfShortWindowSin;
delete[] pfShortWindowKBD;
delete[] pfSavedBuffer;
delete[] pfReal;
delete[] pfImag;
delete[] pfRealLongTwiddle;
delete[] pfImagLongTwiddle;
delete[] pfRealShort;
delete[] pfImagShort;
delete[] pfRealShortTwiddle;
delete[] pfImagShortTwiddle;
delete[] pfTempBuffer;
delete[] pfEightWindowsBuffer;
}
}
int IMDCTObject::Transform( float*pfData,
int iWindowType,
int iWindowShape)
{
int n,k;
float *pfWindowFirst;
float *pfWindowSecond;
int eightShortSequenceFlag;
float* pfDataShortBlock;
switch(iWindowType){
case 0:
if(iOldShape == SINE_WINDOW){
pfWindowFirst=pfLongWindowSin;
}
else{
pfWindowFirst=pfLongWindowKBD;
}
if(iWindowShape == SINE_WINDOW){
pfWindowSecond=pfLongWindowSin;
}
else{
pfWindowSecond=pfLongWindowKBD;
}
eightShortSequenceFlag = 0;
break;
case 1:
if(iOldShape == SINE_WINDOW){
pfWindowFirst=pfLongWindowSin;
}
else{
pfWindowFirst=pfLongWindowKBD;
}
if(iWindowShape == SINE_WINDOW){
pfWindowSecond=pfS2LWindowSin;
}
else{
pfWindowSecond=pfS2LWindowKBD;
}
eightShortSequenceFlag = 0;
break;
case 2:
eightShortSequenceFlag = 1;
break;
case 3:
if(iOldShape == SINE_WINDOW){
pfWindowFirst=pfS2LWindowSin;
}
else{
pfWindowFirst=pfS2LWindowKBD;
}
if(iWindowShape == SINE_WINDOW){
pfWindowSecond=pfLongWindowSin;
}
else{
pfWindowSecond=pfLongWindowKBD;
}
eightShortSequenceFlag = 0;
break;
default:
//printf("Invalid Window Type\n");
return -1;
}
if (eightShortSequenceFlag == 0)
{
//Copy Data
memcpy(pfTempBuffer,pfData,iHLongSize*sizeof(float));
//IMDCT:
imdct(pfTempBuffer, LONG_BLOCK);
//DGC Goes Here
//Window
for(n=0,k=iHLongSize-1;n<iHLongSize;n++,k--){
pfTempBuffer[n]*=pfWindowFirst[n];
pfTempBuffer[n+iHLongSize]*=pfWindowSecond[k];
}
} else {
//Copy coefficient Data to a (possibly larger) array in preparation
//for imdct.
//CNC: the use of the constact 256 is really ugly here!!!
//256 = (2 * CShortBlock::MaximumBins), but this expression
//is inconvenient to insert in the code below due to access restrictions.
//The hardcoding of the constant 256 refers to the fixed spacing
//of the mdct coefficients in the data pfData, independent of whether
//or not we're dealing with a single or a double length transform.
//Note: the imdct only requires N/2 freq. coefficients to
//produce N (time aliased) time samples. In the case of a double
//length transform, we'll need to copy the spectrally extended
//short blocks, one by one, to their proper place in the larger
//array, pfEightWindowsBuffer. Since the source and destination
//arrays might be of different sizes due to using a single *or* a
//double length transform, the block-to-block spacing of the mdct
//coefficients could be different in each of the arrays.
for (n=0;n<8;n++)
{
memcpy(&pfEightWindowsBuffer[n*iShortSize],
&pfData[n*256],
256*sizeof(float));
}
// clear the TempBuffer, which will hold the time-aliased
// output for the entire frame (all overlap-added short blocks)
for (k = 0 ; k < iLongSize ; k++)
{
pfTempBuffer[k] = 0 ;
}
for(n=0;n<8;n++)
{
// IMDCT
pfDataShortBlock = &pfEightWindowsBuffer[n*iShortSize];
imdct(pfDataShortBlock,SHORT_BLOCK);
// DGC goes here
// Window the time-aliased, time domain data.. Take into account possible window shape switching on
// the first of the eight short windows.
// Note that the AAC standard says that
// "The window shape of the previous block influences the first of the eight short blocks (w_0(m)) only."
// ISO/IEC 13818-7:1997(E), page 78.
// This means that the rising edge of the zeroth short block must match the previous window frame's window
// shape. However, all subsequent rising and falling edges of remaining short blocks should reflect the
// currently decoded window shape type.
if (n==0)
{
// rising edge depends on old shape
if (iOldShape == SINE_WINDOW)
{
for (k=0;k<iHShortSize;k++)
{
pfDataShortBlock[k]*=pfShortWindowSin[k];
}
}
else if (iOldShape == KBD_WINDOW)
{
for (k=0;k<iHShortSize;k++)
{
pfDataShortBlock[k]*=pfShortWindowKBD[k];
}
}
// falling edge reflects new shape
if (iWindowShape == SINE_WINDOW)
{
for (k=0;k<iHShortSize;k++)
{
pfDataShortBlock[k+iHShortSize]*=pfShortWindowSin[iHShortSize-k-1];
}
}
else if (iWindowShape == KBD_WINDOW)
{
for (k=0;k<iHShortSize;k++)
{
pfDataShortBlock[k+iHShortSize]*=pfShortWindowKBD[iHShortSize-k-1];
}
}
}
else // n != 0
{
if (iWindowShape == SINE_WINDOW)
{
for (k=0;k<iHShortSize;k++)
{
pfDataShortBlock[k]*=pfShortWindowSin[k];
pfDataShortBlock[k+iHShortSize]*=pfShortWindowSin[iHShortSize-k-1];
}
}
else if (iWindowShape == KBD_WINDOW)
{
for (k=0;k<iHShortSize;k++)
{
pfDataShortBlock[k]*=pfShortWindowKBD[k];
pfDataShortBlock[k+iHShortSize]*=pfShortWindowKBD[iHShortSize-k-1];
}
}
}
// overlap add the 8 windows in this block
for (k = 0 ; k < iShortSize ; k++)
{
pfTempBuffer[(iLongSize/4 - iShortSize/4) + (iHShortSize * n) + k] += pfDataShortBlock[k] ;
}
} // for n...
} // if (eightShortSequenceFlag...)
//OLA:
for(n=0;n<iHLongSize;n++){
pfData[n]=pfTempBuffer[n]+pfSavedBuffer[n];
}
//Update Saved Buffer:
memcpy(pfSavedBuffer,&pfTempBuffer[iHLongSize],iHLongSize*sizeof(float));
iOldShape=iWindowShape;
return 0;
}
void IMDCTObject::imdct(float*pfData, int blockType)
{
float fTempReal,fTempImag;
float fFactor;
int n,k,iLast,iRotation,iMiddle,iSize;
float *realData, *imagData, *realTwiddle, *imagTwiddle;
if (blockType == LONG_BLOCK)
{
iLast=iLongFFTSize;
iRotation=iLongFFTSize/2;
iMiddle=iHLongSize;
iSize=iLongSize;
fFactor=2.0f/(float)iLongSize;
realData = pfReal;
imagData = pfImag;
realTwiddle = pfRealLongTwiddle;
imagTwiddle = pfImagLongTwiddle;
}
else if (blockType == SHORT_BLOCK)
{
iLast=iShortFFTSize;
iRotation=iShortFFTSize/2;
iMiddle=iHShortSize;
iSize=iShortSize;
fFactor=2.0f/(float)iShortSize;
realData = pfRealShort;
imagData = pfImagShort;
realTwiddle = pfRealShortTwiddle;
imagTwiddle = pfImagShortTwiddle;
}
for(k=0;k<iLast;k++){
n=2*k;
fTempReal=-pfData[n];
fTempImag=pfData[iMiddle-1-n];
realData[k]=fTempReal*realTwiddle[k]-fTempImag*imagTwiddle[k];
imagData[k]=-fTempImag*realTwiddle[k]-fTempReal*imagTwiddle[k];
}
fftl(realData,imagData,iLast);
for(k=0;k<iLast;k++){
//conj!
fTempReal=fFactor*(realData[k]*realTwiddle[k]+imagData[k]*imagTwiddle[k]);
fTempImag=fFactor*(-imagData[k]*realTwiddle[k]+realData[k]*imagTwiddle[k]);
n=2*k;
pfData[iMiddle+iLast-1-n]=fTempReal;
pfData[iLast+n]=fTempImag;
if(k<iRotation){
pfData[iMiddle+iLast+n]=fTempReal;
pfData[iLast-1-n]=-fTempImag;
}
else{
pfData[n-iLast]=-fTempReal;
pfData[iLast+iSize-1-n]=fTempImag;
}
}
}
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