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/******************************** MPEG Audio Encoder **************************
(C) Copyright Fraunhofer IIS (1999)
All Rights Reserved
Please be advised that this software and/or program delivery is
Confidential Information of Fraunhofer and subject to and covered by the
Fraunhofer IIS Software Evaluation Agreement
between Google Inc. and Fraunhofer
effective and in full force since March 1, 2012.
You may use this software and/or program only under the terms and
conditions described in the above mentioned Fraunhofer IIS Software
Evaluation Agreement. Any other and/or further use requires a separate agreement.
This software and/or program is protected by copyright law and international
treaties. Any reproduction or distribution of this software and/or program,
or any portion of it, may result in severe civil and criminal penalties, and
will be prosecuted to the maximum extent possible under law.
$Id$
Initial author: M.Werner
contents/description: Quantization
******************************************************************************/
#include "quantize.h"
#include "aacEnc_rom.h"
/*****************************************************************************
functionname: FDKaacEnc_quantizeLines
description: quantizes spectrum lines
returns:
input: global gain, number of lines to process, spectral data
output: quantized spectrum
*****************************************************************************/
static void FDKaacEnc_quantizeLines(INT gain,
INT noOfLines,
FIXP_DBL *mdctSpectrum,
SHORT *quaSpectrum)
{
int line;
FIXP_DBL k = FL2FXCONST_DBL(-0.0946f + 0.5f)>>16;
FIXP_QTD quantizer = FDKaacEnc_quantTableQ[(-gain)&3];
INT quantizershift = ((-gain)>>2)+1;
for (line = 0; line < noOfLines; line++)
{
FIXP_DBL accu = fMultDiv2(mdctSpectrum[line],quantizer);
if (accu < FL2FXCONST_DBL(0.0f))
{
accu=-accu;
/* normalize */
INT accuShift = CntLeadingZeros(accu) - 1; /* CountLeadingBits() is not necessary here since test value is always > 0 */
accu <<= accuShift;
INT tabIndex = (INT)(accu>>(DFRACT_BITS-2-MANT_DIGITS))&(~MANT_SIZE);
INT totalShift = quantizershift-accuShift+1;
accu = fMultDiv2(FDKaacEnc_mTab_3_4[tabIndex],FDKaacEnc_quantTableE[totalShift&3]);
totalShift = (16-4)-(3*(totalShift>>2));
FDK_ASSERT(totalShift >=0); /* MAX_QUANT_VIOLATION */
accu>>=totalShift;
quaSpectrum[line] = (SHORT)(-((LONG)(k + accu) >> (DFRACT_BITS-1-16)));
}
else if(accu > FL2FXCONST_DBL(0.0f))
{
/* normalize */
INT accuShift = CntLeadingZeros(accu) - 1; /* CountLeadingBits() is not necessary here since test value is always > 0 */
accu <<= accuShift;
INT tabIndex = (INT)(accu>>(DFRACT_BITS-2-MANT_DIGITS))&(~MANT_SIZE);
INT totalShift = quantizershift-accuShift+1;
accu = fMultDiv2(FDKaacEnc_mTab_3_4[tabIndex],FDKaacEnc_quantTableE[totalShift&3]);
totalShift = (16-4)-(3*(totalShift>>2));
FDK_ASSERT(totalShift >=0); /* MAX_QUANT_VIOLATION */
accu>>=totalShift;
quaSpectrum[line] = (SHORT)((LONG)(k + accu) >> (DFRACT_BITS-1-16));
}
else
quaSpectrum[line]=0;
}
}
/*****************************************************************************
functionname:iFDKaacEnc_quantizeLines
description: iquantizes spectrum lines
mdctSpectrum = iquaSpectrum^4/3 *2^(0.25*gain)
input: global gain, number of lines to process,quantized spectrum
output: spectral data
*****************************************************************************/
static void FDKaacEnc_invQuantizeLines(INT gain,
INT noOfLines,
SHORT *quantSpectrum,
FIXP_DBL *mdctSpectrum)
{
INT iquantizermod;
INT iquantizershift;
INT line;
iquantizermod = gain&3;
iquantizershift = gain>>2;
for (line = 0; line < noOfLines; line++) {
if(quantSpectrum[line] < 0) {
FIXP_DBL accu;
INT ex,specExp,tabIndex;
FIXP_DBL s,t;
accu = (FIXP_DBL) -quantSpectrum[line];
ex = CountLeadingBits(accu);
accu <<= ex;
specExp = (DFRACT_BITS-1) - ex;
FDK_ASSERT(specExp < 14); /* this fails if abs(value) > 8191 */
tabIndex = (INT)(accu>>(DFRACT_BITS-2-MANT_DIGITS))&(~MANT_SIZE);
/* calculate "mantissa" ^4/3 */
s = FDKaacEnc_mTab_4_3Elc[tabIndex];
/* get approperiate exponent multiplier for specExp^3/4 combined with scfMod */
t = FDKaacEnc_specExpMantTableCombElc[iquantizermod][specExp];
/* multiply "mantissa" ^4/3 with exponent multiplier */
accu = fMult(s,t);
/* get approperiate exponent shifter */
specExp = FDKaacEnc_specExpTableComb[iquantizermod][specExp]-1; /* -1 to avoid overflows in accu */
if ((-iquantizershift-specExp) < 0)
accu <<= -(-iquantizershift-specExp);
else
accu >>= -iquantizershift-specExp;
mdctSpectrum[line] = -accu;
}
else if (quantSpectrum[line] > 0) {
FIXP_DBL accu;
INT ex,specExp,tabIndex;
FIXP_DBL s,t;
accu = (FIXP_DBL)(INT)quantSpectrum[line];
ex = CountLeadingBits(accu);
accu <<= ex;
specExp = (DFRACT_BITS-1) - ex;
FDK_ASSERT(specExp < 14); /* this fails if abs(value) > 8191 */
tabIndex = (INT)(accu>>(DFRACT_BITS-2-MANT_DIGITS))&(~MANT_SIZE);
/* calculate "mantissa" ^4/3 */
s = FDKaacEnc_mTab_4_3Elc[tabIndex];
/* get approperiate exponent multiplier for specExp^3/4 combined with scfMod */
t = FDKaacEnc_specExpMantTableCombElc[iquantizermod][specExp];
/* multiply "mantissa" ^4/3 with exponent multiplier */
accu = fMult(s,t);
/* get approperiate exponent shifter */
specExp = FDKaacEnc_specExpTableComb[iquantizermod][specExp]-1; /* -1 to avoid overflows in accu */
if (( -iquantizershift-specExp) < 0)
accu <<= -(-iquantizershift-specExp);
else
accu >>= -iquantizershift-specExp;
mdctSpectrum[line] = accu;
}
else {
mdctSpectrum[line] = FL2FXCONST_DBL(0.0f);
}
}
}
/*****************************************************************************
functionname: FDKaacEnc_QuantizeSpectrum
description: quantizes the entire spectrum
returns:
input: number of scalefactor bands to be quantized, ...
output: quantized spectrum
*****************************************************************************/
void FDKaacEnc_QuantizeSpectrum(INT sfbCnt,
INT maxSfbPerGroup,
INT sfbPerGroup,
INT *sfbOffset,
FIXP_DBL *mdctSpectrum,
INT globalGain,
INT *scalefactors,
SHORT *quantizedSpectrum)
{
INT sfbOffs,sfb;
/* in FDKaacEnc_quantizeLines quaSpectrum is calculated with:
spec^(3/4) * 2^(-3/16*QSS) * 2^(3/4*scale) + k
simplify scaling calculation and reduce QSS before:
spec^(3/4) * 2^(-3/16*(QSS - 4*scale)) */
for(sfbOffs=0;sfbOffs<sfbCnt;sfbOffs+=sfbPerGroup)
for (sfb = 0; sfb < maxSfbPerGroup; sfb++)
{
INT scalefactor = scalefactors[sfbOffs+sfb] ;
FDKaacEnc_quantizeLines(globalGain - scalefactor, /* QSS */
sfbOffset[sfbOffs+sfb+1] - sfbOffset[sfbOffs+sfb],
mdctSpectrum + sfbOffset[sfbOffs+sfb],
quantizedSpectrum + sfbOffset[sfbOffs+sfb]);
}
}
/*****************************************************************************
functionname: FDKaacEnc_calcSfbDist
description: calculates distortion of quantized values
returns: distortion
input: gain, number of lines to process, spectral data
output:
*****************************************************************************/
FIXP_DBL FDKaacEnc_calcSfbDist(FIXP_DBL *mdctSpectrum,
SHORT *quantSpectrum,
INT noOfLines,
INT gain
)
{
INT i,scale;
FIXP_DBL xfsf;
FIXP_DBL diff;
FIXP_DBL invQuantSpec;
xfsf = FL2FXCONST_DBL(0.0f);
for (i=0; i<noOfLines; i++) {
/* quantization */
FDKaacEnc_quantizeLines(gain,
1,
&mdctSpectrum[i],
&quantSpectrum[i]);
/* inverse quantization */
FDKaacEnc_invQuantizeLines(gain,1,&quantSpectrum[i],&invQuantSpec);
/* dist */
diff = fixp_abs(fixp_abs(invQuantSpec) - fixp_abs(mdctSpectrum[i]>>1));
scale = CountLeadingBits(diff);
diff = scaleValue(diff, scale);
diff = fPow2(diff);
scale = fixMin(2*(scale-1), DFRACT_BITS-1);
diff = scaleValue(diff, -scale);
xfsf = xfsf + diff;
}
xfsf = CalcLdData(xfsf);
return xfsf;
}
/*****************************************************************************
functionname: FDKaacEnc_calcSfbQuantEnergyAndDist
description: calculates energy and distortion of quantized values
returns:
input: gain, number of lines to process, quantized spectral data,
spectral data
output: energy, distortion
*****************************************************************************/
void FDKaacEnc_calcSfbQuantEnergyAndDist(FIXP_DBL *mdctSpectrum,
SHORT *quantSpectrum,
INT noOfLines,
INT gain,
FIXP_DBL *en,
FIXP_DBL *dist)
{
INT i,scale;
FIXP_DBL invQuantSpec;
FIXP_DBL diff;
*en = FL2FXCONST_DBL(0.0f);
*dist = FL2FXCONST_DBL(0.0f);
for (i=0; i<noOfLines; i++) {
/* inverse quantization */
FDKaacEnc_invQuantizeLines(gain,1,&quantSpectrum[i],&invQuantSpec);
/* energy */
*en += fPow2(invQuantSpec);
/* dist */
diff = fixp_abs(fixp_abs(invQuantSpec) - fixp_abs(mdctSpectrum[i]>>1));
scale = CountLeadingBits(diff);
diff = scaleValue(diff, scale);
diff = fPow2(diff);
scale = fixMin(2*(scale-1), DFRACT_BITS-1);
diff = scaleValue(diff, -scale);
*dist += diff;
}
*en = CalcLdData(*en)+FL2FXCONST_DBL(0.03125f);
*dist = CalcLdData(*dist);
}
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