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Utilize dynamic scaling in slotAmp() to avoid signed integer overflows. am: 56de8e29ce 

Original change: https://googleplex-android-review.googlesource.com/c/platform/external/aac/+/14470258

Change-Id: I9959ecb8bb6f1283a701011af6f398dfaf2aa906
This commit is contained in:
Fraunhofer IIS FDK 2021-05-07 21:48:07 +00:00 committed by Automerger Merge Worker
parent 99424039a2 56de8e29ce
commit 41c2942fda
1 changed files with 54 additions and 23 deletions
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77
libSACdec/src/sac_reshapeBBEnv.cpp
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@ -1,7 +1,7 @@
/* -----------------------------------------------------------------------------
Software License for The Fraunhofer FDK AAC Codec Library for Android
© Copyright 1995 - 2019 Fraunhofer-Gesellschaft zur Förderung der angewandten
© Copyright 1995 - 2021 Fraunhofer-Gesellschaft zur Förderung der angewandten
Forschung e.V. All rights reserved.
1. INTRODUCTION
@ -241,29 +241,56 @@ static inline void combineDryWet(FIXP_DBL *RESTRICT pReal,
}
}
static inline void slotAmp(FIXP_DBL *RESTRICT slotAmp_dry,
FIXP_DBL *RESTRICT slotAmp_wet,
FIXP_DBL *RESTRICT pHybOutputRealDry,
FIXP_DBL *RESTRICT pHybOutputImagDry,
FIXP_DBL *RESTRICT pHybOutputRealWet,
FIXP_DBL *RESTRICT pHybOutputImagWet, INT cplxBands,
INT hybBands) {
INT qs;
static inline void slotAmp(
FIXP_DBL *RESTRICT slotAmp_dry, INT *RESTRICT slotAmp_dry_e,
FIXP_DBL *RESTRICT slotAmp_wet, INT *RESTRICT slotAmp_wet_e,
FIXP_DBL *RESTRICT pHybOutputRealDry, FIXP_DBL *RESTRICT pHybOutputImagDry,
FIXP_DBL *RESTRICT pHybOutputRealWet, FIXP_DBL *RESTRICT pHybOutputImagWet,
INT cplxBands, INT hybBands) {
INT qs, s1, s2, headroom_dry, headroom_wet;
FIXP_DBL dry, wet;
/* headroom can be reduced by 1 bit due to use of fPow2Div2 */
s1 = DFRACT_BITS - 1 - CntLeadingZeros(hybBands + cplxBands);
headroom_dry = fMin(getScalefactor(pHybOutputRealDry, hybBands),
getScalefactor(pHybOutputImagDry, cplxBands));
headroom_wet = fMin(getScalefactor(pHybOutputRealWet, hybBands),
getScalefactor(pHybOutputImagWet, cplxBands));
dry = wet = FL2FXCONST_DBL(0.0f);
for (qs = 0; qs < cplxBands; qs++) {
dry = fAddSaturate(dry, fPow2Div2(pHybOutputRealDry[qs] << (1)) +
fPow2Div2(pHybOutputImagDry[qs] << (1)));
wet = fAddSaturate(wet, fPow2Div2(pHybOutputRealWet[qs] << (1)) +
fPow2Div2(pHybOutputImagWet[qs] << (1)));
/* sum up dry part */
dry += (fPow2Div2(pHybOutputRealDry[qs] << headroom_dry) >> s1);
dry += (fPow2Div2(pHybOutputImagDry[qs] << headroom_dry) >> s1);
/* sum up wet part */
wet += (fPow2Div2(pHybOutputRealWet[qs] << headroom_wet) >> s1);
wet += (fPow2Div2(pHybOutputImagWet[qs] << headroom_wet) >> s1);
}
for (; qs < hybBands; qs++) {
dry = fAddSaturate(dry, fPow2Div2(pHybOutputRealDry[qs] << (1)));
wet = fAddSaturate(wet, fPow2Div2(pHybOutputRealWet[qs] << (1)));
dry += (fPow2Div2(pHybOutputRealDry[qs] << headroom_dry) >> s1);
wet += (fPow2Div2(pHybOutputRealWet[qs] << headroom_wet) >> s1);
}
/* consider fPow2Div2() */
s1 += 1;
/* normalize dry part, ensure that exponent is even */
s2 = fixMax(0, CntLeadingZeros(dry) - 1);
*slotAmp_dry = dry << s2;
*slotAmp_dry_e = s1 - s2 - 2 * headroom_dry;
if (*slotAmp_dry_e & 1) {
*slotAmp_dry = *slotAmp_dry >> 1;
*slotAmp_dry_e += 1;
}
/* normalize wet part, ensure that exponent is even */
s2 = fixMax(0, CntLeadingZeros(wet) - 1);
*slotAmp_wet = wet << s2;
*slotAmp_wet_e = s1 - s2 - 2 * headroom_wet;
if (*slotAmp_wet_e & 1) {
*slotAmp_wet = *slotAmp_wet >> 1;
*slotAmp_wet_e += 1;
}
*slotAmp_dry = dry >> (2 * (1));
*slotAmp_wet = wet >> (2 * (1));
}
#if defined(__aarch64__)
@ -533,6 +560,7 @@ void SpatialDecReshapeBBEnv(spatialDec *self, const SPATIAL_BS_FRAME *frame,
INT ts) {
INT ch, scale;
INT dryFacSF, slotAmpSF;
INT slotAmp_dry_e, slotAmp_wet_e;
FIXP_DBL tmp, dryFac, envShape;
FIXP_DBL slotAmp_dry, slotAmp_wet, slotAmp_ratio;
FIXP_DBL envDry[MAX_OUTPUT_CHANNELS], envDmx[2];
@ -594,22 +622,25 @@ void SpatialDecReshapeBBEnv(spatialDec *self, const SPATIAL_BS_FRAME *frame,
dryFacSF = SF_SHAPE + 2 * dryFacSF;
}
slotAmp_dry_e = slotAmp_wet_e = 0;
/* calculate slotAmp_dry and slotAmp_wet */
slotAmp(&slotAmp_dry, &slotAmp_wet, &self->hybOutputRealDry__FDK[ch][6],
slotAmp(&slotAmp_dry, &slotAmp_dry_e, &slotAmp_wet, &slotAmp_wet_e,
&self->hybOutputRealDry__FDK[ch][6],
&self->hybOutputImagDry__FDK[ch][6],
&self->hybOutputRealWet__FDK[ch][6],
&self->hybOutputImagWet__FDK[ch][6], cplxBands, hybBands);
/* exponents must be even due to subsequent square root calculation */
FDK_ASSERT(((slotAmp_dry_e & 1) == 0) && ((slotAmp_wet_e & 1) == 0));
/* slotAmp_ratio will be scaled by slotAmpSF bits */
if (slotAmp_dry != FL2FXCONST_DBL(0.0f)) {
sc = fixMax(0, CntLeadingZeros(slotAmp_wet) - 1);
sc = sc - (sc & 1);
slotAmp_wet = sqrtFixp(slotAmp_wet << sc);
slotAmp_wet = sqrtFixp(slotAmp_wet);
slotAmp_dry = invSqrtNorm2(slotAmp_dry, &slotAmpSF);
slotAmp_ratio = fMult(slotAmp_wet, slotAmp_dry);
slotAmpSF = slotAmpSF - (sc >> 1);
slotAmpSF = slotAmpSF + (slotAmp_wet_e >> 1) - (slotAmp_dry_e >> 1);
}
/* calculate common scale factor */