xref: /aosp_15_r20/external/aac/libSACdec/src/sac_reshapeBBEnv.cpp (revision e54365361535b070c2db7374cec45c159c7d0e7a)

/* -----------------------------------------------------------------------------
Software License for The Fraunhofer FDK AAC Codec Library for Android

© Copyright  1995 - 2021 Fraunhofer-Gesellschaft zur Förderung der angewandten
Forschung e.V. All rights reserved.

 1.    INTRODUCTION
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that implements the MPEG Advanced Audio Coding ("AAC") encoding and decoding
scheme for digital audio. This FDK AAC Codec software is intended to be used on
a wide variety of Android devices.

AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient
general perceptual audio codecs. AAC-ELD is considered the best-performing
full-bandwidth communications codec by independent studies and is widely
deployed. AAC has been standardized by ISO and IEC as part of the MPEG
specifications.

Patent licenses for necessary patent claims for the FDK AAC Codec (including
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Attention: Audio and Multimedia Departments - FDK AAC LL
Am Wolfsmantel 33
91058 Erlangen, Germany

www.iis.fraunhofer.de/amm
[email protected]
----------------------------------------------------------------------------- */

/*********************** MPEG surround decoder library *************************

   Author(s):

   Description: SAC Dec guided envelope shaping

*******************************************************************************/

#include "sac_reshapeBBEnv.h"

#include "sac_dec.h"
#include "sac_bitdec.h"
#include "sac_calcM1andM2.h"
#include "sac_reshapeBBEnv.h"
#include "sac_rom.h"

#define INP_DRY_WET 0
#define INP_DMX 1

#define SF_SHAPE 1
#define SF_DIV32 6
#define SF_FACTOR_SLOT 5

#define START_BB_ENV 0 /* 10 */
#define END_BB_ENV 9   /* 18 */

#define SF_ALPHA1 8
#define SF_BETA1 4

void initBBEnv(spatialDec *self, int initStatesFlag) {
  INT ch, k;

  for (ch = 0; ch < self->numOutputChannels; ch++) {
    k = row2channelGES[self->treeConfig][ch];
    self->row2channelDmxGES[ch] = k;
    if (k == -1) continue;

    switch (self->treeConfig) {
      case TREE_212:
        self->row2channelDmxGES[ch] = 0;
        break;
      default:;
    }
  }

  if (initStatesFlag) {
    for (k = 0; k < 2 * MAX_OUTPUT_CHANNELS + MAX_INPUT_CHANNELS; k++) {
      self->reshapeBBEnvState->normNrgPrev__FDK[k] =
          FL2FXCONST_DBL(0.5f); /* 32768.f*32768.f */
      self->reshapeBBEnvState->normNrgPrevSF[k] = DFRACT_BITS - 1;
      self->reshapeBBEnvState->partNrgPrevSF[k] = 0;
      self->reshapeBBEnvState->partNrgPrev2SF[k] = 0;
      self->reshapeBBEnvState->frameNrgPrevSF[k] = 0;
    }
  }

  self->reshapeBBEnvState->alpha__FDK =
      FL2FXCONST_DBL(0.99637845575f); /* FDKexp(-64 / (0.4f  * 44100)) */
  self->reshapeBBEnvState->beta__FDK =
      FL2FXCONST_DBL(0.96436909488f); /* FDKexp(-64 / (0.04f * 44100)) */
}

static inline void getSlotNrgHQ(FIXP_DBL *RESTRICT pReal,
                                FIXP_DBL *RESTRICT pImag,
                                FIXP_DBL *RESTRICT slotNrg, INT maxValSF,
                                INT hybBands) {
  INT qs;
  FIXP_DBL nrg;

  /* qs = 12, 13, 14 */
  slotNrg[0] = ((fPow2Div2((*pReal++) << maxValSF) >> (SF_FACTOR_SLOT - 1)) +
                (fPow2Div2((*pImag++) << maxValSF) >> (SF_FACTOR_SLOT - 1)));
  slotNrg[1] = ((fPow2Div2((*pReal++) << maxValSF) >> (SF_FACTOR_SLOT - 1)) +
                (fPow2Div2((*pImag++) << maxValSF) >> (SF_FACTOR_SLOT - 1)));
  slotNrg[2] = ((fPow2Div2((*pReal++) << maxValSF) >> (SF_FACTOR_SLOT - 1)) +
                (fPow2Div2((*pImag++) << maxValSF) >> (SF_FACTOR_SLOT - 1)));
  /* qs = 15 */
  slotNrg[3] = ((fPow2Div2((*pReal++) << maxValSF) >> (SF_FACTOR_SLOT - 1)) +
                (fPow2Div2((*pImag++) << maxValSF) >> (SF_FACTOR_SLOT - 1)));
  /* qs = 16, 17 */
  nrg = ((fPow2Div2((*pReal++) << maxValSF) >> (SF_FACTOR_SLOT - 1)) +
         (fPow2Div2((*pImag++) << maxValSF) >> (SF_FACTOR_SLOT - 1)));
  slotNrg[4] =
      nrg + ((fPow2Div2((*pReal++) << maxValSF) >> (SF_FACTOR_SLOT - 1)) +
             (fPow2Div2((*pImag++) << maxValSF) >> (SF_FACTOR_SLOT - 1)));
  /* qs = 18, 19, 20 */
  nrg = ((fPow2Div2((*pReal++) << maxValSF) >> (SF_FACTOR_SLOT - 1)) +
         (fPow2Div2((*pImag++) << maxValSF) >> (SF_FACTOR_SLOT - 1)));
  nrg += ((fPow2Div2((*pReal++) << maxValSF) >> (SF_FACTOR_SLOT - 1)) +
          (fPow2Div2((*pImag++) << maxValSF) >> (SF_FACTOR_SLOT - 1)));
  slotNrg[5] =
      nrg + ((fPow2Div2((*pReal++) << maxValSF) >> (SF_FACTOR_SLOT - 1)) +
             (fPow2Div2((*pImag++) << maxValSF) >> (SF_FACTOR_SLOT - 1)));
  /* qs = 21, 22 */
  nrg = ((fPow2Div2((*pReal++) << maxValSF) >> (SF_FACTOR_SLOT - 1)) +
         (fPow2Div2((*pImag++) << maxValSF) >> (SF_FACTOR_SLOT - 1)));
  slotNrg[6] =
      nrg + ((fPow2Div2((*pReal++) << maxValSF) >> (SF_FACTOR_SLOT - 1)) +
             (fPow2Div2((*pImag++) << maxValSF) >> (SF_FACTOR_SLOT - 1)));
  /* qs = 23, 24 */
  if (hybBands > 23) {
    slotNrg[6] += ((fPow2Div2((*pReal++) << maxValSF) >> (SF_FACTOR_SLOT - 1)) +
                   (fPow2Div2((*pImag++) << maxValSF) >> (SF_FACTOR_SLOT - 1)));
    slotNrg[6] += ((fPow2Div2((*pReal++) << maxValSF) >> (SF_FACTOR_SLOT - 1)) +
                   (fPow2Div2((*pImag++) << maxValSF) >> (SF_FACTOR_SLOT - 1)));
    /* qs = 25, 26, 29, 28, 29 */
    nrg = ((fPow2Div2((*pReal++) << maxValSF) >> (SF_FACTOR_SLOT - 1)) +
           (fPow2Div2((*pImag++) << maxValSF) >> (SF_FACTOR_SLOT - 1)));
    nrg += ((fPow2Div2((*pReal++) << maxValSF) >> (SF_FACTOR_SLOT - 1)) +
            (fPow2Div2((*pImag++) << maxValSF) >> (SF_FACTOR_SLOT - 1)));
    nrg += ((fPow2Div2((*pReal++) << maxValSF) >> (SF_FACTOR_SLOT - 1)) +
            (fPow2Div2((*pImag++) << maxValSF) >> (SF_FACTOR_SLOT - 1)));
    nrg += ((fPow2Div2((*pReal++) << maxValSF) >> (SF_FACTOR_SLOT - 1)) +
            (fPow2Div2((*pImag++) << maxValSF) >> (SF_FACTOR_SLOT - 1)));
    slotNrg[7] =
        nrg + ((fPow2Div2((*pReal++) << maxValSF) >> (SF_FACTOR_SLOT - 1)) +
               (fPow2Div2((*pImag++) << maxValSF) >> (SF_FACTOR_SLOT - 1)));
    /* qs = 30 ... min(41,hybBands-1) */
    nrg = ((fPow2Div2((*pReal++) << maxValSF) >> (SF_FACTOR_SLOT - 1)) +
           (fPow2Div2((*pImag++) << maxValSF) >> (SF_FACTOR_SLOT - 1)));
    for (qs = 31; qs < hybBands; qs++) {
      nrg += ((fPow2Div2((*pReal++) << maxValSF) >> (SF_FACTOR_SLOT - 1)) +
              (fPow2Div2((*pImag++) << maxValSF) >> (SF_FACTOR_SLOT - 1)));
    }
    slotNrg[8] = nrg;
  } else {
    slotNrg[7] = (FIXP_DBL)0;
    slotNrg[8] = (FIXP_DBL)0;
  }
}

static inline void combineDryWet(FIXP_DBL *RESTRICT pReal,
                                 FIXP_DBL *RESTRICT pImag,
                                 FIXP_DBL *RESTRICT pHybOutputRealDry,
                                 FIXP_DBL *RESTRICT pHybOutputImagDry,
                                 FIXP_DBL *RESTRICT pHybOutputRealWet,
                                 FIXP_DBL *RESTRICT pHybOutputImagWet,
                                 INT cplxBands, INT hybBands) {
  INT qs;

  for (qs = 12; qs < cplxBands; qs++) {
    pReal[qs] = (pHybOutputRealDry[qs] >> 1) + (pHybOutputRealWet[qs] >> 1);
    pImag[qs] = (pHybOutputImagDry[qs] >> 1) + (pHybOutputImagWet[qs] >> 1);
  }
  for (; qs < hybBands; qs++) {
    pReal[qs] = (pHybOutputRealDry[qs] >> 1) + (pHybOutputRealWet[qs] >> 1);
  }
}

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++) {
    /* 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 += (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;
  }
}

#if defined(__aarch64__)
__attribute__((noinline))
#endif
static void
shapeBBEnv(FIXP_DBL *pHybOutputRealDry, FIXP_DBL *pHybOutputImagDry,
           FIXP_DBL dryFac, INT scale, INT cplxBands, INT hybBands) {
  INT qs;

  if (scale == 0) {
    for (qs = 0; qs < cplxBands; qs++) {
      pHybOutputRealDry[qs] = fMultDiv2(pHybOutputRealDry[qs], dryFac);
      pHybOutputImagDry[qs] = fMultDiv2(pHybOutputImagDry[qs], dryFac);
    }
    for (; qs < hybBands; qs++) {
      pHybOutputRealDry[qs] = fMultDiv2(pHybOutputRealDry[qs], dryFac);
    }
  } else {
    for (qs = 0; qs < cplxBands; qs++) {
      pHybOutputRealDry[qs] = SATURATE_LEFT_SHIFT(
          fMultDiv2(pHybOutputRealDry[qs], dryFac), scale, DFRACT_BITS);
      pHybOutputImagDry[qs] = SATURATE_LEFT_SHIFT(
          fMultDiv2(pHybOutputImagDry[qs], dryFac), scale, DFRACT_BITS);
    }
    for (; qs < hybBands; qs++) {
      pHybOutputRealDry[qs] = SATURATE_LEFT_SHIFT(
          fMultDiv2(pHybOutputRealDry[qs], dryFac), scale, DFRACT_BITS);
    }
  }
}

static void extractBBEnv(spatialDec *self, INT inp, INT start, INT channels,
                         FIXP_DBL *pEnv, const SPATIAL_BS_FRAME *frame) {
  INT ch, pb, prevChOffs;
  INT clz, scale, scale_min, envSF;
  INT scaleCur, scalePrev, commonScale;
  INT slotNrgSF, partNrgSF, frameNrgSF;
  INT *pPartNrgPrevSF, *pFrameNrgPrevSF;
  INT *pNormNrgPrevSF, *pPartNrgPrev2SF;

  FIXP_DBL maxVal, env, frameNrg, normNrg;
  FIXP_DBL *pReal, *pImag;
  FIXP_DBL *partNrg, *partNrgPrev;

  C_ALLOC_SCRATCH_START(pScratchBuffer, FIXP_DBL,
                        (2 * 42 + MAX_PARAMETER_BANDS));
  C_ALLOC_SCRATCH_START(resPb, FIXP_DBL, (END_BB_ENV - START_BB_ENV));
  C_ALLOC_SCRATCH_START(resPbSF, INT, (END_BB_ENV - START_BB_ENV));

  FIXP_DBL *slotNrg = pScratchBuffer + (2 * 42);

  RESHAPE_BBENV_STATE *pBBEnvState = self->reshapeBBEnvState;

  FIXP_DBL alpha = pBBEnvState->alpha__FDK;
  /*FIXP_DBL  alpha1 = (FL2FXCONST_DBL(1.0f) - alpha) << SF_ALPHA1;*/
  FIXP_DBL alpha1 = ((FIXP_DBL)MAXVAL_DBL - alpha) << SF_ALPHA1;
  FIXP_DBL beta = pBBEnvState->beta__FDK;
  /*FIXP_DBL  beta1  = (FL2FXCONST_DBL(1.0f) - beta) << SF_BETA1;*/
  FIXP_DBL beta1 = ((FIXP_DBL)MAXVAL_DBL - beta) << SF_BETA1;

  INT shapeActiv = 1;
  INT hybBands = fixMin(42, self->hybridBands);
  INT staticScale = self->staticDecScale + (1);
  INT cplxBands;
  cplxBands = fixMin(42, self->hybridBands);

  for (ch = start; ch < channels; ch++) {
    if (inp == INP_DRY_WET) {
      INT ch2 = row2channelGES[self->treeConfig][ch];
      if (ch2 == -1) {
        continue;
      } else {
        if (frame->tempShapeEnableChannelGES[ch2]) {
          shapeActiv = 1;
        } else {
          shapeActiv = 0;
        }
      }
      prevChOffs = ch;
      pReal = pScratchBuffer;
      pImag = pScratchBuffer + 42;
      combineDryWet(pReal, pImag, self->hybOutputRealDry__FDK[ch],
                    self->hybOutputImagDry__FDK[ch],
                    self->hybOutputRealWet__FDK[ch],
                    self->hybOutputImagWet__FDK[ch], cplxBands, hybBands);
      clz = fMin(getScalefactor(&pReal[12], fMax(0, hybBands - 12)),
                 getScalefactor(&pImag[12], fMax(0, cplxBands - 12)));
    } else {
      prevChOffs = ch + self->numOutputChannels;
      pReal = self->hybInputReal__FDK[ch];
      pImag = self->hybInputImag__FDK[ch];
      clz = fMin(getScalefactor(&pReal[12], fMax(0, hybBands - 12)),
                 getScalefactor(&pImag[12], fMax(0, cplxBands - 12)));
    }

    partNrg = partNrgPrev = pBBEnvState->partNrgPrev__FDK[prevChOffs];
    pPartNrgPrevSF = &pBBEnvState->partNrgPrevSF[prevChOffs];
    pFrameNrgPrevSF = &pBBEnvState->frameNrgPrevSF[prevChOffs];
    pNormNrgPrevSF = &pBBEnvState->normNrgPrevSF[prevChOffs];
    pPartNrgPrev2SF = &pBBEnvState->partNrgPrev2SF[prevChOffs];

    /* calculate slot energy */
    {
      getSlotNrgHQ(&pReal[12], &pImag[12], slotNrg, clz,
                   fixMin(42, self->hybridBands)); /* scale slotNrg:
                                                      2*(staticScale-clz) +
                                                      SF_FACTOR_SLOT */
    }

    slotNrgSF = 2 * (staticScale - clz + ((inp == INP_DRY_WET) ? 1 : 0)) +
                SF_FACTOR_SLOT;
    frameNrgSF = 2 * (staticScale - clz + ((inp == INP_DRY_WET) ? 1 : 0)) +
                 SF_FACTOR_SLOT;

    partNrgSF = fixMax(slotNrgSF - SF_ALPHA1 + 1,
                       pPartNrgPrevSF[0] - pPartNrgPrev2SF[0] + 1);
    scalePrev = fixMax(fixMin(partNrgSF - pPartNrgPrevSF[0], DFRACT_BITS - 1),
                       -(DFRACT_BITS - 1));
    scaleCur =
        fixMax(fixMin(partNrgSF - slotNrgSF + SF_ALPHA1, DFRACT_BITS - 1),
               -(DFRACT_BITS - 1));

    maxVal = FL2FXCONST_DBL(0.0f);
    frameNrg = FL2FXCONST_DBL(0.0f);
    if ((scaleCur < 0) && (scalePrev < 0)) {
      scaleCur = -scaleCur;
      scalePrev = -scalePrev;
      for (pb = START_BB_ENV; pb < END_BB_ENV; pb++) {
        partNrg[pb] = ((fMultDiv2(alpha1, slotNrg[pb]) << scaleCur) +
                       (fMultDiv2(alpha, partNrgPrev[pb]) << scalePrev))
                      << 1;
        maxVal |= partNrg[pb];
        frameNrg += slotNrg[pb] >> 3;
      }
    } else if ((scaleCur >= 0) && (scalePrev >= 0)) {
      for (pb = START_BB_ENV; pb < END_BB_ENV; pb++) {
        partNrg[pb] = ((fMultDiv2(alpha1, slotNrg[pb]) >> scaleCur) +
                       (fMultDiv2(alpha, partNrgPrev[pb]) >> scalePrev))
                      << 1;
        maxVal |= partNrg[pb];
        frameNrg += slotNrg[pb] >> 3;
      }
    } else if ((scaleCur < 0) && (scalePrev >= 0)) {
      scaleCur = -scaleCur;
      for (pb = START_BB_ENV; pb < END_BB_ENV; pb++) {
        partNrg[pb] = ((fMultDiv2(alpha1, slotNrg[pb]) << scaleCur) +
                       (fMultDiv2(alpha, partNrgPrev[pb]) >> scalePrev))
                      << 1;
        maxVal |= partNrg[pb];
        frameNrg += slotNrg[pb] >> 3;
      }
    } else { /* if ( (scaleCur >= 0) && (scalePrev < 0) ) */
      scalePrev = -scalePrev;
      for (pb = START_BB_ENV; pb < END_BB_ENV; pb++) {
        partNrg[pb] = ((fMultDiv2(alpha1, slotNrg[pb]) >> scaleCur) +
                       (fMultDiv2(alpha, partNrgPrev[pb]) << scalePrev))
                      << 1;
        maxVal |= partNrg[pb];
        frameNrg += slotNrg[pb] >> 3;
      }
    }

    /* frameNrg /= (END_BB_ENV - START_BB_ENV); 0.88888888888f =
     * (1/(END_BB_ENV-START_BB_ENV)<<3; shift with 3 is compensated in loop
     * above */
    frameNrg = fMult(frameNrg, FL2FXCONST_DBL(0.88888888888f));

    /* store scalefactor and headroom for part nrg prev */
    pPartNrgPrevSF[0] = partNrgSF;
    pPartNrgPrev2SF[0] = fixMax(0, CntLeadingZeros(maxVal) - 1);

    commonScale = fixMax(frameNrgSF - SF_ALPHA1 + 1, pFrameNrgPrevSF[0] + 1);
    scalePrev = fixMin(commonScale - pFrameNrgPrevSF[0], DFRACT_BITS - 1);
    scaleCur = fixMin(commonScale - frameNrgSF + SF_ALPHA1, DFRACT_BITS - 1);
    frameNrgSF = commonScale;

    frameNrg = ((fMultDiv2(alpha1, frameNrg) >> scaleCur) +
                (fMultDiv2(alpha, pBBEnvState->frameNrgPrev__FDK[prevChOffs]) >>
                 scalePrev))
               << 1;

    clz = fixMax(0, CntLeadingZeros(frameNrg) - 1);
    pBBEnvState->frameNrgPrev__FDK[prevChOffs] = frameNrg << clz;
    pFrameNrgPrevSF[0] = frameNrgSF - clz;

    env = FL2FXCONST_DBL(0.0f);
    scale = clz + partNrgSF - frameNrgSF;
    scale_min = DFRACT_BITS - 1;
    for (pb = START_BB_ENV; pb < END_BB_ENV; pb++) {
      if ((partNrg[pb] | slotNrg[pb]) != FL2FXCONST_DBL(0.0f)) {
        INT s;
        INT sc = 0;
        INT sn = fixMax(0, CntLeadingZeros(slotNrg[pb]) - 1);
        FIXP_DBL inv_sqrt = invSqrtNorm2(partNrg[pb], &sc);
        FIXP_DBL res = fMult(slotNrg[pb] << sn, fPow2(inv_sqrt));

        s = fixMax(0, CntLeadingZeros(res) - 1);
        res = res << s;

        sc = scale - (2 * sc - sn - s);
        scale_min = fixMin(scale_min, sc);

        resPb[pb] = res;
        resPbSF[pb] = sc;
      } else {
        resPb[pb] = (FIXP_DBL)0;
        resPbSF[pb] = 0;
      }
    }

    scale_min = 4 - scale_min;

    for (pb = START_BB_ENV; pb < END_BB_ENV; pb++) {
      INT sc = fixMax(fixMin(resPbSF[pb] + scale_min, DFRACT_BITS - 1),
                      -(DFRACT_BITS - 1));

      if (sc < 0) {
        env += resPb[pb] << (-sc);
      } else {
        env += resPb[pb] >> (sc);
      }
    }

    env = fMultDiv2(env, pBBEnvState->frameNrgPrev__FDK[prevChOffs]);
    envSF = slotNrgSF + scale_min + 1;

    commonScale = fixMax(envSF - SF_BETA1 + 1, pNormNrgPrevSF[0] + 1);
    scalePrev = fixMin(commonScale - pNormNrgPrevSF[0], DFRACT_BITS - 1);
    scaleCur = fixMin(commonScale - envSF + SF_BETA1, DFRACT_BITS - 1);

    normNrg = ((fMultDiv2(beta1, env) >> scaleCur) +
               (fMultDiv2(beta, pBBEnvState->normNrgPrev__FDK[prevChOffs]) >>
                scalePrev))
              << 1;

    clz = fixMax(0, CntLeadingZeros(normNrg) - 1);
    pBBEnvState->normNrgPrev__FDK[prevChOffs] = normNrg << clz;
    pNormNrgPrevSF[0] = commonScale - clz;

    if (shapeActiv) {
      if ((env | normNrg) != FL2FXCONST_DBL(0.0f)) {
        INT sc, se, sn;
        se = fixMax(0, CntLeadingZeros(env) - 1);
        sc = commonScale + SF_DIV32 - envSF + se;
        env = fMult(sqrtFixp((env << se) >> (sc & 0x1)),
                    invSqrtNorm2(normNrg, &sn));

        sc = fixMin((sc >> 1) - sn, DFRACT_BITS - 1);
        if (sc < 0) {
          env <<= (-sc);
        } else {
          env >>= (sc);
        }
      }
      /* env is scaled by SF_DIV32/2 bits */
    }
    pEnv[ch] = env;
  }

  C_ALLOC_SCRATCH_END(resPbSF, INT, (END_BB_ENV - START_BB_ENV));
  C_ALLOC_SCRATCH_END(resPb, FIXP_DBL, (END_BB_ENV - START_BB_ENV));
  C_ALLOC_SCRATCH_END(pScratchBuffer, FIXP_DBL, (2 * 42 + MAX_PARAMETER_BANDS));
}

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];

  INT cplxBands;
  INT hybBands = self->hybridBands - 6;

  cplxBands = self->hybridBands - 6;

  /* extract downmix envelope(s) */
  switch (self->treeConfig) {
    default:
      extractBBEnv(self, INP_DMX, 0, fMin(self->numInputChannels, 2), envDmx,
                   frame);
  }

  /* extract dry and wet envelopes */
  extractBBEnv(self, INP_DRY_WET, 0, self->numOutputChannels, envDry, frame);

  for (ch = 0; ch < self->numOutputChannels; ch++) {
    INT ch2;

    ch2 = row2channelGES[self->treeConfig][ch];

    if (ch2 == -1) continue;

    if (frame->tempShapeEnableChannelGES[ch2]) {
      INT sc;

      /* reshape dry and wet signals according to transmitted envelope */

      /* De-quantize GES data */
      FDK_ASSERT((frame->bsEnvShapeData[ch2][ts] >= 0) &&
                 (frame->bsEnvShapeData[ch2][ts] <= 4));
      FDK_ASSERT((self->envQuantMode == 0) || (self->envQuantMode == 1));
      envShape =
          FX_CFG2FX_DBL(envShapeDataTable__FDK[frame->bsEnvShapeData[ch2][ts]]
                                              [self->envQuantMode]);

      /* get downmix channel */
      ch2 = self->row2channelDmxGES[ch];

      /* multiply ratio with dmx envelope; tmp is scaled by SF_DIV32/2+SF_SHAPE
       * bits */
      if (ch2 == 2) {
        tmp = fMultDiv2(envShape, envDmx[0]) + fMultDiv2(envShape, envDmx[1]);
      } else {
        tmp = fMult(envShape, envDmx[ch2]);
      }

      /* weighting factors */
      dryFacSF = slotAmpSF = 0;
      dryFac = slotAmp_ratio = FL2FXCONST_DBL(0.0f);

      /* dryFac will be scaled by dryFacSF bits */
      if (envDry[ch] != FL2FXCONST_DBL(0.0f)) {
        envDry[ch] = invSqrtNorm2(envDry[ch], &dryFacSF);
        dryFac = fMultDiv2(tmp, fPow2Div2(envDry[ch])) << 2;
        dryFacSF = SF_SHAPE + 2 * dryFacSF;
      }

      slotAmp_dry_e = slotAmp_wet_e = 0;

      /* calculate slotAmp_dry and slotAmp_wet */
      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)) {
        slotAmp_wet = sqrtFixp(slotAmp_wet);
        slotAmp_dry = invSqrtNorm2(slotAmp_dry, &slotAmpSF);

        slotAmp_ratio = fMult(slotAmp_wet, slotAmp_dry);
        slotAmpSF = slotAmpSF + (slotAmp_wet_e >> 1) - (slotAmp_dry_e >> 1);
      }

      /* calculate common scale factor */
      scale =
          fixMax(3, fixMax(dryFacSF, slotAmpSF)); /* scale is at least with 3
                                                     bits to avoid overflows
                                                     when calculating dryFac  */
      dryFac = dryFac >> fixMin(scale - dryFacSF, DFRACT_BITS - 1);
      slotAmp_ratio =
          slotAmp_ratio >> fixMin(scale - slotAmpSF, DFRACT_BITS - 1);

      /* limit dryFac */
      dryFac = fixMax(
          FL2FXCONST_DBL(0.25f) >> (INT)fixMin(2 * scale, DFRACT_BITS - 1),
          fMult(dryFac, slotAmp_ratio) -
              (slotAmp_ratio >> fixMin(scale, DFRACT_BITS - 1)) +
              (dryFac >> fixMin(scale, DFRACT_BITS - 1)));
      dryFac = fixMin(
          FL2FXCONST_DBL(0.50f) >> (INT)fixMin(2 * scale - 3, DFRACT_BITS - 1),
          dryFac); /* reduce shift bits by 3, because upper
                      limit 4.0 is scaled with 3 bits */
      scale = 2 * scale + 1;

      /* improve precision for dryFac */
      sc = fixMax(0, CntLeadingZeros(dryFac) - 1);
      dryFac = dryFac << (INT)fixMin(scale, sc);
      scale = scale - fixMin(scale, sc);

      /* shaping */
      shapeBBEnv(&self->hybOutputRealDry__FDK[ch][6],
                 &self->hybOutputImagDry__FDK[ch][6], dryFac,
                 fixMin(scale, DFRACT_BITS - 1), cplxBands, hybBands);
    }
  }
}