text: /* -----------------------------------------------------------------------------
  Software License for The Fraunhofer FDK AAC Codec Library for Android
  
  © Copyright  1995 - 2018 Fraunhofer-Gesellschaft zur Förderung der angewandten
  Forschung e.V. All rights reserved.
  
   1.    INTRODUCTION
  The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software
  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
  those of Fraunhofer) may be obtained through Via Licensing
  (www.vialicensing.com) or through the respective patent owners individually for
  the purpose of encoding or decoding bit streams in products that are compliant
  with the ISO/IEC MPEG audio standards. Please note that most manufacturers of
  Android devices already license these patent claims through Via Licensing or
  directly from the patent owners, and therefore FDK AAC Codec software may
  already be covered under those patent licenses when it is used for those
  licensed purposes only.
  
  Commercially-licensed AAC software libraries, including floating-point versions
  with enhanced sound quality, are also available from Fraunhofer. Users are
  encouraged to check the Fraunhofer website for additional applications
  information and documentation.
  
  2.    COPYRIGHT LICENSE
  
  Redistribution and use in source and binary forms, with or without modification,
  are permitted without payment of copyright license fees provided that you
  satisfy the following conditions:
  
  You must retain the complete text of this software license in redistributions of
  the FDK AAC Codec or your modifications thereto in source code form.
  
  You must retain the complete text of this software license in the documentation
  and/or other materials provided with redistributions of the FDK AAC Codec or
  your modifications thereto in binary form. You must make available free of
  charge copies of the complete source code of the FDK AAC Codec and your
  modifications thereto to recipients of copies in binary form.
  
  The name of Fraunhofer may not be used to endorse or promote products derived
  from this library without prior written permission.
  
  You may not charge copyright license fees for anyone to use, copy or distribute
  the FDK AAC Codec software or your modifications thereto.
  
  Your modified versions of the FDK AAC Codec must carry prominent notices stating
  that you changed the software and the date of any change. For modified versions
  of the FDK AAC Codec, the term "Fraunhofer FDK AAC Codec Library for Android"
  must be replaced by the term "Third-Party Modified Version of the Fraunhofer FDK
  AAC Codec Library for Android."
  
  3.    NO PATENT LICENSE
  
  NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without
  limitation the patents of Fraunhofer, ARE GRANTED BY THIS SOFTWARE LICENSE.
  Fraunhofer provides no warranty of patent non-infringement with respect to this
  software.
  
  You may use this FDK AAC Codec software or modifications thereto only for
  purposes that are authorized by appropriate patent licenses.
  
  4.    DISCLAIMER
  
  This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright
  holders and contributors "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES,
  including but not limited to the implied warranties of merchantability and
  fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
  CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary,
  or consequential damages, including but not limited to procurement of substitute
  goods or services; loss of use, data, or profits, or business interruption,
  however caused and on any theory of liability, whether in contract, strict
  liability, or tort (including negligence), arising in any way out of the use of
  this software, even if advised of the possibility of such damage.
  
  5.    CONTACT INFORMATION
  
  Fraunhofer Institute for Integrated Circuits IIS
  Attention: Audio and Multimedia Departments - FDK AAC LL
  Am Wolfsmantel 33
  91058 Erlangen, Germany
  
  www.iis.fraunhofer.de/amm
  amm-info@iis.fraunhofer.de
  ----------------------------------------------------------------------------- */
  
  /**************************** SBR decoder library ******************************
  
     Author(s):   Christian Griebel
  
     Description: Dynamic range control (DRC) decoder tool for SBR
  
  *******************************************************************************/
  
  #include "sbrdec_drc.h"
  
  /* DRC - Offset table for QMF interpolation. Shifted by one index position.
     The table defines the (short) window borders rounded to the nearest QMF
     timeslot. It has the size 16 because it is accessed with the
     drcInterpolationScheme that is read from the bitstream with 4 bit. */
  static const UCHAR winBorderToColMappingTab[2][16] = {
      /*-1, 0, 1, 2,  3,  4,  5,  6,  7,  8 */
      {0, 0, 4, 8, 12, 16, 20, 24, 28, 32, 32, 32, 32, 32, 32,
       32}, /* 1024 framing */
      {0, 0, 4, 8, 11, 15, 19, 23, 26, 30, 30, 30, 30, 30, 30,
       30} /*  960 framing */
  };
  
  /*!
    \brief Initialize DRC QMF factors
  
    \hDrcData Handle to DRC channel data.
  
    \return none
  */
  void sbrDecoder_drcInitChannel(HANDLE_SBR_DRC_CHANNEL hDrcData) {
    int band;
  
    if (hDrcData == NULL) {
      return;
    }
  
    for (band = 0; band < (64); band++) {
      hDrcData->prevFact_mag[band] = FL2FXCONST_DBL(0.5f);
    }
  
    for (band = 0; band < SBRDEC_MAX_DRC_BANDS; band++) {
      hDrcData->currFact_mag[band] = FL2FXCONST_DBL(0.5f);
      hDrcData->nextFact_mag[band] = FL2FXCONST_DBL(0.5f);
    }
  
    hDrcData->prevFact_exp = 1;
    hDrcData->currFact_exp = 1;
    hDrcData->nextFact_exp = 1;
  
    hDrcData->numBandsCurr = 1;
    hDrcData->numBandsNext = 1;
  
    hDrcData->winSequenceCurr = 0;
    hDrcData->winSequenceNext = 0;
  
    hDrcData->drcInterpolationSchemeCurr = 0;
    hDrcData->drcInterpolationSchemeNext = 0;
  
    hDrcData->enable = 0;
  }
  
  /*!
    \brief Swap DRC QMF scaling factors after they have been applied.
  
    \hDrcData Handle to DRC channel data.
  
    \return none
  */
  void sbrDecoder_drcUpdateChannel(HANDLE_SBR_DRC_CHANNEL hDrcData) {
    if (hDrcData == NULL) {
      return;
    }
    if (hDrcData->enable != 1) {
      return;
    }
  
    /* swap previous data */
    FDKmemcpy(hDrcData->currFact_mag, hDrcData->nextFact_mag,
              SBRDEC_MAX_DRC_BANDS * sizeof(FIXP_DBL));
  
    hDrcData->currFact_exp = hDrcData->nextFact_exp;
  
    hDrcData->numBandsCurr = hDrcData->numBandsNext;
  
    FDKmemcpy(hDrcData->bandTopCurr, hDrcData->bandTopNext,
              SBRDEC_MAX_DRC_BANDS * sizeof(USHORT));
  
    hDrcData->drcInterpolationSchemeCurr = hDrcData->drcInterpolationSchemeNext;
  
    hDrcData->winSequenceCurr = hDrcData->winSequenceNext;
  }
  
  /*!
    \brief Apply DRC factors slot based.
  
    \hDrcData Handle to DRC channel data.
    \qmfRealSlot Pointer to real valued QMF data of one time slot.
    \qmfImagSlot Pointer to the imaginary QMF data of one time slot.
    \col Number of the time slot.
    \numQmfSubSamples Total number of time slots for one frame.
    \scaleFactor Pointer to the out scale factor of the time slot.
  
    \return None.
  */
  void sbrDecoder_drcApplySlot(HANDLE_SBR_DRC_CHANNEL hDrcData,
                               FIXP_DBL *qmfRealSlot, FIXP_DBL *qmfImagSlot,
                               int col, int numQmfSubSamples, int maxShift) {
    const UCHAR *winBorderToColMap;
  
    int band, bottomMdct, topMdct, bin, useLP;
    int indx = numQmfSubSamples - (numQmfSubSamples >> 1) - 10; /* l_border */
    int frameLenFlag = (numQmfSubSamples == 30) ? 1 : 0;
    int frameSize = (frameLenFlag == 1) ? 960 : 1024;
  
    const FIXP_DBL *fact_mag = NULL;
    INT fact_exp = 0;
    UINT numBands = 0;
    USHORT *bandTop = NULL;
    int shortDrc = 0;
  
    FIXP_DBL alphaValue = FL2FXCONST_DBL(0.0f);
  
    if (hDrcData == NULL) {
      return;
    }
    if (hDrcData->enable != 1) {
      return;
    }
  
    winBorderToColMap = winBorderToColMappingTab[frameLenFlag];
  
    useLP = (qmfImagSlot == NULL) ? 1 : 0;
  
    col += indx;
    bottomMdct = 0;
  
    /* get respective data and calc interpolation factor */
    if (col < (numQmfSubSamples >> 1)) {    /* first half of current frame */
      if (hDrcData->winSequenceCurr != 2) { /* long window */
        int j = col + (numQmfSubSamples >> 1);
  
        if (hDrcData->drcInterpolationSchemeCurr == 0) {
          INT k = (frameLenFlag) ? 0x4444445 : 0x4000000;
  
          alphaValue = (FIXP_DBL)(j * k);
        } else {
          if (j >= (int)winBorderToColMap[hDrcData->drcInterpolationSchemeCurr]) {
            alphaValue = (FIXP_DBL)MAXVAL_DBL;
          }
        }
      } else { /* short windows */
        shortDrc = 1;
      }
  
      fact_mag = hDrcData->currFact_mag;
      fact_exp = hDrcData->currFact_exp;
      numBands = hDrcData->numBandsCurr;
      bandTop = hDrcData->bandTopCurr;
    } else if (col < numQmfSubSamples) {    /* second half of current frame */
      if (hDrcData->winSequenceNext != 2) { /* next: long window */
        int j = col - (numQmfSubSamples >> 1);
  
        if (hDrcData->drcInterpolationSchemeNext == 0) {
          INT k = (frameLenFlag) ? 0x4444445 : 0x4000000;
  
          alphaValue = (FIXP_DBL)(j * k);
        } else {
          if (j >= (int)winBorderToColMap[hDrcData->drcInterpolationSchemeNext]) {
            alphaValue = (FIXP_DBL)MAXVAL_DBL;
          }
        }
  
        fact_mag = hDrcData->nextFact_mag;
        fact_exp = hDrcData->nextFact_exp;
        numBands = hDrcData->numBandsNext;
        bandTop = hDrcData->bandTopNext;
      } else {                                /* next: short windows */
        if (hDrcData->winSequenceCurr != 2) { /* current: long window */
          alphaValue = (FIXP_DBL)0;
  
          fact_mag = hDrcData->nextFact_mag;
          fact_exp = hDrcData->nextFact_exp;
          numBands = hDrcData->numBandsNext;
          bandTop = hDrcData->bandTopNext;
        } else { /* current: short windows */
          shortDrc = 1;
  
          fact_mag = hDrcData->currFact_mag;
          fact_exp = hDrcData->currFact_exp;
          numBands = hDrcData->numBandsCurr;
          bandTop = hDrcData->bandTopCurr;
        }
      }
    } else {                                /* first half of next frame */
      if (hDrcData->winSequenceNext != 2) { /* long window */
        int j = col - (numQmfSubSamples >> 1);
  
        if (hDrcData->drcInterpolationSchemeNext == 0) {
          INT k = (frameLenFlag) ? 0x4444445 : 0x4000000;
  
          alphaValue = (FIXP_DBL)(j * k);
        } else {
          if (j >= (int)winBorderToColMap[hDrcData->drcInterpolationSchemeNext]) {
            alphaValue = (FIXP_DBL)MAXVAL_DBL;
          }
        }
      } else { /* short windows */
        shortDrc = 1;
      }
  
      fact_mag = hDrcData->nextFact_mag;
      fact_exp = hDrcData->nextFact_exp;
      numBands = hDrcData->numBandsNext;
      bandTop = hDrcData->bandTopNext;
  
      col -= numQmfSubSamples;
    }
  
    /* process bands */
    for (band = 0; band < (int)numBands; band++) {
      int bottomQmf, topQmf;
  
      FIXP_DBL drcFact_mag = (FIXP_DBL)MAXVAL_DBL;
  
      topMdct = (bandTop[band] + 1) << 2;
  
      if (!shortDrc) { /* long window */
        if (frameLenFlag) {
          /* 960 framing */
          bottomQmf = fMultIfloor((FIXP_DBL)0x4444445, bottomMdct);
          topQmf = fMultIfloor((FIXP_DBL)0x4444445, topMdct);
  
          topMdct = 30 * topQmf;
        } else {
          /* 1024 framing */
          topMdct &= ~0x1f;
  
          bottomQmf = bottomMdct >> 5;
          topQmf = topMdct >> 5;
        }
  
        if (band == ((int)numBands - 1)) {
          topQmf = (64);
        }
  
        for (bin = bottomQmf; bin < topQmf; bin++) {
          FIXP_DBL drcFact1_mag = hDrcData->prevFact_mag[bin];
          FIXP_DBL drcFact2_mag = fact_mag[band];
  
          /* normalize scale factors */
          if (hDrcData->prevFact_exp < maxShift) {
            drcFact1_mag >>= maxShift - hDrcData->prevFact_exp;
          }
          if (fact_exp < maxShift) {
            drcFact2_mag >>= maxShift - fact_exp;
          }
  
          /* interpolate */
          if (alphaValue == (FIXP_DBL)0) {
            drcFact_mag = drcFact1_mag;
          } else if (alphaValue == (FIXP_DBL)MAXVAL_DBL) {
            drcFact_mag = drcFact2_mag;
          } else {
            drcFact_mag =
                fMult(alphaValue, drcFact2_mag) +
                fMult(((FIXP_DBL)MAXVAL_DBL - alphaValue), drcFact1_mag);
          }
  
          /* apply scaling */
          qmfRealSlot[bin] = fMult(qmfRealSlot[bin], drcFact_mag);
          if (!useLP) {
            qmfImagSlot[bin] = fMult(qmfImagSlot[bin], drcFact_mag);
          }
  
          /* save previous factors */
          if (col == (numQmfSubSamples >> 1) - 1) {
            hDrcData->prevFact_mag[bin] = fact_mag[band];
          }
        }
      } else { /* short windows */
        unsigned startWinIdx, stopWinIdx;
        int startCol, stopCol;
        FIXP_DBL invFrameSizeDiv8 =
            (frameLenFlag) ? (FIXP_DBL)0x1111112 : (FIXP_DBL)0x1000000;
  
        /* limit top at the frame borders */
        if (topMdct < 0) {
          topMdct = 0;
        }
        if (topMdct >= frameSize) {
          topMdct = frameSize - 1;
        }
  
        if (frameLenFlag) {
          /*  960 framing */
          topMdct = fMultIfloor((FIXP_DBL)0x78000000,
                                fMultIfloor((FIXP_DBL)0x22222223, topMdct) << 2);
  
          startWinIdx = fMultIfloor(invFrameSizeDiv8, bottomMdct) +
                        1; /* winBorderToColMap table has offset of 1 */
          stopWinIdx = fMultIceil(invFrameSizeDiv8 - (FIXP_DBL)1, topMdct) + 1;
        } else {
          /* 1024 framing */
          topMdct &= ~0x03;
  
          startWinIdx = fMultIfloor(invFrameSizeDiv8, bottomMdct) + 1;
          stopWinIdx = fMultIceil(invFrameSizeDiv8, topMdct) + 1;
        }
  
        /* startCol is truncated to the nearest corresponding start subsample in
           the QMF of the short window bottom is present in:*/
        startCol = (int)winBorderToColMap[startWinIdx];
  
        /* stopCol is rounded upwards to the nearest corresponding stop subsample
           in the QMF of the short window top is present in. */
        stopCol = (int)winBorderToColMap[stopWinIdx];
  
        bottomQmf = fMultIfloor(invFrameSizeDiv8,
                                ((bottomMdct % (numQmfSubSamples << 2)) << 5));
        topQmf = fMultIfloor(invFrameSizeDiv8,
                             ((topMdct % (numQmfSubSamples << 2)) << 5));
  
        /* extend last band */
        if (band == ((int)numBands - 1)) {
          topQmf = (64);
          stopCol = numQmfSubSamples;
          stopWinIdx = 10;
        }
  
        if (topQmf == 0) {
          if (frameLenFlag) {
            FIXP_DBL rem = fMult(invFrameSizeDiv8,
                                 (FIXP_DBL)(topMdct << (DFRACT_BITS - 12)));
            if ((LONG)rem & (LONG)0x1F) {
              stopWinIdx -= 1;
              stopCol = (int)winBorderToColMap[stopWinIdx];
            }
          }
          topQmf = (64);
        }
  
        /* save previous factors */
        if (stopCol == numQmfSubSamples) {
          int tmpBottom = bottomQmf;
  
          if ((int)winBorderToColMap[8] > startCol) {
            tmpBottom = 0; /* band starts in previous short window */
          }
  
          for (bin = tmpBottom; bin < topQmf; bin++) {
            hDrcData->prevFact_mag[bin] = fact_mag[band];
          }
        }
  
        /* apply */
        if ((col >= startCol) && (col < stopCol)) {
          if (col >= (int)winBorderToColMap[startWinIdx + 1]) {
            bottomQmf = 0; /* band starts in previous short window */
          }
          if (col < (int)winBorderToColMap[stopWinIdx - 1]) {
            topQmf = (64); /* band ends in next short window */
          }
  
          drcFact_mag = fact_mag[band];
  
          /* normalize scale factor */
          if (fact_exp < maxShift) {
            drcFact_mag >>= maxShift - fact_exp;
          }
  
          /* apply scaling */
          for (bin = bottomQmf; bin < topQmf; bin++) {
            qmfRealSlot[bin] = fMult(qmfRealSlot[bin], drcFact_mag);
            if (!useLP) {
              qmfImagSlot[bin] = fMult(qmfImagSlot[bin], drcFact_mag);
            }
          }
        }
      }
  
      bottomMdct = topMdct;
    } /* end of bands loop */
  
    if (col == (numQmfSubSamples >> 1) - 1) {
      hDrcData->prevFact_exp = fact_exp;
    }
  }
  
  /*!
    \brief Apply DRC factors frame based.
  
    \hDrcData Handle to DRC channel data.
    \qmfRealSlot Pointer to real valued QMF data of the whole frame.
    \qmfImagSlot Pointer to the imaginary QMF data of the whole frame.
    \numQmfSubSamples Total number of time slots for one frame.
    \scaleFactor Pointer to the out scale factor of the frame.
  
    \return None.
  */
  void sbrDecoder_drcApply(HANDLE_SBR_DRC_CHANNEL hDrcData,
                           FIXP_DBL **QmfBufferReal, FIXP_DBL **QmfBufferImag,
                           int numQmfSubSamples, int *scaleFactor) {
    int col;
    int maxShift = 0;
  
    if (hDrcData == NULL) {
      return;
    }
    if (hDrcData->enable == 0) {
      return; /* Avoid changing the scaleFactor even though the processing is
                 disabled. */
    }
  
    /* get max scale factor */
    if (hDrcData->prevFact_exp > maxShift) {
      maxShift = hDrcData->prevFact_exp;
    }
    if (hDrcData->currFact_exp > maxShift) {
      maxShift = hDrcData->currFact_exp;
    }
    if (hDrcData->nextFact_exp > maxShift) {
      maxShift = hDrcData->nextFact_exp;
    }
  
    for (col = 0; col < numQmfSubSamples; col++) {
      FIXP_DBL *qmfSlotReal = QmfBufferReal[col];
      FIXP_DBL *qmfSlotImag = (QmfBufferImag == NULL) ? NULL : QmfBufferImag[col];
  
      sbrDecoder_drcApplySlot(hDrcData, qmfSlotReal, qmfSlotImag, col,
                              numQmfSubSamples, maxShift);
    }
  
    *scaleFactor += maxShift;
  }
  