/* -----------------------------------------------------------------------------

Software License for The Fraunhofer FDK AAC Codec Library for Android

© Copyright  1995 - 2020 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 (j < winBorderToColMap[15]) {

        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 {

        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 (j < winBorderToColMap[15]) {

        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 {

        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 (j < winBorderToColMap[15]) {

        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 {

        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;

}