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

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

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

/**************************** AAC decoder library ******************************

   Author(s):

   Description:

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

/*!

  \file

  \brief  rvlc concealment

  \author Josef Hoepfl

*/

#include "rvlcconceal.h"

#include "block.h"

#include "rvlc.h"

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

  function:      calcRefValFwd

  description:   The function determines the scalefactor which is closed to the

scalefactorband conceal_min. The same is done for intensity data and noise

energies.

-----------------------------------------------------------------------------------------------

  output:        - reference value scf

                 - reference value internsity data

                 - reference value noise energy

-----------------------------------------------------------------------------------------------

  return:        -

--------------------------------------------------------------------------------------------

*/

static void calcRefValFwd(CErRvlcInfo *pRvlc,

                          CAacDecoderChannelInfo *pAacDecoderChannelInfo,

                          int *refIsFwd, int *refNrgFwd, int *refScfFwd) {

  int band, bnds, group, startBand;

  int idIs, idNrg, idScf;

  int conceal_min, conceal_group_min;

  int MaximumScaleFactorBands;

  if (GetWindowSequence(&pAacDecoderChannelInfo->icsInfo) == BLOCK_SHORT)

    MaximumScaleFactorBands = 16;

  else

    MaximumScaleFactorBands = 64;

  conceal_min = pRvlc->conceal_min % MaximumScaleFactorBands;

  conceal_group_min = pRvlc->conceal_min / MaximumScaleFactorBands;

  /* calculate first reference value for approach in forward direction */

  idIs = idNrg = idScf = 1;

  /* set reference values */

  *refIsFwd = -SF_OFFSET;

  *refNrgFwd = pAacDecoderChannelInfo->pDynData->RawDataInfo.GlobalGain -

               SF_OFFSET - 90 - 256;

  *refScfFwd =

      pAacDecoderChannelInfo->pDynData->RawDataInfo.GlobalGain - SF_OFFSET;

  startBand = conceal_min - 1;

  for (group = conceal_group_min; group >= 0; group--) {

    for (band = startBand; band >= 0; band--) {

      bnds = 16 * group + band;

      switch (pAacDecoderChannelInfo->pDynData->aCodeBook[bnds]) {

        case ZERO_HCB:

          break;

        case INTENSITY_HCB:

        case INTENSITY_HCB2:

          if (idIs) {

            *refIsFwd =

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds];

            idIs = 0; /* reference value has been set */

          }

          break;

        case NOISE_HCB:

          if (idNrg) {

            *refNrgFwd =

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds];

            idNrg = 0; /* reference value has been set */

          }

          break;

        default:

          if (idScf) {

            *refScfFwd =

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds];

            idScf = 0; /* reference value has been set */

          }

          break;

      }

    }

    startBand = pRvlc->maxSfbTransmitted - 1;

  }

}

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

  function:      calcRefValBwd

  description:   The function determines the scalefactor which is closed to the

scalefactorband conceal_max. The same is done for intensity data and noise

energies.

-----------------------------------------------------------------------------------------------

  output:        - reference value scf

                 - reference value internsity data

                 - reference value noise energy

-----------------------------------------------------------------------------------------------

  return:        -

--------------------------------------------------------------------------------------------

*/

static void calcRefValBwd(CErRvlcInfo *pRvlc,

                          CAacDecoderChannelInfo *pAacDecoderChannelInfo,

                          int *refIsBwd, int *refNrgBwd, int *refScfBwd) {

  int band, bnds, group, startBand;

  int idIs, idNrg, idScf;

  int conceal_max, conceal_group_max;

  int MaximumScaleFactorBands;

  if (GetWindowSequence(&pAacDecoderChannelInfo->icsInfo) == BLOCK_SHORT)

    MaximumScaleFactorBands = 16;

  else

    MaximumScaleFactorBands = 64;

  conceal_max = pRvlc->conceal_max % MaximumScaleFactorBands;

  conceal_group_max = pRvlc->conceal_max / MaximumScaleFactorBands;

  /* calculate first reference value for approach in backward direction */

  idIs = idNrg = idScf = 1;

  /* set reference values */

  *refIsBwd = pRvlc->dpcm_is_last_position - SF_OFFSET;

  *refNrgBwd = pRvlc->rev_global_gain + pRvlc->dpcm_noise_last_position -

               SF_OFFSET - 90 - 256 + pRvlc->dpcm_noise_nrg;

  *refScfBwd = pRvlc->rev_global_gain - SF_OFFSET;

  startBand = conceal_max + 1;

  /* if needed, re-set reference values */

  for (group = conceal_group_max; group < pRvlc->numWindowGroups; group++) {

    for (band = startBand; band < pRvlc->maxSfbTransmitted; band++) {

      bnds = 16 * group + band;

      switch (pAacDecoderChannelInfo->pDynData->aCodeBook[bnds]) {

        case ZERO_HCB:

          break;

        case INTENSITY_HCB:

        case INTENSITY_HCB2:

          if (idIs) {

            *refIsBwd =

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfBwd[bnds];

            idIs = 0; /* reference value has been set */

          }

          break;

        case NOISE_HCB:

          if (idNrg) {

            *refNrgBwd =

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfBwd[bnds];

            idNrg = 0; /* reference value has been set */

          }

          break;

        default:

          if (idScf) {

            *refScfBwd =

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfBwd[bnds];

            idScf = 0; /* reference value has been set */

          }

          break;

      }

    }

    startBand = 0;

  }

}

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

  function:      BidirectionalEstimation_UseLowerScfOfCurrentFrame

  description:   This approach by means of bidirectional estimation is generally

performed when a single bit error has been detected, the bit error can be

isolated between 'conceal_min' and 'conceal_max' and the 'sf_concealment' flag

is not set. The sets of scalefactors decoded in forward and backward direction

are compared with each other. The smaller scalefactor will be considered as the

correct one respectively. The reconstruction of the scalefactors with this

approach archieve good results in audio quality. The strategy must be applied to

scalefactors, intensity data and noise energy seperately.

-----------------------------------------------------------------------------------------------

  output:        Concealed scalefactor, noise energy and intensity data between

conceal_min and conceal_max

-----------------------------------------------------------------------------------------------

  return:        -

--------------------------------------------------------------------------------------------

*/

void BidirectionalEstimation_UseLowerScfOfCurrentFrame(

    CAacDecoderChannelInfo *pAacDecoderChannelInfo) {

  CErRvlcInfo *pRvlc =

      &pAacDecoderChannelInfo->pComData->overlay.aac.erRvlcInfo;

  int band, bnds, startBand, endBand, group;

  int conceal_min, conceal_max;

  int conceal_group_min, conceal_group_max;

  int MaximumScaleFactorBands;

  if (GetWindowSequence(&pAacDecoderChannelInfo->icsInfo) == BLOCK_SHORT) {

    MaximumScaleFactorBands = 16;

  } else {

    MaximumScaleFactorBands = 64;

  }

  /* If an error was detected just in forward or backward direction, set the

     corresponding border for concealment to a appropriate scalefactor band. The

     border is set to first or last sfb respectively, because the error will

     possibly not follow directly after the corrupt bit but just after decoding

     some more (wrong) scalefactors. */

  if (pRvlc->conceal_min == CONCEAL_MIN_INIT) pRvlc->conceal_min = 0;

  if (pRvlc->conceal_max == CONCEAL_MAX_INIT)

    pRvlc->conceal_max =

        (pRvlc->numWindowGroups - 1) * 16 + pRvlc->maxSfbTransmitted - 1;

  conceal_min = pRvlc->conceal_min % MaximumScaleFactorBands;

  conceal_group_min = pRvlc->conceal_min / MaximumScaleFactorBands;

  conceal_max = pRvlc->conceal_max % MaximumScaleFactorBands;

  conceal_group_max = pRvlc->conceal_max / MaximumScaleFactorBands;

  if (pRvlc->conceal_min == pRvlc->conceal_max) {

    int refIsFwd, refNrgFwd, refScfFwd;

    int refIsBwd, refNrgBwd, refScfBwd;

    bnds = pRvlc->conceal_min;

    calcRefValFwd(pRvlc, pAacDecoderChannelInfo, &refIsFwd, &refNrgFwd,

                  &refScfFwd);

    calcRefValBwd(pRvlc, pAacDecoderChannelInfo, &refIsBwd, &refNrgBwd,

                  &refScfBwd);

    switch (pAacDecoderChannelInfo->pDynData->aCodeBook[bnds]) {

      case ZERO_HCB:

        break;

      case INTENSITY_HCB:

      case INTENSITY_HCB2:

        if (refIsFwd < refIsBwd)

          pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] = refIsFwd;

        else

          pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] = refIsBwd;

        break;

      case NOISE_HCB:

        if (refNrgFwd < refNrgBwd)

          pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] = refNrgFwd;

        else

          pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] = refNrgBwd;

        break;

      default:

        if (refScfFwd < refScfBwd)

          pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] = refScfFwd;

        else

          pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] = refScfBwd;

        break;

    }

  } else {

    pAacDecoderChannelInfo->pComData->overlay.aac

        .aRvlcScfFwd[pRvlc->conceal_max] =

        pAacDecoderChannelInfo->pComData->overlay.aac

            .aRvlcScfBwd[pRvlc->conceal_max];

    pAacDecoderChannelInfo->pComData->overlay.aac

        .aRvlcScfBwd[pRvlc->conceal_min] =

        pAacDecoderChannelInfo->pComData->overlay.aac

            .aRvlcScfFwd[pRvlc->conceal_min];

    /* consider the smaller of the forward and backward decoded value as the

     * correct one */

    startBand = conceal_min;

    if (conceal_group_min == conceal_group_max)

      endBand = conceal_max;

    else

      endBand = pRvlc->maxSfbTransmitted - 1;

    for (group = conceal_group_min; group <= conceal_group_max; group++) {

      for (band = startBand; band <= endBand; band++) {

        bnds = 16 * group + band;

        if (pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds] <

            pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfBwd[bnds])

          pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] =

              pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds];

        else

          pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] =

              pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfBwd[bnds];

      }

      startBand = 0;

      if ((group + 1) == conceal_group_max) endBand = conceal_max;

    }

  }

  /* now copy all data to the output buffer which needs not to be concealed */

  if (conceal_group_min == 0)

    endBand = conceal_min;

  else

    endBand = pRvlc->maxSfbTransmitted;

  for (group = 0; group <= conceal_group_min; group++) {

    for (band = 0; band < endBand; band++) {

      bnds = 16 * group + band;

      pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] =

          pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds];

    }

    if ((group + 1) == conceal_group_min) endBand = conceal_min;

  }

  startBand = conceal_max + 1;

  for (group = conceal_group_max; group < pRvlc->numWindowGroups; group++) {

    for (band = startBand; band < pRvlc->maxSfbTransmitted; band++) {

      bnds = 16 * group + band;

      pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] =

          pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfBwd[bnds];

    }

    startBand = 0;

  }

}

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

  function:      BidirectionalEstimation_UseScfOfPrevFrameAsReference

  description:   This approach by means of bidirectional estimation is generally

performed when a single bit error has been detected, the bit error can be

isolated between 'conceal_min' and 'conceal_max', the 'sf_concealment' flag is

set and the previous frame has the same block type as the current frame. The

scalefactor decoded in forward and backward direction and the scalefactor of the

previous frame are compared with each other. The smaller scalefactor will be

considered as the correct one. At this the codebook of the previous and current

frame must be of the same set (scf, nrg, is) in each scalefactorband. Otherwise

the scalefactor of the previous frame is not considered in the minimum

calculation. The reconstruction of the scalefactors with this approach archieve

good results in audio quality. The strategy must be applied to scalefactors,

intensity data and noise energy seperately.

-----------------------------------------------------------------------------------------------

  output:        Concealed scalefactor, noise energy and intensity data between

conceal_min and conceal_max

-----------------------------------------------------------------------------------------------

  return:        -

--------------------------------------------------------------------------------------------

*/

void BidirectionalEstimation_UseScfOfPrevFrameAsReference(

    CAacDecoderChannelInfo *pAacDecoderChannelInfo,

    CAacDecoderStaticChannelInfo *pAacDecoderStaticChannelInfo) {

  CErRvlcInfo *pRvlc =

      &pAacDecoderChannelInfo->pComData->overlay.aac.erRvlcInfo;

  int band, bnds, startBand, endBand, group;

  int conceal_min, conceal_max;

  int conceal_group_min, conceal_group_max;

  int MaximumScaleFactorBands;

  SHORT commonMin;

  if (GetWindowSequence(&pAacDecoderChannelInfo->icsInfo) == BLOCK_SHORT) {

    MaximumScaleFactorBands = 16;

  } else {

    MaximumScaleFactorBands = 64;

  }

  /* If an error was detected just in forward or backward direction, set the

     corresponding border for concealment to a appropriate scalefactor band. The

     border is set to first or last sfb respectively, because the error will

     possibly not follow directly after the corrupt bit but just after decoding

     some more (wrong) scalefactors. */

  if (pRvlc->conceal_min == CONCEAL_MIN_INIT) pRvlc->conceal_min = 0;

  if (pRvlc->conceal_max == CONCEAL_MAX_INIT)

    pRvlc->conceal_max =

        (pRvlc->numWindowGroups - 1) * 16 + pRvlc->maxSfbTransmitted - 1;

  conceal_min = pRvlc->conceal_min % MaximumScaleFactorBands;

  conceal_group_min = pRvlc->conceal_min / MaximumScaleFactorBands;

  conceal_max = pRvlc->conceal_max % MaximumScaleFactorBands;

  conceal_group_max = pRvlc->conceal_max / MaximumScaleFactorBands;

  pAacDecoderChannelInfo->pComData->overlay.aac

      .aRvlcScfFwd[pRvlc->conceal_max] =

      pAacDecoderChannelInfo->pComData->overlay.aac

          .aRvlcScfBwd[pRvlc->conceal_max];

  pAacDecoderChannelInfo->pComData->overlay.aac

      .aRvlcScfBwd[pRvlc->conceal_min] =

      pAacDecoderChannelInfo->pComData->overlay.aac

          .aRvlcScfFwd[pRvlc->conceal_min];

  /* consider the smaller of the forward and backward decoded value as the

   * correct one */

  startBand = conceal_min;

  if (conceal_group_min == conceal_group_max)

    endBand = conceal_max;

  else

    endBand = pRvlc->maxSfbTransmitted - 1;

  for (group = conceal_group_min; group <= conceal_group_max; group++) {

    for (band = startBand; band <= endBand; band++) {

      bnds = 16 * group + band;

      switch (pAacDecoderChannelInfo->pDynData->aCodeBook[bnds]) {

        case ZERO_HCB:

          pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] = 0;

          break;

        case INTENSITY_HCB:

        case INTENSITY_HCB2:

          if ((pAacDecoderStaticChannelInfo->concealmentInfo

                   .aRvlcPreviousCodebook[bnds] == INTENSITY_HCB) ||

              (pAacDecoderStaticChannelInfo->concealmentInfo

                   .aRvlcPreviousCodebook[bnds] == INTENSITY_HCB2)) {

            commonMin = fMin(

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds],

                pAacDecoderChannelInfo->pComData->overlay.aac

                    .aRvlcScfBwd[bnds]);

            pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] =

                fMin(commonMin, pAacDecoderStaticChannelInfo->concealmentInfo

                                    .aRvlcPreviousScaleFactor[bnds]);

          } else {

            pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] = fMin(

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds],

                pAacDecoderChannelInfo->pComData->overlay.aac

                    .aRvlcScfBwd[bnds]);

          }

          break;

        case NOISE_HCB:

          if (pAacDecoderStaticChannelInfo->concealmentInfo

                  .aRvlcPreviousCodebook[bnds] == NOISE_HCB) {

            commonMin = fMin(

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds],

                pAacDecoderChannelInfo->pComData->overlay.aac

                    .aRvlcScfBwd[bnds]);

            pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] =

                fMin(commonMin, pAacDecoderStaticChannelInfo->concealmentInfo

                                    .aRvlcPreviousScaleFactor[bnds]);

          } else {

            pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] = fMin(

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds],

                pAacDecoderChannelInfo->pComData->overlay.aac

                    .aRvlcScfBwd[bnds]);

          }

          break;

        default:

          if ((pAacDecoderStaticChannelInfo->concealmentInfo

                   .aRvlcPreviousCodebook[bnds] != ZERO_HCB) &&

              (pAacDecoderStaticChannelInfo->concealmentInfo

                   .aRvlcPreviousCodebook[bnds] != NOISE_HCB) &&

              (pAacDecoderStaticChannelInfo->concealmentInfo

                   .aRvlcPreviousCodebook[bnds] != INTENSITY_HCB) &&

              (pAacDecoderStaticChannelInfo->concealmentInfo

                   .aRvlcPreviousCodebook[bnds] != INTENSITY_HCB2)) {

            commonMin = fMin(

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds],

                pAacDecoderChannelInfo->pComData->overlay.aac

                    .aRvlcScfBwd[bnds]);

            pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] =

                fMin(commonMin, pAacDecoderStaticChannelInfo->concealmentInfo

                                    .aRvlcPreviousScaleFactor[bnds]);

          } else {

            pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] = fMin(

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds],

                pAacDecoderChannelInfo->pComData->overlay.aac

                    .aRvlcScfBwd[bnds]);

          }

          break;

      }

    }

    startBand = 0;

    if ((group + 1) == conceal_group_max) endBand = conceal_max;

  }

  /* now copy all data to the output buffer which needs not to be concealed */

  if (conceal_group_min == 0)

    endBand = conceal_min;

  else

    endBand = pRvlc->maxSfbTransmitted;

  for (group = 0; group <= conceal_group_min; group++) {

    for (band = 0; band < endBand; band++) {

      bnds = 16 * group + band;

      pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] =

          pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds];

    }

    if ((group + 1) == conceal_group_min) endBand = conceal_min;

  }

  startBand = conceal_max + 1;

  for (group = conceal_group_max; group < pRvlc->numWindowGroups; group++) {

    for (band = startBand; band < pRvlc->maxSfbTransmitted; band++) {

      bnds = 16 * group + band;

      pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] =

          pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfBwd[bnds];

    }

    startBand = 0;

  }

}

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

  function:      StatisticalEstimation

  description:   This approach by means of statistical estimation is generally

performed when both the start value and the end value are different and no

further errors have been detected. Considering the forward and backward decoded

scalefactors, the set with the lower scalefactors in sum will be considered as

the correct one. The scalefactors are differentially encoded. Normally it would

reach to compare one pair of the forward and backward decoded scalefactors to

specify the lower set. But having detected no further errors does not

necessarily mean the absence of errors. Therefore all scalefactors decoded in

forward and backward direction are summed up seperately. The set with the lower

sum will be used. The strategy must be applied to scalefactors, intensity data

and noise energy seperately.

-----------------------------------------------------------------------------------------------

  output:        Concealed scalefactor, noise energy and intensity data

-----------------------------------------------------------------------------------------------

  return:        -

--------------------------------------------------------------------------------------------

*/

void StatisticalEstimation(CAacDecoderChannelInfo *pAacDecoderChannelInfo) {

  CErRvlcInfo *pRvlc =

      &pAacDecoderChannelInfo->pComData->overlay.aac.erRvlcInfo;

  int band, bnds, group;

  int sumIsFwd, sumIsBwd;   /* sum of intensity data forward/backward */

  int sumNrgFwd, sumNrgBwd; /* sum of noise energy data forward/backward */

  int sumScfFwd, sumScfBwd; /* sum of scalefactor data forward/backward */

  int useIsFwd, useNrgFwd, useScfFwd; /* the flags signals the elements which

                                         are used for the final result */

  sumIsFwd = sumIsBwd = sumNrgFwd = sumNrgBwd = sumScfFwd = sumScfBwd = 0;

  useIsFwd = useNrgFwd = useScfFwd = 0;

  /* calculate sum of each group (scf,nrg,is) of forward and backward direction

   */

  for (group = 0; group < pRvlc->numWindowGroups; group++) {

    for (band = 0; band < pRvlc->maxSfbTransmitted; band++) {

      bnds = 16 * group + band;

      switch (pAacDecoderChannelInfo->pDynData->aCodeBook[bnds]) {

        case ZERO_HCB:

          break;

        case INTENSITY_HCB:

        case INTENSITY_HCB2:

          sumIsFwd +=

              pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds];

          sumIsBwd +=

              pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfBwd[bnds];

          break;

        case NOISE_HCB:

          sumNrgFwd +=

              pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds];

          sumNrgBwd +=

              pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfBwd[bnds];

          break;

        default:

          sumScfFwd +=

              pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds];

          sumScfBwd +=

              pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfBwd[bnds];

          break;

      }

    }

  }

  /* find for each group (scf,nrg,is) the correct direction */

  if (sumIsFwd < sumIsBwd) useIsFwd = 1;

  if (sumNrgFwd < sumNrgBwd) useNrgFwd = 1;

  if (sumScfFwd < sumScfBwd) useScfFwd = 1;

  /* conceal each group (scf,nrg,is) */

  for (group = 0; group < pRvlc->numWindowGroups; group++) {

    for (band = 0; band < pRvlc->maxSfbTransmitted; band++) {

      bnds = 16 * group + band;

      switch (pAacDecoderChannelInfo->pDynData->aCodeBook[bnds]) {

        case ZERO_HCB:

          break;

        case INTENSITY_HCB:

        case INTENSITY_HCB2:

          if (useIsFwd)

            pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] =

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds];

          else

            pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] =

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfBwd[bnds];

          break;

        case NOISE_HCB:

          if (useNrgFwd)

            pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] =

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds];

          else

            pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] =

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfBwd[bnds];

          break;

        default:

          if (useScfFwd)

            pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] =

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds];

          else

            pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] =

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfBwd[bnds];

          break;

      }

    }

  }

}

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

  description:   Approach by means of predictive interpolation

                 This approach by means of predictive estimation is generally

performed when the error cannot be isolated between 'conceal_min' and

'conceal_max', the 'sf_concealment' flag is set and the previous frame has the

same block type as the current frame. Check for each scalefactorband if the same

type of data (scalefactor, internsity data, noise energies) is transmitted. If

so use the scalefactor (intensity data, noise energy) in the current frame.

Otherwise set the scalefactor (intensity data, noise energy) for this

scalefactorband to zero.

-----------------------------------------------------------------------------------------------

  output:        Concealed scalefactor, noise energy and intensity data

-----------------------------------------------------------------------------------------------

  return:        -

--------------------------------------------------------------------------------------------

*/

void PredictiveInterpolation(

    CAacDecoderChannelInfo *pAacDecoderChannelInfo,

    CAacDecoderStaticChannelInfo *pAacDecoderStaticChannelInfo) {

  CErRvlcInfo *pRvlc =

      &pAacDecoderChannelInfo->pComData->overlay.aac.erRvlcInfo;

  int band, bnds, group;

  SHORT commonMin;

  for (group = 0; group < pRvlc->numWindowGroups; group++) {

    for (band = 0; band < pRvlc->maxSfbTransmitted; band++) {

      bnds = 16 * group + band;

      switch (pAacDecoderChannelInfo->pDynData->aCodeBook[bnds]) {

        case ZERO_HCB:

          pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] = 0;

          break;

        case INTENSITY_HCB:

        case INTENSITY_HCB2:

          if ((pAacDecoderStaticChannelInfo->concealmentInfo

                   .aRvlcPreviousCodebook[bnds] == INTENSITY_HCB) ||

              (pAacDecoderStaticChannelInfo->concealmentInfo

                   .aRvlcPreviousCodebook[bnds] == INTENSITY_HCB2)) {

            commonMin = fMin(

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds],

                pAacDecoderChannelInfo->pComData->overlay.aac

                    .aRvlcScfBwd[bnds]);

            pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] =

                fMin(commonMin, pAacDecoderStaticChannelInfo->concealmentInfo

                                    .aRvlcPreviousScaleFactor[bnds]);

          } else {

            pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] = -110;

          }

          break;

        case NOISE_HCB:

          if (pAacDecoderStaticChannelInfo->concealmentInfo

                  .aRvlcPreviousCodebook[bnds] == NOISE_HCB) {

            commonMin = fMin(

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds],

                pAacDecoderChannelInfo->pComData->overlay.aac

                    .aRvlcScfBwd[bnds]);

            pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] =

                fMin(commonMin, pAacDecoderStaticChannelInfo->concealmentInfo

                                    .aRvlcPreviousScaleFactor[bnds]);

          } else {

            pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] = -110;

          }

          break;

        default:

          if ((pAacDecoderStaticChannelInfo->concealmentInfo

                   .aRvlcPreviousCodebook[bnds] != ZERO_HCB) &&

              (pAacDecoderStaticChannelInfo->concealmentInfo

                   .aRvlcPreviousCodebook[bnds] != NOISE_HCB) &&

              (pAacDecoderStaticChannelInfo->concealmentInfo

                   .aRvlcPreviousCodebook[bnds] != INTENSITY_HCB) &&

              (pAacDecoderStaticChannelInfo->concealmentInfo

                   .aRvlcPreviousCodebook[bnds] != INTENSITY_HCB2)) {

            commonMin = fMin(

                pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds],

                pAacDecoderChannelInfo->pComData->overlay.aac

                    .aRvlcScfBwd[bnds]);

            pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] =

                fMin(commonMin, pAacDecoderStaticChannelInfo->concealmentInfo

                                    .aRvlcPreviousScaleFactor[bnds]);

          } else {

            pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] = 0;

          }

          break;

      }

    }

  }

}