path: root/libAACdec/src/rvlc.cpp

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

                     (C) Copyright Fraunhofer IIS (2004)
                               All Rights Reserved

    Please be advised that this software and/or program delivery is
    Confidential Information of Fraunhofer and subject to and covered by the

    Fraunhofer IIS Software Evaluation Agreement
    between Google Inc. and  Fraunhofer
    effective and in full force since March 1, 2012.

    You may use this software and/or program only under the terms and
    conditions described in the above mentioned Fraunhofer IIS Software
    Evaluation Agreement. Any other and/or further use requires a separate agreement.


   This software and/or program is protected by copyright law and international
   treaties. Any reproduction or distribution of this software and/or program,
   or any portion of it, may result in severe civil and criminal penalties, and
   will be prosecuted to the maximum extent possible under law.

 $Id$

****************************************************************************/
/*!
  \file
  \brief  RVLC Decoder
  \author Robert Weidner
*/

#include "rvlc.h"


#include "block.h"

#include "aac_rom.h"
#include "rvlcbit.h"
#include "rvlcconceal.h"
#include "aacdec_hcr.h"

/*---------------------------------------------------------------------------------------------
     function:     rvlcInit

     description:  init RVLC by data from channelinfo, which was decoded previously and
                   set up pointers
-----------------------------------------------------------------------------------------------
        input:     - pointer rvlc structure
                   - pointer channel info structure
                   - pointer bitstream structure
-----------------------------------------------------------------------------------------------
        return:    -
-------------------------------------------------------------------------------------------- */

static
void rvlcInit (CErRvlcInfo            *pRvlc,
               CAacDecoderChannelInfo *pAacDecoderChannelInfo,
               HANDLE_FDK_BITSTREAM    bs)
{
  /* RVLC common initialization part 2 of 2 */
  SHORT     *pScfEsc = pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfEsc;
  SHORT     *pScfFwd = pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd;
  SHORT     *pScfBwd = pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfBwd;
  SHORT     *pScaleFactor = pAacDecoderChannelInfo->pDynData->aScaleFactor;
  int bnds;

  pAacDecoderChannelInfo->pDynData->specificTo.aac.rvlcIntensityUsed = 0;

  pRvlc->numDecodedEscapeWordsEsc = 0;
  pRvlc->numDecodedEscapeWordsFwd = 0;
  pRvlc->numDecodedEscapeWordsBwd = 0;

  pRvlc->intensity_used = 0;
  pRvlc->errorLogRvlc   = 0;

  pRvlc->conceal_max = CONCEAL_MAX_INIT;
  pRvlc->conceal_min = CONCEAL_MIN_INIT;

  pRvlc->conceal_max_esc = CONCEAL_MAX_INIT;
  pRvlc->conceal_min_esc = CONCEAL_MIN_INIT;

  pRvlc->pHuffTreeRvlcEscape  = aHuffTreeRvlcEscape;
  pRvlc->pHuffTreeRvlCodewds  = aHuffTreeRvlCodewds;

  /* init scf arrays (for savety (in case of there are only zero codebooks)) */
  for (bnds = 0; bnds < RVLC_MAX_SFB; bnds++) {
    pScfFwd[bnds] = 0;
    pScfBwd[bnds] = 0;
    pScfEsc[bnds] = 0;
    pScaleFactor[bnds] = 0;
  }

  /* set base bitstream ptr to the RVL-coded part (start of RVLC data (ESC 2)) */
  FDKsyncCache (bs);

  pRvlc->bitstreamIndexRvlFwd = FDKgetBitCnt(bs); /* first bit within RVL coded block as start address for  forward decoding */
  pRvlc->bitstreamIndexRvlBwd = FDKgetBitCnt(bs) + pRvlc->length_of_rvlc_sf - 1; /* last bit within RVL coded block as start address for backward decoding */

  /* skip RVLC-bitstream-part -- pointing now to escapes (if present) or to TNS data (if present) */
  FDKpushFor (bs, pRvlc->length_of_rvlc_sf);

  if ( pRvlc->sf_escapes_present != 0 ) {

    /* locate internal bitstream ptr at escapes (which is the second part) */
    FDKsyncCache (bs);
    pRvlc->bitstreamIndexEsc = FDKgetBitCnt(bs);

    /* skip escapeRVLC-bitstream-part -- pointing to TNS data (if present)   to make decoder continue */
    /* decoding of RVLC should work despite this second pushFor during initialization because        */
    /* bitstream initialization is valid for both ESC2 data parts (RVL-coded values and ESC-coded values) */
    FDKpushFor (bs, pRvlc->length_of_rvlc_escapes);
  }

#if VERBOSE_RVLC_INIT
  DebugOutputInit(pRvlc,pAacDecoderChannelInfo);
#endif
}


/*---------------------------------------------------------------------------------------------
     function:     rvlcCheckIntensityCb

     description:  Check if a intensity codebook is used in the current channel.
-----------------------------------------------------------------------------------------------
        input:     - pointer rvlc structure
                   - pointer channel info structure
-----------------------------------------------------------------------------------------------
        output:    - intensity_used: 0 no intensity codebook is used
                                     1 intensity codebook is used
-----------------------------------------------------------------------------------------------
        return:    -
-------------------------------------------------------------------------------------------- */

static
void rvlcCheckIntensityCb (CErRvlcInfo            *pRvlc,
                           CAacDecoderChannelInfo *pAacDecoderChannelInfo)
{
  int group, band, bnds;

  pRvlc->intensity_used = 0;

  for (group=0; group < pRvlc->numWindowGroups; group++) {
    for (band=0; band < pRvlc->maxSfbTransmitted; band++) {
      bnds = 16*group+band;
      if ( (pAacDecoderChannelInfo->pDynData->aCodeBook[bnds] == INTENSITY_HCB) || (pAacDecoderChannelInfo->pDynData->aCodeBook[bnds] == INTENSITY_HCB2) ) {
        pRvlc->intensity_used = 1;
        break;
      }
    }
  }
}


/*---------------------------------------------------------------------------------------------
     function:     rvlcDecodeEscapeWord

     description:  Decode a huffman coded RVLC Escape-word. This value is part of a DPCM coded
                   scalefactor.
-----------------------------------------------------------------------------------------------
        input:     - pointer rvlc structure
-----------------------------------------------------------------------------------------------
        return:    - a single RVLC-Escape value which had to be applied to a DPCM value (which
                     has a absolute value of 7)
-------------------------------------------------------------------------------------------- */

static
SCHAR rvlcDecodeEscapeWord (CErRvlcInfo          *pRvlc,
                            HANDLE_FDK_BITSTREAM  bs)
{
  int           i;
  SCHAR         value;
  UCHAR         carryBit;
  UINT          treeNode;
  UINT          branchValue;
  UINT          branchNode;

  USHORT*       pBitstreamIndexEsc;
  const UINT*   pEscTree;

  pEscTree = pRvlc->pHuffTreeRvlcEscape;
  pBitstreamIndexEsc = &(pRvlc->bitstreamIndexEsc);
  treeNode = *pEscTree;                                             /* init at starting node */

  for (i=MAX_LEN_RVLC_ESCAPE_WORD-1; i >= 0; i--) {
    carryBit = rvlcReadBitFromBitstream(bs,                         /* get next bit */
                                        pBitstreamIndexEsc,
                                        FWD);

    CarryBitToBranchValue(carryBit,                                 /* huffman decoding, do a single step in huffman decoding tree */
                          treeNode,
                          &branchValue,
                          &branchNode);

    if ((branchNode & TEST_BIT_10) == TEST_BIT_10) {                /* test bit 10 ; if set --> a RVLC-escape-word is completely decoded */
      value = (SCHAR) branchNode & CLR_BIT_10;
      pRvlc->length_of_rvlc_escapes -= (MAX_LEN_RVLC_ESCAPE_WORD - i);

      if (pRvlc->length_of_rvlc_escapes < 0) {
        pRvlc->errorLogRvlc |= RVLC_ERROR_ALL_ESCAPE_WORDS_INVALID;
        value = -1;
      }

      return value;
    }
    else {
      treeNode = *(pEscTree + branchValue);                         /* update treeNode for further step in decoding tree */
    }
  }

  pRvlc->errorLogRvlc |= RVLC_ERROR_ALL_ESCAPE_WORDS_INVALID;

  return -1;                                                        /* should not be reached */
}


/*---------------------------------------------------------------------------------------------
     function:     rvlcDecodeEscapes

     description:  Decodes all huffman coded RVLC Escape Words.
                   Here a difference to the pseudo-code-implementation from standard can be 
                   found. A while loop (and not two nested for loops) is used for two reasons:

                   1. The plain huffman encoded escapes are decoded before the RVL-coded 
                      scalefactors. Therefore the escapes are present in the second step 
                      when decoding the RVL-coded-scalefactor values in forward and 
                      backward direction.

                      When the RVL-coded scalefactors are decoded and there a escape is 
                      needed, then it is just taken out of the array in ascending order.

                   2. It's faster.
-----------------------------------------------------------------------------------------------
        input:     - pointer rvlc structure
                   - handle to FDK bitstream
-----------------------------------------------------------------------------------------------
        return:    - 0 ok     the decoded escapes seem to be valid
                   - 1 error  there was a error detected during decoding escapes
                              --> all escapes are invalid
-------------------------------------------------------------------------------------------- */

static
void rvlcDecodeEscapes (CErRvlcInfo          *pRvlc,
                        SHORT                *pEsc,
                        HANDLE_FDK_BITSTREAM  bs)
{
  SCHAR  escWord;
  SCHAR  escCnt=0;
  SHORT* pEscBitCntSum;

  pEscBitCntSum = &(pRvlc->length_of_rvlc_escapes);

  /* Decode all RVLC-Escape words with a plain Huffman-Decoder */
  while ( *pEscBitCntSum > 0 ) {
    escWord = rvlcDecodeEscapeWord(pRvlc, bs);

    if (escWord >= 0) {

      pEsc[escCnt] = escWord;
      escCnt++;
    }
    else {
      pRvlc->errorLogRvlc |= RVLC_ERROR_ALL_ESCAPE_WORDS_INVALID;
      pRvlc->numDecodedEscapeWordsEsc = escCnt;

      return;
    }
  } /* all RVLC escapes decoded */

  pRvlc->numDecodedEscapeWordsEsc = escCnt;
}


/*---------------------------------------------------------------------------------------------
     function:     decodeRVLCodeword

     description:  Decodes a RVL-coded dpcm-word (-part).
-----------------------------------------------------------------------------------------------
        input:     - FDK bitstream handle
                   - pointer rvlc structure
-----------------------------------------------------------------------------------------------
        return:    - a dpcm value which is within range [0,1,..,14] in case of no errors.
                     The offset of 7 must be subtracted to get a valid dpcm scalefactor value.
                     In case of errors a forbidden codeword is detected --> returning -1
-------------------------------------------------------------------------------------------- */

SCHAR decodeRVLCodeword (HANDLE_FDK_BITSTREAM  bs, CErRvlcInfo *pRvlc)
{
  int     i;
  SCHAR   value;
  UCHAR   carryBit;
  UINT    branchValue;
  UINT    branchNode;

  const UINT *pRvlCodeTree = pRvlc->pHuffTreeRvlCodewds;
  UCHAR   direction        = pRvlc->direction;
  USHORT *pBitstrIndxRvl   = pRvlc->pBitstrIndxRvl_RVL;
  UINT    treeNode         = *pRvlCodeTree;

  for (i=MAX_LEN_RVLC_CODE_WORD-1; i >= 0; i--) { 
    carryBit = rvlcReadBitFromBitstream(bs,             /* get next bit */
                                        pBitstrIndxRvl,
                                        direction);

    CarryBitToBranchValue(carryBit,                     /* huffman decoding, do a single step in huffman decoding tree */
                          treeNode,
                          &branchValue,
                          &branchNode);

    if ((branchNode & TEST_BIT_10) == TEST_BIT_10) {    /* test bit 10 ; if set --> a RVLC-codeword is completely decoded */
      value = (SCHAR) (branchNode & CLR_BIT_10);
      *pRvlc->pRvlBitCnt_RVL -= (MAX_LEN_RVLC_CODE_WORD - i);  
      
      /* check available bits for decoding */
      if (*pRvlc->pRvlBitCnt_RVL < 0) {
        if (direction ==  FWD) { 
          pRvlc->errorLogRvlc |= RVLC_ERROR_RVL_SUM_BIT_COUNTER_BELOW_ZERO_FWD; }
        else { 
          pRvlc->errorLogRvlc |= RVLC_ERROR_RVL_SUM_BIT_COUNTER_BELOW_ZERO_BWD; }
        value = -1;                                     /* signalize an error in return value, because too many bits was decoded */
      }
      
      /* check max value of dpcm value */
      if (value > MAX_ALLOWED_DPCM_INDEX) {
        if (direction ==  FWD) { 
          pRvlc->errorLogRvlc |= RVLC_ERROR_FORBIDDEN_CW_DETECTED_FWD; 
        }
        else { 
          pRvlc->errorLogRvlc |= RVLC_ERROR_FORBIDDEN_CW_DETECTED_BWD; 
        }
        value = -1;                                     /* signalize an error in return value, because a forbidden cw was detected*/
      }                                                       

      return value;                                     /* return a dpcm value with offset +7 or an error status */
    }
    else {
      treeNode = *(pRvlCodeTree + branchValue);         /* update treeNode for further step in decoding tree */
    }
  }
  
  return -1;  
}


/*---------------------------------------------------------------------------------------------
     function:     rvlcDecodeForward

     description:  Decode RVL-coded codewords in forward direction.
-----------------------------------------------------------------------------------------------
        input:     - pointer rvlc structure
                   - pointer channel info structure
                   - handle to FDK bitstream
-----------------------------------------------------------------------------------------------
        return:    -
-------------------------------------------------------------------------------------------- */

static
void rvlcDecodeForward (CErRvlcInfo            *pRvlc,
                        CAacDecoderChannelInfo *pAacDecoderChannelInfo,
                        HANDLE_FDK_BITSTREAM    bs)
{
  int band  = 0;
  int group = 0;
  int bnds  = 0;

  SHORT dpcm;

  SHORT  factor   = pAacDecoderChannelInfo->pDynData->RawDataInfo.GlobalGain - SF_OFFSET;
  SHORT  position = - SF_OFFSET;
  SHORT  noisenrg = pAacDecoderChannelInfo->pDynData->RawDataInfo.GlobalGain - SF_OFFSET - 90 - 256;

  SHORT* pScfFwd = pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd;
  SHORT* pScfEsc = pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfEsc;
  UCHAR* pEscFwdCnt = &(pRvlc->numDecodedEscapeWordsFwd);
  
  pRvlc->pRvlBitCnt_RVL = &(pRvlc->length_of_rvlc_sf_fwd);
  pRvlc->pBitstrIndxRvl_RVL = &(pRvlc->bitstreamIndexRvlFwd);

  *pEscFwdCnt       = 0;
  pRvlc->direction  = FWD;
  pRvlc->noise_used = 0;
  pRvlc->sf_used    = 0;
  pRvlc->lastScf    = 0;
  pRvlc->lastNrg    = 0;
  pRvlc->lastIs     = 0;         

  rvlcCheckIntensityCb(pRvlc,pAacDecoderChannelInfo);

  /* main loop fwd long */
  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 :
        pScfFwd[bnds] = 0;
        break;

      case INTENSITY_HCB2 :
      case INTENSITY_HCB  :
        /* store dpcm_is_position */
        dpcm = decodeRVLCodeword(bs, pRvlc);
        if ( dpcm < 0 ) {
          pRvlc->conceal_max = bnds;
          return;
        }
        dpcm -= TABLE_OFFSET;
        if ((dpcm == MIN_RVL) || (dpcm == MAX_RVL)) {
          if (pRvlc->length_of_rvlc_escapes) {
            pRvlc->conceal_max = bnds;
            return;
          }
          else {
            if (dpcm == MIN_RVL) { 
              dpcm -= *pScfEsc++; 
            }
            else { 
              dpcm += *pScfEsc++; 
            }
            (*pEscFwdCnt)++;
            if (pRvlc->conceal_max_esc == CONCEAL_MAX_INIT) {
              pRvlc->conceal_max_esc = bnds;
            }
          }
        }
        position += dpcm;
        pScfFwd[bnds] = position;
        pRvlc->lastIs = position;
        break;

      case NOISE_HCB :
        if (pRvlc->noise_used == 0) {
          pRvlc->noise_used = 1;
          pRvlc->first_noise_band = bnds;
          noisenrg += pRvlc->dpcm_noise_nrg;
          pScfFwd[bnds] = 100 + noisenrg;                  
          pRvlc->lastNrg = noisenrg;
        }
        else {
          dpcm = decodeRVLCodeword(bs, pRvlc);
          if ( dpcm < 0 ) {
            pRvlc->conceal_max = bnds;
            return;
          }
          dpcm -= TABLE_OFFSET;
          if ((dpcm == MIN_RVL) || (dpcm == MAX_RVL)) {
            if (pRvlc->length_of_rvlc_escapes) {
              pRvlc->conceal_max = bnds;
              return;
            }
            else {
              if (dpcm == MIN_RVL) { 
                dpcm -= *pScfEsc++; 
              }
              else { 
                dpcm += *pScfEsc++; 
              }
              (*pEscFwdCnt)++;
              if (pRvlc->conceal_max_esc == CONCEAL_MAX_INIT) {
                pRvlc->conceal_max_esc = bnds;
              }
            }
          }
          noisenrg += dpcm;
          pScfFwd[bnds] = 100 + noisenrg;
          pRvlc->lastNrg = noisenrg;         
        }
        pAacDecoderChannelInfo->data.aac.PnsData.pnsUsed[bnds] = 1;
        break ;

      default :
        pRvlc->sf_used = 1;
        dpcm = decodeRVLCodeword(bs, pRvlc);
        if ( dpcm < 0 ) {
          pRvlc->conceal_max = bnds;
          return;
        }
        dpcm -= TABLE_OFFSET;
        if ((dpcm == MIN_RVL) || (dpcm == MAX_RVL)) {
          if (pRvlc->length_of_rvlc_escapes) {
            pRvlc->conceal_max = bnds;
            return;
          }
          else {
            if (dpcm == MIN_RVL) { 
              dpcm -= *pScfEsc++; }
            else { 
              dpcm += *pScfEsc++; 
            }
            (*pEscFwdCnt)++;
            if (pRvlc->conceal_max_esc == CONCEAL_MAX_INIT) {
              pRvlc->conceal_max_esc = bnds;
            }
          }
        }
        factor += dpcm;
        pScfFwd[bnds] = factor;
        pRvlc->lastScf = factor;
        break;
      }
    }
  }

  /* postfetch fwd long */
  if (pRvlc->intensity_used) {
    dpcm = decodeRVLCodeword(bs, pRvlc);      /* dpcm_is_last_position */
    if ( dpcm < 0 ) {
      pRvlc->conceal_max = bnds;
      return;
    }
    dpcm -= TABLE_OFFSET;
    if ((dpcm == MIN_RVL) || (dpcm == MAX_RVL)) {
      if (pRvlc->length_of_rvlc_escapes) {
        pRvlc->conceal_max = bnds;
        return;
      }
      else {
        if (dpcm == MIN_RVL) { 
          dpcm -= *pScfEsc++; 
        }
        else { 
          dpcm += *pScfEsc++; 
        }
        (*pEscFwdCnt)++;  
        if (pRvlc->conceal_max_esc == CONCEAL_MAX_INIT) {
          pRvlc->conceal_max_esc = bnds;
        }
      }
    }
    pRvlc->dpcm_is_last_position = dpcm;
  }
}


/*---------------------------------------------------------------------------------------------
     function:     rvlcDecodeBackward

     description:  Decode RVL-coded codewords in backward direction.
-----------------------------------------------------------------------------------------------
        input:     - pointer rvlc structure
                   - pointer channel info structure
                   - handle FDK bitstream
-----------------------------------------------------------------------------------------------
        return:    -
-------------------------------------------------------------------------------------------- */

static
void rvlcDecodeBackward (CErRvlcInfo            *pRvlc,
                         CAacDecoderChannelInfo *pAacDecoderChannelInfo,
                         HANDLE_FDK_BITSTREAM    bs)
{
  SHORT  band, group, dpcm, offset;
  SHORT  bnds = pRvlc->maxSfbTransmitted-1;

  SHORT  factor     = pRvlc->rev_global_gain - SF_OFFSET;
  SHORT  position   = pRvlc->dpcm_is_last_position - SF_OFFSET;
  SHORT  noisenrg   = pRvlc->rev_global_gain + pRvlc->dpcm_noise_last_position - SF_OFFSET - 90 - 256;

  SHORT *pScfBwd    = pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfBwd;
  SHORT *pScfEsc    = pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfEsc;
  UCHAR *pEscEscCnt = &(pRvlc->numDecodedEscapeWordsEsc);
  UCHAR *pEscBwdCnt = &(pRvlc->numDecodedEscapeWordsBwd);

  pRvlc->pRvlBitCnt_RVL = &(pRvlc->length_of_rvlc_sf_bwd);
  pRvlc->pBitstrIndxRvl_RVL = &(pRvlc->bitstreamIndexRvlBwd);

  *pEscBwdCnt = 0;
  pRvlc->direction = BWD;
  pScfEsc += *pEscEscCnt - 1;             /* set pScfEsc to last entry */
  pRvlc->firstScf = 0;
  pRvlc->firstNrg = 0;
  pRvlc->firstIs = 0;

  /* prefetch long BWD */
  if (pRvlc->intensity_used) {
    dpcm = decodeRVLCodeword(bs, pRvlc);      /* dpcm_is_last_position */
    if ( dpcm < 0 ) {
      pRvlc->dpcm_is_last_position = 0;
      pRvlc->conceal_min = bnds;
      return;
    }
    dpcm -= TABLE_OFFSET;
    if ((dpcm == MIN_RVL) || (dpcm == MAX_RVL)) {
      if (pRvlc->length_of_rvlc_escapes) {
        pRvlc->conceal_min = bnds;
        return;
      }
      else {
        if (dpcm == MIN_RVL) {
          dpcm -= *pScfEsc--;
        }
        else {
          dpcm += *pScfEsc--;
        }
        (*pEscBwdCnt)++;  
        if (pRvlc->conceal_min_esc == CONCEAL_MIN_INIT) {
          pRvlc->conceal_min_esc = bnds;
        }
      }
    }
    pRvlc->dpcm_is_last_position = dpcm;
  }

  /* main loop long BWD */
  for (group=pRvlc->numWindowGroups-1; group >= 0; group--) {
    for (band=pRvlc->maxSfbTransmitted-1; band >= 0; band--) {
      bnds = 16*group+band;
      if ((band == 0) && (pRvlc->numWindowGroups != 1))
        offset = 16 - pRvlc->maxSfbTransmitted + 1;
      else
        offset = 1;

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

      case ZERO_HCB :
        pScfBwd[bnds] = 0;
        break;

      case INTENSITY_HCB2 :
      case INTENSITY_HCB  :
        /* store dpcm_is_position */
        dpcm = decodeRVLCodeword(bs, pRvlc);
        if ( dpcm < 0 ) {
          pScfBwd[bnds] = position;
          pRvlc->conceal_min = FDKmax(0,bnds-offset);
          return;
        }
        dpcm -= TABLE_OFFSET;
        if ((dpcm == MIN_RVL) || (dpcm == MAX_RVL)) {
          if (pRvlc->length_of_rvlc_escapes) {
            pScfBwd[bnds] = position;
            pRvlc->conceal_min = FDKmax(0,bnds-offset);
            return;
          }
          else {
            if (dpcm == MIN_RVL) {
              dpcm -= *pScfEsc--;
            }
            else {
              dpcm += *pScfEsc--;
            }
            (*pEscBwdCnt)++;
            if (pRvlc->conceal_min_esc == CONCEAL_MIN_INIT) {
              pRvlc->conceal_min_esc = FDKmax(0,bnds-offset);
            }
          }
        }
        pScfBwd[bnds] = position;
        position -= dpcm;  
        pRvlc->firstIs = position; 
        break;

      case NOISE_HCB :
        if ( bnds == pRvlc->first_noise_band ) {
          pScfBwd[bnds] = pRvlc->dpcm_noise_nrg + pAacDecoderChannelInfo->pDynData->RawDataInfo.GlobalGain - SF_OFFSET - 90 - 256;         
          pRvlc->firstNrg = pScfBwd[bnds];
        }
        else {
          dpcm = decodeRVLCodeword(bs, pRvlc);
          if ( dpcm < 0 ) {
            pScfBwd[bnds] = noisenrg;
            pRvlc->conceal_min = FDKmax(0,bnds-offset);
            return;
          }
          dpcm -= TABLE_OFFSET;
          if ((dpcm == MIN_RVL) || (dpcm == MAX_RVL)) {
            if (pRvlc->length_of_rvlc_escapes) {
              pScfBwd[bnds] = noisenrg;
              pRvlc->conceal_min = FDKmax(0,bnds-offset);
              return;
            }
            else {
              if (dpcm == MIN_RVL) {
                dpcm -= *pScfEsc--;
              }
              else {
                dpcm += *pScfEsc--;
              }
              (*pEscBwdCnt)++;
              if (pRvlc->conceal_min_esc == CONCEAL_MIN_INIT) {
                pRvlc->conceal_min_esc = FDKmax(0,bnds-offset);
              }
            }
          }
          pScfBwd[bnds] = noisenrg;
          noisenrg -= dpcm;
          pRvlc->firstNrg = noisenrg;
        }
        break ;

      default :
        dpcm = decodeRVLCodeword(bs, pRvlc);
        if ( dpcm < 0 ) {
          pScfBwd[bnds] = factor;
          pRvlc->conceal_min = FDKmax(0,bnds-offset);
          return;
        }
        dpcm -= TABLE_OFFSET;
        if ((dpcm == MIN_RVL) || (dpcm == MAX_RVL)) {
          if (pRvlc->length_of_rvlc_escapes) {
            pScfBwd[bnds] = factor;
            pRvlc->conceal_min = FDKmax(0,bnds-offset);
            return;
          }
          else {
            if (dpcm == MIN_RVL) {
              dpcm -= *pScfEsc--;
            }
            else {
              dpcm += *pScfEsc--;
            }
            (*pEscBwdCnt)++;
            if (pRvlc->conceal_min_esc == CONCEAL_MIN_INIT) {
              pRvlc->conceal_min_esc = FDKmax(0,bnds-offset);
            }
          }
        }
        pScfBwd[bnds] = factor;
        factor -= dpcm;
        pRvlc->firstScf = factor;
        break;
      }
    }
  }
}


/*---------------------------------------------------------------------------------------------
     function:     rvlcFinalErrorDetection             

     description:  Call RVLC concealment if error was detected in decoding process
-----------------------------------------------------------------------------------------------
        input:     - pointer rvlc structure
                   - pointer channel info structure
-----------------------------------------------------------------------------------------------
        return:    -
-------------------------------------------------------------------------------------------- */

static
void rvlcFinalErrorDetection (CAacDecoderChannelInfo  *pAacDecoderChannelInfo,
                              CAacDecoderStaticChannelInfo *pAacDecoderStaticChannelInfo)
{
  CErRvlcInfo *pRvlc = &pAacDecoderChannelInfo->pComData->overlay.aac.erRvlcInfo;
  UCHAR ErrorStatusComplete       = 0;
  UCHAR ErrorStatusLengthFwd      = 0;
  UCHAR ErrorStatusLengthBwd      = 0;
  UCHAR ErrorStatusLengthEscapes  = 0;
  UCHAR ErrorStatusFirstScf       = 0;
  UCHAR ErrorStatusLastScf        = 0;
  UCHAR ErrorStatusFirstNrg       = 0;
  UCHAR ErrorStatusLastNrg        = 0;
  UCHAR ErrorStatusFirstIs        = 0;
  UCHAR ErrorStatusLastIs         = 0;
  UCHAR ErrorStatusForbiddenCwFwd = 0;
  UCHAR ErrorStatusForbiddenCwBwd = 0;
  UCHAR ErrorStatusNumEscapesFwd  = 0;
  UCHAR ErrorStatusNumEscapesBwd  = 0;
  UCHAR ConcealStatus             = 1;
  UCHAR currentBlockType;  /* short: 0, not short: 1*/

#if VERBOSE_RVLC_OUTPUT
  CHAR  Strategy[60]="No";
  SHORT conceal_max;
  SHORT conceal_min;
#endif

  pAacDecoderChannelInfo->pDynData->specificTo.aac.rvlcCurrentScaleFactorOK = 1;

  /* invalid escape words, bit counter unequal zero, forbidden codeword detected */
  if (pRvlc->errorLogRvlc & RVLC_ERROR_FORBIDDEN_CW_DETECTED_FWD)
    ErrorStatusForbiddenCwFwd = 1;

  if (pRvlc->errorLogRvlc & RVLC_ERROR_FORBIDDEN_CW_DETECTED_BWD)
    ErrorStatusForbiddenCwBwd = 1;

  /* bit counter forward unequal zero */
  if (pRvlc->length_of_rvlc_sf_fwd)
    ErrorStatusLengthFwd = 1;

  /* bit counter backward unequal zero */
  if (pRvlc->length_of_rvlc_sf_bwd)
    ErrorStatusLengthBwd = 1;

  /* bit counter escape sequences unequal zero */
  if (pRvlc->sf_escapes_present)
    if (pRvlc->length_of_rvlc_escapes)
      ErrorStatusLengthEscapes = 1;

  if (pRvlc->sf_used) {
    /* first decoded scf does not match to global gain in backward direction */
    if (pRvlc->firstScf != (pAacDecoderChannelInfo->pDynData->RawDataInfo.GlobalGain - SF_OFFSET) ) 
      ErrorStatusFirstScf = 1;

    /* last decoded scf does not match to rev global gain in forward direction */
    if (pRvlc->lastScf != (pRvlc->rev_global_gain - SF_OFFSET) ) 
      ErrorStatusLastScf = 1;
  }

  if (pRvlc->noise_used) {
    /* first decoded nrg does not match to dpcm_noise_nrg in backward direction */
    if (pRvlc->firstNrg != (pAacDecoderChannelInfo->pDynData->RawDataInfo.GlobalGain + pRvlc->dpcm_noise_nrg - SF_OFFSET -90 - 256) ) 
      ErrorStatusFirstNrg = 1;

    /* last decoded nrg does not match to dpcm_noise_last_position in forward direction */
    if (pRvlc->lastNrg != (pRvlc->rev_global_gain + pRvlc->dpcm_noise_last_position - SF_OFFSET - 90 - 256) ) 
      ErrorStatusLastNrg = 1;
  }

  if (pRvlc->intensity_used) {
    /* first decoded is position does not match in backward direction */
    if (pRvlc->firstIs != (-SF_OFFSET) ) 
      ErrorStatusFirstIs = 1;

    /* last decoded is position does not match in forward direction */
    if (pRvlc->lastIs != (pRvlc->dpcm_is_last_position - SF_OFFSET) ) 
      ErrorStatusLastIs = 1;
  }

  /* decoded escapes and used escapes in forward direction do not fit */
  if ((pRvlc->numDecodedEscapeWordsFwd != pRvlc->numDecodedEscapeWordsEsc) && (pRvlc->conceal_max == CONCEAL_MAX_INIT)) {
    ErrorStatusNumEscapesFwd = 1;
  }

  /* decoded escapes and used escapes in backward direction do not fit */
  if ((pRvlc->numDecodedEscapeWordsBwd != pRvlc->numDecodedEscapeWordsEsc) && (pRvlc->conceal_min == CONCEAL_MIN_INIT)) {
    ErrorStatusNumEscapesBwd = 1;
  }

#if VERBOSE_RVLC_OUTPUT
  conceal_max = pRvlc->conceal_max;
  conceal_min = pRvlc->conceal_min;
#endif

  if (    ErrorStatusLengthEscapes
      || ( 
           (   (pRvlc->conceal_max == CONCEAL_MAX_INIT) 
            && (pRvlc->numDecodedEscapeWordsFwd != pRvlc->numDecodedEscapeWordsEsc)
            && (ErrorStatusLastScf || ErrorStatusLastNrg || ErrorStatusLastIs) )
           
            && 

           (   (pRvlc->conceal_min == CONCEAL_MIN_INIT) 
            && (pRvlc->numDecodedEscapeWordsBwd != pRvlc->numDecodedEscapeWordsEsc)
            && (ErrorStatusFirstScf || ErrorStatusFirstNrg || ErrorStatusFirstIs) ) 
         )    
      || (   (pRvlc->conceal_max == CONCEAL_MAX_INIT) 
          && ((pRvlc->rev_global_gain - SF_OFFSET - pRvlc->lastScf) < -15)
         )
      || (   (pRvlc->conceal_min == CONCEAL_MIN_INIT) 
          && ((pAacDecoderChannelInfo->pDynData->RawDataInfo.GlobalGain - SF_OFFSET - pRvlc->firstScf) < -15)
         )
     ) {
    if ((pRvlc->conceal_max == CONCEAL_MAX_INIT) || (pRvlc->conceal_min == CONCEAL_MIN_INIT)) {
      pRvlc->conceal_max = 0; 
      pRvlc->conceal_min = FDKmax(0, (pRvlc->numWindowGroups-1)*16+pRvlc->maxSfbTransmitted-1);
    }
    else {
      pRvlc->conceal_max = FDKmin(pRvlc->conceal_max,pRvlc->conceal_max_esc); 
      pRvlc->conceal_min = FDKmax(pRvlc->conceal_min,pRvlc->conceal_min_esc);
    }
  }

  ErrorStatusComplete =    ErrorStatusLastScf || ErrorStatusFirstScf || ErrorStatusLastNrg || ErrorStatusFirstNrg
                        || ErrorStatusLastIs || ErrorStatusFirstIs || ErrorStatusForbiddenCwFwd || ErrorStatusForbiddenCwBwd 
                        || ErrorStatusLengthFwd || ErrorStatusLengthBwd || ErrorStatusLengthEscapes || ErrorStatusNumEscapesFwd 
                        || ErrorStatusNumEscapesBwd;

  currentBlockType = (GetWindowSequence(&pAacDecoderChannelInfo->icsInfo) == EightShortSequence) ? 0 : 1;

   
  if (!ErrorStatusComplete) {
    int band;
    int group;
    int bnds;
    int lastSfbIndex;

    lastSfbIndex = (pRvlc->numWindowGroups > 1) ? 16 : 64;

    for (group=0; group < pRvlc->numWindowGroups; group++) {
      for (band=0; band<pRvlc->maxSfbTransmitted; band++) {
        bnds = 16*group+band;
        pAacDecoderChannelInfo->pDynData->aScaleFactor[bnds] = pAacDecoderStaticChannelInfo->concealmentInfo.aRvlcPreviousScaleFactor[bnds] = pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfFwd[bnds];
      }
    }

    for (group=0; group < pRvlc->numWindowGroups; group++)
    {
      for (band=0; band<pRvlc->maxSfbTransmitted; band++) {
        bnds = 16*group+band;
        pAacDecoderStaticChannelInfo->concealmentInfo.aRvlcPreviousCodebook[bnds] = pAacDecoderChannelInfo->pDynData->aCodeBook[bnds];
      }
      for (; band <lastSfbIndex; band++) {
        bnds = 16*group+band;
        FDK_ASSERT(bnds >= 0 && bnds < RVLC_MAX_SFB);
        pAacDecoderStaticChannelInfo->concealmentInfo.aRvlcPreviousCodebook[bnds] = ZERO_HCB;
      }
    }
  }
  else {
    int band;
    int group;

    /* A single bit error was detected in decoding of dpcm values. It also could be an error with more bits in decoding
       of escapes and dpcm values whereby an illegal codeword followed not directly after the corrupted bits but just 
       after decoding some more (wrong) scalefactors. Use the smaller scalefactor from forward decoding, backward decoding
       and previous frame. */
    if (   ((pRvlc->conceal_min != CONCEAL_MIN_INIT) || (pRvlc->conceal_max != CONCEAL_MAX_INIT)) && (pRvlc->conceal_min <= pRvlc->conceal_max) 
        && (pAacDecoderStaticChannelInfo->concealmentInfo.rvlcPreviousBlockType == currentBlockType) && pAacDecoderStaticChannelInfo->concealmentInfo.rvlcPreviousScaleFactorOK
        && pRvlc->sf_concealment && ConcealStatus )
    {
      BidirectionalEstimation_UseScfOfPrevFrameAsReference (pAacDecoderChannelInfo, pAacDecoderStaticChannelInfo);
      ConcealStatus=0;
#if VERBOSE_RVLC_OUTPUT
      FDKstrcpy(Strategy,"Yes (BidirectionalEstimation_UseScfOfPrevFrameAsReference)");
#endif
    }

    /* A single bit error was detected in decoding of dpcm values. It also could be an error with more bits in decoding
       of escapes and dpcm values whereby an illegal codeword followed not directly after the corrupted bits but just 
       after decoding some more (wrong) scalefactors. Use the smaller scalefactor from forward and backward decoding. */
    if (   (pRvlc->conceal_min <= pRvlc->conceal_max)  && ((pRvlc->conceal_min != CONCEAL_MIN_INIT) || (pRvlc->conceal_max != CONCEAL_MAX_INIT))
        && !(pAacDecoderStaticChannelInfo->concealmentInfo.rvlcPreviousScaleFactorOK && pRvlc->sf_concealment && (pAacDecoderStaticChannelInfo->concealmentInfo.rvlcPreviousBlockType == currentBlockType))
        && ConcealStatus )
    {
      BidirectionalEstimation_UseLowerScfOfCurrentFrame (pAacDecoderChannelInfo);
      ConcealStatus=0;
#if VERBOSE_RVLC_OUTPUT
      FDKstrcpy(Strategy,"Yes (BidirectionalEstimation_UseLowerScfOfCurrentFrame)");
#endif
    }

    /* No errors were detected in decoding of escapes and dpcm values however the first and last value 
       of a group (is,nrg,sf) is incorrect */                        
    if (   (pRvlc->conceal_min <= pRvlc->conceal_max)  && ((ErrorStatusLastScf && ErrorStatusFirstScf) 
        || (ErrorStatusLastNrg && ErrorStatusFirstNrg) || (ErrorStatusLastIs && ErrorStatusFirstIs)) 
        && !(ErrorStatusForbiddenCwFwd || ErrorStatusForbiddenCwBwd || ErrorStatusLengthEscapes ) && ConcealStatus)
    {
      StatisticalEstimation (pAacDecoderChannelInfo);
      ConcealStatus=0;
#if VERBOSE_RVLC_OUTPUT
      FDKstrcpy(Strategy,"Yes (StatisticalEstimation)");
#endif
    }

    /* A error with more bits in decoding of escapes and dpcm values was detected. Use the smaller scalefactor from forward 
       decoding, backward decoding and previous frame. */
    if (   (pRvlc->conceal_min <= pRvlc->conceal_max) && pAacDecoderStaticChannelInfo->concealmentInfo.rvlcPreviousScaleFactorOK && pRvlc->sf_concealment
        && (pAacDecoderStaticChannelInfo->concealmentInfo.rvlcPreviousBlockType == currentBlockType) && ConcealStatus )
    {
      PredictiveInterpolation(pAacDecoderChannelInfo, pAacDecoderStaticChannelInfo);
      ConcealStatus=0;
#if VERBOSE_RVLC_OUTPUT
      FDKstrcpy(Strategy,"Yes (PredictiveInterpolation)");
#endif
    }

    /* Call frame concealment, because no better strategy was found. Setting the scalefactors to zero is done for debugging 
       purposes */
    if (ConcealStatus) {
      for (group=0; group < pRvlc->numWindowGroups; group++) {
        for (band=0; band<pRvlc->maxSfbTransmitted; band++) {
          pAacDecoderChannelInfo->pDynData->aScaleFactor[16*group+band] = 0;
        }
      }
      pAacDecoderChannelInfo->pDynData->specificTo.aac.rvlcCurrentScaleFactorOK = 0;
#if VERBOSE_RVLC_OUTPUT
      FDKstrcpy(Strategy,"Yes (FrameConcealment)");
#endif
    }
  }

#if VERBOSE_RVLC_OUTPUT
  DebugOutputDistortedBitstreams(pRvlc,pAacDecoderChannelInfo,ErrorStatusLengthFwd,ErrorStatusLengthBwd,
                                 ErrorStatusLengthEscapes,ErrorStatusFirstScf,ErrorStatusLastScf,
                                 ErrorStatusFirstNrg,ErrorStatusLastNrg,ErrorStatusFirstIs,ErrorStatusLastIs,
                                 ErrorStatusForbiddenCwFwd,ErrorStatusForbiddenCwBwd,ErrorStatusNumEscapesFwd,
                                 ErrorStatusNumEscapesBwd,conceal_max,conceal_min,Strategy);
#endif
}


/*---------------------------------------------------------------------------------------------
     function:     CRvlc_Read             

     description:  Read RVLC ESC1 data (side info) from bitstream.
-----------------------------------------------------------------------------------------------
        input:     - pointer rvlc structure
                   - pointer channel info structure
                   - pointer bitstream structure
-----------------------------------------------------------------------------------------------
        return:    -
-------------------------------------------------------------------------------------------- */

void CRvlc_Read (
                 CAacDecoderChannelInfo *pAacDecoderChannelInfo,
                 HANDLE_FDK_BITSTREAM    bs)
{
  CErRvlcInfo *pRvlc = &pAacDecoderChannelInfo->pComData->overlay.aac.erRvlcInfo;

  int  group,band;

  /* RVLC long specific initialization  Init part 1 of 2 */
  pRvlc->numWindowGroups   = GetWindowGroups(&pAacDecoderChannelInfo->icsInfo);
  pRvlc->maxSfbTransmitted = GetScaleFactorBandsTransmitted(&pAacDecoderChannelInfo->icsInfo);
  pRvlc->noise_used               =  0;                  /* noise detection */
  pRvlc->dpcm_noise_nrg           =  0;                  /* only for debugging */
  pRvlc->dpcm_noise_last_position =  0;                  /* only for debugging */
  pRvlc->length_of_rvlc_escapes   = -1; /* default value is used for error detection and concealment */

  /* read only error sensitivity class 1 data (ESC 1 - data) */
  pRvlc->sf_concealment    = FDKreadBits(bs,1);                    /* #1 */
  pRvlc->rev_global_gain   = FDKreadBits(bs,8);                    /* #2 */

  if (GetWindowSequence(&pAacDecoderChannelInfo->icsInfo) == EightShortSequence) {
    pRvlc->length_of_rvlc_sf = FDKreadBits(bs,11);                 /* #3 */
  }            
  else {
    pRvlc->length_of_rvlc_sf = FDKreadBits(bs,9);                  /* #3 */
  }

  /* check if noise codebook is used */
  for (group = 0; group < pRvlc->numWindowGroups; group++) {
    for (band=0; band < pRvlc->maxSfbTransmitted; band++) {
      if (pAacDecoderChannelInfo->pDynData->aCodeBook[16*group+band] == NOISE_HCB) {
        pRvlc->noise_used = 1;
        break;  
      }
    }
  }

  if (pRvlc->noise_used) 
    pRvlc->dpcm_noise_nrg = FDKreadBits(bs, 9);              /* #4  PNS */    

  pRvlc->sf_escapes_present = FDKreadBits(bs, 1);            /* #5      */

  if ( pRvlc->sf_escapes_present) {
    pRvlc->length_of_rvlc_escapes = FDKreadBits(bs, 8);      /* #6      */
  }

  if (pRvlc->noise_used) { 
    pRvlc->dpcm_noise_last_position = FDKreadBits(bs, 9);    /* #7  PNS */    
    pRvlc->length_of_rvlc_sf -= 9;
  }

  pRvlc->length_of_rvlc_sf_fwd = pRvlc->length_of_rvlc_sf;
  pRvlc->length_of_rvlc_sf_bwd = pRvlc->length_of_rvlc_sf;
}


/*---------------------------------------------------------------------------------------------
     function:     CRvlc_Decode             

     description:  Decode rvlc data
                   The function reads both the escape sequences and the scalefactors in forward
                   and backward direction. If an error occured during decoding process which can 
                   not be concealed with the rvlc concealment frame concealment will be initiated. 
                   Then the element "rvlcCurrentScaleFactorOK" in the decoder channel info is set 
                   to 0 otherwise it is set to 1. 
-----------------------------------------------------------------------------------------------
        input:     - pointer rvlc structure
                   - pointer channel info structure
                   - pointer to persistent channel info structure
                   - pointer bitstream structure
-----------------------------------------------------------------------------------------------
        return:    ErrorStatus = AAC_DEC_OK
-------------------------------------------------------------------------------------------- */

void CRvlc_Decode (
        CAacDecoderChannelInfo  *pAacDecoderChannelInfo,
        CAacDecoderStaticChannelInfo *pAacDecoderStaticChannelInfo,
        HANDLE_FDK_BITSTREAM     bs
        )
{
  CErRvlcInfo *pRvlc = &pAacDecoderChannelInfo->pComData->overlay.aac.erRvlcInfo;
  INT  bitCntOffst;
  UINT saveBitCnt;

  rvlcInit(pRvlc,pAacDecoderChannelInfo,bs);  

  /* save bitstream position */
  saveBitCnt = FDKgetBitCnt(bs);

#if RVLC_ADVANCED_BITSTREAM_ERROR_GENERATOR_SF
  GenerateSingleBitError(pRvlc,
                         &(pRvlc->bitstreamIndexRvlFwd),
                         pRvlc->length_of_rvlc_sf,
                         0);
#endif

#if RVLC_ADVANCED_BITSTREAM_ERROR_GENERATOR_ESC
  if (pRvlc->sf_escapes_present)
    GenerateSingleBitError(pRvlc,
                           &(pRvlc->bitstreamIndexEsc),
                           pRvlc->length_of_rvlc_escapes,
                           1);
#endif

  if ( pRvlc->sf_escapes_present)
    rvlcDecodeEscapes(pRvlc, pAacDecoderChannelInfo->pComData->overlay.aac.aRvlcScfEsc, bs);

  rvlcDecodeForward(pRvlc,pAacDecoderChannelInfo, bs);    
  rvlcDecodeBackward(pRvlc,pAacDecoderChannelInfo, bs);
  rvlcFinalErrorDetection(pAacDecoderChannelInfo, pAacDecoderStaticChannelInfo);

  pAacDecoderChannelInfo->pDynData->specificTo.aac.rvlcIntensityUsed = pRvlc->intensity_used;
  pAacDecoderChannelInfo->data.aac.PnsData.PnsActive = pRvlc->noise_used;

  /* restore bitstream position */
  bitCntOffst = saveBitCnt - FDKgetBitCnt(bs);
  if( bitCntOffst ) {
    FDKpushBiDirectional(bs, bitCntOffst);
  }
}

void CRvlc_ElementCheck (
        CAacDecoderChannelInfo *pAacDecoderChannelInfo[],
        CAacDecoderStaticChannelInfo *pAacDecoderStaticChannelInfo[],
        const UINT flags,
        const INT elChannels
        )
{
  int ch;

  /* Required for MPS residuals. */
  if (pAacDecoderStaticChannelInfo == NULL) {
    return;
  }

  /* RVLC specific sanity checks */
  if ( (flags & AC_ER_RVLC) && (elChannels == 2)) { /* to be reviewed */
    if ( ( (pAacDecoderChannelInfo[0]->pDynData->specificTo.aac.rvlcCurrentScaleFactorOK == 0) ||
           (pAacDecoderChannelInfo[1]->pDynData->specificTo.aac.rvlcCurrentScaleFactorOK == 0) )
        &&  pAacDecoderChannelInfo[0]->pComData->jointStereoData.MsMaskPresent  ) {
      pAacDecoderChannelInfo[0]->pDynData->specificTo.aac.rvlcCurrentScaleFactorOK = 0;
      pAacDecoderChannelInfo[1]->pDynData->specificTo.aac.rvlcCurrentScaleFactorOK = 0;
    }

    if (   (pAacDecoderChannelInfo[0]->pDynData->specificTo.aac.rvlcCurrentScaleFactorOK == 0)
        && (pAacDecoderChannelInfo[1]->pDynData->specificTo.aac.rvlcCurrentScaleFactorOK == 1)
        && (pAacDecoderChannelInfo[1]->pDynData->specificTo.aac.rvlcIntensityUsed == 1) ){
      pAacDecoderChannelInfo[1]->pDynData->specificTo.aac.rvlcCurrentScaleFactorOK = 0;
    }
  }

  for (ch = 0; ch < elChannels; ch ++)
  {
    pAacDecoderStaticChannelInfo[ch]->concealmentInfo.rvlcPreviousBlockType = (GetWindowSequence(&pAacDecoderChannelInfo[ch]->icsInfo) == EightShortSequence) ? 0 : 1;
    if (flags & AC_ER_RVLC) {
      pAacDecoderStaticChannelInfo[ch]->concealmentInfo.rvlcPreviousScaleFactorOK = pAacDecoderChannelInfo[ch]->pDynData->specificTo.aac.rvlcCurrentScaleFactorOK;
    }
    else {
      pAacDecoderStaticChannelInfo[ch]->concealmentInfo.rvlcPreviousScaleFactorOK = 0;
    }
  }
}