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+
+/* -----------------------------------------------------------------------------------------------------------
+Software License for The Fraunhofer FDK AAC Codec Library for Android
+
+© Copyright  1995 - 2012 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
+----------------------------------------------------------------------------------------------------------- */
+
+#include "invf_est.h"
+#include "sbr_misc.h"
+
+#include "genericStds.h"
+
+#define MAX_NUM_REGIONS 10
+#define SCALE_FAC_QUO   512.0f
+#define SCALE_FAC_NRG   256.0f
+
+#ifndef min
+#define min(a,b) ( a < b ? a:b)
+#endif
+
+#ifndef max
+#define max(a,b) ( a > b ? a:b)
+#endif
+
+static const FIXP_DBL quantStepsSbr[4]  =  { 0x00400000, 0x02800000, 0x03800000, 0x04c00000 } ;    /* table scaled with SCALE_FAC_QUO */
+static const FIXP_DBL quantStepsOrig[4] =  { 0x00000000, 0x00c00000, 0x01c00000, 0x02800000 } ;    /* table scaled with SCALE_FAC_QUO */
+static const FIXP_DBL nrgBorders[4]     =  { 0x0c800000, 0x0f000000, 0x11800000, 0x14000000 } ;    /* table scaled with SCALE_FAC_NRG */
+
+static const DETECTOR_PARAMETERS detectorParamsAAC = {
+    quantStepsSbr,
+    quantStepsOrig,
+    nrgBorders,
+    4,                              /* Number of borders SBR. */
+    4,                              /* Number of borders orig. */
+    4,                              /* Number of borders Nrg. */
+    {                               /* Region space. */
+      {INVF_MID_LEVEL,   INVF_LOW_LEVEL,  INVF_OFF,        INVF_OFF, INVF_OFF}, /*    |      */
+      {INVF_MID_LEVEL,   INVF_LOW_LEVEL,  INVF_OFF,        INVF_OFF, INVF_OFF}, /*    |      */
+      {INVF_HIGH_LEVEL,  INVF_MID_LEVEL,  INVF_LOW_LEVEL,  INVF_OFF, INVF_OFF}, /* regionSbr */
+      {INVF_HIGH_LEVEL,  INVF_HIGH_LEVEL, INVF_MID_LEVEL,  INVF_OFF, INVF_OFF}, /*    |      */
+      {INVF_HIGH_LEVEL,  INVF_HIGH_LEVEL, INVF_MID_LEVEL,  INVF_OFF, INVF_OFF}  /*    |      */
+    },/*------------------------ regionOrig ---------------------------------*/
+    {                               /* Region space transient. */
+      {INVF_LOW_LEVEL,   INVF_LOW_LEVEL,  INVF_LOW_LEVEL,  INVF_OFF, INVF_OFF}, /*    |      */
+      {INVF_LOW_LEVEL,   INVF_LOW_LEVEL,  INVF_LOW_LEVEL,  INVF_OFF, INVF_OFF}, /*    |      */
+      {INVF_HIGH_LEVEL,  INVF_MID_LEVEL,  INVF_MID_LEVEL,  INVF_OFF, INVF_OFF}, /* regionSbr */
+      {INVF_HIGH_LEVEL,  INVF_HIGH_LEVEL, INVF_MID_LEVEL,  INVF_OFF, INVF_OFF}, /*    |      */
+      {INVF_HIGH_LEVEL,  INVF_HIGH_LEVEL, INVF_MID_LEVEL,  INVF_OFF, INVF_OFF}  /*    |      */
+    },/*------------------------ regionOrig ---------------------------------*/
+    {-4, -3, -2, -1, 0} /* Reduction factor of the inverse filtering for low energies.*/
+};
+
+static const FIXP_DBL hysteresis = 0x00400000 ; /* Delta value for hysteresis. scaled with SCALE_FAC_QUO */
+
+/*
+ * AAC+SBR PARAMETERS for Speech
+ *********************************/
+static const DETECTOR_PARAMETERS detectorParamsAACSpeech = {
+    quantStepsSbr,
+    quantStepsOrig,
+    nrgBorders,
+    4,                              /* Number of borders SBR. */
+    4,                              /* Number of borders orig. */
+    4,                              /* Number of borders Nrg. */
+    {                               /* Region space. */
+      {INVF_MID_LEVEL,   INVF_MID_LEVEL,  INVF_LOW_LEVEL,  INVF_OFF, INVF_OFF}, /*    |      */
+      {INVF_MID_LEVEL,   INVF_MID_LEVEL,  INVF_LOW_LEVEL,  INVF_OFF, INVF_OFF}, /*    |      */
+      {INVF_HIGH_LEVEL,  INVF_MID_LEVEL,  INVF_MID_LEVEL,  INVF_OFF, INVF_OFF}, /* regionSbr */
+      {INVF_HIGH_LEVEL,  INVF_HIGH_LEVEL, INVF_MID_LEVEL,  INVF_OFF, INVF_OFF}, /*    |      */
+      {INVF_HIGH_LEVEL,  INVF_HIGH_LEVEL, INVF_MID_LEVEL,  INVF_OFF, INVF_OFF}  /*    |      */
+    },/*------------------------ regionOrig ---------------------------------*/
+    {                               /* Region space transient. */
+      {INVF_MID_LEVEL,   INVF_MID_LEVEL,  INVF_LOW_LEVEL,  INVF_OFF, INVF_OFF}, /*    |      */
+      {INVF_MID_LEVEL,   INVF_MID_LEVEL,  INVF_LOW_LEVEL,  INVF_OFF, INVF_OFF}, /*    |      */
+      {INVF_HIGH_LEVEL,  INVF_MID_LEVEL,  INVF_MID_LEVEL,  INVF_OFF, INVF_OFF}, /* regionSbr */
+      {INVF_HIGH_LEVEL,  INVF_HIGH_LEVEL, INVF_MID_LEVEL,  INVF_OFF, INVF_OFF}, /*    |      */
+      {INVF_HIGH_LEVEL,  INVF_HIGH_LEVEL, INVF_MID_LEVEL,  INVF_OFF, INVF_OFF}  /*    |      */
+    },/*------------------------ regionOrig ---------------------------------*/
+    {-4, -3, -2, -1, 0} /* Reduction factor of the inverse filtering for low energies.*/
+};
+
+/*
+ * Smoothing filters.
+ ************************/
+typedef const FIXP_DBL FIR_FILTER[5];
+
+static const FIR_FILTER fir_0 = { 0x7fffffff, 0x00000000, 0x00000000, 0x00000000, 0x00000000 } ;
+static const FIR_FILTER fir_1 = { 0x2aaaaa80, 0x555554ff, 0x00000000, 0x00000000, 0x00000000 } ;
+static const FIR_FILTER fir_2 = { 0x10000000, 0x30000000, 0x40000000, 0x00000000, 0x00000000 } ;
+static const FIR_FILTER fir_3 = { 0x077f80e8, 0x199999a0, 0x2bb3b240, 0x33333340, 0x00000000 } ;
+static const FIR_FILTER fir_4 = { 0x04130598, 0x0ebdb000, 0x1becfa60, 0x2697a4c0, 0x2aaaaa80 } ;
+
+
+static const FIR_FILTER *const fir_table[5] = {
+  &fir_0,
+  &fir_1,
+  &fir_2,
+  &fir_3,
+  &fir_4
+};
+
+/**************************************************************************/
+/*!
+  \brief     Calculates the values used for the detector.
+
+
+  \return    none
+
+*/
+/**************************************************************************/
+static void
+calculateDetectorValues(FIXP_DBL **quotaMatrixOrig,       /*!< Matrix holding the tonality values of the original. */
+                        SCHAR    *indexVector,            /*!< Index vector to obtain the patched data. */
+                        FIXP_DBL *nrgVector,              /*!< Energy vector. */
+                        DETECTOR_VALUES *detectorValues,  /*!< pointer to DETECTOR_VALUES struct. */
+                        INT startChannel,                 /*!< Start channel. */
+                        INT stopChannel,                  /*!< Stop channel. */
+                        INT startIndex,                   /*!< Start index. */
+                        INT stopIndex,                    /*!< Stop index. */
+                        INT numberOfStrongest             /*!< The number of sorted tonal components to be considered. */
+                        )
+{
+  INT i,temp, j;
+
+  const FIXP_DBL* filter = *fir_table[INVF_SMOOTHING_LENGTH];
+  FIXP_DBL origQuotaMeanStrongest, sbrQuotaMeanStrongest;
+  FIXP_DBL origQuota, sbrQuota;
+  FIXP_DBL invIndex, invChannel, invTemp;
+  FIXP_DBL quotaVecOrig[64], quotaVecSbr[64];
+
+  FDKmemclear(quotaVecOrig,64*sizeof(FIXP_DBL));
+  FDKmemclear(quotaVecSbr,64*sizeof(FIXP_DBL));
+
+  invIndex = GetInvInt(stopIndex-startIndex);
+  invChannel = GetInvInt(stopChannel-startChannel);
+
+  /*
+   Calculate the mean value, over the current time segment, for the original, the HFR
+   and the difference, over all channels in the current frequency range.
+   NOTE: the averaging is done on the values quota/(1 - quota + RELAXATION).
+   */
+
+  /* The original, the sbr signal and the total energy */
+  detectorValues->avgNrg = FL2FXCONST_DBL(0.0f);
+  for(j=startIndex; j<stopIndex; j++) {
+    for(i=startChannel; i<stopChannel; i++) {
+      quotaVecOrig[i] += fMult(quotaMatrixOrig[j][i], invIndex);
+
+      if(indexVector[i] != -1)
+        quotaVecSbr[i] += fMult(quotaMatrixOrig[j][indexVector[i]], invIndex);
+    }
+    detectorValues->avgNrg += fMult(nrgVector[j], invIndex);
+  }
+
+  /*
+   Calculate the mean value, over the current frequency range, for the original, the HFR
+   and the difference. Also calculate the same mean values for the three vectors, but only
+   includeing the x strongest copmponents.
+   */
+
+  origQuota = FL2FXCONST_DBL(0.0f);
+  sbrQuota  = FL2FXCONST_DBL(0.0f);
+  for(i=startChannel; i<stopChannel; i++) {
+    origQuota += fMultDiv2(quotaVecOrig[i], invChannel);
+    sbrQuota  += fMultDiv2(quotaVecSbr[i], invChannel);
+  }
+
+  /*
+   Calculate the mean value for the x strongest components
+  */
+  FDKsbrEnc_Shellsort_fract(quotaVecOrig+startChannel,stopChannel-startChannel);
+  FDKsbrEnc_Shellsort_fract(quotaVecSbr+startChannel,stopChannel-startChannel);
+
+  origQuotaMeanStrongest = FL2FXCONST_DBL(0.0f);
+  sbrQuotaMeanStrongest  = FL2FXCONST_DBL(0.0f);
+
+  temp = min(stopChannel - startChannel, numberOfStrongest);
+  invTemp = GetInvInt(temp);
+
+  for(i=0; i<temp; i++) {
+    origQuotaMeanStrongest += fMultDiv2(quotaVecOrig[i + stopChannel - temp], invTemp);
+    sbrQuotaMeanStrongest  += fMultDiv2(quotaVecSbr[i + stopChannel - temp], invTemp);
+  }
+
+  /*
+   The value for the strongest component
+  */
+  detectorValues->origQuotaMax = quotaVecOrig[stopChannel - 1];
+  detectorValues->sbrQuotaMax  = quotaVecSbr[stopChannel - 1];
+
+  /*
+   Buffer values
+  */
+  FDKmemmove(detectorValues->origQuotaMean, detectorValues->origQuotaMean + 1, INVF_SMOOTHING_LENGTH*sizeof(FIXP_DBL));
+  FDKmemmove(detectorValues->sbrQuotaMean, detectorValues->sbrQuotaMean + 1, INVF_SMOOTHING_LENGTH*sizeof(FIXP_DBL));
+  FDKmemmove(detectorValues->origQuotaMeanStrongest, detectorValues->origQuotaMeanStrongest + 1, INVF_SMOOTHING_LENGTH*sizeof(FIXP_DBL));
+  FDKmemmove(detectorValues->sbrQuotaMeanStrongest, detectorValues->sbrQuotaMeanStrongest + 1, INVF_SMOOTHING_LENGTH*sizeof(FIXP_DBL));
+
+  detectorValues->origQuotaMean[INVF_SMOOTHING_LENGTH]          = origQuota<<1;
+  detectorValues->sbrQuotaMean[INVF_SMOOTHING_LENGTH]           = sbrQuota<<1;
+  detectorValues->origQuotaMeanStrongest[INVF_SMOOTHING_LENGTH] = origQuotaMeanStrongest<<1;
+  detectorValues->sbrQuotaMeanStrongest[INVF_SMOOTHING_LENGTH]  = sbrQuotaMeanStrongest<<1;
+
+  /*
+   Filter values
+  */
+  detectorValues->origQuotaMeanFilt = FL2FXCONST_DBL(0.0f);
+  detectorValues->sbrQuotaMeanFilt = FL2FXCONST_DBL(0.0f);
+  detectorValues->origQuotaMeanStrongestFilt = FL2FXCONST_DBL(0.0f);
+  detectorValues->sbrQuotaMeanStrongestFilt = FL2FXCONST_DBL(0.0f);
+
+  for(i=0;i<INVF_SMOOTHING_LENGTH+1;i++) {
+    detectorValues->origQuotaMeanFilt += fMult(detectorValues->origQuotaMean[i], filter[i]);
+    detectorValues->sbrQuotaMeanFilt  += fMult(detectorValues->sbrQuotaMean[i], filter[i]);
+    detectorValues->origQuotaMeanStrongestFilt += fMult(detectorValues->origQuotaMeanStrongest[i], filter[i]);
+    detectorValues->sbrQuotaMeanStrongestFilt  += fMult(detectorValues->sbrQuotaMeanStrongest[i], filter[i]);
+  }
+}
+
+/**************************************************************************/
+/*!
+  \brief     Returns the region in which the input value belongs.
+
+
+
+  \return    region.
+
+*/
+/**************************************************************************/
+static INT
+findRegion(FIXP_DBL currVal,        /*!< The current value. */
+           const FIXP_DBL *borders, /*!< The border of the regions. */
+           const INT numBorders     /*!< The number of borders. */
+           )
+{
+  INT i;
+
+  if(currVal < borders[0]){
+    return 0;
+  }
+
+  for(i = 1; i < numBorders; i++){
+    if( currVal >= borders[i-1] && currVal < borders[i]){
+      return i;
+    }
+  }
+
+  if(currVal >= borders[numBorders-1]){
+    return numBorders;
+  }
+
+  return 0;  /* We never get here, it's just to avoid compiler warnings.*/
+}
+
+/**************************************************************************/
+/*!
+  \brief     Makes a clever decision based on the quota vector.
+
+
+  \return     decision on which invf mode to use
+
+*/
+/**************************************************************************/
+static INVF_MODE
+decisionAlgorithm(const DETECTOR_PARAMETERS *detectorParams,     /*!< Struct with the detector parameters. */
+                  DETECTOR_VALUES *detectorValues,               /*!< Struct with the detector values. */
+                  INT transientFlag,                             /*!< Flag indicating if there is a transient present.*/
+                  INT* prevRegionSbr,                            /*!< The previous region in which the Sbr value was. */
+                  INT* prevRegionOrig                            /*!< The previous region in which the Orig value was. */
+                  )
+{
+  INT invFiltLevel, regionSbr, regionOrig, regionNrg;
+
+  /*
+   Current thresholds.
+   */
+  const FIXP_DBL *quantStepsSbr  = detectorParams->quantStepsSbr;
+  const FIXP_DBL *quantStepsOrig = detectorParams->quantStepsOrig;
+  const FIXP_DBL *nrgBorders     = detectorParams->nrgBorders;
+  const INT numRegionsSbr     = detectorParams->numRegionsSbr;
+  const INT numRegionsOrig    = detectorParams->numRegionsOrig;
+  const INT numRegionsNrg     = detectorParams->numRegionsNrg;
+
+  FIXP_DBL quantStepsSbrTmp[MAX_NUM_REGIONS];
+  FIXP_DBL quantStepsOrigTmp[MAX_NUM_REGIONS];
+
+  /*
+   Current detector values.
+   */
+  FIXP_DBL origQuotaMeanFilt;
+  FIXP_DBL sbrQuotaMeanFilt;
+  FIXP_DBL nrg;
+
+  /* 0.375 = 3.0 / 8.0; 0.31143075889 = log2(RELAXATION)/64.0; 0.625 = log(16)/64.0; 0.6875 = 44/64.0 */
+  origQuotaMeanFilt = (fMultDiv2(FL2FXCONST_DBL(2.f*0.375f), (FIXP_DBL)(CalcLdData(max(detectorValues->origQuotaMeanFilt,(FIXP_DBL)1)) + FL2FXCONST_DBL(0.31143075889f)))) << 0;  /* scaled by 1/2^9 */
+  sbrQuotaMeanFilt  = (fMultDiv2(FL2FXCONST_DBL(2.f*0.375f), (FIXP_DBL)(CalcLdData(max(detectorValues->sbrQuotaMeanFilt,(FIXP_DBL)1)) + FL2FXCONST_DBL(0.31143075889f)))) << 0;   /* scaled by 1/2^9 */
+  /* If energy is zero then we will get different results for different word lengths. */
+  nrg               = (fMultDiv2(FL2FXCONST_DBL(2.f*0.375f), (FIXP_DBL)(CalcLdData(detectorValues->avgNrg+(FIXP_DBL)1) + FL2FXCONST_DBL(0.0625f) + FL2FXCONST_DBL(0.6875f)))) << 0;     /* scaled by 1/2^8; 2^44 -> qmf energy scale */
+
+  FDKmemcpy(quantStepsSbrTmp,quantStepsSbr,numRegionsSbr*sizeof(FIXP_DBL));
+  FDKmemcpy(quantStepsOrigTmp,quantStepsOrig,numRegionsOrig*sizeof(FIXP_DBL));
+
+  if(*prevRegionSbr < numRegionsSbr)
+    quantStepsSbrTmp[*prevRegionSbr] = quantStepsSbr[*prevRegionSbr] + hysteresis;
+  if(*prevRegionSbr > 0)
+    quantStepsSbrTmp[*prevRegionSbr - 1] = quantStepsSbr[*prevRegionSbr - 1] - hysteresis;
+
+  if(*prevRegionOrig < numRegionsOrig)
+    quantStepsOrigTmp[*prevRegionOrig] = quantStepsOrig[*prevRegionOrig] + hysteresis;
+  if(*prevRegionOrig > 0)
+    quantStepsOrigTmp[*prevRegionOrig - 1] = quantStepsOrig[*prevRegionOrig - 1] - hysteresis;
+
+  regionSbr  = findRegion(sbrQuotaMeanFilt, quantStepsSbrTmp, numRegionsSbr);
+  regionOrig = findRegion(origQuotaMeanFilt, quantStepsOrigTmp, numRegionsOrig);
+  regionNrg  = findRegion(nrg,nrgBorders,numRegionsNrg);
+
+  *prevRegionSbr = regionSbr;
+  *prevRegionOrig = regionOrig;
+
+  /* Use different settings if a transient is present*/
+  invFiltLevel = (transientFlag == 1) ? detectorParams->regionSpaceTransient[regionSbr][regionOrig]
+                                      : detectorParams->regionSpace[regionSbr][regionOrig];
+
+  /* Compensate for low energy.*/
+  invFiltLevel = max(invFiltLevel + detectorParams->EnergyCompFactor[regionNrg],0);
+
+  return (INVF_MODE) (invFiltLevel);
+}
+
+/**************************************************************************/
+/*!
+  \brief     Estiamtion of the inverse filtering level required
+             in the decoder.
+
+   A second order LPC is calculated for every filterbank channel, using
+   the covariance method. THe ratio between the energy of the predicted
+   signal and the energy of the non-predictable signal is calcualted.
+
+  \return    none.
+
+*/
+/**************************************************************************/
+void
+FDKsbrEnc_qmfInverseFilteringDetector(HANDLE_SBR_INV_FILT_EST hInvFilt,  /*!< Handle to the SBR_INV_FILT_EST struct. */
+                            FIXP_DBL **quotaMatrix,            /*!< The matrix holding the tonality values of the original. */
+                            FIXP_DBL *nrgVector,               /*!< The energy vector. */
+                            SCHAR    *indexVector,             /*!< Index vector to obtain the patched data. */
+                            INT startIndex,                    /*!< Start index. */
+                            INT stopIndex,                     /*!< Stop index. */
+                            INT transientFlag,                 /*!< Flag indicating if a transient is present or not.*/
+                            INVF_MODE* infVec                  /*!< Vector holding the inverse filtering levels. */
+                            )
+{
+  INT band;
+
+  /*
+   * Do the inverse filtering level estimation.
+   *****************************************************/
+  for(band = 0 ; band < hInvFilt->noDetectorBands; band++){
+    INT startChannel = hInvFilt->freqBandTableInvFilt[band];
+    INT stopChannel  = hInvFilt->freqBandTableInvFilt[band+1];
+
+
+    calculateDetectorValues( quotaMatrix,
+                             indexVector,
+                             nrgVector,
+                            &hInvFilt->detectorValues[band],
+                             startChannel,
+                             stopChannel,
+                             startIndex,
+                             stopIndex,
+                             hInvFilt->numberOfStrongest);
+
+    infVec[band]= decisionAlgorithm( hInvFilt->detectorParams,
+                                    &hInvFilt->detectorValues[band],
+                                     transientFlag,
+                                    &hInvFilt->prevRegionSbr[band],
+                                    &hInvFilt->prevRegionOrig[band]);
+  }
+
+}
+
+
+/**************************************************************************/
+/*!
+  \brief     Initialize an instance of the inverse filtering level estimator.
+
+
+  \return   errorCode, noError if successful.
+
+*/
+/**************************************************************************/
+INT
+FDKsbrEnc_initInvFiltDetector (HANDLE_SBR_INV_FILT_EST hInvFilt,   /*!< Pointer to a handle to the SBR_INV_FILT_EST struct. */
+                       INT* freqBandTableDetector,          /*!< Frequency band table for the inverse filtering. */
+                       INT numDetectorBands,                /*!< Number of inverse filtering bands. */
+                       UINT useSpeechConfig         /*!< Flag: adapt tuning parameters according to speech*/
+                       )
+{
+  INT i;
+
+  FDKmemclear( hInvFilt,sizeof(SBR_INV_FILT_EST));
+
+  hInvFilt->detectorParams = (useSpeechConfig) ? &detectorParamsAACSpeech
+                                               : &detectorParamsAAC ;
+
+  hInvFilt->noDetectorBandsMax = numDetectorBands;
+
+  /*
+     Memory initialisation
+  */
+  for(i=0;i<hInvFilt->noDetectorBandsMax;i++){
+    FDKmemclear(&hInvFilt->detectorValues[i], sizeof(DETECTOR_VALUES));
+    hInvFilt->prevInvfMode[i]   = INVF_OFF;
+    hInvFilt->prevRegionOrig[i] = 0;
+    hInvFilt->prevRegionSbr[i]  = 0;
+  }
+
+  /*
+  Reset the inverse fltering detector.
+  */
+  FDKsbrEnc_resetInvFiltDetector(hInvFilt,
+                       freqBandTableDetector,
+                       hInvFilt->noDetectorBandsMax);
+
+  return (0);
+}
+
+
+/**************************************************************************/
+/*!
+  \brief     resets sbr inverse filtering structure.
+
+
+
+  \return   errorCode, noError if successful.
+
+*/
+/**************************************************************************/
+INT
+FDKsbrEnc_resetInvFiltDetector(HANDLE_SBR_INV_FILT_EST hInvFilt, /*!< Handle to the SBR_INV_FILT_EST struct. */
+                     INT* freqBandTableDetector,       /*!< Frequency band table for the inverse filtering. */
+                     INT numDetectorBands)             /*!< Number of inverse filtering bands. */
+{
+
+  hInvFilt->numberOfStrongest     = 1;
+  FDKmemcpy(hInvFilt->freqBandTableInvFilt,freqBandTableDetector,(numDetectorBands+1)*sizeof(INT));
+  hInvFilt->noDetectorBands = numDetectorBands;
+
+  return (0);
+}
+
+