Include patched FDK-AAC in the repository

The initial idea was to get the DAB+ patch into upstream, but since
that follows the android source releases, there is no place for a custom
DAB+ patch there.

So instead of having to maintain a patched fdk-aac that has to have the
same .so version as the distribution package on which it is installed,
we prefer having a separate fdk-aac-dab library to avoid collision.

At that point, there's no reason to keep fdk-aac in a separate
repository, as odr-audioenc is the only tool that needs DAB+ encoding
support. Including it here simplifies installation, and makes it
consistent with toolame-dab, also shipped in this repository.

DAB+ decoding support (needed by ODR-SourceCompanion, dablin, etisnoop,
welle.io and others) can be done using upstream FDK-AAC.

1 files changed, 610 insertions, 0 deletions

diff --git a/fdk-aac/libSBRenc/src/invf_est.cpp b/fdk-aac/libSBRenc/src/invf_est.cpp
new file mode 100644
index 0000000..53b47ac
--- /dev/null
+++ b/fdk-aac/libSBRenc/src/invf_est.cpp
@@ -0,0 +1,610 @@
+/* -----------------------------------------------------------------------------
+Software License for The Fraunhofer FDK AAC Codec Library for Android
+
+© Copyright  1995 - 2018 Fraunhofer-Gesellschaft zur Förderung der angewandten
+Forschung e.V. All rights reserved.
+
+ 1.    INTRODUCTION
+The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software
+that implements the MPEG Advanced Audio Coding ("AAC") encoding and decoding
+scheme for digital audio. This FDK AAC Codec software is intended to be used on
+a wide variety of Android devices.
+
+AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient
+general perceptual audio codecs. AAC-ELD is considered the best-performing
+full-bandwidth communications codec by independent studies and is widely
+deployed. AAC has been standardized by ISO and IEC as part of the MPEG
+specifications.
+
+Patent licenses for necessary patent claims for the FDK AAC Codec (including
+those of Fraunhofer) may be obtained through Via Licensing
+(www.vialicensing.com) or through the respective patent owners individually for
+the purpose of encoding or decoding bit streams in products that are compliant
+with the ISO/IEC MPEG audio standards. Please note that most manufacturers of
+Android devices already license these patent claims through Via Licensing or
+directly from the patent owners, and therefore FDK AAC Codec software may
+already be covered under those patent licenses when it is used for those
+licensed purposes only.
+
+Commercially-licensed AAC software libraries, including floating-point versions
+with enhanced sound quality, are also available from Fraunhofer. Users are
+encouraged to check the Fraunhofer website for additional applications
+information and documentation.
+
+2.    COPYRIGHT LICENSE
+
+Redistribution and use in source and binary forms, with or without modification,
+are permitted without payment of copyright license fees provided that you
+satisfy the following conditions:
+
+You must retain the complete text of this software license in redistributions of
+the FDK AAC Codec or your modifications thereto in source code form.
+
+You must retain the complete text of this software license in the documentation
+and/or other materials provided with redistributions of the FDK AAC Codec or
+your modifications thereto in binary form. You must make available free of
+charge copies of the complete source code of the FDK AAC Codec and your
+modifications thereto to recipients of copies in binary form.
+
+The name of Fraunhofer may not be used to endorse or promote products derived
+from this library without prior written permission.
+
+You may not charge copyright license fees for anyone to use, copy or distribute
+the FDK AAC Codec software or your modifications thereto.
+
+Your modified versions of the FDK AAC Codec must carry prominent notices stating
+that you changed the software and the date of any change. For modified versions
+of the FDK AAC Codec, the term "Fraunhofer FDK AAC Codec Library for Android"
+must be replaced by the term "Third-Party Modified Version of the Fraunhofer FDK
+AAC Codec Library for Android."
+
+3.    NO PATENT LICENSE
+
+NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without
+limitation the patents of Fraunhofer, ARE GRANTED BY THIS SOFTWARE LICENSE.
+Fraunhofer provides no warranty of patent non-infringement with respect to this
+software.
+
+You may use this FDK AAC Codec software or modifications thereto only for
+purposes that are authorized by appropriate patent licenses.
+
+4.    DISCLAIMER
+
+This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright
+holders and contributors "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES,
+including but not limited to the implied warranties of merchantability and
+fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary,
+or consequential damages, including but not limited to procurement of substitute
+goods or services; loss of use, data, or profits, or business interruption,
+however caused and on any theory of liability, whether in contract, strict
+liability, or tort (including negligence), arising in any way out of the use of
+this software, even if advised of the possibility of such damage.
+
+5.    CONTACT INFORMATION
+
+Fraunhofer Institute for Integrated Circuits IIS
+Attention: Audio and Multimedia Departments - FDK AAC LL
+Am Wolfsmantel 33
+91058 Erlangen, Germany
+
+www.iis.fraunhofer.de/amm
+amm-info@iis.fraunhofer.de
+----------------------------------------------------------------------------- */
+
+/**************************** SBR encoder library ******************************
+
+   Author(s):
+
+   Description:
+
+*******************************************************************************/
+
+#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 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, detectorParams->quantStepsSbr,
+            numRegionsSbr * sizeof(FIXP_DBL));
+  FDKmemcpy(quantStepsOrigTmp, detectorParams->quantStepsOrig,
+            numRegionsOrig * sizeof(FIXP_DBL));
+
+  if (*prevRegionSbr < numRegionsSbr)
+    quantStepsSbrTmp[*prevRegionSbr] =
+        detectorParams->quantStepsSbr[*prevRegionSbr] + hysteresis;
+  if (*prevRegionSbr > 0)
+    quantStepsSbrTmp[*prevRegionSbr - 1] =
+        detectorParams->quantStepsSbr[*prevRegionSbr - 1] - hysteresis;
+
+  if (*prevRegionOrig < numRegionsOrig)
+    quantStepsOrigTmp[*prevRegionOrig] =
+        detectorParams->quantStepsOrig[*prevRegionOrig] + hysteresis;
+  if (*prevRegionOrig > 0)
+    quantStepsOrigTmp[*prevRegionOrig - 1] =
+        detectorParams->quantStepsOrig[*prevRegionOrig - 1] - hysteresis;
+
+  regionSbr = findRegion(sbrQuotaMeanFilt, quantStepsSbrTmp, numRegionsSbr);
+  regionOrig = findRegion(origQuotaMeanFilt, quantStepsOrigTmp, numRegionsOrig);
+  regionNrg = findRegion(nrg, detectorParams->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);
+}