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

Software License for The Fraunhofer FDK AAC Codec Library for Android

© Copyright  1995 - 2018 Fraunhofer-Gesellschaft zur Förderung der angewandten

Forschung e.V. All rights reserved.

 1.    INTRODUCTION

The Fraunhofer FDK AAC Codec Library for Android ("FDK AAC Codec") is software

that implements the MPEG Advanced Audio Coding ("AAC") encoding and decoding

scheme for digital audio. This FDK AAC Codec software is intended to be used on

a wide variety of Android devices.

AAC's HE-AAC and HE-AAC v2 versions are regarded as today's most efficient

general perceptual audio codecs. AAC-ELD is considered the best-performing

full-bandwidth communications codec by independent studies and is widely

deployed. AAC has been standardized by ISO and IEC as part of the MPEG

specifications.

Patent licenses for necessary patent claims for the FDK AAC Codec (including

those of Fraunhofer) may be obtained through Via Licensing

(www.vialicensing.com) or through the respective patent owners individually for

the purpose of encoding or decoding bit streams in products that are compliant

with the ISO/IEC MPEG audio standards. Please note that most manufacturers of

Android devices already license these patent claims through Via Licensing or

directly from the patent owners, and therefore FDK AAC Codec software may

already be covered under those patent licenses when it is used for those

licensed purposes only.

Commercially-licensed AAC software libraries, including floating-point versions

with enhanced sound quality, are also available from Fraunhofer. Users are

encouraged to check the Fraunhofer website for additional applications

information and documentation.

2.    COPYRIGHT LICENSE

Redistribution and use in source and binary forms, with or without modification,

are permitted without payment of copyright license fees provided that you

satisfy the following conditions:

You must retain the complete text of this software license in redistributions of

the FDK AAC Codec or your modifications thereto in source code form.

You must retain the complete text of this software license in the documentation

and/or other materials provided with redistributions of the FDK AAC Codec or

your modifications thereto in binary form. You must make available free of

charge copies of the complete source code of the FDK AAC Codec and your

modifications thereto to recipients of copies in binary form.

The name of Fraunhofer may not be used to endorse or promote products derived

from this library without prior written permission.

You may not charge copyright license fees for anyone to use, copy or distribute

the FDK AAC Codec software or your modifications thereto.

Your modified versions of the FDK AAC Codec must carry prominent notices stating

that you changed the software and the date of any change. For modified versions

of the FDK AAC Codec, the term "Fraunhofer FDK AAC Codec Library for Android"

must be replaced by the term "Third-Party Modified Version of the Fraunhofer FDK

AAC Codec Library for Android."

3.    NO PATENT LICENSE

NO EXPRESS OR IMPLIED LICENSES TO ANY PATENT CLAIMS, including without

limitation the patents of Fraunhofer, ARE GRANTED BY THIS SOFTWARE LICENSE.

Fraunhofer provides no warranty of patent non-infringement with respect to this

software.

You may use this FDK AAC Codec software or modifications thereto only for

purposes that are authorized by appropriate patent licenses.

4.    DISCLAIMER

This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright

holders and contributors "AS IS" and WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES,

including but not limited to the implied warranties of merchantability and

fitness for a particular purpose. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR

CONTRIBUTORS BE LIABLE for any direct, indirect, incidental, special, exemplary,

or consequential damages, including but not limited to procurement of substitute

goods or services; loss of use, data, or profits, or business interruption,

however caused and on any theory of liability, whether in contract, strict

liability, or tort (including negligence), arising in any way out of the use of

this software, even if advised of the possibility of such damage.

5.    CONTACT INFORMATION

Fraunhofer Institute for Integrated Circuits IIS

Attention: Audio and Multimedia Departments - FDK AAC LL

Am Wolfsmantel 33

91058 Erlangen, Germany

www.iis.fraunhofer.de/amm

amm-info@iis.fraunhofer.de

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

/**************************** AAC encoder library ******************************

   Author(s):   Alex Groeschel, Tobias Chalupka

   Description: Temporal noise shaping

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

#include "aacenc_tns.h"

#include "psy_const.h"

#include "psy_configuration.h"

#include "tns_func.h"

#include "aacEnc_rom.h"

#include "aacenc_tns.h"

#include "FDK_lpc.h"

#define FILTER_DIRECTION 0 /* 0 = up, 1 = down */

static const FIXP_DBL acfWindowLong[12 + 3 + 1] = {

    0x7fffffff, 0x7fb80000, 0x7ee00000, 0x7d780000, 0x7b800000, 0x78f80000,

    0x75e00000, 0x72380000, 0x6e000000, 0x69380000, 0x63e00000, 0x5df80000,

    0x57800000, 0x50780000, 0x48e00000, 0x40b80000};

static const FIXP_DBL acfWindowShort[4 + 3 + 1] = {

    0x7fffffff, 0x7e000000, 0x78000000, 0x6e000000,

    0x60000000, 0x4e000000, 0x38000000, 0x1e000000};

typedef struct {

  INT bitRateFrom[2];                  /* noneSbr=0, useSbr=1 */

  INT bitRateTo[2];                    /* noneSbr=0, useSbr=1 */

  TNS_PARAMETER_TABULATED paramTab[2]; /* mono=0, stereo=1 */

} TNS_INFO_TAB;

#define TNS_TIMERES_SCALE (1)

#define FL2_TIMERES_FIX(a) (FL2FXCONST_DBL(a / (float)(1 << TNS_TIMERES_SCALE)))

static const TNS_INFO_TAB tnsInfoTab[] = {

    {{16000, 13500},

     {32000, 28000},

     {{{1, 1},

       {1437, 1500},

       {1400, 600},

       {12, 12},

       {FILTER_DIRECTION, FILTER_DIRECTION},

       {3, 1},

       {FL2_TIMERES_FIX(0.4f), FL2_TIMERES_FIX(1.2f)},

       1},

      {{1, 1},

       {1437, 1500},

       {1400, 600},

       {12, 12},

       {FILTER_DIRECTION, FILTER_DIRECTION},

       {3, 1},

       {FL2_TIMERES_FIX(0.4f), FL2_TIMERES_FIX(1.2f)},

       1}}},

    {{32001, 28001},

     {60000, 52000},

     {{{1, 1},

       {1437, 1500},

       {1400, 600},

       {12, 10},

       {FILTER_DIRECTION, FILTER_DIRECTION},

       {3, 1},

       {FL2_TIMERES_FIX(0.4f), FL2_TIMERES_FIX(1.0f)},

       1},

      {{1, 1},

       {1437, 1500},

       {1400, 600},

       {12, 10},

       {FILTER_DIRECTION, FILTER_DIRECTION},

       {3, 1},

       {FL2_TIMERES_FIX(0.4f), FL2_TIMERES_FIX(1.0f)},

       1}}},

    {{60001, 52001},

     {384000, 384000},

     {{{1, 1},

       {1437, 1500},

       {1400, 600},

       {12, 8},

       {FILTER_DIRECTION, FILTER_DIRECTION},

       {3, 1},

       {FL2_TIMERES_FIX(0.4f), FL2_TIMERES_FIX(1.0f)},

       1},

      {{1, 1},

       {1437, 1500},

       {1400, 600},

       {12, 8},

       {FILTER_DIRECTION, FILTER_DIRECTION},

       {3, 1},

       {FL2_TIMERES_FIX(0.4f), FL2_TIMERES_FIX(1.0f)},

       1}}}};

typedef struct {

  INT samplingRate;

  SCHAR maxBands[2]; /* long=0; short=1 */

} TNS_MAX_TAB_ENTRY;

static const TNS_MAX_TAB_ENTRY tnsMaxBandsTab1024[] = {

    {96000, {31, 9}},  {88200, {31, 9}},  {64000, {34, 10}}, {48000, {40, 14}},

    {44100, {42, 14}}, {32000, {51, 14}}, {24000, {46, 14}}, {22050, {46, 14}},

    {16000, {42, 14}}, {12000, {42, 14}}, {11025, {42, 14}}, {8000, {39, 14}}};

static const TNS_MAX_TAB_ENTRY tnsMaxBandsTab120[] = {

    {48000, {12, -1}}, /* 48000 */

    {44100, {12, -1}}, /* 44100 */

    {32000, {15, -1}}, /* 32000 */

    {24000, {15, -1}}, /* 24000 */

    {22050, {15, -1}}  /* 22050 */

};

static const TNS_MAX_TAB_ENTRY tnsMaxBandsTab128[] = {

    {48000, {12, -1}}, /* 48000 */

    {44100, {12, -1}}, /* 44100 */

    {32000, {15, -1}}, /* 32000 */

    {24000, {15, -1}}, /* 24000 */

    {22050, {15, -1}}  /* 22050 */

};

static const TNS_MAX_TAB_ENTRY tnsMaxBandsTab240[] = {

    {96000, {22, -1}}, /* 96000 */

    {48000, {22, -1}}, /* 48000 */

    {44100, {22, -1}}, /* 44100 */

    {32000, {21, -1}}, /* 32000 */

    {24000, {21, -1}}, /* 24000 */

    {22050, {21, -1}}  /* 22050 */

};

static const TNS_MAX_TAB_ENTRY tnsMaxBandsTab256[] = {

    {96000, {25, -1}}, /* 96000 */

    {48000, {25, -1}}, /* 48000 */

    {44100, {25, -1}}, /* 44100 */

    {32000, {24, -1}}, /* 32000 */

    {24000, {24, -1}}, /* 24000 */

    {22050, {24, -1}}  /* 22050 */

};

static const TNS_MAX_TAB_ENTRY tnsMaxBandsTab480[] = {{48000, {31, -1}},

                                                      {44100, {32, -1}},

                                                      {32000, {37, -1}},

                                                      {24000, {30, -1}},

                                                      {22050, {30, -1}}};

static const TNS_MAX_TAB_ENTRY tnsMaxBandsTab512[] = {{48000, {31, -1}},

                                                      {44100, {32, -1}},

                                                      {32000, {37, -1}},

                                                      {24000, {31, -1}},

                                                      {22050, {31, -1}}};

static void FDKaacEnc_Parcor2Index(const FIXP_LPC *parcor, INT *RESTRICT index,

                                   const INT order, const INT bitsPerCoeff);

static void FDKaacEnc_Index2Parcor(const INT *index, FIXP_LPC *RESTRICT parcor,

                                   const INT order, const INT bitsPerCoeff);

static void FDKaacEnc_CalcGaussWindow(FIXP_DBL *win, const int winSize,

                                      const INT samplingRate,

                                      const INT transformResolution,

                                      const FIXP_DBL timeResolution,

                                      const INT timeResolution_e);

static const TNS_PARAMETER_TABULATED *FDKaacEnc_GetTnsParam(const INT bitRate,

                                                            const INT channels,

                                                            const INT sbrLd) {

  int i;

  const TNS_PARAMETER_TABULATED *tnsConfigTab = NULL;

  for (i = 0; i < (int)(sizeof(tnsInfoTab) / sizeof(TNS_INFO_TAB)); i++) {

    if ((bitRate >= tnsInfoTab[i].bitRateFrom[sbrLd ? 1 : 0]) &&

        bitRate <= tnsInfoTab[i].bitRateTo[sbrLd ? 1 : 0]) {

      tnsConfigTab = &tnsInfoTab[i].paramTab[(channels == 1) ? 0 : 1];

    }

  }

  return tnsConfigTab;

}

static INT getTnsMaxBands(const INT sampleRate, const INT granuleLength,

                          const INT isShortBlock) {

  int i;

  INT numBands = -1;

  const TNS_MAX_TAB_ENTRY *pMaxBandsTab = NULL;

  int maxBandsTabSize = 0;

  switch (granuleLength) {

    case 960:

    case 1024:

      pMaxBandsTab = tnsMaxBandsTab1024;

      maxBandsTabSize = sizeof(tnsMaxBandsTab1024) / sizeof(TNS_MAX_TAB_ENTRY);

      break;

    case 120:

      pMaxBandsTab = tnsMaxBandsTab120;

      maxBandsTabSize = sizeof(tnsMaxBandsTab120) / sizeof(TNS_MAX_TAB_ENTRY);

      break;

    case 128:

      pMaxBandsTab = tnsMaxBandsTab128;

      maxBandsTabSize = sizeof(tnsMaxBandsTab128) / sizeof(TNS_MAX_TAB_ENTRY);

      break;

    case 240:

      pMaxBandsTab = tnsMaxBandsTab240;

      maxBandsTabSize = sizeof(tnsMaxBandsTab240) / sizeof(TNS_MAX_TAB_ENTRY);

      break;

    case 256:

      pMaxBandsTab = tnsMaxBandsTab256;

      maxBandsTabSize = sizeof(tnsMaxBandsTab256) / sizeof(TNS_MAX_TAB_ENTRY);

      break;

    case 480:

      pMaxBandsTab = tnsMaxBandsTab480;

      maxBandsTabSize = sizeof(tnsMaxBandsTab480) / sizeof(TNS_MAX_TAB_ENTRY);

      break;

    case 512:

      pMaxBandsTab = tnsMaxBandsTab512;

      maxBandsTabSize = sizeof(tnsMaxBandsTab512) / sizeof(TNS_MAX_TAB_ENTRY);

      break;

    default:

      numBands = -1;

  }

  if (pMaxBandsTab != NULL) {

    for (i = 0; i < maxBandsTabSize; i++) {

      numBands = pMaxBandsTab[i].maxBands[(!isShortBlock) ? 0 : 1];

      if (sampleRate >= pMaxBandsTab[i].samplingRate) {

        break;

      }

    }

  }

  return numBands;

}

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

/*!

  \brief     FDKaacEnc_FreqToBandWidthRounding

  Returns index of nearest band border

  \param frequency

  \param sampling frequency

  \param total number of bands

  \param pointer to table of band borders

  \return band border

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

INT FDKaacEnc_FreqToBandWidthRounding(const INT freq, const INT fs,

                                      const INT numOfBands,

                                      const INT *bandStartOffset) {

  INT lineNumber, band;

  /*  assert(freq >= 0);  */

  lineNumber = (freq * bandStartOffset[numOfBands] * 4 / fs + 1) / 2;

  /* freq > fs/2 */

  if (lineNumber >= bandStartOffset[numOfBands]) return numOfBands;

  /* find band the line number lies in */

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

    if (bandStartOffset[band + 1] > lineNumber) break;

  }

  /* round to nearest band border */

  if (lineNumber - bandStartOffset[band] >

      bandStartOffset[band + 1] - lineNumber) {

    band++;

  }

  return (band);

}

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

    functionname: FDKaacEnc_InitTnsConfiguration

    description:  fill TNS_CONFIG structure with sensible content

    returns:

    input:        bitrate, samplerate, number of channels,

                  blocktype (long or short),

                  TNS Config struct (modified),

                  psy config struct,

                  tns active flag

    output:

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

AAC_ENCODER_ERROR FDKaacEnc_InitTnsConfiguration(

    INT bitRate, INT sampleRate, INT channels, INT blockType, INT granuleLength,

    INT isLowDelay, INT ldSbrPresent, TNS_CONFIG *tC, PSY_CONFIGURATION *pC,

    INT active, INT useTnsPeak) {

  int i;

  // float acfTimeRes   = (blockType == SHORT_WINDOW) ? 0.125f : 0.046875f;

  if (channels <= 0) return (AAC_ENCODER_ERROR)1;

  tC->isLowDelay = isLowDelay;

  /* initialize TNS filter flag, order, and coefficient resolution (in bits per

   * coeff) */

  tC->tnsActive = (active) ? TRUE : FALSE;

  tC->maxOrder = (blockType == SHORT_WINDOW) ? 5 : 12; /* maximum: 7, 20 */

  if (bitRate < 16000) tC->maxOrder -= 2;

  tC->coefRes = (blockType == SHORT_WINDOW) ? 3 : 4;

  /* LPC stop line: highest MDCT line to be coded, but do not go beyond

   * TNS_MAX_BANDS! */

  tC->lpcStopBand = getTnsMaxBands(sampleRate, granuleLength,

                                   (blockType == SHORT_WINDOW) ? 1 : 0);

  if (tC->lpcStopBand < 0) {

    return (AAC_ENCODER_ERROR)1;

  }

  tC->lpcStopBand = fMin(tC->lpcStopBand, pC->sfbActive);

  tC->lpcStopLine = pC->sfbOffset[tC->lpcStopBand];

  switch (granuleLength) {

    case 960:

    case 1024:

      /* TNS start line: skip lower MDCT lines to prevent artifacts due to

       * filter mismatch */

      if (blockType == SHORT_WINDOW) {

        tC->lpcStartBand[LOFILT] = 0;

      } else {

        tC->lpcStartBand[LOFILT] =

            (sampleRate < 9391) ? 2 : ((sampleRate < 18783) ? 4 : 8);

      }

      tC->lpcStartLine[LOFILT] = pC->sfbOffset[tC->lpcStartBand[LOFILT]];

      i = tC->lpcStopBand;

      while (pC->sfbOffset[i] >

             (tC->lpcStartLine[LOFILT] +

              (tC->lpcStopLine - tC->lpcStartLine[LOFILT]) / 4))

        i--;

      tC->lpcStartBand[HIFILT] = i;

      tC->lpcStartLine[HIFILT] = pC->sfbOffset[i];

      tC->confTab.threshOn[HIFILT] = 1437;

      tC->confTab.threshOn[LOFILT] = 1500;

      tC->confTab.tnsLimitOrder[HIFILT] = tC->maxOrder;

      tC->confTab.tnsLimitOrder[LOFILT] = fMax(0, tC->maxOrder - 7);

      tC->confTab.tnsFilterDirection[HIFILT] = FILTER_DIRECTION;

      tC->confTab.tnsFilterDirection[LOFILT] = FILTER_DIRECTION;

      tC->confTab.acfSplit[HIFILT] =

          -1; /* signal Merged4to2QuartersAutoCorrelation in

                 FDKaacEnc_MergedAutoCorrelation*/

      tC->confTab.acfSplit[LOFILT] =

          -1; /* signal Merged4to2QuartersAutoCorrelation in

                 FDKaacEnc_MergedAutoCorrelation */

      tC->confTab.filterEnabled[HIFILT] = 1;

      tC->confTab.filterEnabled[LOFILT] = 1;

      tC->confTab.seperateFiltersAllowed = 1;

      /* compute autocorrelation window based on maximum filter order for given

       * block type */

      /* for (i = 0; i <= tC->maxOrder + 3; i++) {

           float acfWinTemp = acfTimeRes * i;

           acfWindow[i] = FL2FXCONST_DBL(1.0f - acfWinTemp * acfWinTemp);

         }

      */

      if (blockType == SHORT_WINDOW) {

        FDKmemcpy(tC->acfWindow[HIFILT], acfWindowShort,

                  fMin((LONG)sizeof(acfWindowShort),

                       (LONG)sizeof(tC->acfWindow[HIFILT])));

        FDKmemcpy(tC->acfWindow[LOFILT], acfWindowShort,

                  fMin((LONG)sizeof(acfWindowShort),

                       (LONG)sizeof(tC->acfWindow[HIFILT])));

      } else {

        FDKmemcpy(tC->acfWindow[HIFILT], acfWindowLong,

                  fMin((LONG)sizeof(acfWindowLong),

                       (LONG)sizeof(tC->acfWindow[HIFILT])));

        FDKmemcpy(tC->acfWindow[LOFILT], acfWindowLong,

                  fMin((LONG)sizeof(acfWindowLong),

                       (LONG)sizeof(tC->acfWindow[HIFILT])));

      }

      break;

    case 480:

    case 512: {

      const TNS_PARAMETER_TABULATED *pCfg =

          FDKaacEnc_GetTnsParam(bitRate, channels, ldSbrPresent);

      if (pCfg != NULL) {

        FDKmemcpy(&(tC->confTab), pCfg, sizeof(tC->confTab));

        tC->lpcStartBand[HIFILT] = FDKaacEnc_FreqToBandWidthRounding(

            pCfg->filterStartFreq[HIFILT], sampleRate, pC->sfbCnt,

            pC->sfbOffset);

        tC->lpcStartLine[HIFILT] = pC->sfbOffset[tC->lpcStartBand[HIFILT]];

        tC->lpcStartBand[LOFILT] = FDKaacEnc_FreqToBandWidthRounding(

            pCfg->filterStartFreq[LOFILT], sampleRate, pC->sfbCnt,

            pC->sfbOffset);

        tC->lpcStartLine[LOFILT] = pC->sfbOffset[tC->lpcStartBand[LOFILT]];

        FDKaacEnc_CalcGaussWindow(

            tC->acfWindow[HIFILT], tC->maxOrder + 1, sampleRate, granuleLength,

            pCfg->tnsTimeResolution[HIFILT], TNS_TIMERES_SCALE);

        FDKaacEnc_CalcGaussWindow(

            tC->acfWindow[LOFILT], tC->maxOrder + 1, sampleRate, granuleLength,

            pCfg->tnsTimeResolution[LOFILT], TNS_TIMERES_SCALE);

      } else {

        tC->tnsActive =

            FALSE; /* no configuration available, disable tns tool */

      }

    } break;

    default:

      tC->tnsActive = FALSE; /* no configuration available, disable tns tool */

  }

  return AAC_ENC_OK;

}

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

/*!

  \brief     FDKaacEnc_ScaleUpSpectrum

  Scales up spectrum lines in a given frequency section

  \param scaled spectrum

  \param original spectrum

  \param frequency line to start scaling

  \param frequency line to enc scaling

  \return scale factor

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

static inline INT FDKaacEnc_ScaleUpSpectrum(FIXP_DBL *dest, const FIXP_DBL *src,

                                            const INT startLine,

                                            const INT stopLine) {

  INT i, scale;

  FIXP_DBL maxVal = FL2FXCONST_DBL(0.f);

  /* Get highest value in given spectrum */

  for (i = startLine; i < stopLine; i++) {

    maxVal = fixMax(maxVal, fixp_abs(src[i]));

  }

  scale = CountLeadingBits(maxVal);

  /* Scale spectrum according to highest value */

  for (i = startLine; i < stopLine; i++) {

    dest[i] = src[i] << scale;

  }

  return scale;

}

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

/*!

  \brief     FDKaacEnc_CalcAutoCorrValue

  Calculate autocorellation value for one lag

  \param pointer to spectrum

  \param start line

  \param stop line

  \param lag to be calculated

  \param scaling of the lag

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

static inline FIXP_DBL FDKaacEnc_CalcAutoCorrValue(const FIXP_DBL *spectrum,

                                                   const INT startLine,

                                                   const INT stopLine,

                                                   const INT lag,

                                                   const INT scale) {

  int i;

  FIXP_DBL result = FL2FXCONST_DBL(0.f);

  /* This versions allows to save memory accesses, when computing pow2 */

  /* It is of interest for ARM, XTENSA without parallel memory access  */

  if (lag == 0) {

    for (i = startLine; i < stopLine; i++) {

      result += (fPow2(spectrum[i]) >> scale);

    }

  } else {

    for (i = startLine; i < (stopLine - lag); i++) {

      result += (fMult(spectrum[i], spectrum[i + lag]) >> scale);

    }

  }

  return result;

}

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

/*!

  \brief     FDKaacEnc_AutoCorrNormFac

  Autocorrelation function for 1st and 2nd half of the spectrum

  \param pointer to spectrum

  \param pointer to autocorrelation window

  \param filter start line

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

static inline FIXP_DBL FDKaacEnc_AutoCorrNormFac(const FIXP_DBL value,

                                                 const INT scale, INT *sc) {

#define HLM_MIN_NRG 0.0000000037252902984619140625f /* 2^-28 */

#define MAX_INV_NRGFAC (1.f / HLM_MIN_NRG)

  FIXP_DBL retValue;

  FIXP_DBL A, B;

  if (scale >= 0) {

    A = value;

    B = FL2FXCONST_DBL(HLM_MIN_NRG) >> fixMin(DFRACT_BITS - 1, scale);

  } else {

    A = value >> fixMin(DFRACT_BITS - 1, (-scale));

    B = FL2FXCONST_DBL(HLM_MIN_NRG);

  }

  if (A > B) {

    int shift = 0;

    FIXP_DBL tmp = invSqrtNorm2(value, &shift);

    retValue = fMult(tmp, tmp);

    *sc += (2 * shift);

  } else {

    /* MAX_INV_NRGFAC*FDKpow(2,-28) = 1/2^-28 * 2^-28 = 1.0 */

    retValue =

        /*FL2FXCONST_DBL(MAX_INV_NRGFAC*FDKpow(2,-28))*/ (FIXP_DBL)MAXVAL_DBL;

    *sc += scale + 28;

  }

  return retValue;

}

static void FDKaacEnc_MergedAutoCorrelation(

    const FIXP_DBL *spectrum, const INT isLowDelay,

    const FIXP_DBL acfWindow[MAX_NUM_OF_FILTERS][TNS_MAX_ORDER + 3 + 1],

    const INT lpcStartLine[MAX_NUM_OF_FILTERS], const INT lpcStopLine,

    const INT maxOrder, const INT acfSplit[MAX_NUM_OF_FILTERS], FIXP_DBL *_rxx1,

    FIXP_DBL *_rxx2) {

  int i, idx0, idx1, idx2, idx3, idx4, lag;

  FIXP_DBL rxx1_0, rxx2_0, rxx3_0, rxx4_0;

  /* buffer for temporal spectrum */

  C_ALLOC_SCRATCH_START(pSpectrum, FIXP_DBL, (1024))

  /* MDCT line indices separating the 1st, 2nd, 3rd, and 4th analysis quarters

   */

  if ((acfSplit[LOFILT] == -1) || (acfSplit[HIFILT] == -1)) {

    /* autocorrelation function for 1st, 2nd, 3rd, and 4th quarter of the

     * spectrum */

    idx0 = lpcStartLine[LOFILT];

    i = lpcStopLine - lpcStartLine[LOFILT];

    idx1 = idx0 + i / 4;

    idx2 = idx0 + i / 2;

    idx3 = idx0 + i * 3 / 4;

    idx4 = lpcStopLine;

  } else {

    FDK_ASSERT(acfSplit[LOFILT] == 1);

    FDK_ASSERT(acfSplit[HIFILT] == 3);

    i = (lpcStopLine - lpcStartLine[HIFILT]) / 3;

    idx0 = lpcStartLine[LOFILT];

    idx1 = lpcStartLine[HIFILT];

    idx2 = idx1 + i;

    idx3 = idx2 + i;

    idx4 = lpcStopLine;

  }

  /* copy spectrum to temporal buffer and scale up as much as possible */

  INT sc1 = FDKaacEnc_ScaleUpSpectrum(pSpectrum, spectrum, idx0, idx1);

  INT sc2 = FDKaacEnc_ScaleUpSpectrum(pSpectrum, spectrum, idx1, idx2);

  INT sc3 = FDKaacEnc_ScaleUpSpectrum(pSpectrum, spectrum, idx2, idx3);

  INT sc4 = FDKaacEnc_ScaleUpSpectrum(pSpectrum, spectrum, idx3, idx4);

  /* get scaling values for summation */

  INT nsc1, nsc2, nsc3, nsc4;

  for (nsc1 = 1; (1 << nsc1) < (idx1 - idx0); nsc1++)

    ;

  for (nsc2 = 1; (1 << nsc2) < (idx2 - idx1); nsc2++)

    ;

  for (nsc3 = 1; (1 << nsc3) < (idx3 - idx2); nsc3++)

    ;

  for (nsc4 = 1; (1 << nsc4) < (idx4 - idx3); nsc4++)

    ;

  /* compute autocorrelation value at lag zero, i. e. energy, for each quarter

   */

  rxx1_0 = FDKaacEnc_CalcAutoCorrValue(pSpectrum, idx0, idx1, 0, nsc1);

  rxx2_0 = FDKaacEnc_CalcAutoCorrValue(pSpectrum, idx1, idx2, 0, nsc2);

  rxx3_0 = FDKaacEnc_CalcAutoCorrValue(pSpectrum, idx2, idx3, 0, nsc3);

  rxx4_0 = FDKaacEnc_CalcAutoCorrValue(pSpectrum, idx3, idx4, 0, nsc4);

  /* compute energy normalization factors, i. e. 1/energy (saves some divisions)

   */

  if (rxx1_0 != FL2FXCONST_DBL(0.f)) {

    INT sc_fac1 = -1;

    FIXP_DBL fac1 =

        FDKaacEnc_AutoCorrNormFac(rxx1_0, ((-2 * sc1) + nsc1), &sc_fac1);

    _rxx1[0] = scaleValue(fMult(rxx1_0, fac1), sc_fac1);

    if (isLowDelay) {

      for (lag = 1; lag <= maxOrder; lag++) {

        /* compute energy-normalized and windowed autocorrelation values at this

         * lag */

        FIXP_DBL x1 =

            FDKaacEnc_CalcAutoCorrValue(pSpectrum, idx0, idx1, lag, nsc1);

        _rxx1[lag] =

            fMult(scaleValue(fMult(x1, fac1), sc_fac1), acfWindow[LOFILT][lag]);

      }

    } else {

      for (lag = 1; lag <= maxOrder; lag++) {

        if ((3 * lag) <= maxOrder + 3) {

          FIXP_DBL x1 =

              FDKaacEnc_CalcAutoCorrValue(pSpectrum, idx0, idx1, lag, nsc1);

          _rxx1[lag] = fMult(scaleValue(fMult(x1, fac1), sc_fac1),

                             acfWindow[LOFILT][3 * lag]);

        }

      }

    }

  }

  /* auto corr over upper 3/4 of spectrum */

  if (!((rxx2_0 == FL2FXCONST_DBL(0.f)) && (rxx3_0 == FL2FXCONST_DBL(0.f)) &&

        (rxx4_0 == FL2FXCONST_DBL(0.f)))) {

    FIXP_DBL fac2, fac3, fac4;

    fac2 = fac3 = fac4 = FL2FXCONST_DBL(0.f);

    INT sc_fac2, sc_fac3, sc_fac4;

    sc_fac2 = sc_fac3 = sc_fac4 = 0;

    if (rxx2_0 != FL2FXCONST_DBL(0.f)) {

      fac2 = FDKaacEnc_AutoCorrNormFac(rxx2_0, ((-2 * sc2) + nsc2), &sc_fac2);

      sc_fac2 -= 2;

    }

    if (rxx3_0 != FL2FXCONST_DBL(0.f)) {

      fac3 = FDKaacEnc_AutoCorrNormFac(rxx3_0, ((-2 * sc3) + nsc3), &sc_fac3);

      sc_fac3 -= 2;

    }

    if (rxx4_0 != FL2FXCONST_DBL(0.f)) {

      fac4 = FDKaacEnc_AutoCorrNormFac(rxx4_0, ((-2 * sc4) + nsc4), &sc_fac4);

      sc_fac4 -= 2;

    }

    _rxx2[0] = scaleValue(fMult(rxx2_0, fac2), sc_fac2) +

               scaleValue(fMult(rxx3_0, fac3), sc_fac3) +

               scaleValue(fMult(rxx4_0, fac4), sc_fac4);

    for (lag = 1; lag <= maxOrder; lag++) {

      /* merge quarters 2, 3, 4 into one autocorrelation; quarter 1 stays

       * separate */

      FIXP_DBL x2 = scaleValue(fMult(FDKaacEnc_CalcAutoCorrValue(

                                         pSpectrum, idx1, idx2, lag, nsc2),

                                     fac2),

                               sc_fac2) +

                    scaleValue(fMult(FDKaacEnc_CalcAutoCorrValue(

                                         pSpectrum, idx2, idx3, lag, nsc3),

                                     fac3),

                               sc_fac3) +

                    scaleValue(fMult(FDKaacEnc_CalcAutoCorrValue(

                                         pSpectrum, idx3, idx4, lag, nsc4),

                                     fac4),

                               sc_fac4);

      _rxx2[lag] = fMult(x2, acfWindow[HIFILT][lag]);

    }

  }

  C_ALLOC_SCRATCH_END(pSpectrum, FIXP_DBL, (1024))

}

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

    functionname: FDKaacEnc_TnsDetect

    description:  do decision, if TNS shall be used or not

    returns:

    input:        tns data structure (modified),

                  tns config structure,

                  scalefactor size and table,

                  spectrum,

                  subblock num, blocktype,

                  sfb-wise energy.

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

INT FDKaacEnc_TnsDetect(TNS_DATA *tnsData, const TNS_CONFIG *tC,

                        TNS_INFO *tnsInfo, INT sfbCnt, const FIXP_DBL *spectrum,

                        INT subBlockNumber, INT blockType) {

  /* autocorrelation function for 1st, 2nd, 3rd, and 4th quarter of the

   * spectrum. */

  FIXP_DBL rxx1[TNS_MAX_ORDER + 1]; /* higher part */

  FIXP_DBL rxx2[TNS_MAX_ORDER + 1]; /* lower part */

  FIXP_LPC parcor_tmp[TNS_MAX_ORDER];

  int i;

  FDKmemclear(rxx1, sizeof(rxx1));

  FDKmemclear(rxx2, sizeof(rxx2));

  TNS_SUBBLOCK_INFO *tsbi =

      (blockType == SHORT_WINDOW)

          ? &tnsData->dataRaw.Short.subBlockInfo[subBlockNumber]

          : &tnsData->dataRaw.Long.subBlockInfo;

  tnsData->filtersMerged = FALSE;

  tsbi->tnsActive[HIFILT] = FALSE;

  tsbi->predictionGain[HIFILT] = 1000;

  tsbi->tnsActive[LOFILT] = FALSE;

  tsbi->predictionGain[LOFILT] = 1000;

  tnsInfo->numOfFilters[subBlockNumber] = 0;

  tnsInfo->coefRes[subBlockNumber] = tC->coefRes;

  for (i = 0; i < tC->maxOrder; i++) {

    tnsInfo->coef[subBlockNumber][HIFILT][i] =

        tnsInfo->coef[subBlockNumber][LOFILT][i] = 0;

  }

  tnsInfo->length[subBlockNumber][HIFILT] =

      tnsInfo->length[subBlockNumber][LOFILT] = 0;

  tnsInfo->order[subBlockNumber][HIFILT] =

      tnsInfo->order[subBlockNumber][LOFILT] = 0;

  if ((tC->tnsActive) && (tC->maxOrder > 0)) {

    int sumSqrCoef;

    FDKaacEnc_MergedAutoCorrelation(

        spectrum, tC->isLowDelay, tC->acfWindow, tC->lpcStartLine,

        tC->lpcStopLine, tC->maxOrder, tC->confTab.acfSplit, rxx1, rxx2);

    /* compute higher TNS filter coefficients in lattice form (ParCor) with

     * LeRoux-Gueguen/Schur algorithm */

    {

      FIXP_DBL predictionGain_m;

      INT predictionGain_e;

      CLpc_AutoToParcor(rxx2, 0, parcor_tmp, tC->confTab.tnsLimitOrder[HIFILT],

                        &predictionGain_m, &predictionGain_e);

      tsbi->predictionGain[HIFILT] =

          (INT)fMultNorm(predictionGain_m, predictionGain_e, 1000, 31, 31);

    }

    /* non-linear quantization of TNS lattice coefficients with given resolution

     */

    FDKaacEnc_Parcor2Index(parcor_tmp, tnsInfo->coef[subBlockNumber][HIFILT],

                           tC->confTab.tnsLimitOrder[HIFILT], tC->coefRes);

    /* reduce filter order by truncating trailing zeros, compute sum(abs(coefs))

     */

    for (i = tC->confTab.tnsLimitOrder[HIFILT] - 1; i >= 0; i--) {

      if (tnsInfo->coef[subBlockNumber][HIFILT][i] != 0) {

        break;

      }

    }

    tnsInfo->order[subBlockNumber][HIFILT] = i + 1;

    sumSqrCoef = 0;

    for (; i >= 0; i--) {

      sumSqrCoef += tnsInfo->coef[subBlockNumber][HIFILT][i] *

                    tnsInfo->coef[subBlockNumber][HIFILT][i];

    }

    tnsInfo->direction[subBlockNumber][HIFILT] =

        tC->confTab.tnsFilterDirection[HIFILT];

    tnsInfo->length[subBlockNumber][HIFILT] = sfbCnt - tC->lpcStartBand[HIFILT];

    /* disable TNS if predictionGain is less than 3dB or sumSqrCoef is too small

     */

    if ((tsbi->predictionGain[HIFILT] > tC->confTab.threshOn[HIFILT]) ||

        (sumSqrCoef > (tC->confTab.tnsLimitOrder[HIFILT] / 2 + 2))) {

      tsbi->tnsActive[HIFILT] = TRUE;

      tnsInfo->numOfFilters[subBlockNumber]++;

      /* compute second filter for lower quarter; only allowed for long windows!

       */

      if ((blockType != SHORT_WINDOW) && (tC->confTab.filterEnabled[LOFILT]) &&

          (tC->confTab.seperateFiltersAllowed)) {

        /* compute second filter for lower frequencies */

        /* compute TNS filter in lattice (ParCor) form with LeRoux-Gueguen

         * algorithm */

        INT predGain;

        {

          FIXP_DBL predictionGain_m;

          INT predictionGain_e;

          CLpc_AutoToParcor(rxx1, 0, parcor_tmp,

                            tC->confTab.tnsLimitOrder[LOFILT],

                            &predictionGain_m, &predictionGain_e);

          predGain =

              (INT)fMultNorm(predictionGain_m, predictionGain_e, 1000, 31, 31);

        }

        /* non-linear quantization of TNS lattice coefficients with given

         * resolution */

        FDKaacEnc_Parcor2Index(parcor_tmp,

                               tnsInfo->coef[subBlockNumber][LOFILT],

                               tC->confTab.tnsLimitOrder[LOFILT], tC->coefRes);

        /* reduce filter order by truncating trailing zeros, compute

         * sum(abs(coefs)) */

        for (i = tC->confTab.tnsLimitOrder[LOFILT] - 1; i >= 0; i--) {

          if (tnsInfo->coef[subBlockNumber][LOFILT][i] != 0) {

            break;

          }

        }

        tnsInfo->order[subBlockNumber][LOFILT] = i + 1;

        sumSqrCoef = 0;

        for (; i >= 0; i--) {

          sumSqrCoef += tnsInfo->coef[subBlockNumber][LOFILT][i] *

                        tnsInfo->coef[subBlockNumber][LOFILT][i];

        }

        tnsInfo->direction[subBlockNumber][LOFILT] =

            tC->confTab.tnsFilterDirection[LOFILT];

        tnsInfo->length[subBlockNumber][LOFILT] =

            tC->lpcStartBand[HIFILT] - tC->lpcStartBand[LOFILT];

        /* filter lower quarter if gain is high enough, but not if it's too high

         */

        if (((predGain > tC->confTab.threshOn[LOFILT]) &&

             (predGain < (16000 * tC->confTab.tnsLimitOrder[LOFILT]))) ||

            ((sumSqrCoef > 9) &&

             (sumSqrCoef < 22 * tC->confTab.tnsLimitOrder[LOFILT]))) {

          /* compare lower to upper filter; if they are very similar, merge them

           */

          tsbi->tnsActive[LOFILT] = TRUE;

          sumSqrCoef = 0;

          for (i = 0; i < tC->confTab.tnsLimitOrder[LOFILT]; i++) {

            sumSqrCoef += fAbs(tnsInfo->coef[subBlockNumber][HIFILT][i] -

                               tnsInfo->coef[subBlockNumber][LOFILT][i]);

          }

          if ((sumSqrCoef < 2) &&

              (tnsInfo->direction[subBlockNumber][LOFILT] ==

               tnsInfo->direction[subBlockNumber][HIFILT])) {

            tnsData->filtersMerged = TRUE;

            tnsInfo->length[subBlockNumber][HIFILT] =

                sfbCnt - tC->lpcStartBand[LOFILT];

            for (; i < tnsInfo->order[subBlockNumber][HIFILT]; i++) {

              if (fAbs(tnsInfo->coef[subBlockNumber][HIFILT][i]) > 1) {

                break;

              }