xref: /external/aac/libAACdec/src/aacdec_tns.cpp

/* -----------------------------------------------------------------------------
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.

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Fraunhofer provides no warranty of patent non-infringement with respect to this
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You may use this FDK AAC Codec software or modifications thereto only for
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This FDK AAC Codec software is provided by Fraunhofer on behalf of the copyright
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5.    CONTACT INFORMATION

Fraunhofer Institute for Integrated Circuits IIS
Attention: Audio and Multimedia Departments - FDK AAC LL
Am Wolfsmantel 33
91058 Erlangen, Germany

www.iis.fraunhofer.de/amm
amm-info@iis.fraunhofer.de
----------------------------------------------------------------------------- */

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

   Author(s):   Josef Hoepfl

   Description: temporal noise shaping tool

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

#include "aacdec_tns.h"
#include "aac_rom.h"
#include "FDK_bitstream.h"
#include "channelinfo.h"

#include "FDK_lpc.h"

#define TNS_MAXIMUM_ORDER_AAC 12

/*!
  \brief Reset tns data

  The function resets the tns data

  \return  none
*/
void CTns_Reset(CTnsData *pTnsData) {
  /* Note: the following FDKmemclear should not be required. */
  FDKmemclear(pTnsData->Filter,
              TNS_MAX_WINDOWS * TNS_MAXIMUM_FILTERS * sizeof(CFilter));
  FDKmemclear(pTnsData->NumberOfFilters, TNS_MAX_WINDOWS * sizeof(UCHAR));
  pTnsData->DataPresent = 0;
  pTnsData->Active = 0;
}

void CTns_ReadDataPresentFlag(
    HANDLE_FDK_BITSTREAM bs, /*!< pointer to bitstream */
    CTnsData *pTnsData)      /*!< pointer to aac decoder channel info */
{
  pTnsData->DataPresent = (UCHAR)FDKreadBits(bs, 1);
}

/*!
  \brief Read tns data from bitstream

  The function reads the elements for tns from
  the bitstream.

  \return  none
*/
AAC_DECODER_ERROR CTns_Read(HANDLE_FDK_BITSTREAM bs, CTnsData *pTnsData,
                            const CIcsInfo *pIcsInfo, const UINT flags) {
  UCHAR n_filt, order;
  UCHAR length, coef_res, coef_compress;
  UCHAR window;
  UCHAR wins_per_frame;
  UCHAR isLongFlag;
  UCHAR start_window;
  AAC_DECODER_ERROR ErrorStatus = AAC_DEC_OK;

  if (!pTnsData->DataPresent) {
    return ErrorStatus;
  }

  {
    start_window = 0;
    wins_per_frame = GetWindowsPerFrame(pIcsInfo);
    isLongFlag = IsLongBlock(pIcsInfo);
  }

  pTnsData->GainLd = 0;

  for (window = start_window; window < wins_per_frame; window++) {
    pTnsData->NumberOfFilters[window] = n_filt =
        (UCHAR)FDKreadBits(bs, isLongFlag ? 2 : 1);

    if (n_filt) {
      int index;
      UCHAR nextstopband;

      coef_res = (UCHAR)FDKreadBits(bs, 1);

      nextstopband = GetScaleFactorBandsTotal(pIcsInfo);

      for (index = 0; index < n_filt; index++) {
        CFilter *filter = &pTnsData->Filter[window][index];

        length = (UCHAR)FDKreadBits(bs, isLongFlag ? 6 : 4);

        if (length > nextstopband) {
          length = nextstopband;
        }

        filter->StartBand = nextstopband - length;
        filter->StopBand = nextstopband;
        nextstopband = filter->StartBand;

        if (flags & (AC_USAC | AC_RSVD50 | AC_RSV603DA)) {
          /* max(Order) = 15 (long), 7 (short) */
          filter->Order = order = (UCHAR)FDKreadBits(bs, isLongFlag ? 4 : 3);
        } else {
          filter->Order = order = (UCHAR)FDKreadBits(bs, isLongFlag ? 5 : 3);

          if (filter->Order > TNS_MAXIMUM_ORDER) {
            ErrorStatus = AAC_DEC_TNS_READ_ERROR;
            return ErrorStatus;
          }
        }

        FDK_ASSERT(order <=
                   TNS_MAXIMUM_ORDER); /* avoid illegal memory access */
        if (order) {
          UCHAR coef, s_mask;
          UCHAR i;
          SCHAR n_mask;

          static const UCHAR sgn_mask[] = {0x2, 0x4, 0x8};
          static const SCHAR neg_mask[] = {~0x3, ~0x7, ~0xF};

          filter->Direction = FDKreadBits(bs, 1) ? -1 : 1;

          coef_compress = (UCHAR)FDKreadBits(bs, 1);

          filter->Resolution = coef_res + 3;

          s_mask = sgn_mask[coef_res + 1 - coef_compress];
          n_mask = neg_mask[coef_res + 1 - coef_compress];

          for (i = 0; i < order; i++) {
            coef = (UCHAR)FDKreadBits(bs, filter->Resolution - coef_compress);
            filter->Coeff[i] = (coef & s_mask) ? (coef | n_mask) : coef;
          }
          pTnsData->GainLd = 4;
        }
      }
    }
  }

  pTnsData->Active = 1;

  return ErrorStatus;
}

void CTns_ReadDataPresentUsac(HANDLE_FDK_BITSTREAM hBs, CTnsData *pTnsData0,
                              CTnsData *pTnsData1, UCHAR *ptns_on_lr,
                              const CIcsInfo *pIcsInfo, const UINT flags,
                              const UINT elFlags, const int fCommonWindow) {
  int common_tns = 0;

  if (fCommonWindow) {
    common_tns = FDKreadBit(hBs);
  }
  { *ptns_on_lr = FDKreadBit(hBs); }
  if (common_tns) {
    pTnsData0->DataPresent = 1;
    CTns_Read(hBs, pTnsData0, pIcsInfo, flags);

    pTnsData0->DataPresent = 0;
    pTnsData0->Active = 1;
    *pTnsData1 = *pTnsData0;
  } else {
    int tns_present_both;

    tns_present_both = FDKreadBit(hBs);
    if (tns_present_both) {
      pTnsData0->DataPresent = 1;
      pTnsData1->DataPresent = 1;
    } else {
      pTnsData1->DataPresent = FDKreadBit(hBs);
      pTnsData0->DataPresent = !pTnsData1->DataPresent;
    }
  }
}

/*!
  \brief Apply tns to spectral lines

  The function applies the tns to the spectrum,

  \return  none
*/
void CTns_Apply(CTnsData *RESTRICT pTnsData, /*!< pointer to aac decoder info */
                const CIcsInfo *pIcsInfo, SPECTRAL_PTR pSpectralCoefficient,
                const SamplingRateInfo *pSamplingRateInfo,
                const INT granuleLength, const UCHAR nbands,
                const UCHAR igf_active, const UINT flags) {
  int window, index, start, stop, size, start_window, wins_per_frame;

  if (pTnsData->Active) {
    C_AALLOC_SCRATCH_START(coeff, FIXP_TCC, TNS_MAXIMUM_ORDER)

    {
      start_window = 0;
      wins_per_frame = GetWindowsPerFrame(pIcsInfo);
    }

    for (window = start_window; window < wins_per_frame; window++) {
      FIXP_DBL *pSpectrum;

      { pSpectrum = SPEC(pSpectralCoefficient, window, granuleLength); }

      for (index = 0; index < pTnsData->NumberOfFilters[window]; index++) {
        CFilter *filter = &pTnsData->Filter[window][index];

        if (filter->Order > 0) {
          FIXP_TCC *pCoeff;
          UCHAR tns_max_bands;

          pCoeff = coeff;
          if (filter->Resolution == 3) {
            int i;
            for (i = 0; i < filter->Order; i++)
              *pCoeff++ = FDKaacDec_tnsCoeff3[filter->Coeff[i] + 4];
          } else {
            int i;
            for (i = 0; i < filter->Order; i++)
              *pCoeff++ = FDKaacDec_tnsCoeff4[filter->Coeff[i] + 8];
          }

          switch (granuleLength) {
            case 480:
              tns_max_bands =
                  tns_max_bands_tbl_480[pSamplingRateInfo->samplingRateIndex];
              break;
            case 512:
              tns_max_bands =
                  tns_max_bands_tbl_512[pSamplingRateInfo->samplingRateIndex];
              break;
            default:
              tns_max_bands = GetMaximumTnsBands(
                  pIcsInfo, pSamplingRateInfo->samplingRateIndex);
              /* See redefinition of TNS_MAX_BANDS table */
              if ((flags & (AC_USAC | AC_RSVD50 | AC_RSV603DA)) &&
                  (pSamplingRateInfo->samplingRateIndex > 5)) {
                tns_max_bands += 1;
              }
              break;
          }

          start = fixMin(fixMin(filter->StartBand, tns_max_bands), nbands);

          start = GetScaleFactorBandOffsets(pIcsInfo, pSamplingRateInfo)[start];

          if (igf_active) {
            stop = fixMin(filter->StopBand, nbands);
          } else {
            stop = fixMin(fixMin(filter->StopBand, tns_max_bands), nbands);
          }

          stop = GetScaleFactorBandOffsets(pIcsInfo, pSamplingRateInfo)[stop];

          size = stop - start;

          if (size) {
            C_ALLOC_SCRATCH_START(state, FIXP_DBL, TNS_MAXIMUM_ORDER)

            FDKmemclear(state, TNS_MAXIMUM_ORDER * sizeof(FIXP_DBL));
            CLpc_SynthesisLattice(pSpectrum + start, size, 0, 0,
                                  filter->Direction, coeff, filter->Order,
                                  state);

            C_ALLOC_SCRATCH_END(state, FIXP_DBL, TNS_MAXIMUM_ORDER)
          }
        }
      }
    }
    C_AALLOC_SCRATCH_END(coeff, FIXP_TCC, TNS_MAXIMUM_ORDER)
  }
}