libDRCdec/src/drcDec_tools.cpp

/* -----------------------------------------------------------------------------
Software License for The Fraunhofer FDK AAC Codec Library for Android

© Copyright  1995 - 2018 Fraunhofer-Gesellschaft zur Förderung der angewandten
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 1.    INTRODUCTION
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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
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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
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Commercially-licensed AAC software libraries, including floating-point versions
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Fraunhofer Institute for Integrated Circuits IIS
Attention: Audio and Multimedia Departments - FDK AAC LL
Am Wolfsmantel 33
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www.iis.fraunhofer.de/amm
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----------------------------------------------------------------------------- */

/************************* MPEG-D DRC decoder library **************************

   Author(s):

   Description:

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

#include "drcDec_types.h"
#include "drcDec_tools.h"
#include "fixpoint_math.h"
#include "drcDecoder.h"

int getDeltaTmin(const int sampleRate) {
  /* half_ms = round (0.0005 * sampleRate); */
  int half_ms = (sampleRate + 1000) / 2000;
  int deltaTmin = 1;
  if (sampleRate < 1000) {
    return DE_NOT_OK;
  }
  while (deltaTmin <= half_ms) {
    deltaTmin = deltaTmin << 1;
  }
  return deltaTmin;
}

DRC_COEFFICIENTS_UNI_DRC* selectDrcCoefficients(
    HANDLE_UNI_DRC_CONFIG hUniDrcConfig, const int location) {
  int n;
  int c = -1;
  for (n = 0; n < hUniDrcConfig->drcCoefficientsUniDrcCount; n++) {
    if (hUniDrcConfig->drcCoefficientsUniDrc[n].drcLocation == location) {
      c = n;
    }
  }
  if (c >= 0) {
    return &(hUniDrcConfig->drcCoefficientsUniDrc[c]);
  }
  return NULL; /* possible during bitstream parsing */
}

DRC_INSTRUCTIONS_UNI_DRC* selectDrcInstructions(
    HANDLE_UNI_DRC_CONFIG hUniDrcConfig, const int drcSetId) {
  int i;
  for (i = 0; i < hUniDrcConfig->drcInstructionsCountInclVirtual; i++) {
    if (hUniDrcConfig->drcInstructionsUniDrc[i].drcSetId == drcSetId) {
      return &(hUniDrcConfig->drcInstructionsUniDrc[i]);
    }
  }
  return NULL;
}

DOWNMIX_INSTRUCTIONS* selectDownmixInstructions(
    HANDLE_UNI_DRC_CONFIG hUniDrcConfig, const int downmixId) {
  int i;
  for (i = 0; i < hUniDrcConfig->downmixInstructionsCount; i++) {
    if (hUniDrcConfig->downmixInstructions[i].downmixId == downmixId) {
      return &(hUniDrcConfig->downmixInstructions[i]);
    }
  }
  return NULL;
}

DRC_ERROR
deriveDrcChannelGroups(
    const int drcSetEffect,                                    /* in */
    const int channelCount,                                    /* in */
    const SCHAR* gainSetIndex,                                 /* in */
    const DUCKING_MODIFICATION* duckingModificationForChannel, /* in */
    UCHAR* nDrcChannelGroups,                                  /* out */
    SCHAR* uniqueIndex,     /* out (gainSetIndexForChannelGroup) */
    SCHAR* groupForChannel, /* out */
    DUCKING_MODIFICATION* duckingModificationForChannelGroup) /* out */
{
  int duckingSequence = -1;
  int c, n, g, match, idx;
  FIXP_SGL factor;
  FIXP_SGL uniqueScaling[8];

  for (g = 0; g < 8; g++) {
    uniqueIndex[g] = -10;
    uniqueScaling[g] = FIXP_SGL(-1.0f);
  }

  g = 0;

  if (drcSetEffect & EB_DUCK_OTHER) {
    for (c = 0; c < channelCount; c++) {
      match = 0;
      if (c >= 8) return DE_MEMORY_ERROR;
      idx = gainSetIndex[c];
      factor = duckingModificationForChannel[c].duckingScaling;
      if (idx < 0) {
        for (n = 0; n < g; n++) {
          if (uniqueScaling[n] == factor) {
            match = 1;
            groupForChannel[c] = n;
            break;
          }
        }
        if (match == 0) {
          if (g >= 8) return DE_MEMORY_ERROR;
          uniqueIndex[g] = idx;
          uniqueScaling[g] = factor;
          groupForChannel[c] = g;
          g++;
        }
      } else {
        if ((duckingSequence > 0) && (duckingSequence != idx)) {
          return DE_NOT_OK;
        }
        duckingSequence = idx;
        groupForChannel[c] = -1;
      }
    }
    if (duckingSequence == -1) {
      return DE_NOT_OK;
    }
  } else if (drcSetEffect & EB_DUCK_SELF) {
    for (c = 0; c < channelCount; c++) {
      match = 0;
      if (c >= 8) return DE_MEMORY_ERROR;
      idx = gainSetIndex[c];
      factor = duckingModificationForChannel[c].duckingScaling;
      if (idx >= 0) {
        for (n = 0; n < g; n++) {
          if ((uniqueIndex[n] == idx) && (uniqueScaling[n] == factor)) {
            match = 1;
            groupForChannel[c] = n;
            break;
          }
        }
        if (match == 0) {
          if (g >= 8) return DE_MEMORY_ERROR;
          uniqueIndex[g] = idx;
          uniqueScaling[g] = factor;
          groupForChannel[c] = g;
          g++;
        }
      } else {
        groupForChannel[c] = -1;
      }
    }
  } else { /* no ducking */
    for (c = 0; c < channelCount; c++) {
      if (c >= 8) return DE_MEMORY_ERROR;
      idx = gainSetIndex[c];
      match = 0;
      if (idx >= 0) {
        for (n = 0; n < g; n++) {
          if (uniqueIndex[n] == idx) {
            match = 1;
            groupForChannel[c] = n;
            break;
          }
        }
        if (match == 0) {
          if (g >= 8) return DE_MEMORY_ERROR;
          uniqueIndex[g] = idx;
          groupForChannel[c] = g;
          g++;
        }
      } else {
        groupForChannel[c] = -1;
      }
    }
  }
  *nDrcChannelGroups = g;

  if (drcSetEffect & (EB_DUCK_OTHER | EB_DUCK_SELF)) {
    for (g = 0; g < *nDrcChannelGroups; g++) {
      if (drcSetEffect & EB_DUCK_OTHER) {
        uniqueIndex[g] = duckingSequence;
      }
      duckingModificationForChannelGroup[g].duckingScaling = uniqueScaling[g];
      if (uniqueScaling[g] != FL2FXCONST_SGL(1.0f / (float)(1 << 2))) {
        duckingModificationForChannelGroup[g].duckingScalingPresent = 1;
      } else {
        duckingModificationForChannelGroup[g].duckingScalingPresent = 0;
      }
    }
  }

  return DE_OK;
}

FIXP_DBL
dB2lin(const FIXP_DBL dB_m, const int dB_e, int* pLin_e) {
  /* get linear value from dB.
     return lin_val = 10^(dB_val/20) = 2^(log2(10)/20*dB_val)
     with dB_val = dB_m *2^dB_e and lin_val = lin_m * 2^lin_e */
  FIXP_DBL lin_m =
      f2Pow(fMult(dB_m, FL2FXCONST_DBL(0.1660964f * (float)(1 << 2))), dB_e - 2,
            pLin_e);

  return lin_m;
}

FIXP_DBL
lin2dB(const FIXP_DBL lin_m, const int lin_e, int* pDb_e) {
  /* get dB value from linear value.
     return dB_val = 20*log10(lin_val)
     with dB_val = dB_m *2^dB_e and lin_val = lin_m * 2^lin_e */
  FIXP_DBL dB_m;

  if (lin_m == (FIXP_DBL)0) { /* return very small value representing -inf */
    dB_m = (FIXP_DBL)MINVAL_DBL;
    *pDb_e = DFRACT_BITS - 1;
  } else {
    /* 20*log10(lin_val) = 20/log2(10)*log2(lin_val) */
    dB_m = fMultDiv2(FL2FXCONST_DBL(6.02059991f / (float)(1 << 3)),
                     fLog2(lin_m, lin_e, pDb_e));
    *pDb_e += 3 + 1;
  }

  return dB_m;
}

FIXP_DBL
approxDb2lin(const FIXP_DBL dB_m, const int dB_e, int* pLin_e) {
  /* get linear value from approximate dB.
     return lin_val = 2^(dB_val/6)
     with dB_val = dB_m *2^dB_e and lin_val = lin_m * 2^lin_e */
  FIXP_DBL lin_m =
      f2Pow(fMult(dB_m, FL2FXCONST_DBL(0.1666667f * (float)(1 << 2))), dB_e - 2,
            pLin_e);

  return lin_m;
}

int bitstreamContainsMultibandDrc(HANDLE_UNI_DRC_CONFIG hUniDrcConfig,
                                  const int downmixId) {
  int i, g, d, seq;
  DRC_INSTRUCTIONS_UNI_DRC* pInst;
  DRC_COEFFICIENTS_UNI_DRC* pCoef = NULL;
  int isMultiband = 0;

  pCoef = selectDrcCoefficients(hUniDrcConfig, LOCATION_SELECTED);
  if (pCoef == NULL) return 0;

  for (i = 0; i < hUniDrcConfig->drcInstructionsUniDrcCount; i++) {
    pInst = &(hUniDrcConfig->drcInstructionsUniDrc[i]);
    for (d = 0; d < pInst->downmixIdCount; d++) {
      if (downmixId == pInst->downmixId[d]) {
        for (g = 0; g < pInst->nDrcChannelGroups; g++) {
          seq = pInst->gainSetIndexForChannelGroup[g];
          if (pCoef->gainSet[seq].bandCount > 1) {
            isMultiband = 1;
          }
        }
      }
    }
  }

  return isMultiband;
}

FIXP_DBL getDownmixOffset(DOWNMIX_INSTRUCTIONS* pDown, int baseChannelCount) {
  FIXP_DBL downmixOffset = FL2FXCONST_DBL(1.0f / (1 << 1)); /* e = 1 */
  if ((pDown->bsDownmixOffset == 1) || (pDown->bsDownmixOffset == 2)) {
    int e_a, e_downmixOffset;
    FIXP_DBL a, q;
    if (baseChannelCount <= pDown->targetChannelCount) return downmixOffset;

    q = fDivNorm((FIXP_DBL)pDown->targetChannelCount,
                 (FIXP_DBL)baseChannelCount); /* e = 0 */
    a = lin2dB(q, 0, &e_a);
    if (pDown->bsDownmixOffset == 2) {
      e_a += 1; /* a *= 2 */
    }
    /* a = 0.5 * round (a) */
    a = fixp_round(a, e_a) >> 1;
    downmixOffset = dB2lin(a, e_a, &e_downmixOffset);
    downmixOffset = scaleValue(downmixOffset, e_downmixOffset - 1);
  }
  return downmixOffset;
}