xref: /external/aac/libSBRenc/src/sbrenc_freq_sca.cpp

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

� Copyright  1995 - 2012 Fraunhofer-Gesellschaft zur F�rderung der angewandten Forschung e.V.
  All rights reserved.

 1.    INTRODUCTION
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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)
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Commercially-licensed AAC software libraries, including floating-point versions with enhanced sound quality,
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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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----------------------------------------------------------------------------------------------------------- */

/*!
  \file
  \brief  frequency scale
*/

#include "sbrenc_freq_sca.h"
#include "sbr_misc.h"

#include "genericStds.h"

/*  StartFreq */
static INT getStartFreq(INT fs, const INT start_freq);

/* StopFreq */
static INT getStopFreq(INT fs, const INT stop_freq, const INT noChannels);

static INT  numberOfBands(INT b_p_o, INT start, INT stop, FIXP_DBL warp_factor);
static void CalcBands(INT * diff, INT start , INT stop , INT num_bands);
static INT  modifyBands(INT max_band, INT * diff, INT length);
static void cumSum(INT start_value, INT* diff, INT length, UCHAR  *start_adress);



/*******************************************************************************
 Functionname:  FDKsbrEnc_getSbrStartFreqRAW
 *******************************************************************************
 Description:

 Arguments:

 Return:
 *******************************************************************************/

INT
FDKsbrEnc_getSbrStartFreqRAW (INT startFreq, INT QMFbands, INT fs)
{
  INT result;

  if ( startFreq < 0 || startFreq > 15) {
    return -1;
  }
  /* Update startFreq struct */
  result = getStartFreq(fs, startFreq);

  result = (result*fs/QMFbands+1)>>1;

  return (result);

} /* End FDKsbrEnc_getSbrStartFreqRAW */


/*******************************************************************************
 Functionname:  getSbrStopFreq
 *******************************************************************************
 Description:

 Arguments:

 Return:
 *******************************************************************************/
INT FDKsbrEnc_getSbrStopFreqRAW  (INT stopFreq, INT QMFbands, INT fs)
{
  INT result;

  if ( stopFreq < 0 || stopFreq > 13)
    return -1;


  /* Uppdate stopFreq struct */
  result = getStopFreq( fs, stopFreq, QMFbands);
  result =   (result*fs/QMFbands+1)>>1;

  return (result);
} /* End getSbrStopFreq */


/*******************************************************************************
 Functionname:  getStartFreq
 *******************************************************************************
 Description:

 Arguments:

 Return:
 *******************************************************************************/
static INT
getStartFreq(INT fs, const INT start_freq)
{
  INT k0_min;

  switch(fs){
  case 16000: k0_min = 24;
    break;
  case 22050: k0_min = 17;
    break;
  case 24000: k0_min = 16;
    break;
  case 32000: k0_min = 16;
    break;
  case 44100: k0_min = 12;
    break;
  case 48000: k0_min = 11;
    break;
  case 64000: k0_min = 10;
    break;
  case 88200: k0_min = 7;
    break;
  case 96000: k0_min = 7;
    break;
  default:
    k0_min=11; /* illegal fs */
  }


  switch (fs) {

  case 16000:
    {
      INT v_offset[]= {-8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7};
      return (k0_min + v_offset[start_freq]);
    }
  case 22050:
    {
      INT v_offset[]= {-5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 9, 11, 13};
      return (k0_min + v_offset[start_freq]);
    }
  case 24000:
    {
      INT v_offset[]= {-5, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 9, 11, 13, 16};
      return (k0_min + v_offset[start_freq]);
    }
  case 32000:
    {
      INT v_offset[]= {-6, -4, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 9, 11, 13, 16};
      return (k0_min + v_offset[start_freq]);
    }
  case 44100:
  case 48000:
  case 64000:
    {
      INT v_offset[]= {-4, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 9, 11, 13, 16, 20};
      return (k0_min + v_offset[start_freq]);
    }
  case 88200:
  case 96000:
    {
      INT v_offset[]= {-2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 9, 11, 13, 16, 20, 24};
      return (k0_min + v_offset[start_freq]);
    }
  default:
    {
      INT v_offset[]= {0, 1, 2, 3, 4, 5, 6, 7, 9, 11, 13, 16, 20, 24, 28, 33};
      return (k0_min + v_offset[start_freq]);
    }
  }
} /* End getStartFreq */


/*******************************************************************************
 Functionname:  getStopFreq
 *******************************************************************************
 Description:

 Arguments:

 Return:
 *******************************************************************************/
 static INT
getStopFreq(INT fs, const INT stop_freq, const INT noChannels)
{
  INT result,i;
  INT k1_min;
  INT v_dstop[13];


  INT *v_stop_freq = NULL;
  INT v_stop_freq_16[14] = {48,49,50,51,52,54,55,56,57,59,60,61,63,64};
  INT v_stop_freq_22[14] = {35,37,38,40,42,44,46,48,51,53,56,58,61,64};
  INT v_stop_freq_24[14] = {32,34,36,38,40,42,44,46,49,52,55,58,61,64};
  INT v_stop_freq_32[14] = {32,34,36,38,40,42,44,46,49,52,55,58,61,64};
  INT v_stop_freq_44[14] = {23,25,27,29,32,34,37,40,43,47,51,55,59,64};
  INT v_stop_freq_48[14] = {21,23,25,27,30,32,35,38,42,45,49,54,59,64};
  INT v_stop_freq_64[14] = {20,22,24,26,29,31,34,37,41,45,49,54,59,64};
  INT v_stop_freq_88[14] = {15,17,19,21,23,26,29,33,37,41,46,51,57,64};
  INT v_stop_freq_96[14] = {13,15,17,19,21,24,27,31,35,39,44,50,57,64};

  switch(fs){
  case 16000: k1_min = 48;
              v_stop_freq =v_stop_freq_16;
    break;
  case 22050: k1_min = 35;
              v_stop_freq =v_stop_freq_22;
    break;
  case 24000: k1_min = 32;
              v_stop_freq =v_stop_freq_24;
    break;
  case 32000: k1_min = 32;
              v_stop_freq =v_stop_freq_32;
    break;
  case 44100: k1_min = 23;
              v_stop_freq =v_stop_freq_44;
    break;
  case 48000: k1_min = 21;
              v_stop_freq =v_stop_freq_48;
    break;
  case 64000: k1_min = 20;
              v_stop_freq =v_stop_freq_64;
    break;
  case 88200: k1_min = 15;
              v_stop_freq =v_stop_freq_88;
    break;
  case 96000: k1_min = 13;
              v_stop_freq =v_stop_freq_96;
    break;
  default:
    k1_min = 21; /* illegal fs  */
  }


  /* Ensure increasing bandwidth */
  for(i = 0; i <= 12; i++) {
    v_dstop[i] = v_stop_freq[i+1] - v_stop_freq[i];
  }

  FDKsbrEnc_Shellsort_int(v_dstop, 13); /* Sort bandwidth changes */

  result = k1_min;
  for(i = 0; i < stop_freq; i++) {
    result = result + v_dstop[i];
  }

  return(result);

}/* End getStopFreq */


/*******************************************************************************
 Functionname:  FDKsbrEnc_FindStartAndStopBand
 *******************************************************************************
 Description:

 Arguments:

 Return:
 *******************************************************************************/
INT
FDKsbrEnc_FindStartAndStopBand(const INT samplingFreq,
                     const INT noChannels,
                     const INT startFreq,
                     const INT stopFreq,
                     const SR_MODE sampleRateMode,
                     INT *k0,
                     INT *k2)
{

  /* Update startFreq struct */
  *k0 = getStartFreq(samplingFreq, startFreq);

  /* Test if start freq is outside corecoder range */
  if( ( sampleRateMode == 1 ) &&
      ( samplingFreq*noChannels  <
        2**k0 * samplingFreq) ) {
    return (1); /* raise the cross-over frequency and/or lower the number
                   of target bands per octave (or lower the sampling frequency) */
  }

  /*Update stopFreq struct */
  if ( stopFreq < 14 ) {
    *k2 = getStopFreq(samplingFreq, stopFreq, noChannels);
  } else if( stopFreq == 14 ) {
    *k2 = 2 * *k0;
  } else {
    *k2 = 3 * *k0;
  }

  /* limit to Nyqvist */
  if (*k2 > noChannels) {
    *k2 = noChannels;
  }



  /* Test for invalid  k0 k2 combinations */
  if ( (samplingFreq == 44100) && ( (*k2 - *k0) > MAX_FREQ_COEFFS_FS44100 ) )
    return (1); /* Number of bands exceeds valid range of MAX_FREQ_COEFFS for fs=44.1kHz */

  if ( (samplingFreq >= 48000) && ( (*k2 - *k0) > MAX_FREQ_COEFFS_FS48000 ) )
    return (1); /* Number of bands exceeds valid range of MAX_FREQ_COEFFS for fs>=48kHz */

  if ((*k2 - *k0) > MAX_FREQ_COEFFS)
    return (1);/*Number of bands exceeds valid range of MAX_FREQ_COEFFS */

  if ((*k2 - *k0) < 0)
    return (1);/* Number of bands is negative */


  return(0);
}

/*******************************************************************************
 Functionname:  FDKsbrEnc_UpdateFreqScale
 *******************************************************************************
 Description:

 Arguments:

 Return:
 *******************************************************************************/
INT
FDKsbrEnc_UpdateFreqScale(UCHAR  *v_k_master, INT *h_num_bands,
                const INT k0, const INT k2,
                const INT freqScale,
                const INT alterScale)

{

  INT     b_p_o = 0;        /* bands_per_octave */
  FIXP_DBL   warp = FL2FXCONST_DBL(0.0f);
  INT     dk = 0;

  /* Internal variables */
  INT     k1 = 0, i;
  INT     num_bands0;
  INT     num_bands1;
  INT     diff_tot[MAX_OCTAVE + MAX_SECOND_REGION];
  INT     *diff0 = diff_tot;
  INT     *diff1 = diff_tot+MAX_OCTAVE;
  INT     k2_achived;
  INT     k2_diff;
  INT     incr = 0;

  /* Init */
  if (freqScale==1)  b_p_o = 12;
  if (freqScale==2)  b_p_o = 10;
  if (freqScale==3)  b_p_o = 8;


  if(freqScale > 0) /*Bark*/
    {
      if(alterScale==0)
        warp = FL2FXCONST_DBL(0.5f);        /* 1.0/(1.0*2.0) */
      else
        warp = FL2FXCONST_DBL(1.0f/2.6f);   /* 1.0/(1.3*2.0); */


      if(4*k2 >= 9*k0)  /*two or more regions*/
        {
          k1=2*k0;

          num_bands0=numberOfBands(b_p_o, k0, k1, FL2FXCONST_DBL(0.5f));
          num_bands1=numberOfBands(b_p_o, k1, k2, warp);

          CalcBands(diff0, k0, k1, num_bands0);/*CalcBands1 => diff0 */
          FDKsbrEnc_Shellsort_int( diff0, num_bands0);/*SortBands sort diff0 */

          if (diff0[0] == 0) /* too wide FB bands for target tuning */
          {
            return (1);/* raise the cross-over frequency and/or lower the number
                          of target bands per octave (or lower the sampling frequency */
          }

          cumSum(k0, diff0, num_bands0, v_k_master); /* cumsum */

          CalcBands(diff1, k1, k2, num_bands1);     /* CalcBands2 => diff1 */
          FDKsbrEnc_Shellsort_int( diff1, num_bands1);            /* SortBands sort diff1 */
          if(diff0[num_bands0-1] > diff1[0])        /* max(1) > min(2) */
            {
              if(modifyBands(diff0[num_bands0-1],diff1, num_bands1))
                return(1);
            }

          /* Add 2'nd region */
          cumSum(k1, diff1, num_bands1, &v_k_master[num_bands0]);
          *h_num_bands=num_bands0+num_bands1;     /* Output nr of bands */

        }
      else /* one region */
        {
          k1=k2;

          num_bands0=numberOfBands(b_p_o, k0, k1, FL2FXCONST_DBL(0.5f));
          CalcBands(diff0, k0, k1, num_bands0);/* CalcBands1 => diff0 */
          FDKsbrEnc_Shellsort_int( diff0, num_bands0);       /* SortBands sort diff0 */

          if (diff0[0] == 0) /* too wide FB bands for target tuning */
          {
            return (1); /* raise the cross-over frequency and/or lower the number
                           of target bands per octave (or lower the sampling frequency */
          }

          cumSum(k0, diff0, num_bands0, v_k_master);/* cumsum */
          *h_num_bands=num_bands0;        /* Output nr of bands */

        }
    }
  else /* Linear mode */
    {
      if (alterScale==0) {
        dk = 1;
        num_bands0 = 2 * ((k2 - k0)/2);         /* FLOOR to get to few number of bands*/
      } else {
        dk = 2;
        num_bands0 = 2 * (((k2 - k0)/dk +1)/2); /* ROUND to get closest fit */
      }

      k2_achived = k0 + num_bands0*dk;
      k2_diff = k2 - k2_achived;

      for(i=0;i<num_bands0;i++)
        diff_tot[i] = dk;

      /* If linear scale wasn't achived */
      /* and we got wide SBR are */
      if (k2_diff < 0) {
          incr = 1;
          i = 0;
      }

      /* If linear scale wasn't achived */
      /* and we got small SBR are */
      if (k2_diff > 0) {
          incr = -1;
          i = num_bands0-1;
      }

      /* Adjust diff vector to get sepc. SBR range */
      while (k2_diff != 0) {
        diff_tot[i] = diff_tot[i] - incr;
        i = i + incr;
        k2_diff = k2_diff + incr;
      }

      cumSum(k0, diff_tot, num_bands0, v_k_master);/* cumsum */
      *h_num_bands=num_bands0;        /* Output nr of bands */

    }

  if (*h_num_bands < 1)
    return(1); /*To small sbr area */

  return (0);
}/* End FDKsbrEnc_UpdateFreqScale */

static INT
numberOfBands(INT b_p_o, INT start, INT stop, FIXP_DBL warp_factor)
{
  INT result=0;
  /* result = 2* (INT) ( (double)b_p_o * (double)(FDKlog((double)stop/(double)start)/FDKlog((double)2)) * (double)FX_DBL2FL(warp_factor) + 0.5); */
  result = ( ( b_p_o * fMult( (CalcLdInt(stop) - CalcLdInt(start)),  warp_factor) + (FL2FX_DBL(0.5f)>>LD_DATA_SHIFT)
               ) >> ((DFRACT_BITS-1)-LD_DATA_SHIFT) ) << 1; /* do not optimize anymore (rounding!!) */

  return(result);
}


static void
CalcBands(INT * diff, INT start , INT stop , INT num_bands)
{
    INT i, qb, qe, qtmp;
    INT previous;
    INT current;
    FIXP_DBL base, exp, tmp;

    previous=start;
    for(i=1; i<= num_bands; i++)
    {
        base = fDivNorm((FIXP_DBL)stop, (FIXP_DBL)start, &qb);
        exp = fDivNorm((FIXP_DBL)i, (FIXP_DBL)num_bands, &qe);
        tmp = fPow(base, qb, exp, qe, &qtmp);
        tmp = fMult(tmp, (FIXP_DBL)(start<<24));
        current   = (INT)scaleValue(tmp, qtmp-23);
        current   = (current+1) >> 1; /* rounding*/
        diff[i-1] = current-previous;
        previous  = current;
    }

}/* End CalcBands */


static void
cumSum(INT start_value, INT* diff, INT length,  UCHAR *start_adress)
{
  INT i;
  start_adress[0]=start_value;
  for(i=1;i<=length;i++)
    start_adress[i]=start_adress[i-1]+diff[i-1];
} /* End cumSum */


static INT
modifyBands(INT max_band_previous, INT * diff, INT length)
{
  INT change=max_band_previous-diff[0];

  /* Limit the change so that the last band cannot get narrower than the first one */
  if ( change > (diff[length-1] - diff[0]) / 2 )
    change = (diff[length-1] - diff[0]) / 2;

  diff[0] += change;
  diff[length-1] -= change;
  FDKsbrEnc_Shellsort_int(diff, length);

  return(0);
}/* End modifyBands */


/*******************************************************************************
 Functionname:  FDKsbrEnc_UpdateHiRes
 *******************************************************************************
 Description:

 Arguments:

 Return:
 *******************************************************************************/
INT
FDKsbrEnc_UpdateHiRes(UCHAR *h_hires, INT *num_hires,UCHAR * v_k_master,
            INT num_master , INT *xover_band, SR_MODE drOrSr,
            INT noQMFChannels)
{
  INT i;
  INT divider;
  INT max1,max2;

  /* Check if we use a Dual rate => diver=2 else 1 */
  divider = (drOrSr == DUAL_RATE) ? 2 : 1;

  if( (v_k_master[*xover_band] > (noQMFChannels/divider) ) ||
      ( *xover_band > num_master ) )  {
      /* xover_band error, too big for this startFreq. Will be clipped */

    /* Calculate maximum value for xover_band */
    max1=0;
    max2=num_master;
    while( (v_k_master[max1+1] < (noQMFChannels/divider)) &&
           ( (max1+1) < max2) )
      {
        max1++;
      }

    *xover_band=max1;
  }

  *num_hires = num_master - *xover_band;
  for(i = *xover_band; i <= num_master; i++)
    {
      h_hires[i - *xover_band] = v_k_master[i];
    }

  return (0);
}/* End FDKsbrEnc_UpdateHiRes */


/*******************************************************************************
 Functionname:  FDKsbrEnc_UpdateLoRes
 *******************************************************************************
 Description:

 Arguments:

 Return:
 *******************************************************************************/
void
FDKsbrEnc_UpdateLoRes(UCHAR * h_lores, INT *num_lores, UCHAR * h_hires, INT num_hires)
{
  INT i;

  if(num_hires%2 == 0) /* if even number of hires bands */
    {
      *num_lores=num_hires/2;
      /* Use every second lores=hires[0,2,4...] */
      for(i=0;i<=*num_lores;i++)
        h_lores[i]=h_hires[i*2];

    }
  else            /* odd number of hires which means xover is odd */
    {
      *num_lores=(num_hires+1)/2;

      /* Use lores=hires[0,1,3,5 ...] */
      h_lores[0]=h_hires[0];
      for(i=1;i<=*num_lores;i++)
        {
          h_lores[i]=h_hires[i*2-1];
        }
    }

}/* End FDKsbrEnc_UpdateLoRes */