aacquant.c

来自「faac-1.25.rar音频编解码器demo」· C语言 代码 · 共 688 行 · 第 1/2 页

        x1 += QUANTFAC(rx1);
        XRPOW_FTOI(x8, rx8);
        x2 += QUANTFAC(rx2);
        XRPOW_FTOI(x1,*ix++);
        x3 += QUANTFAC(rx3);
        XRPOW_FTOI(x2,*ix++);
        x4 += QUANTFAC(rx4);
        XRPOW_FTOI(x3,*ix++);
        x5 += QUANTFAC(rx5);
        XRPOW_FTOI(x4,*ix++);
        x6 += QUANTFAC(rx6);
        XRPOW_FTOI(x5,*ix++);
        x7 += QUANTFAC(rx7);
        XRPOW_FTOI(x6,*ix++);
        x8 += QUANTFAC(rx8);
        XRPOW_FTOI(x7,*ix++);
        XRPOW_FTOI(x8,*ix++);
    }
}
#endif
static void QuantizeBand(const double *xp, int *ix, double istep,
			 int offset, int end, double *adj43)
{
  int j;

  for (j = offset; j < end; j++)
  {
    double x0 = istep * xp[j];
    x0 += adj43[(int)x0];
    ix[j] = (int)x0;
  }
}
#endif

static void CalcAllowedDist(CoderInfo *coderInfo, PsyInfo *psyInfo,
                            double *xr, double *xmin, int quality)
{
  int sfb, start, end, l;
  const double globalthr = 132.0 / (double)quality;
  int last = coderInfo->lastx;
  int lastsb = 0;
  int *cb_offset = coderInfo->sfb_offset;
  int num_cb = coderInfo->nr_of_sfb;
  double avgenrg = coderInfo->avgenrg;

  for (sfb = 0; sfb < num_cb; sfb++)
  {
    if (last > cb_offset[sfb])
      lastsb = sfb;
  }

  for (sfb = 0; sfb < num_cb; sfb++)
  {
    double thr, tmp;
    double enrg = 0.0;

    start = cb_offset[sfb];
    end = cb_offset[sfb + 1];

    if (sfb > lastsb)
    {
      xmin[sfb] = 0;
      continue;
    }

    if (coderInfo->block_type != ONLY_SHORT_WINDOW)
    {
      double enmax = -1.0;
      double lmax;

      lmax = start;
      for (l = start; l < end; l++)
      {
	if (enmax < (xr[l] * xr[l]))
	{
	  enmax = xr[l] * xr[l];
	  lmax = l;
	}
      }

      start = lmax - 2;
      end = lmax + 3;
      if (start < 0)
	start = 0;
      if (end > last)
	end = last;
    }

    for (l = start; l < end; l++)
    {
      enrg += xr[l]*xr[l];
    }

    thr = enrg/((double)(end-start)*avgenrg);
    thr = pow(thr, 0.1*(lastsb-sfb)/lastsb + 0.3);

    tmp = 1.0 - ((double)start / (double)last);
    tmp = tmp * tmp * tmp + 0.075;

    thr = 1.0 / (1.4*thr + tmp);

    xmin[sfb] = ((coderInfo->block_type == ONLY_SHORT_WINDOW) ? 0.65 : 1.12)
      * globalthr * thr;
  }
}

static int FixNoise(CoderInfo *coderInfo,
		    const double *xr,
		    double *xr_pow,
		    int *xi,
		    double *xmin,
		    double *pow43,
		    double *adj43)
{
    int i, sb;
    int start, end;
    double diffvol;
    double tmp;
    const double ifqstep = pow(2.0, 0.1875);
    const double log_ifqstep = 1.0 / log(ifqstep);
    const double maxstep = 0.05;

    for (sb = 0; sb < coderInfo->nr_of_sfb; sb++)
    {
      double sfacfix;
      double fixstep = 0.25;
      int sfac;
      double fac;
      int dist;
      double sfacfix0 = 1.0, dist0 = 1e50;
      double maxx;

      start = coderInfo->sfb_offset[sb];
      end = coderInfo->sfb_offset[sb+1];

      if (!xmin[sb])
	goto nullsfb;

      maxx = 0.0;
      for (i = start; i < end; i++)
      {
	if (xr_pow[i] > maxx)
	  maxx = xr_pow[i];
      }

      //printf("band %d: maxx: %f\n", sb, maxx);
      if (maxx < 10.0)
      {
      nullsfb:
	for (i = start; i < end; i++)
	  xi[i] = 0;
	coderInfo->scale_factor[sb] = 10;
	continue;
      }

      sfacfix = 1.0 / maxx;
      sfac = (int)(log(sfacfix) * log_ifqstep - 0.5);
      for (i = start; i < end; i++)
	xr_pow[i] *= sfacfix;
      maxx *= sfacfix;
      coderInfo->scale_factor[sb] = sfac;
      QuantizeBand(xr_pow, xi, IPOW20(coderInfo->global_gain), start, end,
		   adj43);
      //printf("\tsfac: %d\n", sfac);

    calcdist:
      diffvol = 0.0;
      for (i = start; i < end; i++)
      {
	tmp = xi[i];
	diffvol += tmp * tmp;  // ~x^(3/2)
      }

      if (diffvol < 1e-6)
	diffvol = 1e-6;
      tmp = pow(diffvol / (double)(end - start), -0.666);

      if (fabs(fixstep) > maxstep)
      {
	double dd = 0.5*(tmp / xmin[sb] - 1.0);

	if (fabs(dd) < fabs(fixstep))
	{
	  fixstep = dd;

	  if (fabs(fixstep) < maxstep)
	    fixstep = maxstep * ((fixstep > 0) ? 1 : -1);
	}
      }

      if (fixstep > 0)
      {
	if (tmp < dist0)
	{
	  dist0 = tmp;
	  sfacfix0 = sfacfix;
	}
	else
	{
	  if (fixstep > .1)
	    fixstep = .1;
	}
      }
      else
      {
	dist0 = tmp;
	sfacfix0 = sfacfix;
      }

      dist = (tmp > xmin[sb]);
      fac = 0.0;
      if (fabs(fixstep) >= maxstep)
      {
	if ((dist && (fixstep < 0))
	    || (!dist && (fixstep > 0)))
	{
	  fixstep = -0.5 * fixstep;
	}

	fac = 1.0 + fixstep;
      }
      else if (dist)
      {
	fac = 1.0 + fabs(fixstep);
      }

      if (fac != 0.0)
      {
	if (maxx * fac >= IXMAX_VAL)
	{
	  // restore best noise
	  fac = sfacfix0 / sfacfix;
	  for (i = start; i < end; i++)
	    xr_pow[i] *= fac;
	  maxx *= fac;
	  sfacfix *= fac;
	  coderInfo->scale_factor[sb] = log(sfacfix) * log_ifqstep - 0.5;
	  QuantizeBand(xr_pow, xi, IPOW20(coderInfo->global_gain), start, end,
		       adj43);
	  continue;
	}

	if (coderInfo->scale_factor[sb] < -10)
	{
	  for (i = start; i < end; i++)
	    xr_pow[i] *= fac;
          maxx *= fac;
          sfacfix *= fac;
	  coderInfo->scale_factor[sb] = log(sfacfix) * log_ifqstep - 0.5;
	  QuantizeBand(xr_pow, xi, IPOW20(coderInfo->global_gain), start, end,
		       adj43);
	  goto calcdist;
	}
      }
    }
    return 0;
}

int SortForGrouping(CoderInfo* coderInfo,
                           PsyInfo *psyInfo,
                           ChannelInfo *channelInfo,
                           int *sfb_width_table,
                           double *xr)
{
    int i,j,ii;
    int index = 0;
    double xr_tmp[FRAME_LEN];
    int group_offset=0;
    int k=0;
    int windowOffset = 0;


    /* set up local variables for used quantInfo elements */
    int* sfb_offset = coderInfo->sfb_offset;
    int* nr_of_sfb = &(coderInfo->nr_of_sfb);
    int* window_group_length;
    int num_window_groups;
    *nr_of_sfb = coderInfo->max_sfb;              /* Init to max_sfb */
    window_group_length = coderInfo->window_group_length;
    num_window_groups = coderInfo->num_window_groups;

    /* calc org sfb_offset just for shortblock */
    sfb_offset[k]=0;
    for (k=1 ; k <*nr_of_sfb+1; k++) {
        sfb_offset[k] = sfb_offset[k-1] + sfb_width_table[k-1];
    }

    /* sort the input spectral coefficients */
    index = 0;
    group_offset=0;
    for (i=0; i< num_window_groups; i++) {
        for (k=0; k<*nr_of_sfb; k++) {
            for (j=0; j < window_group_length[i]; j++) {
                for (ii=0;ii< sfb_width_table[k];ii++)
                    xr_tmp[index++] = xr[ii+ sfb_offset[k] + BLOCK_LEN_SHORT*j +group_offset];
            }
        }
        group_offset +=  BLOCK_LEN_SHORT*window_group_length[i];
    }

    for (k=0; k<FRAME_LEN; k++){
        xr[k] = xr_tmp[k];
    }


    /* now calc the new sfb_offset table for the whole p_spectrum vector*/
    index = 0;
    sfb_offset[index++] = 0;
    windowOffset = 0;
    for (i=0; i < num_window_groups; i++) {
        for (k=0 ; k <*nr_of_sfb; k++) {
            sfb_offset[index] = sfb_offset[index-1] + sfb_width_table[k]*window_group_length[i] ;
            index++;
        }
        windowOffset += window_group_length[i];
    }

    *nr_of_sfb = *nr_of_sfb * num_window_groups;  /* Number interleaved bands. */

    return 0;
}

void CalcAvgEnrg(CoderInfo *coderInfo,
		 const double *xr)
{
  int end, l;
  int last = 0;
  double totenrg = 0.0;

  end = coderInfo->sfb_offset[coderInfo->nr_of_sfb];
  for (l = 0; l < end; l++)
  {
    if (xr[l])
    {
      last = l;
      totenrg += xr[l] * xr[l];
    }
    }
  last++;

  coderInfo->lastx = last;
  coderInfo->avgenrg = totenrg / last;
}