path: root/libtoolame-dab/psycho_3.c

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#include "common.h"
#include "options.h"
#include "encoder.h"
#include "mem.h"
#include "fft.h"
#include "ath.h"
#define OLDTHRESHx
#include "psycho_3.h"
#include "psycho_3priv.h"

/* This is a reimplementation of psy model 1 using the ISO11172 standard.
   I found the original dist10 code (which is full of pointers) to be 
   a horrible thing to try and understand and debug.
   This implementation is not built for speed, but is rather meant to 
   clearly outline the steps specified by the standard (still, it's only
   a tiny fraction slower than the dist10 code, and nothing has been optimized)
   MFC Feb 2003 */

/* Keep a table to fudge the adding of dB */
#define DBTAB 1000
static double dbtable[DBTAB];

#define CRITBANDMAX 32 /* this is much higher than it needs to be. really only about 24 */
int cbands=0; /* How many critical bands there really are */
int cbandindex[CRITBANDMAX]; /* The spectral line index of the start of
				each critical band */

#define SUBSIZE 136
int freq_subset[SUBSIZE];
FLOAT bark[HBLKSIZE], ath[HBLKSIZE];

int *numlines;
FLOAT *cbval;
int partition[HBLKSIZE];
static D1408 *fft_buf;

frame_header *header;


double psycho_3_add_db (double a, double b)
{
  /* MFC - if the difference between a and b is large (>99), then just return the
     largest one. (about 10% of the time)
     - For differences between 0 and 99, return the largest value, but add
     in a pre-calculated difference value.  
     - the value 99 was chosen arbitarily.
     - maximum (a-b) i've seen is 572 */
  FLOAT fdiff;
  int idiff;
  fdiff = (10.0 * (a - b));

  if (fdiff > 990.0) {
    return a;
  }
  if (fdiff < -990.0) {
    return (b);
  }

  idiff = (int) fdiff;
  if (idiff >= 0) {
    return (a + dbtable[idiff]);
  }

  return (b + dbtable[-idiff]);
}

void psycho_3 (short buffer[2][1152], double scale[2][SBLIMIT],
	       double ltmin[2][SBLIMIT], frame_info * frame, options *glopts)
{
  int nch = frame->nch;
  int sblimit = frame->sblimit;
  int k, i;
  static char init = 0;
  static int off[2] = { 256, 256 };
  FLOAT sample[BLKSIZE];

  FLOAT energy[BLKSIZE];
  FLOAT power[HBLKSIZE];
  FLOAT Xtm[HBLKSIZE], Xnm[HBLKSIZE];
  int tonelabel[HBLKSIZE], noiselabel[HBLKSIZE];
  FLOAT LTg[HBLKSIZE];
  double Lsb[SBLIMIT];

  header = frame->header;

  if (init==0) {		
    psycho_3_init(glopts);
    init++;
  }
  

  for (k = 0; k < nch; k++) {
    int ok = off[k] % 1408;
    for (i = 0; i < 1152; i++) {
      fft_buf[k][ok++] = (FLOAT) buffer[k][i] / SCALE;
      if (ok >= 1408)
	ok = 0;
    }
    ok = (off[k] + 1216) % 1408;
    for (i = 0; i < BLKSIZE; i++) {
      sample[i] = fft_buf[k][ok++];
      if (ok >= 1408)
	ok = 0;
    }

    off[k] += 1152;
    off[k] %= 1408;

    psycho_3_fft(sample, energy);
    psycho_3_powerdensityspectrum(energy, power);    
    psycho_3_spl(Lsb, power, &scale[k][0]);
    psycho_3_tonal_label (power, tonelabel, Xtm);
    psycho_3_noise_label (power, energy, tonelabel, noiselabel, Xnm);
    if (glopts->verbosity > 20)
      psycho_3_dump(tonelabel, Xtm, noiselabel, Xnm);
    psycho_3_decimation(ath, tonelabel, Xtm, noiselabel, Xnm, bark);
    psycho_3_threshold(LTg, tonelabel, Xtm, noiselabel, Xnm, bark, ath, bitrate[header->version][header->bitrate_index] / nch, freq_subset);
    psycho_3_minimummasking(LTg, &ltmin[k][0], freq_subset);
    psycho_3_smr(&ltmin[k][0], Lsb);
  }
}

/* ISO11172 Sec D.1 Step 1 - Window with HANN and then perform the FFT */
void psycho_3_fft(FLOAT sample[BLKSIZE], FLOAT energy[BLKSIZE])
{
  FLOAT x_real[BLKSIZE];
  int i;
  static int init = 0;
  static FLOAT *window;

  if (!init) { /* calculate window function for the Fourier transform */
    window = (FLOAT *) mem_alloc (sizeof (DFFT), "window");
    register FLOAT sqrt_8_over_3 = pow (8.0 / 3.0, 0.5);
    for (i = 0; i < BLKSIZE; i++) {
      window[i] = sqrt_8_over_3 * 0.5 * (1 - cos (2.0 * PI * i / (BLKSIZE))) / BLKSIZE;
    }
    init++;
  }

  /* convolve the samples with the hann window */
  for (i = 0; i < BLKSIZE; i++)
    x_real[i] = (FLOAT) (sample[i] * window[i]);
  /* do the FFT */
  psycho_1_fft (x_real, energy, BLKSIZE);
}

/* Sect D.1 Step 1 - convert the energies into dB */
void psycho_3_powerdensityspectrum(FLOAT energy[BLKSIZE], FLOAT power[HBLKSIZE]) {
  int i;
  for (i=1;i<HBLKSIZE;i++) {	
    if (energy[i] < 1E-20)
      power[i] = -200.0 + POWERNORM;
    else
      power[i] = 10 * log10 (energy[i]) + POWERNORM;
  }
}

/* Sect D.1 Step 2 - Determine the sound pressure level in each subband */
void psycho_3_spl(double *Lsb, FLOAT *power, double *scale) {
  int i;
  FLOAT Xmax[SBLIMIT];

  for (i=0;i<SBLIMIT;i++) {
    Xmax[i] = DBMIN;
  }
  /* Find the maximum SPL in the power spectrum */
  for (i=1;i<HBLKSIZE;i++) {
    int index = i>>4;
    if (Xmax[index] < power[i])
      Xmax[index] = power[i];
  }

  /* Compare it to the sound pressure based upon the scale for this subband 
     and pick the maximum one */
  for (i=0;i<SBLIMIT;i++) {
    double val =  20 * log10 (scale[i] * 32768) - 10;
    Lsb[i] = MAX(Xmax[i], val);
  }  
}

/* Sect D.1 Step 4 Label the Tonal Components */
void psycho_3_tonal_label (FLOAT power[HBLKSIZE], int *tonelabel, FLOAT Xtm[HBLKSIZE])
{
  int i;
  int maxima[HBLKSIZE];

  /* Find the maxima as per ISO11172 D.1.4.a */
  maxima[0]=maxima[HBLKSIZE-1]=0;
  tonelabel[0]=tonelabel[HBLKSIZE-1]=0;
  Xtm[0] = Xtm[HBLKSIZE-1] = DBMIN;
  for (i=1;i<HBLKSIZE-1;i++) {
    tonelabel[i] = 0;
    Xtm[i] = DBMIN;
    if (power[i]>power[i-1] && power[i]>power[i+1]) /* The first criteria for a maximum */
      maxima[i]=1;
    else
      maxima[i]=0;
  }

  {
    /* Now find the tones as per ISO11172 D.1 Step4.b */
    /* The standard is a bit vague (surprise surprise).
       So I'm going to assume that 
       - a tone must be 7dB greater than *all* the relevant neighbours 
       - once a tone is found, the neighbours are immediately set to -inf dB
    */

    psycho_3_tonal_label_range(power, tonelabel, maxima, Xtm, 2, 63, 2);
    psycho_3_tonal_label_range(power, tonelabel, maxima, Xtm, 63,127,3);
    psycho_3_tonal_label_range(power, tonelabel, maxima, Xtm, 127,255,6);
    psycho_3_tonal_label_range(power, tonelabel, maxima, Xtm, 255,500,12);

  }
}

/* Sect D.1 Step4b 
   A tone within the range (start -> end), must be 7.0 dB greater than
   all it's neighbours within +/- srange. Don't count its immediate neighbours. */
void psycho_3_tonal_label_range(FLOAT *power, int *tonelabel, int *maxima, FLOAT *Xtm, int start, int end, int srange) {
  int j,k;

  for (k=start;k<end;k++)  /* Search for all the maxima in this range */
    if (maxima[k] == 1) {
      tonelabel[k] = TONE; /* assume it's a TONE and then prove otherwise */
      for (j=-srange;j<=+srange;j++) /* Check the neighbours within +/- srange */
	if (abs(j) > 1) /* Don't count the immediate neighbours, or itself */
	  if ((power[k] - power[k+j]) < 7.0)
	    tonelabel[k] = 0; /* Not greater by 7dB, therefore not a tone */
      if (tonelabel[k] == TONE) {
	/* Calculate the sound pressure level for this tone by summing 
	   the adjacent spectral lines
	   Xtm[k] = 10 * log10( pow(10.0, 0.1*power[k-1]) + pow(10.0, 0.1*power[k]) 
	                      + pow(10.0, 0.1*power[k+1]) ); */
	double temp = psycho_3_add_db(power[k-1], power[k]);
	Xtm[k] = psycho_3_add_db(temp, power[k+1]);
	
	/* *ALL* spectral lines within +/- srange are set to -inf dB 
	   So that when we do the noise calculate, they are not counted */
	for (j=-srange;j<=+srange;j++)
	    power[k+j] = DBMIN;
      }
    }
}

void psycho_3_init_add_db (void)
{
  int i;
  double x;
  for (i = 0; i < DBTAB; i++) {
    x = (double) i / 10.0;
    dbtable[i] = 10 * log10 (1 + pow (10.0, x / 10.0)) - x;
  }
}

/* D.1 Step 4.c Labelling non-tonal (noise) components 
   Sum the energies in each critical band (the tone energies have been removed 
   during the tone labelling).
   Find the "geometric mean" of these energies - i.e. find the best spot to put the
   sum of energies within this critical band. */
void psycho_3_noise_label (FLOAT power[HBLKSIZE], FLOAT energy[BLKSIZE], int *tonelabel, int *noiselabel, FLOAT Xnm[HBLKSIZE]) {
  int i,j;
  
  Xnm[0] = DBMIN;
  for (i=0;i<cbands;i++) {
    /* for each critical band */
    double sum = DBMIN;
    double esum=0;
    double centreweight = 0;
    int centre;
    for (j=cbandindex[i]; j<cbandindex[i+1]; j++) {
      Xnm[j] = DBMIN;
      /* go through all the spectral lines within the critical band, 
	 adding the energies. The tone energies have already been removed */
      if (power[j] != DBMIN) {
	/* Found a noise energy, add it to the sum */
	sum = psycho_3_add_db(power[j], sum);
	
	/* calculations for the geometric mean 
	   FIXME MFC Feb 2003: Would it just be easier to
	   do the *whole* of psycho_1 in the energy domain rather than 
	   in the dB domain? 
	   FIXME: This is just a lazy arsed arithmetic mean. Don't know 
	   if it's really going to make that much difference */
	esum += energy[j]; /* Calculate the sum of energies */
	centreweight += (j - cbandindex[i]) * energy[j]; /* And the energy moment */
      }
    }

    if (sum<=DBMIN) 
      /* If the energy sum is really small, just pretend the noise occurs 
	 in the centre frequency line */
      centre = (cbandindex[i] + cbandindex[i+1])/2;
    else
      /* Otherwise, work out the mean position of the noise, and put it there. */
      centre = cbandindex[i] + (int)(centreweight/esum);

    Xnm[centre] = sum;
    noiselabel[centre] = NOISE;
  }
}

/* ISO11172 D.1 Step 5
   Get rid of noise/tones that aren't greater than the ATH
   If two tones are within 0.5bark, then delete the tone with the lower energy */
void psycho_3_decimation(FLOAT *ath, int *tonelabel, FLOAT *Xtm, int *noiselabel, FLOAT *Xnm, FLOAT *bark) {
  int i;

  /* Delete components which aren't above the ATH */
  for (i=1;i<HBLKSIZE;i++) {
    if (noiselabel[i]==NOISE) {
      if (Xnm[i] < ath[i]) {
	/* this masker isn't above the ATH : delete it */
	Xnm[i] = DBMIN;
	noiselabel[i]=0;
      }
    } 
    if (tonelabel[i] == TONE) {
      if (Xtm[i] < ath[i]) {
	Xtm[i] = DBMIN;
	tonelabel[i]=0;
      }
    }
  }
  /* Search for tones that are within 0.5 bark */
  /* MFC FIXME Feb 2003: haven't done this yet */

}

/* ISO11172 Sect D.1 Step 6
   Calculation of individual masking thresholds
   Work out how each of the tones&noises maskes other frequencies 
   NOTE: Only a subset of other frequencies is checked. According to the 
   standard different subbands are subsampled to different amounts.
   See psycho_3_init and freq_subset */
void psycho_3_threshold(FLOAT *LTg, int *tonelabel, FLOAT *Xtm, int *noiselabel, FLOAT *Xnm, FLOAT *bark, FLOAT *ath, int bit_rate, int *freq_subset) {
  int i,j,k;
  FLOAT LTtm[SUBSIZE];
  FLOAT LTnm[SUBSIZE];

  for (i=0;i<SUBSIZE;i++) {
    LTtm[i] = DBMIN;
    LTnm[i] = DBMIN;
  }
  /* Loop over the entire spectrum and find every noise and tone 
     And then with each noise/tone work out how it masks 
     the spectral lines around it */
  for (k=1;k<HBLKSIZE;k++) {
    /* Find every tone */
    if (tonelabel[k]==TONE) {
      for (j=0;j<SUBSIZE;j++) {
	/* figure out how it masks the levels around it */  
	FLOAT dz = bark[freq_subset[j]] - bark[k];     
	if (dz >= -3.0 && dz < 8.0) {
	  FLOAT vf;
	  FLOAT av = -1.525 - 0.275 * bark[k] - 4.5 + Xtm[k];
	  /* masking function for lower & upper slopes */
	  if (dz < -1)
	    vf = 17 * (dz + 1) - (0.4 * Xtm[k] + 6);
	  else if (dz < 0)
	    vf = (0.4 * Xtm[k] + 6) * dz;
	  else if (dz < 1)
	    vf = (-17 * dz);
	  else
	    vf = -(dz - 1) * (17 - 0.15 * Xtm[k]) - 17;
	  LTtm[j] = psycho_3_add_db (LTtm[j], av + vf);
	}    
      }
    }

    /* find every noise label */
    if (noiselabel[k]==NOISE) {
      for (j=0;j<SUBSIZE;j++) {
	/* figure out how it masks the levels around it */  
	FLOAT dz = bark[freq_subset[j]] - bark[k];     
	if (dz >= -3.0 && dz < 8.0) {
	  FLOAT vf;
	  FLOAT av = -1.525 - 0.175 * bark[k] - 0.5 + Xnm[k]; 
	  /* masking function for lower & upper slopes */
	  if (dz < -1)
	    vf = 17 * (dz + 1) - (0.4 * Xnm[k] + 6);
	  else if (dz < 0)
	    vf = (0.4 * Xnm[k] + 6) * dz;
	  else if (dz < 1)
	    vf = (-17 * dz);
	  else
	    vf = -(dz - 1) * (17 - 0.15 * Xnm[k]) - 17;
	  LTnm[j] = psycho_3_add_db (LTnm[j], av + vf);
	}    
      }
    }
  }

  /* ISO11172 D.1 Step 7
     Calculate the global masking threhold */
  for (i=0;i<SUBSIZE;i++) {
    LTg[i] = psycho_3_add_db(LTnm[i], LTtm[i]);
    if (bit_rate < 96)
      LTg[i] = psycho_3_add_db(ath[freq_subset[i]], LTg[i]);
    else
      LTg[i] = psycho_3_add_db(ath[freq_subset[i]]-12.0, LTg[i]);
  }
}

  /* Find the minimum LTg for each subband. ISO11172 Sec D.1 Step 8 */
void psycho_3_minimummasking(FLOAT *LTg, double *LTmin, int *freq_subset) {
  int i;

  for (i=0;i<SBLIMIT;i++)
    LTmin[i] = 999999.9;

  for (i=0;i<SUBSIZE;i++) {
    int index = freq_subset[i]>>4;
    if (LTmin[index] > LTg[i]) {
      LTmin[index] = LTg[i];
    }
  }
}

/* ISO11172 Sect D.1 Step 9
   Calculate the signal-to-mask ratio 
   MFC FIXME Feb 2003 for better calling from
   toolame, add a "float SMR[]" array and return it */
void psycho_3_smr(double *LTmin, double *Lsb) {
  int i;
  for (i=0;i<SBLIMIT;i++) {
    LTmin[i] = Lsb[i] - LTmin[i];
  }
}

void psycho_3_init(options *glopts) {
  int i;
  int cbase = 0; /* current base index for the bark range calculation */

  fft_buf = (D1408 *) mem_alloc ((long) sizeof (D1408) * 2, "fft_buf");
  
  /* Initialise the tables for the adding dB */
  psycho_3_init_add_db();
  
  /* For each spectral line calculate the bark and the ATH (in dB) */
  FLOAT sfreq = (FLOAT) s_freq[header->version][header->sampling_frequency] * 1000;
  for (i=1;i<HBLKSIZE; i++) {
    FLOAT freq = i * sfreq/BLKSIZE;
    bark[i] = freq2bark(freq);
    ath[i] = ATH_dB(freq,glopts->athlevel);
  }
  
  { /* Work out the critical bands
       Starting from line 0, all lines within 1 bark of the starting
       bark are added to the same critical band. When a line is greater
       by 1.0 of a bark, start a new critical band.  */
    
    numlines = (int *)calloc(HBLKSIZE, sizeof(int));
    cbval = (float *)calloc(HBLKSIZE, sizeof(float));
    cbandindex[0] = 1;
    for (i=1;i<HBLKSIZE;i++) {
      if ((bark[i] - bark[cbase]) > 1.0) { /* 1 critical band? 1 bark? */
	/* this frequency line is too different from the starting line,
	   (in terms of the bark distance)
	   so make this spectral line the first member of the next critical band */
	cbase = i; /* Start the new critical band from this frequency line */
	cbands++;
	cbandindex[cbands] = cbase;
      } 
      /* partition[i] tells us which critical band the i'th frequency line is in */
      partition[i] = cbands;
      /* keep a count of how many frequency lines are in each partition */
      numlines[cbands]++;
    }
    
    cbands++;
    cbandindex[cbands] = 513; /* Set the top of the last critical band */

    /* For each crtical band calculate the average bark value 
       cbval [central bark value] */
    for (i=1;i<HBLKSIZE;i++) 
      cbval[partition[i]] += bark[i]; /* sum up all the bark values */
    for (i=1;i<CBANDS;i++) {
      if (numlines[i] != 0)
	cbval[i] /= numlines[i]; /* divide by the number of values */
      else {
	cbval[i]=0; /* this isn't a partition */
      }
    }     
  }
  
  {
    /* For Step6 - For the calculation of individual masking thresholds
       the spectral lines are subsampled 
       i.e. no need to work out the masking for every single spectral line.
       Depending upon which subband the calculation is for, you
       can skip a number of lines 
       There are 16 lines per subband -> 32 * 16 = 512 
       Subband 0-2 : Every line        (3 * 16 = 48 lines)
       Subband 3-5 : Every Second line (3 * 16/2 = 24 lines)
       Subband 6-11 : Every 4th line   (6 * 16/4 = 24 lines)
       Subband 12-31 : Every 12th line (20 * 16/8 = 40 lines) 
       
       create this subset of frequencies (freq_subset) */
    int freq_index=0;
    for (i=1;i<(3*16)+1;i++) 
      freq_subset[freq_index++] = i;
    for (;i<(6*16)+1;i+=2)
      freq_subset[freq_index++] = i;
    for (;i<(12*16)+1;i+=4)
      freq_subset[freq_index++] = i;
    for (;i<(32*16)+1;i+=8)
      freq_subset[freq_index++] = i;
  }

  if (glopts->verbosity > 4) {
    fprintf(stdout,"%i critical bands\n",cbands);
    for (i=0;i<cbands;i++)
      fprintf(stdout,"cband %i spectral line index %i\n",i,cbandindex[i]);
    fprintf(stdout,"%i Subsampled spectral lines\n",SUBSIZE);
    for (i=0;i<SUBSIZE;i++) 
      fprintf(stdout,"%i Spectral line %i Bark %.2f\n",i,freq_subset[i], bark[freq_subset[i]]);
  }
}

void psycho_3_dump(int *tonelabel, FLOAT *Xtm, int *noiselabel, FLOAT *Xnm) {
  int i;
  fprintf(stdout,"3 Ton:");
  for (i=1;i<HAN_SIZE;i++) {
    if (tonelabel[i] == TONE)
      fprintf(stdout,"[%i] %3.0f ",i,Xtm[i]);
  }
  fprintf(stdout,"\n");  

  fprintf(stdout,"3 Nos:");
  for (i=1;i<HAN_SIZE;i++) {
    if (noiselabel[i] == NOISE)
      fprintf(stdout,"[%i] %3.0f ",i,Xnm[i]);
  }
  fprintf(stdout,"\n");
}