/* 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;
}
}
}
/* 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. */
static void psycho_3_noise_label(psycho_3_mem * mem, FLOAT power[HBLKSIZE], FLOAT energy[BLKSIZE],
int *tonelabel, int *noiselabel, FLOAT Xnm[HBLKSIZE])
{
int i, j;
int cbands = mem->cbands;
int *cbandindex = mem->cbandindex;
Xnm[0] = DBMIN;
for (i = 0; i < cbands; i++) {
/* for each critical band */
FLOAT sum = DBMIN;
FLOAT esum = 0;
FLOAT 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(mem, 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 */
}
}
/* MEANX, crash on AMD64 without this hack. See
https://sourceforge.net/tracker/?func=detail&atid=735435&aid=1453400&group_id=136040
Probably a better way to do this */
if (sum <= DBMIN || esum < 0.00001)
/* 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);
}
// /MEANX
Xnm[centre] = sum;
noiselabel[centre] = NOISE;
}
}
/* 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 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]);
}
}
