/**
* Calculate the allowed distortion for each scalefactor band, as determined by the psychoacoustic
* model. xmin(sb) = ratio(sb) * en(sb) / bw(sb)
*
* <p>returns number of sfb's with energy > ATH
*/
public final int calc_xmin(
final LameGlobalFlags gfp,
final III_psy_ratio ratio,
final GrInfo cod_info,
final float[] pxmin) {
int pxminPos = 0;
final LameInternalFlags gfc = gfp.internal_flags;
int gsfb, j = 0, ath_over = 0;
final ATH ATH = gfc.ATH;
final float[] xr = cod_info.xr;
final int enable_athaa_fix = (gfp.getVBR() == VbrMode.vbr_mtrh) ? 1 : 0;
float masking_lower = gfc.masking_lower;
if (gfp.getVBR() == VbrMode.vbr_mtrh || gfp.getVBR() == VbrMode.vbr_mt) {
/* was already done in PSY-Model */
masking_lower = 1.0f;
}
for (gsfb = 0; gsfb < cod_info.psy_lmax; gsfb++) {
float en0, xmin;
float rh1, rh2;
int width, l;
if (gfp.getVBR() == VbrMode.vbr_rh || gfp.getVBR() == VbrMode.vbr_mtrh)
xmin = athAdjust(ATH.adjust, ATH.l[gsfb], ATH.floor);
else xmin = ATH.adjust * ATH.l[gsfb];
width = cod_info.width[gsfb];
rh1 = xmin / width;
rh2 = DBL_EPSILON;
l = width >> 1;
en0 = 0.0f;
do {
float xa, xb;
xa = xr[j] * xr[j];
en0 += xa;
rh2 += (xa < rh1) ? xa : rh1;
j++;
xb = xr[j] * xr[j];
en0 += xb;
rh2 += (xb < rh1) ? xb : rh1;
j++;
} while (--l > 0);
if (en0 > xmin) ath_over++;
if (gsfb == Encoder.SBPSY_l) {
float x = xmin * gfc.nsPsy.longfact[gsfb];
if (rh2 < x) {
rh2 = x;
}
}
if (enable_athaa_fix != 0) {
xmin = rh2;
}
if (!gfp.ATHonly) {
final float e = ratio.en.l[gsfb];
if (e > 0.0f) {
float x;
x = en0 * ratio.thm.l[gsfb] * masking_lower / e;
if (enable_athaa_fix != 0) x *= gfc.nsPsy.longfact[gsfb];
if (xmin < x) xmin = x;
}
}
if (enable_athaa_fix != 0) pxmin[pxminPos++] = xmin;
else pxmin[pxminPos++] = xmin * gfc.nsPsy.longfact[gsfb];
} /* end of long block loop */
/* use this function to determine the highest non-zero coeff */
int max_nonzero = 575;
if (cod_info.block_type != Encoder.SHORT_TYPE) {
// NORM, START or STOP type, but not SHORT
int k = 576;
while (k-- != 0 && BitStream.EQ(xr[k], 0)) {
max_nonzero = k;
}
}
cod_info.max_nonzero_coeff = max_nonzero;
for (int sfb = cod_info.sfb_smin; gsfb < cod_info.psymax; sfb++, gsfb += 3) {
int width, b;
float tmpATH;
if (gfp.getVBR() == VbrMode.vbr_rh || gfp.getVBR() == VbrMode.vbr_mtrh)
tmpATH = athAdjust(ATH.adjust, ATH.s[sfb], ATH.floor);
else tmpATH = ATH.adjust * ATH.s[sfb];
width = cod_info.width[gsfb];
for (b = 0; b < 3; b++) {
float en0 = 0.0f, xmin;
float rh1, rh2;
int l = width >> 1;
rh1 = tmpATH / width;
rh2 = DBL_EPSILON;
do {
float xa, xb;
xa = xr[j] * xr[j];
en0 += xa;
rh2 += (xa < rh1) ? xa : rh1;
j++;
xb = xr[j] * xr[j];
en0 += xb;
rh2 += (xb < rh1) ? xb : rh1;
j++;
} while (--l > 0);
if (en0 > tmpATH) ath_over++;
if (sfb == Encoder.SBPSY_s) {
float x = tmpATH * gfc.nsPsy.shortfact[sfb];
if (rh2 < x) {
rh2 = x;
}
}
if (enable_athaa_fix != 0) xmin = rh2;
else xmin = tmpATH;
if (!gfp.ATHonly && !gfp.ATHshort) {
final float e = ratio.en.s[sfb][b];
if (e > 0.0f) {
float x;
x = en0 * ratio.thm.s[sfb][b] * masking_lower / e;
if (enable_athaa_fix != 0) x *= gfc.nsPsy.shortfact[sfb];
if (xmin < x) xmin = x;
}
}
if (enable_athaa_fix != 0) pxmin[pxminPos++] = xmin;
else pxmin[pxminPos++] = xmin * gfc.nsPsy.shortfact[sfb];
} /* b */
if (gfp.useTemporal) {
if (pxmin[pxminPos - 3] > pxmin[pxminPos - 3 + 1])
pxmin[pxminPos - 3 + 1] += (pxmin[pxminPos - 3] - pxmin[pxminPos - 3 + 1]) * gfc.decay;
if (pxmin[pxminPos - 3 + 1] > pxmin[pxminPos - 3 + 2])
pxmin[pxminPos - 3 + 2] +=
(pxmin[pxminPos - 3 + 1] - pxmin[pxminPos - 3 + 2]) * gfc.decay;
}
} /* end of short block sfb loop */
return ath_over;
}
