float thr = band->thr;
if (band->energy > thr) {
- thr = powf(thr, 0.25f) + reduction;
- thr = powf(thr, 4.0f);
+ thr = sqrtf(thr);
+ thr = sqrtf(thr) + reduction;
+ thr *= thr;
+ thr *= thr;
/* This deviates from the 3GPP spec to match the reference encoder.
* It performs min(thr_reduced, max(thr, energy/min_snr)) only for bands
AacPsyBand *band = &pch->band[w+g];
float form_factor = 0.0f;
+ float Temp;
band->energy = 0.0f;
for (i = 0; i < band_sizes[g]; i++) {
band->energy += coefs[start+i] * coefs[start+i];
form_factor += sqrtf(fabs(coefs[start+i]));
}
+ Temp = band->energy > 0 ? sqrtf((float)band_sizes[g] / band->energy) : 0;
band->thr = band->energy * 0.001258925f;
- band->nz_lines = band->energy>0 ? form_factor / powf(band->energy / band_sizes[g], 0.25f) : 0;
+ band->nz_lines = form_factor * sqrtf(Temp);
start += band_sizes[g];
}