static void apply_tns(float coef[1024], TemporalNoiseShaping *tns, IndividualChannelStream *ics, int decode) { const int mmm = FFMIN(ics->tns_max_bands, ics->max_sfb); int w, filt, m, i; int bottom, top, order, start, end, size, inc; float lpc[TNS_MAX_ORDER]; float tmp[TNS_MAX_ORDER]; for (w = 0; w < ics->num_windows; w++) { bottom = ics->num_swb; for (filt = 0; filt < tns->n_filt[w]; filt++) { top = bottom; bottom = FFMAX(0, top - tns->length[w][filt]); order = tns->order[w][filt]; if (order == 0) continue; // tns_decode_coef compute_lpc_coefs(tns->coef[w][filt], order, lpc, 0, 0, 0); start = ics->swb_offset[FFMIN(bottom, mmm)]; end = ics->swb_offset[FFMIN( top, mmm)]; if ((size = end - start) <= 0) continue; if (tns->direction[w][filt]) { inc = -1; start = end - 1; } else { inc = 1; } start += w * 128; if (decode) { // ar filter for (m = 0; m < size; m++, start += inc) for (i = 1; i <= FFMIN(m, order); i++) coef[start] -= coef[start - i * inc] * lpc[i - 1]; } else { // ma filter for (m = 0; m < size; m++, start += inc) { tmp[0] = coef[start]; for (i = 1; i <= FFMIN(m, order); i++) coef[start] += tmp[i] * lpc[i - 1]; for (i = order; i > 0; i--) tmp[i] = tmp[i - 1]; } } } } }