void ff_aac_search_for_is(AACEncContext *s, AVCodecContext *avctx, ChannelElement *cpe) { SingleChannelElement *sce0 = &cpe->ch[0]; SingleChannelElement *sce1 = &cpe->ch[1]; int start = 0, count = 0, w, w2, g, i, prev_sf1 = -1; const float freq_mult = avctx->sample_rate/(1024.0f/sce0->ics.num_windows)/2.0f; uint8_t nextband1[128]; if (!cpe->common_window) return; /** Scout out next nonzero bands */ ff_init_nextband_map(sce1, nextband1); for (w = 0; w < sce0->ics.num_windows; w += sce0->ics.group_len[w]) { start = 0; for (g = 0; g < sce0->ics.num_swb; g++) { if (start*freq_mult > INT_STEREO_LOW_LIMIT*(s->lambda/170.0f) && cpe->ch[0].band_type[w*16+g] != NOISE_BT && !cpe->ch[0].zeroes[w*16+g] && cpe->ch[1].band_type[w*16+g] != NOISE_BT && !cpe->ch[1].zeroes[w*16+g] && ff_sfdelta_can_remove_band(sce1, nextband1, prev_sf1, w*16+g)) { float ener0 = 0.0f, ener1 = 0.0f, ener01 = 0.0f, ener01p = 0.0f; struct AACISError ph_err1, ph_err2, *best; if (sce0->band_type[w*16+g] == NOISE_BT || sce1->band_type[w*16+g] == NOISE_BT) { start += sce0->ics.swb_sizes[g]; continue; } for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) { for (i = 0; i < sce0->ics.swb_sizes[g]; i++) { float coef0 = fabsf(sce0->coeffs[start+(w+w2)*128+i]); float coef1 = fabsf(sce1->coeffs[start+(w+w2)*128+i]); ener0 += coef0*coef0; ener1 += coef1*coef1; ener01 += (coef0 + coef1)*(coef0 + coef1); ener01p += (coef0 - coef1)*(coef0 - coef1); } } ph_err1 = ff_aac_is_encoding_err(s, cpe, start, w, g, ener0, ener1, ener01p, 0, -1); ph_err2 = ff_aac_is_encoding_err(s, cpe, start, w, g, ener0, ener1, ener01, 0, +1); best = (ph_err1.pass && ph_err1.error < ph_err2.error) ? &ph_err1 : &ph_err2; if (best->pass) { cpe->is_mask[w*16+g] = 1; cpe->ms_mask[w*16+g] = 0; cpe->ch[0].is_ener[w*16+g] = sqrt(ener0 / best->ener01); cpe->ch[1].is_ener[w*16+g] = ener0/ener1; cpe->ch[1].band_type[w*16+g] = (best->phase > 0) ? INTENSITY_BT : INTENSITY_BT2; count++; } } if (!sce1->zeroes[w*16+g] && sce1->band_type[w*16+g] < RESERVED_BT) prev_sf1 = sce1->sf_idx[w*16+g]; start += sce0->ics.swb_sizes[g]; } } cpe->is_mode = !!count; }