void ff_aac_search_for_tns(AACEncContext *s, SingleChannelElement *sce)
{
    TemporalNoiseShaping *tns = &sce->tns;
    double gain, coefs[MAX_LPC_ORDER];
    int w, w2, g, count = 0;
    const int mmm = FFMIN(sce->ics.tns_max_bands, sce->ics.max_sfb);
    const int is8 = sce->ics.window_sequence[0] == EIGHT_SHORT_SEQUENCE;
    const int c_bits = is8 ? TNS_Q_BITS_IS8 == 4 : TNS_Q_BITS == 4;
    const int slant = sce->ics.window_sequence[0] == LONG_STOP_SEQUENCE  ? 1 :
                      sce->ics.window_sequence[0] == LONG_START_SEQUENCE ? 0 : 2;

    int sfb_start = av_clip(tns_min_sfb[is8][s->samplerate_index], 0, mmm);
    int sfb_end   = av_clip(sce->ics.num_swb, 0, mmm);
    int order = is8 ? 5 : s->profile == FF_PROFILE_AAC_LOW ? 12 : TNS_MAX_ORDER;

    for (w = 0; w < sce->ics.num_windows; w++) {
        float en[2] = {0.0f, 0.0f};
        int coef_start = w*sce->ics.num_swb + sce->ics.swb_offset[sfb_start];
        int coef_len = sce->ics.swb_offset[sfb_end] - sce->ics.swb_offset[sfb_start];

        for (g = 0;  g < sce->ics.num_swb; g++) {
            if (w*16+g < sfb_start || w*16+g > sfb_end)
                continue;
            for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
                FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
                if ((w+w2)*16+g > sfb_start + ((sfb_end - sfb_start)/2))
                    en[1] += band->energy;
                else
                    en[0] += band->energy;
            }
        }

        if (coef_len <= 0 || (sfb_end - sfb_start) <= 0)
            continue;

        /* LPC */
        gain = ff_lpc_calc_ref_coefs_f(&s->lpc, &sce->coeffs[coef_start],
                                       coef_len, order, coefs);

        if (!order || gain < TNS_GAIN_THRESHOLD_LOW || gain > TNS_GAIN_THRESHOLD_HIGH)
            continue;
        if (is8 && (gain < TNS_GAIN_THRESHOLD_LOW_IS8 || gain > TNS_GAIN_THRESHOLD_HIGH_IS8))
                continue;
        if (is8 || order < 2) {
            tns->n_filt[w] = 1;
            for (g = 0; g < tns->n_filt[w]; g++) {
                tns->length[w][g] = sfb_end - sfb_start;
                tns->direction[w][g] = slant != 2 ? slant : en[0] < en[1];
                tns->order[w][g] = order;
                quantize_coefs(coefs, tns->coef_idx[w][g], tns->coef[w][g],
                               order, c_bits);
            }
        } else {  /* 2 filters due to energy disbalance */
            tns->n_filt[w] = 2;
            for (g = 0; g < tns->n_filt[w]; g++) {
                tns->direction[w][g] = slant != 2 ? slant : en[g] < en[!g];
                tns->order[w][g] = !g ? order/2 : order - tns->order[w][g-1];
                tns->length[w][g] = !g ? (sfb_end - sfb_start)/2 : \
                                    (sfb_end - sfb_start) - tns->length[w][g-1];
                quantize_coefs(&coefs[!g ? 0 : order - tns->order[w][g-1]],
                               tns->coef_idx[w][g], tns->coef[w][g],
                               tns->order[w][g], c_bits);
            }
        }
        count += tns->n_filt[w];
    }
    sce->tns.present = !!count;
}