Function search_for_quantizers_faac

libavcodec/aaccoder.c:671–837

}

static void search_for_quantizers_faac(AVCodecContext *avctx, AACEncContext *s,
                                       SingleChannelElement *sce,
                                       const float lambda)
{
    int start = 0, i, w, w2, g;
    float uplim[128], maxq[128];
    int minq, maxsf;
    float distfact = ((sce->ics.num_windows > 1) ? 85.80 : 147.84) / lambda;
    int last = 0, lastband = 0, curband = 0;
    float avg_energy = 0.0;
    if (sce->ics.num_windows == 1) {
        start = 0;
        for (i = 0; i < 1024; i++) {
            if (i - start >= sce->ics.swb_sizes[curband]) {
                start += sce->ics.swb_sizes[curband];
                curband++;
            }
            if (sce->coeffs[i]) {
                avg_energy += sce->coeffs[i] * sce->coeffs[i];
                last = i;
                lastband = curband;
            }
        }
    } else {
        for (w = 0; w < 8; w++) {
            const float *coeffs = sce->coeffs + w*128;
            start = 0;
            for (i = 0; i < 128; i++) {
                if (i - start >= sce->ics.swb_sizes[curband]) {
                    start += sce->ics.swb_sizes[curband];
                    curband++;
                }
                if (coeffs[i]) {
                    avg_energy += coeffs[i] * coeffs[i];
                    last = FFMAX(last, i);
                    lastband = FFMAX(lastband, curband);
                }
            }
        }
    }
    last++;
    avg_energy /= last;
    if (avg_energy == 0.0f) {
        for (i = 0; i < FF_ARRAY_ELEMS(sce->sf_idx); i++)
            sce->sf_idx[i] = SCALE_ONE_POS;
        return;
    }
    for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
        start = w*128;
        for (g = 0; g < sce->ics.num_swb; g++) {
            float *coefs   = sce->coeffs + start;
            const int size = sce->ics.swb_sizes[g];
            int start2 = start, end2 = start + size, peakpos = start;
            float maxval = -1, thr = 0.0f, t;
            maxq[w*16+g] = 0.0f;
            if (g > lastband) {
                maxq[w*16+g] = 0.0f;
                start += size;