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aacenc: add a faster version of twoloop as the "fast" coder
Does nothing fancy but still sounds very decent at 128kbps. Still room to improve by bringing in the low pass and PNS management from the main big twoloop which should improve its quality but not sacrifice that much speed. Signed-off-by: Rostislav Pehlivanov <atomnuker@gmail.com>
This commit is contained in:
Rostislav Pehlivanov
parent
3a81775bde
commit
c92cc2d559
@ -396,34 +396,148 @@ static void search_for_quantizers_fast(AVCodecContext *avctx, AACEncContext *s,
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SingleChannelElement *sce,
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const float lambda)
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{
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int i, w, w2, g;
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int minq = 255;
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int start = 0, i, w, w2, g;
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int destbits = avctx->bit_rate * 1024.0 / avctx->sample_rate / avctx->channels * (lambda / 120.f);
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float dists[128] = { 0 }, uplims[128] = { 0 };
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float maxvals[128];
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int fflag, minscaler;
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int its = 0;
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int allz = 0;
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float minthr = INFINITY;
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memset(sce->sf_idx, 0, sizeof(sce->sf_idx));
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// for values above this the decoder might end up in an endless loop
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// due to always having more bits than what can be encoded.
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destbits = FFMIN(destbits, 5800);
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//XXX: some heuristic to determine initial quantizers will reduce search time
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//determine zero bands and upper limits
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for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
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for (g = 0; g < sce->ics.num_swb; g++) {
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start = 0;
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for (g = 0; g < sce->ics.num_swb; g++) {
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int nz = 0;
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float uplim = 0.0f, energy = 0.0f;
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for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
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FFPsyBand *band = &s->psy.ch[s->cur_channel].psy_bands[(w+w2)*16+g];
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if (band->energy <= band->threshold) {
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sce->sf_idx[(w+w2)*16+g] = 218;
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uplim += band->threshold;
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energy += band->energy;
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if (band->energy <= band->threshold || band->threshold == 0.0f) {
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sce->zeroes[(w+w2)*16+g] = 1;
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} else {
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sce->sf_idx[(w+w2)*16+g] = av_clip(SCALE_ONE_POS - SCALE_DIV_512 + log2f(band->threshold), 80, 218);
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sce->zeroes[(w+w2)*16+g] = 0;
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continue;
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}
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minq = FFMIN(minq, sce->sf_idx[(w+w2)*16+g]);
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nz = 1;
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}
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uplims[w*16+g] = uplim *512;
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sce->band_type[w*16+g] = 0;
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sce->zeroes[w*16+g] = !nz;
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if (nz)
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minthr = FFMIN(minthr, uplim);
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allz |= nz;
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start += sce->ics.swb_sizes[g];
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}
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}
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for (i = 0; i < 128; i++) {
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sce->sf_idx[i] = 140;
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//av_clip(sce->sf_idx[i], minq, minq + SCALE_MAX_DIFF - 1);
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for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
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for (g = 0; g < sce->ics.num_swb; g++) {
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if (sce->zeroes[w*16+g]) {
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sce->sf_idx[w*16+g] = SCALE_ONE_POS;
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continue;
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}
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sce->sf_idx[w*16+g] = SCALE_ONE_POS + FFMIN(log2f(uplims[w*16+g]/minthr)*4,59);
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}
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}
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//set the same quantizers inside window groups
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for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w])
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for (g = 0; g < sce->ics.num_swb; g++)
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for (w2 = 1; w2 < sce->ics.group_len[w]; w2++)
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sce->sf_idx[(w+w2)*16+g] = sce->sf_idx[w*16+g];
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if (!allz)
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return;
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abs_pow34_v(s->scoefs, sce->coeffs, 1024);
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ff_quantize_band_cost_cache_init(s);
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for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
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start = w*128;
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for (g = 0; g < sce->ics.num_swb; g++) {
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const float *scaled = s->scoefs + start;
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maxvals[w*16+g] = find_max_val(sce->ics.group_len[w], sce->ics.swb_sizes[g], scaled);
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start += sce->ics.swb_sizes[g];
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}
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}
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//perform two-loop search
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//outer loop - improve quality
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do {
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int tbits, qstep;
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minscaler = sce->sf_idx[0];
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//inner loop - quantize spectrum to fit into given number of bits
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qstep = its ? 1 : 32;
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do {
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int prev = -1;
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tbits = 0;
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for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
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start = w*128;
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for (g = 0; g < sce->ics.num_swb; g++) {
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const float *coefs = sce->coeffs + start;
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const float *scaled = s->scoefs + start;
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int bits = 0;
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int cb;
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float dist = 0.0f;
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if (sce->zeroes[w*16+g] || sce->sf_idx[w*16+g] >= 218) {
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start += sce->ics.swb_sizes[g];
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continue;
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}
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minscaler = FFMIN(minscaler, sce->sf_idx[w*16+g]);
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cb = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]);
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for (w2 = 0; w2 < sce->ics.group_len[w]; w2++) {
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int b;
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dist += quantize_band_cost_cached(s, w + w2, g,
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coefs + w2*128,
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scaled + w2*128,
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sce->ics.swb_sizes[g],
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sce->sf_idx[w*16+g],
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cb, 1.0f, INFINITY,
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&b, NULL, 0);
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bits += b;
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}
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dists[w*16+g] = dist - bits;
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if (prev != -1) {
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bits += ff_aac_scalefactor_bits[sce->sf_idx[w*16+g] - prev + SCALE_DIFF_ZERO];
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}
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tbits += bits;
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start += sce->ics.swb_sizes[g];
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prev = sce->sf_idx[w*16+g];
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}
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}
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if (tbits > destbits) {
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for (i = 0; i < 128; i++)
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if (sce->sf_idx[i] < 218 - qstep)
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sce->sf_idx[i] += qstep;
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} else {
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for (i = 0; i < 128; i++)
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if (sce->sf_idx[i] > 60 - qstep)
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sce->sf_idx[i] -= qstep;
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}
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qstep >>= 1;
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if (!qstep && tbits > destbits*1.02 && sce->sf_idx[0] < 217)
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qstep = 1;
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} while (qstep);
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fflag = 0;
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minscaler = av_clip(minscaler, 60, 255 - SCALE_MAX_DIFF);
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for (w = 0; w < sce->ics.num_windows; w += sce->ics.group_len[w]) {
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for (g = 0; g < sce->ics.num_swb; g++) {
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int prevsc = sce->sf_idx[w*16+g];
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if (dists[w*16+g] > uplims[w*16+g] && sce->sf_idx[w*16+g] > 60) {
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if (find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]-1))
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sce->sf_idx[w*16+g]--;
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else //Try to make sure there is some energy in every band
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sce->sf_idx[w*16+g]-=2;
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}
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sce->sf_idx[w*16+g] = av_clip(sce->sf_idx[w*16+g], minscaler, minscaler + SCALE_MAX_DIFF);
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sce->sf_idx[w*16+g] = FFMIN(sce->sf_idx[w*16+g], 219);
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if (sce->sf_idx[w*16+g] != prevsc)
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fflag = 1;
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sce->band_type[w*16+g] = find_min_book(maxvals[w*16+g], sce->sf_idx[w*16+g]);
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}
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}
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its++;
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} while (fflag && its < 10);
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}
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static void search_for_pns(AACEncContext *s, AVCodecContext *avctx, SingleChannelElement *sce)
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@ -828,7 +942,7 @@ AACCoefficientsEncoder ff_aac_coders[AAC_CODER_NB] = {
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},
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[AAC_CODER_FAST] = {
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search_for_quantizers_fast,
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encode_window_bands_info,
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codebook_trellis_rate,
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quantize_and_encode_band,
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ff_aac_encode_tns_info,
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ff_aac_encode_ltp_info,
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