/* * AAC encoder intensity stereo * Copyright (C) 2015 Rostislav Pehlivanov * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * AAC encoder Intensity Stereo * @author Rostislav Pehlivanov ( atomnuker gmail com ) */ #include "aacenc.h" #include "aacenc_utils.h" #include "aacenc_is.h" #include "aacenc_quantization.h" struct AACISError ff_aac_is_encoding_err(AACEncContext *s, ChannelElement *cpe, int start, int w, int g, float ener0, float ener1, float ener01, int use_pcoeffs, int phase) { int i, w2; SingleChannelElement *sce0 = &cpe->ch[0]; SingleChannelElement *sce1 = &cpe->ch[1]; float *L = use_pcoeffs ? sce0->pcoeffs : sce0->coeffs; float *R = use_pcoeffs ? sce1->pcoeffs : sce1->coeffs; float *L34 = &s->scoefs[256*0], *R34 = &s->scoefs[256*1]; float *IS = &s->scoefs[256*2], *I34 = &s->scoefs[256*3]; float dist1 = 0.0f, dist2 = 0.0f; struct AACISError is_error = {0}; if (ener01 <= 0 || ener0 <= 0) { is_error.pass = 0; return is_error; } for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) { FFPsyBand *band0 = &s->psy.ch[s->cur_channel+0].psy_bands[(w+w2)*16+g]; FFPsyBand *band1 = &s->psy.ch[s->cur_channel+1].psy_bands[(w+w2)*16+g]; int is_band_type, is_sf_idx = FFMAX(1, sce0->sf_idx[w*16+g]-4); float e01_34 = phase*pos_pow34(ener1/ener0); float maxval, dist_spec_err = 0.0f; float minthr = FFMIN(band0->threshold, band1->threshold); for (i = 0; i < sce0->ics.swb_sizes[g]; i++) IS[i] = (L[start+(w+w2)*128+i] + phase*R[start+(w+w2)*128+i])*sqrt(ener0/ener01); s->abs_pow34(L34, &L[start+(w+w2)*128], sce0->ics.swb_sizes[g]); s->abs_pow34(R34, &R[start+(w+w2)*128], sce0->ics.swb_sizes[g]); s->abs_pow34(I34, IS, sce0->ics.swb_sizes[g]); maxval = find_max_val(1, sce0->ics.swb_sizes[g], I34); is_band_type = find_min_book(maxval, is_sf_idx); dist1 += quantize_band_cost(s, &L[start + (w+w2)*128], L34, sce0->ics.swb_sizes[g], sce0->sf_idx[w*16+g], sce0->band_type[w*16+g], s->lambda / band0->threshold, INFINITY, NULL, NULL, 0); dist1 += quantize_band_cost(s, &R[start + (w+w2)*128], R34, sce1->ics.swb_sizes[g], sce1->sf_idx[w*16+g], sce1->band_type[w*16+g], s->lambda / band1->threshold, INFINITY, NULL, NULL, 0); dist2 += quantize_band_cost(s, IS, I34, sce0->ics.swb_sizes[g], is_sf_idx, is_band_type, s->lambda / minthr, INFINITY, NULL, NULL, 0); for (i = 0; i < sce0->ics.swb_sizes[g]; i++) { dist_spec_err += (L34[i] - I34[i])*(L34[i] - I34[i]); dist_spec_err += (R34[i] - I34[i]*e01_34)*(R34[i] - I34[i]*e01_34); } dist_spec_err *= s->lambda / minthr; dist2 += dist_spec_err; } is_error.pass = dist2 <= dist1; is_error.phase = phase; is_error.error = dist2 - dist1; is_error.dist1 = dist1; is_error.dist2 = dist2; is_error.ener01 = ener01; return is_error; } 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, prev_bt = -1, prev_is = 0; 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; for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) { for (i = 0; i < sce0->ics.swb_sizes[g]; i++) { float coef0 = sce0->coeffs[start+(w+w2)*128+i]; float coef1 = 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; if (prev_is && prev_bt != cpe->ch[1].band_type[w*16+g]) { /** Flip M/S mask and pick the other CB, since it encodes more efficiently */ cpe->ms_mask[w*16+g] = 1; cpe->ch[1].band_type[w*16+g] = (best->phase > 0) ? INTENSITY_BT2 : INTENSITY_BT; } prev_bt = cpe->ch[1].band_type[w*16+g]; count++; } } if (!sce1->zeroes[w*16+g] && sce1->band_type[w*16+g] < RESERVED_BT) prev_sf1 = sce1->sf_idx[w*16+g]; prev_is = cpe->is_mask[w*16+g]; start += sce0->ics.swb_sizes[g]; } } cpe->is_mode = !!count; }