1/* 2 * AAC encoder intensity stereo 3 * Copyright (C) 2015 Rostislav Pehlivanov 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22/** 23 * @file 24 * AAC encoder Intensity Stereo 25 * @author Rostislav Pehlivanov ( atomnuker gmail com ) 26 */ 27 28#include "aacenc.h" 29#include "aacenc_utils.h" 30#include "aacenc_is.h" 31#include "aacenc_quantization.h" 32 33struct AACISError ff_aac_is_encoding_err(AACEncContext *s, ChannelElement *cpe, 34 int start, int w, int g, float ener0, 35 float ener1, float ener01, 36 int use_pcoeffs, int phase) 37{ 38 int i, w2; 39 SingleChannelElement *sce0 = &cpe->ch[0]; 40 SingleChannelElement *sce1 = &cpe->ch[1]; 41 float *L = use_pcoeffs ? sce0->pcoeffs : sce0->coeffs; 42 float *R = use_pcoeffs ? sce1->pcoeffs : sce1->coeffs; 43 float *L34 = &s->scoefs[256*0], *R34 = &s->scoefs[256*1]; 44 float *IS = &s->scoefs[256*2], *I34 = &s->scoefs[256*3]; 45 float dist1 = 0.0f, dist2 = 0.0f; 46 struct AACISError is_error = {0}; 47 48 if (ener01 <= 0 || ener0 <= 0) { 49 is_error.pass = 0; 50 return is_error; 51 } 52 53 for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) { 54 FFPsyBand *band0 = &s->psy.ch[s->cur_channel+0].psy_bands[(w+w2)*16+g]; 55 FFPsyBand *band1 = &s->psy.ch[s->cur_channel+1].psy_bands[(w+w2)*16+g]; 56 int is_band_type, is_sf_idx = FFMAX(1, sce0->sf_idx[w*16+g]-4); 57 float e01_34 = phase*pos_pow34(ener1/ener0); 58 float maxval, dist_spec_err = 0.0f; 59 float minthr = FFMIN(band0->threshold, band1->threshold); 60 for (i = 0; i < sce0->ics.swb_sizes[g]; i++) 61 IS[i] = (L[start+(w+w2)*128+i] + phase*R[start+(w+w2)*128+i])*sqrt(ener0/ener01); 62 s->abs_pow34(L34, &L[start+(w+w2)*128], sce0->ics.swb_sizes[g]); 63 s->abs_pow34(R34, &R[start+(w+w2)*128], sce0->ics.swb_sizes[g]); 64 s->abs_pow34(I34, IS, sce0->ics.swb_sizes[g]); 65 maxval = find_max_val(1, sce0->ics.swb_sizes[g], I34); 66 is_band_type = find_min_book(maxval, is_sf_idx); 67 dist1 += quantize_band_cost(s, &L[start + (w+w2)*128], L34, 68 sce0->ics.swb_sizes[g], 69 sce0->sf_idx[w*16+g], 70 sce0->band_type[w*16+g], 71 s->lambda / band0->threshold, INFINITY, NULL, NULL, 0); 72 dist1 += quantize_band_cost(s, &R[start + (w+w2)*128], R34, 73 sce1->ics.swb_sizes[g], 74 sce1->sf_idx[w*16+g], 75 sce1->band_type[w*16+g], 76 s->lambda / band1->threshold, INFINITY, NULL, NULL, 0); 77 dist2 += quantize_band_cost(s, IS, I34, sce0->ics.swb_sizes[g], 78 is_sf_idx, is_band_type, 79 s->lambda / minthr, INFINITY, NULL, NULL, 0); 80 for (i = 0; i < sce0->ics.swb_sizes[g]; i++) { 81 dist_spec_err += (L34[i] - I34[i])*(L34[i] - I34[i]); 82 dist_spec_err += (R34[i] - I34[i]*e01_34)*(R34[i] - I34[i]*e01_34); 83 } 84 dist_spec_err *= s->lambda / minthr; 85 dist2 += dist_spec_err; 86 } 87 88 is_error.pass = dist2 <= dist1; 89 is_error.phase = phase; 90 is_error.error = dist2 - dist1; 91 is_error.dist1 = dist1; 92 is_error.dist2 = dist2; 93 is_error.ener01 = ener01; 94 95 return is_error; 96} 97 98void ff_aac_search_for_is(AACEncContext *s, AVCodecContext *avctx, ChannelElement *cpe) 99{ 100 SingleChannelElement *sce0 = &cpe->ch[0]; 101 SingleChannelElement *sce1 = &cpe->ch[1]; 102 int start = 0, count = 0, w, w2, g, i, prev_sf1 = -1, prev_bt = -1, prev_is = 0; 103 const float freq_mult = avctx->sample_rate/(1024.0f/sce0->ics.num_windows)/2.0f; 104 uint8_t nextband1[128]; 105 106 if (!cpe->common_window) 107 return; 108 109 /** Scout out next nonzero bands */ 110 ff_init_nextband_map(sce1, nextband1); 111 112 for (w = 0; w < sce0->ics.num_windows; w += sce0->ics.group_len[w]) { 113 start = 0; 114 for (g = 0; g < sce0->ics.num_swb; g++) { 115 if (start*freq_mult > INT_STEREO_LOW_LIMIT*(s->lambda/170.0f) && 116 cpe->ch[0].band_type[w*16+g] != NOISE_BT && !cpe->ch[0].zeroes[w*16+g] && 117 cpe->ch[1].band_type[w*16+g] != NOISE_BT && !cpe->ch[1].zeroes[w*16+g] && 118 ff_sfdelta_can_remove_band(sce1, nextband1, prev_sf1, w*16+g)) { 119 float ener0 = 0.0f, ener1 = 0.0f, ener01 = 0.0f, ener01p = 0.0f; 120 struct AACISError ph_err1, ph_err2, *best; 121 for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) { 122 for (i = 0; i < sce0->ics.swb_sizes[g]; i++) { 123 float coef0 = sce0->coeffs[start+(w+w2)*128+i]; 124 float coef1 = sce1->coeffs[start+(w+w2)*128+i]; 125 ener0 += coef0*coef0; 126 ener1 += coef1*coef1; 127 ener01 += (coef0 + coef1)*(coef0 + coef1); 128 ener01p += (coef0 - coef1)*(coef0 - coef1); 129 } 130 } 131 ph_err1 = ff_aac_is_encoding_err(s, cpe, start, w, g, 132 ener0, ener1, ener01p, 0, -1); 133 ph_err2 = ff_aac_is_encoding_err(s, cpe, start, w, g, 134 ener0, ener1, ener01, 0, +1); 135 best = (ph_err1.pass && ph_err1.error < ph_err2.error) ? &ph_err1 : &ph_err2; 136 if (best->pass) { 137 cpe->is_mask[w*16+g] = 1; 138 cpe->ms_mask[w*16+g] = 0; 139 cpe->ch[0].is_ener[w*16+g] = sqrt(ener0 / best->ener01); 140 cpe->ch[1].is_ener[w*16+g] = ener0/ener1; 141 cpe->ch[1].band_type[w*16+g] = (best->phase > 0) ? INTENSITY_BT : INTENSITY_BT2; 142 if (prev_is && prev_bt != cpe->ch[1].band_type[w*16+g]) { 143 /** Flip M/S mask and pick the other CB, since it encodes more efficiently */ 144 cpe->ms_mask[w*16+g] = 1; 145 cpe->ch[1].band_type[w*16+g] = (best->phase > 0) ? INTENSITY_BT2 : INTENSITY_BT; 146 } 147 prev_bt = cpe->ch[1].band_type[w*16+g]; 148 count++; 149 } 150 } 151 if (!sce1->zeroes[w*16+g] && sce1->band_type[w*16+g] < RESERVED_BT) 152 prev_sf1 = sce1->sf_idx[w*16+g]; 153 prev_is = cpe->is_mask[w*16+g]; 154 start += sce0->ics.swb_sizes[g]; 155 } 156 } 157 cpe->is_mode = !!count; 158} 159