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
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)33 struct 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
ff_aac_search_for_is(AACEncContext * s,AVCodecContext * avctx,ChannelElement * cpe)98 void 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