git.sesse.net Git - ffmpeg/blob - libavcodec/aacenc_is.c

   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
  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
  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 }