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, int phase)
  36 {
  37     int i, w2;
  38     float *L34 = &s->scoefs[256*0], *R34 = &s->scoefs[256*1];
  39     float *IS  = &s->scoefs[256*2], *I34 = &s->scoefs[256*3];
  40     float dist1 = 0.0f, dist2 = 0.0f;
  41     struct AACISError is_error = {0};
  42     SingleChannelElement *sce0 = &cpe->ch[0];
  43     SingleChannelElement *sce1 = &cpe->ch[1];
  44
  45     for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
  46         FFPsyBand *band0 = &s->psy.ch[s->cur_channel+0].psy_bands[(w+w2)*16+g];
  47         FFPsyBand *band1 = &s->psy.ch[s->cur_channel+1].psy_bands[(w+w2)*16+g];
  48         int is_band_type, is_sf_idx = FFMAX(1, sce0->sf_idx[(w+w2)*16+g]-4);
  49         float e01_34 = phase*pow(sqrt(ener1/ener0), 3.0/4.0);
  50         float maxval, dist_spec_err = 0.0f;
  51         float minthr = FFMIN(band0->threshold, band1->threshold);
  52         for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
  53             IS[i] = (sce0->pcoeffs[start+(w+w2)*128+i]+
  54                      phase*sce1->pcoeffs[start+(w+w2)*128+i])*
  55                      sqrt(ener0/ener01);
  56         }
  57         abs_pow34_v(L34, &sce0->coeffs[start+(w+w2)*128], sce0->ics.swb_sizes[g]);
  58         abs_pow34_v(R34, &sce1->coeffs[start+(w+w2)*128], sce0->ics.swb_sizes[g]);
  59         abs_pow34_v(I34, IS,                            sce0->ics.swb_sizes[g]);
  60         maxval = find_max_val(1, sce0->ics.swb_sizes[g], I34);
  61         is_band_type = find_min_book(maxval, is_sf_idx);
  62         dist1 += quantize_band_cost(s, &sce0->coeffs[start + (w+w2)*128], L34,
  63                                     sce0->ics.swb_sizes[g],
  64                                     sce0->sf_idx[(w+w2)*16+g],
  65                                     sce0->band_type[(w+w2)*16+g],
  66                                     s->lambda / band0->threshold, INFINITY, NULL, 0);
  67         dist1 += quantize_band_cost(s, &sce1->coeffs[start + (w+w2)*128], R34,
  68                                     sce1->ics.swb_sizes[g],
  69                                     sce1->sf_idx[(w+w2)*16+g],
  70                                     sce1->band_type[(w+w2)*16+g],
  71                                     s->lambda / band1->threshold, INFINITY, NULL, 0);
  72         dist2 += quantize_band_cost(s, IS, I34, sce0->ics.swb_sizes[g],
  73                                     is_sf_idx, is_band_type,
  74                                     s->lambda / minthr, INFINITY, NULL, 0);
  75         for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
  76             dist_spec_err += (L34[i] - I34[i])*(L34[i] - I34[i]);
  77             dist_spec_err += (R34[i] - I34[i]*e01_34)*(R34[i] - I34[i]*e01_34);
  78         }
  79         dist_spec_err *= s->lambda / minthr;
  80         dist2 += dist_spec_err;
  81     }
  82
  83     is_error.pass = dist2 <= dist1;
  84     is_error.phase = phase;
  85     is_error.error = fabsf(dist1 - dist2);
  86     is_error.dist1 = dist1;
  87     is_error.dist2 = dist2;
  88
  89     return is_error;
  90 }
  91
  92 void ff_aac_search_for_is(AACEncContext *s, AVCodecContext *avctx, ChannelElement *cpe)
  93 {
  94     SingleChannelElement *sce0 = &cpe->ch[0];
  95     SingleChannelElement *sce1 = &cpe->ch[1];
  96     int start = 0, count = 0, w, w2, g, i;
  97     const float freq_mult = avctx->sample_rate/(1024.0f/sce0->ics.num_windows)/2.0f;
  98
  99     if (!cpe->common_window)
 100         return;
 101
 102     for (w = 0; w < sce0->ics.num_windows; w += sce0->ics.group_len[w]) {
 103         start = 0;
 104         for (g = 0;  g < sce0->ics.num_swb; g++) {
 105             if (start*freq_mult > INT_STEREO_LOW_LIMIT*(s->lambda/170.0f) &&
 106                 cpe->ch[0].band_type[w*16+g] != NOISE_BT && !cpe->ch[0].zeroes[w*16+g] &&
 107                 cpe->ch[1].band_type[w*16+g] != NOISE_BT && !cpe->ch[1].zeroes[w*16+g]) {
 108                 float ener0 = 0.0f, ener1 = 0.0f, ener01 = 0.0f;
 109                 struct AACISError ph_err1, ph_err2, *erf;
 110                 for (w2 = 0; w2 < sce0->ics.group_len[w]; w2++) {
 111                     for (i = 0; i < sce0->ics.swb_sizes[g]; i++) {
 112                         float coef0 = sce0->pcoeffs[start+(w+w2)*128+i];
 113                         float coef1 = sce1->pcoeffs[start+(w+w2)*128+i];
 114                         ener0 += coef0*coef0;
 115                         ener1 += coef1*coef1;
 116                         ener01 += (coef0 + coef1)*(coef0 + coef1);
 117                     }
 118                 }
 119                 ph_err1 = ff_aac_is_encoding_err(s, cpe, start, w, g,
 120                                                  ener0, ener1, ener01, -1);
 121                 ph_err2 = ff_aac_is_encoding_err(s, cpe, start, w, g,
 122                                                  ener0, ener1, ener01, +1);
 123                 erf = ph_err1.error < ph_err2.error ? &ph_err1 : &ph_err2;
 124                 if (erf->pass) {
 125                     cpe->is_mask[w*16+g] = 1;
 126                     cpe->ch[0].is_ener[w*16+g] = sqrt(ener0/ener01);
 127                     cpe->ch[1].is_ener[w*16+g] = ener0/ener1;
 128                     cpe->ch[1].band_type[w*16+g] = erf->phase ? INTENSITY_BT : INTENSITY_BT2;
 129                     count++;
 130                 }
 131             }
 132             start += sce0->ics.swb_sizes[g];
 133         }
 134     }
 135     cpe->is_mode = !!count;
 136 }