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Member "ffmpeg-3.4.2/libavcodec/aaccoder_trellis.h" (31 Dec 2017, 7218 Bytes) of package /linux/misc/ffmpeg-3.4.2.tar.xz:


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    1 /*
    2  * AAC encoder trellis codebook selector
    3  * Copyright (C) 2008-2009 Konstantin Shishkov
    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 trellis codebook selector
   25  * @author Konstantin Shishkov
   26  */
   27 
   28 /**
   29  * This file contains a template for the codebook_trellis_rate selector function.
   30  * It needs to be provided, externally, as an already included declaration,
   31  * the following functions from aacenc_quantization/util.h. They're not included
   32  * explicitly here to make it possible to provide alternative implementations:
   33  *  - quantize_band_cost_bits
   34  *  - abs_pow34_v
   35  */
   36 
   37 #ifndef AVCODEC_AACCODER_TRELLIS_H
   38 #define AVCODEC_AACCODER_TRELLIS_H
   39 
   40 #include <float.h>
   41 #include "libavutil/mathematics.h"
   42 #include "avcodec.h"
   43 #include "put_bits.h"
   44 #include "aac.h"
   45 #include "aacenc.h"
   46 #include "aactab.h"
   47 #include "aacenctab.h"
   48 
   49 /**
   50  * structure used in optimal codebook search
   51  */
   52 typedef struct TrellisBandCodingPath {
   53     int prev_idx; ///< pointer to the previous path point
   54     float cost;   ///< path cost
   55     int run;
   56 } TrellisBandCodingPath;
   57 
   58 
   59 static void codebook_trellis_rate(AACEncContext *s, SingleChannelElement *sce,
   60                                   int win, int group_len, const float lambda)
   61 {
   62     TrellisBandCodingPath path[120][CB_TOT_ALL];
   63     int w, swb, cb, start, size;
   64     int i, j;
   65     const int max_sfb  = sce->ics.max_sfb;
   66     const int run_bits = sce->ics.num_windows == 1 ? 5 : 3;
   67     const int run_esc  = (1 << run_bits) - 1;
   68     int idx, ppos, count;
   69     int stackrun[120], stackcb[120], stack_len;
   70     float next_minbits = INFINITY;
   71     int next_mincb = 0;
   72 
   73     s->abs_pow34(s->scoefs, sce->coeffs, 1024);
   74     start = win*128;
   75     for (cb = 0; cb < CB_TOT_ALL; cb++) {
   76         path[0][cb].cost     = run_bits+4;
   77         path[0][cb].prev_idx = -1;
   78         path[0][cb].run      = 0;
   79     }
   80     for (swb = 0; swb < max_sfb; swb++) {
   81         size = sce->ics.swb_sizes[swb];
   82         if (sce->zeroes[win*16 + swb]) {
   83             float cost_stay_here = path[swb][0].cost;
   84             float cost_get_here  = next_minbits + run_bits + 4;
   85             if (   run_value_bits[sce->ics.num_windows == 8][path[swb][0].run]
   86                 != run_value_bits[sce->ics.num_windows == 8][path[swb][0].run+1])
   87                 cost_stay_here += run_bits;
   88             if (cost_get_here < cost_stay_here) {
   89                 path[swb+1][0].prev_idx = next_mincb;
   90                 path[swb+1][0].cost     = cost_get_here;
   91                 path[swb+1][0].run      = 1;
   92             } else {
   93                 path[swb+1][0].prev_idx = 0;
   94                 path[swb+1][0].cost     = cost_stay_here;
   95                 path[swb+1][0].run      = path[swb][0].run + 1;
   96             }
   97             next_minbits = path[swb+1][0].cost;
   98             next_mincb = 0;
   99             for (cb = 1; cb < CB_TOT_ALL; cb++) {
  100                 path[swb+1][cb].cost = 61450;
  101                 path[swb+1][cb].prev_idx = -1;
  102                 path[swb+1][cb].run = 0;
  103             }
  104         } else {
  105             float minbits = next_minbits;
  106             int mincb = next_mincb;
  107             int startcb = sce->band_type[win*16+swb];
  108             startcb = aac_cb_in_map[startcb];
  109             next_minbits = INFINITY;
  110             next_mincb = 0;
  111             for (cb = 0; cb < startcb; cb++) {
  112                 path[swb+1][cb].cost = 61450;
  113                 path[swb+1][cb].prev_idx = -1;
  114                 path[swb+1][cb].run = 0;
  115             }
  116             for (cb = startcb; cb < CB_TOT_ALL; cb++) {
  117                 float cost_stay_here, cost_get_here;
  118                 float bits = 0.0f;
  119                 if (cb >= 12 && sce->band_type[win*16+swb] != aac_cb_out_map[cb]) {
  120                     path[swb+1][cb].cost = 61450;
  121                     path[swb+1][cb].prev_idx = -1;
  122                     path[swb+1][cb].run = 0;
  123                     continue;
  124                 }
  125                 for (w = 0; w < group_len; w++) {
  126                     bits += quantize_band_cost_bits(s, &sce->coeffs[start + w*128],
  127                                                &s->scoefs[start + w*128], size,
  128                                                sce->sf_idx[win*16+swb],
  129                                                aac_cb_out_map[cb],
  130                                                0, INFINITY, NULL, NULL, 0);
  131                 }
  132                 cost_stay_here = path[swb][cb].cost + bits;
  133                 cost_get_here  = minbits            + bits + run_bits + 4;
  134                 if (   run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run]
  135                     != run_value_bits[sce->ics.num_windows == 8][path[swb][cb].run+1])
  136                     cost_stay_here += run_bits;
  137                 if (cost_get_here < cost_stay_here) {
  138                     path[swb+1][cb].prev_idx = mincb;
  139                     path[swb+1][cb].cost     = cost_get_here;
  140                     path[swb+1][cb].run      = 1;
  141                 } else {
  142                     path[swb+1][cb].prev_idx = cb;
  143                     path[swb+1][cb].cost     = cost_stay_here;
  144                     path[swb+1][cb].run      = path[swb][cb].run + 1;
  145                 }
  146                 if (path[swb+1][cb].cost < next_minbits) {
  147                     next_minbits = path[swb+1][cb].cost;
  148                     next_mincb = cb;
  149                 }
  150             }
  151         }
  152         start += sce->ics.swb_sizes[swb];
  153     }
  154 
  155     //convert resulting path from backward-linked list
  156     stack_len = 0;
  157     idx       = 0;
  158     for (cb = 1; cb < CB_TOT_ALL; cb++)
  159         if (path[max_sfb][cb].cost < path[max_sfb][idx].cost)
  160             idx = cb;
  161     ppos = max_sfb;
  162     while (ppos > 0) {
  163         av_assert1(idx >= 0);
  164         cb = idx;
  165         stackrun[stack_len] = path[ppos][cb].run;
  166         stackcb [stack_len] = cb;
  167         idx = path[ppos-path[ppos][cb].run+1][cb].prev_idx;
  168         ppos -= path[ppos][cb].run;
  169         stack_len++;
  170     }
  171     //perform actual band info encoding
  172     start = 0;
  173     for (i = stack_len - 1; i >= 0; i--) {
  174         cb = aac_cb_out_map[stackcb[i]];
  175         put_bits(&s->pb, 4, cb);
  176         count = stackrun[i];
  177         memset(sce->zeroes + win*16 + start, !cb, count);
  178         //XXX: memset when band_type is also uint8_t
  179         for (j = 0; j < count; j++) {
  180             sce->band_type[win*16 + start] = cb;
  181             start++;
  182         }
  183         while (count >= run_esc) {
  184             put_bits(&s->pb, run_bits, run_esc);
  185             count -= run_esc;
  186         }
  187         put_bits(&s->pb, run_bits, count);
  188     }
  189 }
  190 
  191 
  192 #endif /* AVCODEC_AACCODER_TRELLIS_H */