libavcodec/eac3enc.c

   1 /*
   2  * E-AC-3 encoder
   3  * Copyright (c) 2011 Justin Ruggles <justin.ruggles@gmail.com>
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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  * E-AC-3 encoder
  25  */
  26
  27 #define CONFIG_AC3ENC_FLOAT 1
  28 #include "ac3enc.h"
  29 #include "eac3enc.h"
  30 #include "eac3_data.h"
  31
  32
  33 #define AC3ENC_TYPE AC3ENC_TYPE_EAC3
  34 #include "ac3enc_opts_template.c"
  35 static const AVClass eac3enc_class = { "E-AC-3 Encoder", av_default_item_name,
  36                                        ac3_options, LIBAVUTIL_VERSION_INT };
  37
  38
  39 /**
  40  * LUT for finding a matching frame exponent strategy index from a set of
  41  * exponent strategies for a single channel across all 6 blocks.
  42  */
  43 static int8_t eac3_frame_expstr_index_tab[3][4][4][4][4][4];
  44
  45
  46 void ff_eac3_exponent_init(void)
  47 {
  48     int i;
  49
  50     memset(eac3_frame_expstr_index_tab, -1, sizeof(eac3_frame_expstr_index_tab));
  51     for (i = 0; i < 32; i++) {
  52         eac3_frame_expstr_index_tab[ff_eac3_frm_expstr[i][0]-1]
  53                                    [ff_eac3_frm_expstr[i][1]]
  54                                    [ff_eac3_frm_expstr[i][2]]
  55                                    [ff_eac3_frm_expstr[i][3]]
  56                                    [ff_eac3_frm_expstr[i][4]]
  57                                    [ff_eac3_frm_expstr[i][5]] = i;
  58     }
  59 }
  60
  61
  62 void ff_eac3_get_frame_exp_strategy(AC3EncodeContext *s)
  63 {
  64     int ch;
  65
  66     if (s->num_blocks < 6) {
  67         s->use_frame_exp_strategy = 0;
  68         return;
  69     }
  70
  71     s->use_frame_exp_strategy = 1;
  72     for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++) {
  73         int expstr = eac3_frame_expstr_index_tab[s->exp_strategy[ch][0]-1]
  74                                                 [s->exp_strategy[ch][1]]
  75                                                 [s->exp_strategy[ch][2]]
  76                                                 [s->exp_strategy[ch][3]]
  77                                                 [s->exp_strategy[ch][4]]
  78                                                 [s->exp_strategy[ch][5]];
  79         if (expstr < 0) {
  80             s->use_frame_exp_strategy = 0;
  81             break;
  82         }
  83         s->frame_exp_strategy[ch] = expstr;
  84     }
  85 }
  86
  87
  88
  89 void ff_eac3_set_cpl_states(AC3EncodeContext *s)
  90 {
  91     int ch, blk;
  92     int first_cpl_coords[AC3_MAX_CHANNELS];
  93
  94     /* set first cpl coords */
  95     for (ch = 1; ch <= s->fbw_channels; ch++)
  96         first_cpl_coords[ch] = 1;
  97     for (blk = 0; blk < s->num_blocks; blk++) {
  98         AC3Block *block = &s->blocks[blk];
  99         for (ch = 1; ch <= s->fbw_channels; ch++) {
 100             if (block->channel_in_cpl[ch]) {
 101                 if (first_cpl_coords[ch]) {
 102                     block->new_cpl_coords[ch] = 2;
 103                     first_cpl_coords[ch]  = 0;
 104                 }
 105             } else {
 106                 first_cpl_coords[ch] = 1;
 107             }
 108         }
 109     }
 110
 111     /* set first cpl leak */
 112     for (blk = 0; blk < s->num_blocks; blk++) {
 113         AC3Block *block = &s->blocks[blk];
 114         if (block->cpl_in_use) {
 115             block->new_cpl_leak = 2;
 116             break;
 117         }
 118     }
 119 }
 120
 121
 122 void ff_eac3_output_frame_header(AC3EncodeContext *s)
 123 {
 124     int blk, ch;
 125     AC3EncOptions *opt = &s->options;
 126
 127     put_bits(&s->pb, 16, 0x0b77);                   /* sync word */
 128
 129     /* BSI header */
 130     put_bits(&s->pb,  2, 0);                        /* stream type = independent */
 131     put_bits(&s->pb,  3, 0);                        /* substream id = 0 */
 132     put_bits(&s->pb, 11, (s->frame_size / 2) - 1);  /* frame size */
 133     if (s->bit_alloc.sr_shift) {
 134         put_bits(&s->pb, 2, 0x3);                   /* fscod2 */
 135         put_bits(&s->pb, 2, s->bit_alloc.sr_code);  /* sample rate code */
 136     } else {
 137         put_bits(&s->pb, 2, s->bit_alloc.sr_code);  /* sample rate code */
 138         put_bits(&s->pb, 2, s->num_blks_code);      /* number of blocks */
 139     }
 140     put_bits(&s->pb, 3, s->channel_mode);           /* audio coding mode */
 141     put_bits(&s->pb, 1, s->lfe_on);                 /* LFE channel indicator */
 142     put_bits(&s->pb, 5, s->bitstream_id);           /* bitstream id (EAC3=16) */
 143     put_bits(&s->pb, 5, -opt->dialogue_level);      /* dialogue normalization level */
 144     put_bits(&s->pb, 1, 0);                         /* no compression gain */
 145     /* mixing metadata*/
 146     put_bits(&s->pb, 1, opt->eac3_mixing_metadata);
 147     if (opt->eac3_mixing_metadata) {
 148         if (s->channel_mode > AC3_CHMODE_STEREO)
 149             put_bits(&s->pb, 2, opt->preferred_stereo_downmix);
 150         if (s->has_center) {
 151             put_bits(&s->pb, 3, s->ltrt_center_mix_level);
 152             put_bits(&s->pb, 3, s->loro_center_mix_level);
 153         }
 154         if (s->has_surround) {
 155             put_bits(&s->pb, 3, s->ltrt_surround_mix_level);
 156             put_bits(&s->pb, 3, s->loro_surround_mix_level);
 157         }
 158         if (s->lfe_on)
 159             put_bits(&s->pb, 1, 0);
 160         put_bits(&s->pb, 1, 0);                     /* no program scale */
 161         put_bits(&s->pb, 1, 0);                     /* no ext program scale */
 162         put_bits(&s->pb, 2, 0);                     /* no mixing parameters */
 163         if (s->channel_mode < AC3_CHMODE_STEREO)
 164             put_bits(&s->pb, 1, 0);                 /* no pan info */
 165         put_bits(&s->pb, 1, 0);                     /* no frame mix config info */
 166     }
 167     /* info metadata*/
 168     put_bits(&s->pb, 1, opt->eac3_info_metadata);
 169     if (opt->eac3_info_metadata) {
 170         put_bits(&s->pb, 3, s->bitstream_mode);
 171         put_bits(&s->pb, 1, opt->copyright);
 172         put_bits(&s->pb, 1, opt->original);
 173         if (s->channel_mode == AC3_CHMODE_STEREO) {
 174             put_bits(&s->pb, 2, opt->dolby_surround_mode);
 175             put_bits(&s->pb, 2, opt->dolby_headphone_mode);
 176         }
 177         if (s->channel_mode >= AC3_CHMODE_2F2R)
 178             put_bits(&s->pb, 2, opt->dolby_surround_ex_mode);
 179         put_bits(&s->pb, 1, opt->audio_production_info);
 180         if (opt->audio_production_info) {
 181             put_bits(&s->pb, 5, opt->mixing_level - 80);
 182             put_bits(&s->pb, 2, opt->room_type);
 183             put_bits(&s->pb, 1, opt->ad_converter_type);
 184         }
 185         put_bits(&s->pb, 1, 0);
 186     }
 187     if (s->num_blocks != 6)
 188         put_bits(&s->pb, 1, !(s->avctx->frame_number % 6)); /* converter sync flag */
 189     put_bits(&s->pb, 1, 0);                         /* no additional bit stream info */
 190
 191     /* frame header */
 192     if (s->num_blocks == 6) {
 193     put_bits(&s->pb, 1, !s->use_frame_exp_strategy);/* exponent strategy syntax */
 194     put_bits(&s->pb, 1, 0);                         /* aht enabled = no */
 195     }
 196     put_bits(&s->pb, 2, 0);                         /* snr offset strategy = 1 */
 197     put_bits(&s->pb, 1, 0);                         /* transient pre-noise processing enabled = no */
 198     put_bits(&s->pb, 1, 0);                         /* block switch syntax enabled = no */
 199     put_bits(&s->pb, 1, 0);                         /* dither flag syntax enabled = no */
 200     put_bits(&s->pb, 1, 0);                         /* bit allocation model syntax enabled = no */
 201     put_bits(&s->pb, 1, 0);                         /* fast gain codes enabled = no */
 202     put_bits(&s->pb, 1, 0);                         /* dba syntax enabled = no */
 203     put_bits(&s->pb, 1, 0);                         /* skip field syntax enabled = no */
 204     put_bits(&s->pb, 1, 0);                         /* spx enabled = no */
 205     /* coupling strategy use flags */
 206     if (s->channel_mode > AC3_CHMODE_MONO) {
 207         put_bits(&s->pb, 1, s->blocks[0].cpl_in_use);
 208         for (blk = 1; blk < s->num_blocks; blk++) {
 209             AC3Block *block = &s->blocks[blk];
 210             put_bits(&s->pb, 1, block->new_cpl_strategy);
 211             if (block->new_cpl_strategy)
 212                 put_bits(&s->pb, 1, block->cpl_in_use);
 213         }
 214     }
 215     /* exponent strategy */
 216     if (s->use_frame_exp_strategy) {
 217         for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++)
 218             put_bits(&s->pb, 5, s->frame_exp_strategy[ch]);
 219     } else {
 220         for (blk = 0; blk < s->num_blocks; blk++)
 221             for (ch = !s->blocks[blk].cpl_in_use; ch <= s->fbw_channels; ch++)
 222                 put_bits(&s->pb, 2, s->exp_strategy[ch][blk]);
 223     }
 224     if (s->lfe_on) {
 225         for (blk = 0; blk < s->num_blocks; blk++)
 226             put_bits(&s->pb, 1, s->exp_strategy[s->lfe_channel][blk]);
 227     }
 228     /* E-AC-3 to AC-3 converter exponent strategy (not optional when num blocks == 6) */
 229     if (s->num_blocks != 6) {
 230         put_bits(&s->pb, 1, 0);
 231     } else {
 232     for (ch = 1; ch <= s->fbw_channels; ch++) {
 233         if (s->use_frame_exp_strategy)
 234             put_bits(&s->pb, 5, s->frame_exp_strategy[ch]);
 235         else
 236             put_bits(&s->pb, 5, 0);
 237     }
 238     }
 239     /* snr offsets */
 240     put_bits(&s->pb, 6, s->coarse_snr_offset);
 241     put_bits(&s->pb, 4, s->fine_snr_offset[1]);
 242     /* block start info */
 243     if (s->num_blocks > 1)
 244         put_bits(&s->pb, 1, 0);
 245 }
 246
 247
 248 #if CONFIG_EAC3_ENCODER
 249 AVCodec ff_eac3_encoder = {
 250     .name            = "eac3",
 251     .type            = AVMEDIA_TYPE_AUDIO,
 252     .id              = AV_CODEC_ID_EAC3,
 253     .priv_data_size  = sizeof(AC3EncodeContext),
 254     .init            = ff_ac3_encode_init,
 255     .encode2         = ff_ac3_float_encode_frame,
 256     .close           = ff_ac3_encode_close,
 257     .sample_fmts     = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_FLTP,
 258                                                       AV_SAMPLE_FMT_NONE },
 259     .long_name       = NULL_IF_CONFIG_SMALL("ATSC A/52 E-AC-3"),
 260     .priv_class      = &eac3enc_class,
 261     .channel_layouts = ff_ac3_channel_layouts,
 262     .defaults        = ac3_defaults,
 263 };
 264 #endif