text: /*
   * E-AC-3 encoder
   * Copyright (c) 2011 Justin Ruggles <justin.ruggles@gmail.com>
   *
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  /**
   * @file
   * E-AC-3 encoder
   */
  
  #define AC3ENC_FLOAT 1
  
  #include "libavutil/attributes.h"
  #include "ac3enc.h"
  #include "eac3enc.h"
  #include "eac3_data.h"
  
  
  static const AVClass eac3enc_class = {
      .class_name = "E-AC-3 Encoder",
      .item_name  = av_default_item_name,
      .option     = &ff_ac3_enc_options[2], /* First two options are AC-3 only. */
      .version    = LIBAVUTIL_VERSION_INT,
  };
  
  /**
   * LUT for finding a matching frame exponent strategy index from a set of
   * exponent strategies for a single channel across all 6 blocks.
   */
  static int8_t eac3_frame_expstr_index_tab[3][4][4][4][4][4];
  
  
  av_cold void ff_eac3_exponent_init(void)
  {
      int i;
  
      memset(eac3_frame_expstr_index_tab, -1, sizeof(eac3_frame_expstr_index_tab));
      for (i = 0; i < 32; i++) {
          eac3_frame_expstr_index_tab[ff_eac3_frm_expstr[i][0]-1]
                                     [ff_eac3_frm_expstr[i][1]]
                                     [ff_eac3_frm_expstr[i][2]]
                                     [ff_eac3_frm_expstr[i][3]]
                                     [ff_eac3_frm_expstr[i][4]]
                                     [ff_eac3_frm_expstr[i][5]] = i;
      }
  }
  
  
  void ff_eac3_get_frame_exp_strategy(AC3EncodeContext *s)
  {
      int ch;
  
      if (s->num_blocks < 6) {
          s->use_frame_exp_strategy = 0;
          return;
      }
  
      s->use_frame_exp_strategy = 1;
      for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++) {
          int expstr = eac3_frame_expstr_index_tab[s->exp_strategy[ch][0]-1]
                                                  [s->exp_strategy[ch][1]]
                                                  [s->exp_strategy[ch][2]]
                                                  [s->exp_strategy[ch][3]]
                                                  [s->exp_strategy[ch][4]]
                                                  [s->exp_strategy[ch][5]];
          if (expstr < 0) {
              s->use_frame_exp_strategy = 0;
              break;
          }
          s->frame_exp_strategy[ch] = expstr;
      }
  }
  
  
  
  void ff_eac3_set_cpl_states(AC3EncodeContext *s)
  {
      int ch, blk;
      int first_cpl_coords[AC3_MAX_CHANNELS];
  
      /* set first cpl coords */
      for (ch = 1; ch <= s->fbw_channels; ch++)
          first_cpl_coords[ch] = 1;
      for (blk = 0; blk < s->num_blocks; blk++) {
          AC3Block *block = &s->blocks[blk];
          for (ch = 1; ch <= s->fbw_channels; ch++) {
              if (block->channel_in_cpl[ch]) {
                  if (first_cpl_coords[ch]) {
                      block->new_cpl_coords[ch] = 2;
                      first_cpl_coords[ch]  = 0;
                  }
              } else {
                  first_cpl_coords[ch] = 1;
              }
          }
      }
  
      /* set first cpl leak */
      for (blk = 0; blk < s->num_blocks; blk++) {
          AC3Block *block = &s->blocks[blk];
          if (block->cpl_in_use) {
              block->new_cpl_leak = 2;
              break;
          }
      }
  }
  
  
  void ff_eac3_output_frame_header(AC3EncodeContext *s)
  {
      int blk, ch;
      AC3EncOptions *opt = &s->options;
  
      put_bits(&s->pb, 16, 0x0b77);                   /* sync word */
  
      /* BSI header */
      put_bits(&s->pb,  2, 0);                        /* stream type = independent */
      put_bits(&s->pb,  3, 0);                        /* substream id = 0 */
      put_bits(&s->pb, 11, (s->frame_size / 2) - 1);  /* frame size */
      if (s->bit_alloc.sr_shift) {
          put_bits(&s->pb, 2, 0x3);                   /* fscod2 */
          put_bits(&s->pb, 2, s->bit_alloc.sr_code);  /* sample rate code */
      } else {
          put_bits(&s->pb, 2, s->bit_alloc.sr_code);  /* sample rate code */
          put_bits(&s->pb, 2, s->num_blks_code);      /* number of blocks */
      }
      put_bits(&s->pb, 3, s->channel_mode);           /* audio coding mode */
      put_bits(&s->pb, 1, s->lfe_on);                 /* LFE channel indicator */
      put_bits(&s->pb, 5, s->bitstream_id);           /* bitstream id (EAC3=16) */
      put_bits(&s->pb, 5, -opt->dialogue_level);      /* dialogue normalization level */
      put_bits(&s->pb, 1, 0);                         /* no compression gain */
      /* mixing metadata*/
      put_bits(&s->pb, 1, opt->eac3_mixing_metadata);
      if (opt->eac3_mixing_metadata) {
          if (s->channel_mode > AC3_CHMODE_STEREO)
              put_bits(&s->pb, 2, opt->preferred_stereo_downmix);
          if (s->has_center) {
              put_bits(&s->pb, 3, s->ltrt_center_mix_level);
              put_bits(&s->pb, 3, s->loro_center_mix_level);
          }
          if (s->has_surround) {
              put_bits(&s->pb, 3, s->ltrt_surround_mix_level);
              put_bits(&s->pb, 3, s->loro_surround_mix_level);
          }
          if (s->lfe_on)
              put_bits(&s->pb, 1, 0);
          put_bits(&s->pb, 1, 0);                     /* no program scale */
          put_bits(&s->pb, 1, 0);                     /* no ext program scale */
          put_bits(&s->pb, 2, 0);                     /* no mixing parameters */
          if (s->channel_mode < AC3_CHMODE_STEREO)
              put_bits(&s->pb, 1, 0);                 /* no pan info */
          put_bits(&s->pb, 1, 0);                     /* no frame mix config info */
      }
      /* info metadata*/
      put_bits(&s->pb, 1, opt->eac3_info_metadata);
      if (opt->eac3_info_metadata) {
          put_bits(&s->pb, 3, s->bitstream_mode);
          put_bits(&s->pb, 1, opt->copyright);
          put_bits(&s->pb, 1, opt->original);
          if (s->channel_mode == AC3_CHMODE_STEREO) {
              put_bits(&s->pb, 2, opt->dolby_surround_mode);
              put_bits(&s->pb, 2, opt->dolby_headphone_mode);
          }
          if (s->channel_mode >= AC3_CHMODE_2F2R)
              put_bits(&s->pb, 2, opt->dolby_surround_ex_mode);
          put_bits(&s->pb, 1, opt->audio_production_info);
          if (opt->audio_production_info) {
              put_bits(&s->pb, 5, opt->mixing_level - 80);
              put_bits(&s->pb, 2, opt->room_type);
              put_bits(&s->pb, 1, opt->ad_converter_type);
          }
          put_bits(&s->pb, 1, 0);
      }
      if (s->num_blocks != 6)
          put_bits(&s->pb, 1, !(s->avctx->frame_number % 6)); /* converter sync flag */
      put_bits(&s->pb, 1, 0);                         /* no additional bit stream info */
  
      /* frame header */
      if (s->num_blocks == 6) {
      put_bits(&s->pb, 1, !s->use_frame_exp_strategy);/* exponent strategy syntax */
      put_bits(&s->pb, 1, 0);                         /* aht enabled = no */
      }
      put_bits(&s->pb, 2, 0);                         /* snr offset strategy = 1 */
      put_bits(&s->pb, 1, 0);                         /* transient pre-noise processing enabled = no */
      put_bits(&s->pb, 1, 0);                         /* block switch syntax enabled = no */
      put_bits(&s->pb, 1, 0);                         /* dither flag syntax enabled = no */
      put_bits(&s->pb, 1, 0);                         /* bit allocation model syntax enabled = no */
      put_bits(&s->pb, 1, 0);                         /* fast gain codes enabled = no */
      put_bits(&s->pb, 1, 0);                         /* dba syntax enabled = no */
      put_bits(&s->pb, 1, 0);                         /* skip field syntax enabled = no */
      put_bits(&s->pb, 1, 0);                         /* spx enabled = no */
      /* coupling strategy use flags */
      if (s->channel_mode > AC3_CHMODE_MONO) {
          put_bits(&s->pb, 1, s->blocks[0].cpl_in_use);
          for (blk = 1; blk < s->num_blocks; blk++) {
              AC3Block *block = &s->blocks[blk];
              put_bits(&s->pb, 1, block->new_cpl_strategy);
              if (block->new_cpl_strategy)
                  put_bits(&s->pb, 1, block->cpl_in_use);
          }
      }
      /* exponent strategy */
      if (s->use_frame_exp_strategy) {
          for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++)
              put_bits(&s->pb, 5, s->frame_exp_strategy[ch]);
      } else {
          for (blk = 0; blk < s->num_blocks; blk++)
              for (ch = !s->blocks[blk].cpl_in_use; ch <= s->fbw_channels; ch++)
                  put_bits(&s->pb, 2, s->exp_strategy[ch][blk]);
      }
      if (s->lfe_on) {
          for (blk = 0; blk < s->num_blocks; blk++)
              put_bits(&s->pb, 1, s->exp_strategy[s->lfe_channel][blk]);
      }
      /* E-AC-3 to AC-3 converter exponent strategy (not optional when num blocks == 6) */
      if (s->num_blocks != 6) {
          put_bits(&s->pb, 1, 0);
      } else {
      for (ch = 1; ch <= s->fbw_channels; ch++) {
          if (s->use_frame_exp_strategy)
              put_bits(&s->pb, 5, s->frame_exp_strategy[ch]);
          else
              put_bits(&s->pb, 5, 0);
      }
      }
      /* snr offsets */
      put_bits(&s->pb, 6, s->coarse_snr_offset);
      put_bits(&s->pb, 4, s->fine_snr_offset[1]);
      /* block start info */
      if (s->num_blocks > 1)
          put_bits(&s->pb, 1, 0);
  }
  
  
  AVCodec ff_eac3_encoder = {
      .name            = "eac3",
      .long_name       = NULL_IF_CONFIG_SMALL("ATSC A/52 E-AC-3"),
      .type            = AVMEDIA_TYPE_AUDIO,
      .id              = AV_CODEC_ID_EAC3,
      .priv_data_size  = sizeof(AC3EncodeContext),
      .init            = ff_ac3_float_encode_init,
      .encode2         = ff_ac3_float_encode_frame,
      .close           = ff_ac3_encode_close,
      .sample_fmts     = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_FLTP,
                                                        AV_SAMPLE_FMT_NONE },
      .priv_class      = &eac3enc_class,
      .supported_samplerates = ff_ac3_sample_rate_tab,
      .channel_layouts = ff_ac3_channel_layouts,
      .defaults        = ff_ac3_enc_defaults,
      .caps_internal   = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
  };
  