eac3enc.c
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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 
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  eac3_options, LIBAVUTIL_VERSION_INT };
37 
38 
43 static int8_t eac3_frame_expstr_index_tab[3][4][4][4][4][4];
44 
45 
47 {
48  int i;
49 
51  for (i = 0; i < 32; i++) {
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 
63 {
64  int ch;
65 
66  if (s->num_blocks < 6) {
68  return;
69  }
70 
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) {
81  break;
82  }
83  s->frame_exp_strategy[ch] = expstr;
84  }
85 }
86 
87 
88 
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 
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) {
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 */
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 = CODEC_ID_EAC3,
253  .priv_data_size = sizeof(AC3EncodeContext),
255  .encode = ff_ac3_float_encode_frame,
257  .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_FLT,AV_SAMPLE_FMT_NONE},
258  .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52 E-AC-3"),
259  .priv_class = &eac3enc_class,
260  .channel_layouts = ff_ac3_channel_layouts,
261 };
262 #endif