Libav
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 
29 #include "libavutil/attributes.h"
30 #include "ac3enc.h"
31 #include "eac3enc.h"
32 #include "eac3_data.h"
33 
34 
35 #define AC3ENC_TYPE AC3ENC_TYPE_EAC3
36 #include "ac3enc_opts_template.c"
37 static const AVClass eac3enc_class = { "E-AC-3 Encoder", av_default_item_name,
39 
40 
45 static int8_t eac3_frame_expstr_index_tab[3][4][4][4][4][4];
46 
47 
49 {
50  int i;
51 
53  for (i = 0; i < 32; i++) {
55  [ff_eac3_frm_expstr[i][1]]
56  [ff_eac3_frm_expstr[i][2]]
57  [ff_eac3_frm_expstr[i][3]]
58  [ff_eac3_frm_expstr[i][4]]
59  [ff_eac3_frm_expstr[i][5]] = i;
60  }
61 }
62 
63 
65 {
66  int ch;
67 
68  if (s->num_blocks < 6) {
70  return;
71  }
72 
74  for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++) {
75  int expstr = eac3_frame_expstr_index_tab[s->exp_strategy[ch][0]-1]
76  [s->exp_strategy[ch][1]]
77  [s->exp_strategy[ch][2]]
78  [s->exp_strategy[ch][3]]
79  [s->exp_strategy[ch][4]]
80  [s->exp_strategy[ch][5]];
81  if (expstr < 0) {
83  break;
84  }
85  s->frame_exp_strategy[ch] = expstr;
86  }
87 }
88 
89 
90 
92 {
93  int ch, blk;
94  int first_cpl_coords[AC3_MAX_CHANNELS];
95 
96  /* set first cpl coords */
97  for (ch = 1; ch <= s->fbw_channels; ch++)
98  first_cpl_coords[ch] = 1;
99  for (blk = 0; blk < s->num_blocks; blk++) {
100  AC3Block *block = &s->blocks[blk];
101  for (ch = 1; ch <= s->fbw_channels; ch++) {
102  if (block->channel_in_cpl[ch]) {
103  if (first_cpl_coords[ch]) {
104  block->new_cpl_coords[ch] = 2;
105  first_cpl_coords[ch] = 0;
106  }
107  } else {
108  first_cpl_coords[ch] = 1;
109  }
110  }
111  }
112 
113  /* set first cpl leak */
114  for (blk = 0; blk < s->num_blocks; blk++) {
115  AC3Block *block = &s->blocks[blk];
116  if (block->cpl_in_use) {
117  block->new_cpl_leak = 2;
118  break;
119  }
120  }
121 }
122 
123 
125 {
126  int blk, ch;
127  AC3EncOptions *opt = &s->options;
128 
129  put_bits(&s->pb, 16, 0x0b77); /* sync word */
130 
131  /* BSI header */
132  put_bits(&s->pb, 2, 0); /* stream type = independent */
133  put_bits(&s->pb, 3, 0); /* substream id = 0 */
134  put_bits(&s->pb, 11, (s->frame_size / 2) - 1); /* frame size */
135  if (s->bit_alloc.sr_shift) {
136  put_bits(&s->pb, 2, 0x3); /* fscod2 */
137  put_bits(&s->pb, 2, s->bit_alloc.sr_code); /* sample rate code */
138  } else {
139  put_bits(&s->pb, 2, s->bit_alloc.sr_code); /* sample rate code */
140  put_bits(&s->pb, 2, s->num_blks_code); /* number of blocks */
141  }
142  put_bits(&s->pb, 3, s->channel_mode); /* audio coding mode */
143  put_bits(&s->pb, 1, s->lfe_on); /* LFE channel indicator */
144  put_bits(&s->pb, 5, s->bitstream_id); /* bitstream id (EAC3=16) */
145  put_bits(&s->pb, 5, -opt->dialogue_level); /* dialogue normalization level */
146  put_bits(&s->pb, 1, 0); /* no compression gain */
147  /* mixing metadata*/
148  put_bits(&s->pb, 1, opt->eac3_mixing_metadata);
149  if (opt->eac3_mixing_metadata) {
151  put_bits(&s->pb, 2, opt->preferred_stereo_downmix);
152  if (s->has_center) {
153  put_bits(&s->pb, 3, s->ltrt_center_mix_level);
154  put_bits(&s->pb, 3, s->loro_center_mix_level);
155  }
156  if (s->has_surround) {
157  put_bits(&s->pb, 3, s->ltrt_surround_mix_level);
158  put_bits(&s->pb, 3, s->loro_surround_mix_level);
159  }
160  if (s->lfe_on)
161  put_bits(&s->pb, 1, 0);
162  put_bits(&s->pb, 1, 0); /* no program scale */
163  put_bits(&s->pb, 1, 0); /* no ext program scale */
164  put_bits(&s->pb, 2, 0); /* no mixing parameters */
166  put_bits(&s->pb, 1, 0); /* no pan info */
167  put_bits(&s->pb, 1, 0); /* no frame mix config info */
168  }
169  /* info metadata*/
170  put_bits(&s->pb, 1, opt->eac3_info_metadata);
171  if (opt->eac3_info_metadata) {
172  put_bits(&s->pb, 3, s->bitstream_mode);
173  put_bits(&s->pb, 1, opt->copyright);
174  put_bits(&s->pb, 1, opt->original);
175  if (s->channel_mode == AC3_CHMODE_STEREO) {
176  put_bits(&s->pb, 2, opt->dolby_surround_mode);
177  put_bits(&s->pb, 2, opt->dolby_headphone_mode);
178  }
179  if (s->channel_mode >= AC3_CHMODE_2F2R)
180  put_bits(&s->pb, 2, opt->dolby_surround_ex_mode);
181  put_bits(&s->pb, 1, opt->audio_production_info);
182  if (opt->audio_production_info) {
183  put_bits(&s->pb, 5, opt->mixing_level - 80);
184  put_bits(&s->pb, 2, opt->room_type);
185  put_bits(&s->pb, 1, opt->ad_converter_type);
186  }
187  put_bits(&s->pb, 1, 0);
188  }
189  if (s->num_blocks != 6)
190  put_bits(&s->pb, 1, !(s->avctx->frame_number % 6)); /* converter sync flag */
191  put_bits(&s->pb, 1, 0); /* no additional bit stream info */
192 
193  /* frame header */
194  if (s->num_blocks == 6) {
195  put_bits(&s->pb, 1, !s->use_frame_exp_strategy);/* exponent strategy syntax */
196  put_bits(&s->pb, 1, 0); /* aht enabled = no */
197  }
198  put_bits(&s->pb, 2, 0); /* snr offset strategy = 1 */
199  put_bits(&s->pb, 1, 0); /* transient pre-noise processing enabled = no */
200  put_bits(&s->pb, 1, 0); /* block switch syntax enabled = no */
201  put_bits(&s->pb, 1, 0); /* dither flag syntax enabled = no */
202  put_bits(&s->pb, 1, 0); /* bit allocation model syntax enabled = no */
203  put_bits(&s->pb, 1, 0); /* fast gain codes enabled = no */
204  put_bits(&s->pb, 1, 0); /* dba syntax enabled = no */
205  put_bits(&s->pb, 1, 0); /* skip field syntax enabled = no */
206  put_bits(&s->pb, 1, 0); /* spx enabled = no */
207  /* coupling strategy use flags */
208  if (s->channel_mode > AC3_CHMODE_MONO) {
209  put_bits(&s->pb, 1, s->blocks[0].cpl_in_use);
210  for (blk = 1; blk < s->num_blocks; blk++) {
211  AC3Block *block = &s->blocks[blk];
212  put_bits(&s->pb, 1, block->new_cpl_strategy);
213  if (block->new_cpl_strategy)
214  put_bits(&s->pb, 1, block->cpl_in_use);
215  }
216  }
217  /* exponent strategy */
218  if (s->use_frame_exp_strategy) {
219  for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++)
220  put_bits(&s->pb, 5, s->frame_exp_strategy[ch]);
221  } else {
222  for (blk = 0; blk < s->num_blocks; blk++)
223  for (ch = !s->blocks[blk].cpl_in_use; ch <= s->fbw_channels; ch++)
224  put_bits(&s->pb, 2, s->exp_strategy[ch][blk]);
225  }
226  if (s->lfe_on) {
227  for (blk = 0; blk < s->num_blocks; blk++)
228  put_bits(&s->pb, 1, s->exp_strategy[s->lfe_channel][blk]);
229  }
230  /* E-AC-3 to AC-3 converter exponent strategy (not optional when num blocks == 6) */
231  if (s->num_blocks != 6) {
232  put_bits(&s->pb, 1, 0);
233  } else {
234  for (ch = 1; ch <= s->fbw_channels; ch++) {
235  if (s->use_frame_exp_strategy)
236  put_bits(&s->pb, 5, s->frame_exp_strategy[ch]);
237  else
238  put_bits(&s->pb, 5, 0);
239  }
240  }
241  /* snr offsets */
242  put_bits(&s->pb, 6, s->coarse_snr_offset);
243  put_bits(&s->pb, 4, s->fine_snr_offset[1]);
244  /* block start info */
245  if (s->num_blocks > 1)
246  put_bits(&s->pb, 1, 0);
247 }
248 
249 
250 #if CONFIG_EAC3_ENCODER
251 AVCodec ff_eac3_encoder = {
252  .name = "eac3",
253  .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52 E-AC-3"),
254  .type = AVMEDIA_TYPE_AUDIO,
255  .id = AV_CODEC_ID_EAC3,
256  .priv_data_size = sizeof(AC3EncodeContext),
258  .encode2 = ff_ac3_float_encode_frame,
260  .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_FLTP,
262  .priv_class = &eac3enc_class,
263  .channel_layouts = ff_ac3_channel_layouts,
264  .defaults = ac3_defaults,
265 };
266 #endif