FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/eac3enc.c
Date: 2025-07-08 13:42:56
Exec Total Coverage
Lines: 95 139 68.3%
Functions: 5 5 100.0%
Branches: 34 72 47.2%
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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 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 * E-AC-3 encoder
25 */
26
27 #define AC3ENC_FLOAT 1
28
29 #include "libavutil/attributes.h"
30 #include "libavutil/thread.h"
31 #include "ac3enc.h"
32 #include "codec_internal.h"
33 #include "eac3enc.h"
34 #include "eac3_data.h"
35 #include "put_bits.h"
36
37
38 static const AVClass eac3enc_class = {
39 .class_name = "E-AC-3 Encoder",
40 .item_name = av_default_item_name,
41 .option = &ff_ac3_enc_options[2], /* First two options are AC-3 only. */
42 .version = LIBAVUTIL_VERSION_INT,
43 };
44
45 /**
46 * LUT for finding a matching frame exponent strategy index from a set of
47 * exponent strategies for a single channel across all 6 blocks.
48 */
49 static int8_t eac3_frame_expstr_index_tab[3][4][4][4][4][4];
50
51
52 /**
53 * Initialize E-AC-3 exponent tables.
54 */
55 1 static av_cold void eac3_exponent_init(void)
56 {
57 int i;
58
59 1 memset(eac3_frame_expstr_index_tab, -1, sizeof(eac3_frame_expstr_index_tab));
60
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 33 for (i = 0; i < 32; i++) {
61 32 eac3_frame_expstr_index_tab[ff_eac3_frm_expstr[i][0]-1]
62 32 [ff_eac3_frm_expstr[i][1]]
63 32 [ff_eac3_frm_expstr[i][2]]
64 32 [ff_eac3_frm_expstr[i][3]]
65 32 [ff_eac3_frm_expstr[i][4]]
66 32 [ff_eac3_frm_expstr[i][5]] = i;
67 }
68 1 }
69
70
71 273 void ff_eac3_get_frame_exp_strategy(AC3EncodeContext *s)
72 {
73 int ch;
74
75
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 273 if (s->num_blocks < 6) {
76 ✗ s->use_frame_exp_strategy = 0;
77 ✗ return;
78 }
79
80 273 s->use_frame_exp_strategy = 1;
81
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 1092 for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++) {
82 819 int expstr = eac3_frame_expstr_index_tab[s->exp_strategy[ch][0]-1]
83 819 [s->exp_strategy[ch][1]]
84 819 [s->exp_strategy[ch][2]]
85 819 [s->exp_strategy[ch][3]]
86 819 [s->exp_strategy[ch][4]]
87 819 [s->exp_strategy[ch][5]];
88
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 819 if (expstr < 0) {
89 ✗ s->use_frame_exp_strategy = 0;
90 ✗ break;
91 }
92 819 s->frame_exp_strategy[ch] = expstr;
93 }
94 }
95
96
97
98 273 void ff_eac3_set_cpl_states(AC3EncodeContext *s)
99 {
100 int ch, blk;
101 int first_cpl_coords[AC3_MAX_CHANNELS];
102
103 /* set first cpl coords */
104
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 819 for (ch = 1; ch <= s->fbw_channels; ch++)
105 546 first_cpl_coords[ch] = 1;
106
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 1911 for (blk = 0; blk < s->num_blocks; blk++) {
107 1638 AC3Block *block = &s->blocks[blk];
108
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 4914 for (ch = 1; ch <= s->fbw_channels; ch++) {
109
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 3276 if (block->channel_in_cpl[ch]) {
110
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 3276 if (first_cpl_coords[ch]) {
111 546 block->new_cpl_coords[ch] = 2;
112 546 first_cpl_coords[ch] = 0;
113 }
114 } else {
115 ✗ first_cpl_coords[ch] = 1;
116 }
117 }
118 }
119
120 /* set first cpl leak */
121
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 273 for (blk = 0; blk < s->num_blocks; blk++) {
122 273 AC3Block *block = &s->blocks[blk];
123
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 273 if (block->cpl_in_use) {
124 273 block->new_cpl_leak = 2;
125 273 break;
126 }
127 }
128 273 }
129
130 /**
131 * Write the E-AC-3 frame header to the output bitstream.
132 */
133 273 static void eac3_output_frame_header(AC3EncodeContext *s, PutBitContext *pb)
134 {
135 int blk, ch;
136 273 AC3EncOptions *opt = &s->options;
137
138 273 put_bits_assume_flushed(pb);
139
140 273 put_bits(pb, 16, 0x0b77); /* sync word */
141
142 /* BSI header */
143 273 put_bits(pb, 2, 0); /* stream type = independent */
144 273 put_bits(pb, 3, 0); /* substream id = 0 */
145 273 put_bits(pb, 11, (s->frame_size / 2) - 1); /* frame size */
146 273 put_bits(pb, 2, s->bit_alloc.sr_code); /* sample rate code */
147 273 put_bits(pb, 2, s->num_blks_code); /* number of blocks */
148 273 put_bits(pb, 3, s->channel_mode); /* audio coding mode */
149 273 put_bits(pb, 1, s->lfe_on); /* LFE channel indicator */
150 273 put_bits(pb, 5, s->bitstream_id); /* bitstream id (EAC3=16) */
151 273 put_bits(pb, 5, -opt->dialogue_level); /* dialogue normalization level */
152 273 put_bits(pb, 1, 0); /* no compression gain */
153 /* mixing metadata*/
154 273 put_bits(pb, 1, opt->eac3_mixing_metadata);
155
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 273 if (opt->eac3_mixing_metadata) {
156 ✗ if (s->channel_mode > AC3_CHMODE_STEREO)
157 ✗ put_bits(pb, 2, opt->preferred_stereo_downmix);
158 ✗ if (s->has_center) {
159 ✗ put_bits(pb, 3, s->ltrt_center_mix_level);
160 ✗ put_bits(pb, 3, s->loro_center_mix_level);
161 }
162 ✗ if (s->has_surround) {
163 ✗ put_bits(pb, 3, s->ltrt_surround_mix_level);
164 ✗ put_bits(pb, 3, s->loro_surround_mix_level);
165 }
166 ✗ if (s->lfe_on)
167 ✗ put_bits(pb, 1, 0);
168 ✗ put_bits(pb, 1, 0); /* no program scale */
169 ✗ put_bits(pb, 1, 0); /* no ext program scale */
170 ✗ put_bits(pb, 2, 0); /* no mixing parameters */
171 ✗ if (s->channel_mode < AC3_CHMODE_STEREO)
172 ✗ put_bits(pb, 1, 0); /* no pan info */
173 ✗ put_bits(pb, 1, 0); /* no frame mix config info */
174 }
175 /* info metadata*/
176 273 put_bits(pb, 1, opt->eac3_info_metadata);
177
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 273 if (opt->eac3_info_metadata) {
178 ✗ put_bits(pb, 3, s->bitstream_mode);
179 ✗ put_bits(pb, 1, opt->copyright);
180 ✗ put_bits(pb, 1, opt->original);
181 ✗ if (s->channel_mode == AC3_CHMODE_STEREO) {
182 ✗ put_bits(pb, 2, opt->dolby_surround_mode);
183 ✗ put_bits(pb, 2, opt->dolby_headphone_mode);
184 }
185 ✗ if (s->channel_mode >= AC3_CHMODE_2F2R)
186 ✗ put_bits(pb, 2, opt->dolby_surround_ex_mode);
187 ✗ put_bits(pb, 1, opt->audio_production_info);
188 ✗ if (opt->audio_production_info) {
189 ✗ put_bits(pb, 5, opt->mixing_level - 80);
190 ✗ put_bits(pb, 2, opt->room_type);
191 ✗ put_bits(pb, 1, opt->ad_converter_type);
192 }
193 ✗ put_bits(pb, 1, 0);
194 }
195
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 273 if (s->num_blocks != 6)
196 ✗ put_bits(pb, 1, !(s->avctx->frame_num % 6)); /* converter sync flag */
197 273 put_bits(pb, 1, 0); /* no additional bit stream info */
198
199 /* frame header */
200
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 273 if (s->num_blocks == 6) {
201 273 put_bits(pb, 1, !s->use_frame_exp_strategy); /* exponent strategy syntax */
202 273 put_bits(pb, 1, 0); /* aht enabled = no */
203 }
204 273 put_bits(pb, 2, 0); /* snr offset strategy = 1 */
205 273 put_bits(pb, 1, 0); /* transient pre-noise processing enabled = no */
206 273 put_bits(pb, 1, 0); /* block switch syntax enabled = no */
207 273 put_bits(pb, 1, 0); /* dither flag syntax enabled = no */
208 273 put_bits(pb, 1, 0); /* bit allocation model syntax enabled = no */
209 273 put_bits(pb, 1, 0); /* fast gain codes enabled = no */
210 273 put_bits(pb, 1, 0); /* dba syntax enabled = no */
211 273 put_bits(pb, 1, 0); /* skip field syntax enabled = no */
212 273 put_bits(pb, 1, 0); /* spx enabled = no */
213 /* coupling strategy use flags */
214
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 273 if (s->channel_mode > AC3_CHMODE_MONO) {
215 273 put_bits(pb, 1, s->blocks[0].cpl_in_use);
216
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 1638 for (blk = 1; blk < s->num_blocks; blk++) {
217 1365 AC3Block *block = &s->blocks[blk];
218 1365 put_bits(pb, 1, block->new_cpl_strategy);
219
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 1365 if (block->new_cpl_strategy)
220 ✗ put_bits(pb, 1, block->cpl_in_use);
221 }
222 }
223 /* exponent strategy */
224
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 273 if (s->use_frame_exp_strategy) {
225
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 1092 for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++)
226 819 put_bits(pb, 5, s->frame_exp_strategy[ch]);
227 } else {
228 ✗ for (blk = 0; blk < s->num_blocks; blk++)
229 ✗ for (ch = !s->blocks[blk].cpl_in_use; ch <= s->fbw_channels; ch++)
230 ✗ put_bits(pb, 2, s->exp_strategy[ch][blk]);
231 }
232
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 273 if (s->lfe_on) {
233 ✗ for (blk = 0; blk < s->num_blocks; blk++)
234 ✗ put_bits(pb, 1, s->exp_strategy[s->lfe_channel][blk]);
235 }
236 /* E-AC-3 to AC-3 converter exponent strategy (not optional when num blocks == 6) */
237
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 273 if (s->num_blocks != 6) {
238 ✗ put_bits(pb, 1, 0);
239 } else {
240
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 819 for (ch = 1; ch <= s->fbw_channels; ch++) {
241
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 546 if (s->use_frame_exp_strategy)
242 546 put_bits(pb, 5, s->frame_exp_strategy[ch]);
243 else
244 ✗ put_bits(pb, 5, 0);
245 }
246 }
247 /* snr offsets */
248 273 put_bits(pb, 6, s->coarse_snr_offset);
249 273 put_bits(pb, 4, s->fine_snr_offset[1]);
250 /* block start info */
251
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 273 if (s->num_blocks > 1)
252 273 put_bits(pb, 1, 0);
253 273 }
254
255 1 static av_cold int eac3_encode_init(AVCodecContext *avctx)
256 {
257 static AVOnce init_static_once = AV_ONCE_INIT;
258 1 AC3EncodeContext *s = avctx->priv_data;
259
260 1 s->eac3 = 1;
261 1 s->output_frame_header = eac3_output_frame_header;
262
263 1 ff_thread_once(&init_static_once, eac3_exponent_init);
264
265 1 return ff_ac3_float_encode_init(avctx);
266 }
267
268 const FFCodec ff_eac3_encoder = {
269 .p.name = "eac3",
270 CODEC_LONG_NAME("ATSC A/52 E-AC-3"),
271 .p.type = AVMEDIA_TYPE_AUDIO,
272 .p.id = AV_CODEC_ID_EAC3,
273 .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,
274 .priv_data_size = sizeof(AC3EncodeContext),
275 .init = eac3_encode_init,
276 FF_CODEC_ENCODE_CB(ff_ac3_encode_frame),
277 .close = ff_ac3_encode_close,
278 CODEC_SAMPLEFMTS(AV_SAMPLE_FMT_FLTP),
279 .p.priv_class = &eac3enc_class,
280 CODEC_SAMPLERATES_ARRAY(ff_ac3_sample_rate_tab),
281 CODEC_CH_LAYOUTS_ARRAY(ff_ac3_ch_layouts),
282 .defaults = ff_ac3_enc_defaults,
283 .caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
284 };
285