FFmpeg
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 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 "ac3enc.h"
31 #include "codec_internal.h"
32 #include "eac3enc.h"
33 #include "eac3_data.h"
34 
35 
36 static const AVClass eac3enc_class = {
37  .class_name = "E-AC-3 Encoder",
38  .item_name = av_default_item_name,
39  .option = &ff_ac3_enc_options[2], /* First two options are AC-3 only. */
40  .version = LIBAVUTIL_VERSION_INT,
41 };
42 
43 /**
44  * LUT for finding a matching frame exponent strategy index from a set of
45  * exponent strategies for a single channel across all 6 blocks.
46  */
47 static int8_t eac3_frame_expstr_index_tab[3][4][4][4][4][4];
48 
49 
51 {
52  int i;
53 
55  for (i = 0; i < 32; i++) {
57  [ff_eac3_frm_expstr[i][1]]
58  [ff_eac3_frm_expstr[i][2]]
59  [ff_eac3_frm_expstr[i][3]]
60  [ff_eac3_frm_expstr[i][4]]
61  [ff_eac3_frm_expstr[i][5]] = i;
62  }
63 }
64 
65 
67 {
68  int ch;
69 
70  if (s->num_blocks < 6) {
71  s->use_frame_exp_strategy = 0;
72  return;
73  }
74 
75  s->use_frame_exp_strategy = 1;
76  for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++) {
77  int expstr = eac3_frame_expstr_index_tab[s->exp_strategy[ch][0]-1]
78  [s->exp_strategy[ch][1]]
79  [s->exp_strategy[ch][2]]
80  [s->exp_strategy[ch][3]]
81  [s->exp_strategy[ch][4]]
82  [s->exp_strategy[ch][5]];
83  if (expstr < 0) {
84  s->use_frame_exp_strategy = 0;
85  break;
86  }
87  s->frame_exp_strategy[ch] = expstr;
88  }
89 }
90 
91 
92 
94 {
95  int ch, blk;
96  int first_cpl_coords[AC3_MAX_CHANNELS];
97 
98  /* set first cpl coords */
99  for (ch = 1; ch <= s->fbw_channels; ch++)
100  first_cpl_coords[ch] = 1;
101  for (blk = 0; blk < s->num_blocks; blk++) {
102  AC3Block *block = &s->blocks[blk];
103  for (ch = 1; ch <= s->fbw_channels; ch++) {
104  if (block->channel_in_cpl[ch]) {
105  if (first_cpl_coords[ch]) {
106  block->new_cpl_coords[ch] = 2;
107  first_cpl_coords[ch] = 0;
108  }
109  } else {
110  first_cpl_coords[ch] = 1;
111  }
112  }
113  }
114 
115  /* set first cpl leak */
116  for (blk = 0; blk < s->num_blocks; blk++) {
117  AC3Block *block = &s->blocks[blk];
118  if (block->cpl_in_use) {
119  block->new_cpl_leak = 2;
120  break;
121  }
122  }
123 }
124 
125 
127 {
128  int blk, ch;
129  AC3EncOptions *opt = &s->options;
130 
131  put_bits(&s->pb, 16, 0x0b77); /* sync word */
132 
133  /* BSI header */
134  put_bits(&s->pb, 2, 0); /* stream type = independent */
135  put_bits(&s->pb, 3, 0); /* substream id = 0 */
136  put_bits(&s->pb, 11, (s->frame_size / 2) - 1); /* frame size */
137  if (s->bit_alloc.sr_shift) {
138  put_bits(&s->pb, 2, 0x3); /* fscod2 */
139  put_bits(&s->pb, 2, s->bit_alloc.sr_code); /* sample rate code */
140  } else {
141  put_bits(&s->pb, 2, s->bit_alloc.sr_code); /* sample rate code */
142  put_bits(&s->pb, 2, s->num_blks_code); /* number of blocks */
143  }
144  put_bits(&s->pb, 3, s->channel_mode); /* audio coding mode */
145  put_bits(&s->pb, 1, s->lfe_on); /* LFE channel indicator */
146  put_bits(&s->pb, 5, s->bitstream_id); /* bitstream id (EAC3=16) */
147  put_bits(&s->pb, 5, -opt->dialogue_level); /* dialogue normalization level */
148  put_bits(&s->pb, 1, 0); /* no compression gain */
149  /* mixing metadata*/
150  put_bits(&s->pb, 1, opt->eac3_mixing_metadata);
151  if (opt->eac3_mixing_metadata) {
152  if (s->channel_mode > AC3_CHMODE_STEREO)
153  put_bits(&s->pb, 2, opt->preferred_stereo_downmix);
154  if (s->has_center) {
155  put_bits(&s->pb, 3, s->ltrt_center_mix_level);
156  put_bits(&s->pb, 3, s->loro_center_mix_level);
157  }
158  if (s->has_surround) {
159  put_bits(&s->pb, 3, s->ltrt_surround_mix_level);
160  put_bits(&s->pb, 3, s->loro_surround_mix_level);
161  }
162  if (s->lfe_on)
163  put_bits(&s->pb, 1, 0);
164  put_bits(&s->pb, 1, 0); /* no program scale */
165  put_bits(&s->pb, 1, 0); /* no ext program scale */
166  put_bits(&s->pb, 2, 0); /* no mixing parameters */
167  if (s->channel_mode < AC3_CHMODE_STEREO)
168  put_bits(&s->pb, 1, 0); /* no pan info */
169  put_bits(&s->pb, 1, 0); /* no frame mix config info */
170  }
171  /* info metadata*/
172  put_bits(&s->pb, 1, opt->eac3_info_metadata);
173  if (opt->eac3_info_metadata) {
174  put_bits(&s->pb, 3, s->bitstream_mode);
175  put_bits(&s->pb, 1, opt->copyright);
176  put_bits(&s->pb, 1, opt->original);
177  if (s->channel_mode == AC3_CHMODE_STEREO) {
178  put_bits(&s->pb, 2, opt->dolby_surround_mode);
179  put_bits(&s->pb, 2, opt->dolby_headphone_mode);
180  }
181  if (s->channel_mode >= AC3_CHMODE_2F2R)
182  put_bits(&s->pb, 2, opt->dolby_surround_ex_mode);
183  put_bits(&s->pb, 1, opt->audio_production_info);
184  if (opt->audio_production_info) {
185  put_bits(&s->pb, 5, opt->mixing_level - 80);
186  put_bits(&s->pb, 2, opt->room_type);
187  put_bits(&s->pb, 1, opt->ad_converter_type);
188  }
189  put_bits(&s->pb, 1, 0);
190  }
191  if (s->num_blocks != 6)
192  put_bits(&s->pb, 1, !(s->avctx->frame_number % 6)); /* converter sync flag */
193  put_bits(&s->pb, 1, 0); /* no additional bit stream info */
194 
195  /* frame header */
196  if (s->num_blocks == 6) {
197  put_bits(&s->pb, 1, !s->use_frame_exp_strategy); /* exponent strategy syntax */
198  put_bits(&s->pb, 1, 0); /* aht enabled = no */
199  }
200  put_bits(&s->pb, 2, 0); /* snr offset strategy = 1 */
201  put_bits(&s->pb, 1, 0); /* transient pre-noise processing enabled = no */
202  put_bits(&s->pb, 1, 0); /* block switch syntax enabled = no */
203  put_bits(&s->pb, 1, 0); /* dither flag syntax enabled = no */
204  put_bits(&s->pb, 1, 0); /* bit allocation model syntax enabled = no */
205  put_bits(&s->pb, 1, 0); /* fast gain codes enabled = no */
206  put_bits(&s->pb, 1, 0); /* dba syntax enabled = no */
207  put_bits(&s->pb, 1, 0); /* skip field syntax enabled = no */
208  put_bits(&s->pb, 1, 0); /* spx enabled = no */
209  /* coupling strategy use flags */
210  if (s->channel_mode > AC3_CHMODE_MONO) {
211  put_bits(&s->pb, 1, s->blocks[0].cpl_in_use);
212  for (blk = 1; blk < s->num_blocks; blk++) {
213  AC3Block *block = &s->blocks[blk];
214  put_bits(&s->pb, 1, block->new_cpl_strategy);
215  if (block->new_cpl_strategy)
216  put_bits(&s->pb, 1, block->cpl_in_use);
217  }
218  }
219  /* exponent strategy */
220  if (s->use_frame_exp_strategy) {
221  for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++)
222  put_bits(&s->pb, 5, s->frame_exp_strategy[ch]);
223  } else {
224  for (blk = 0; blk < s->num_blocks; blk++)
225  for (ch = !s->blocks[blk].cpl_in_use; ch <= s->fbw_channels; ch++)
226  put_bits(&s->pb, 2, s->exp_strategy[ch][blk]);
227  }
228  if (s->lfe_on) {
229  for (blk = 0; blk < s->num_blocks; blk++)
230  put_bits(&s->pb, 1, s->exp_strategy[s->lfe_channel][blk]);
231  }
232  /* E-AC-3 to AC-3 converter exponent strategy (not optional when num blocks == 6) */
233  if (s->num_blocks != 6) {
234  put_bits(&s->pb, 1, 0);
235  } else {
236  for (ch = 1; ch <= s->fbw_channels; ch++) {
237  if (s->use_frame_exp_strategy)
238  put_bits(&s->pb, 5, s->frame_exp_strategy[ch]);
239  else
240  put_bits(&s->pb, 5, 0);
241  }
242  }
243  /* snr offsets */
244  put_bits(&s->pb, 6, s->coarse_snr_offset);
245  put_bits(&s->pb, 4, s->fine_snr_offset[1]);
246  /* block start info */
247  if (s->num_blocks > 1)
248  put_bits(&s->pb, 1, 0);
249 }
250 
251 
254  .p.name = "eac3",
255  CODEC_LONG_NAME("ATSC A/52 E-AC-3"),
256  .p.type = AVMEDIA_TYPE_AUDIO,
257  .p.id = AV_CODEC_ID_EAC3,
258  .p.capabilities = AV_CODEC_CAP_DR1,
259  .priv_data_size = sizeof(AC3EncodeContext),
262  .close = ff_ac3_encode_close,
263  .p.sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_FLTP,
265  .p.priv_class = &eac3enc_class,
266  .p.supported_samplerates = ff_ac3_sample_rate_tab,
267 #if FF_API_OLD_CHANNEL_LAYOUT
268  .p.channel_layouts = ff_ac3_channel_layouts,
269 #endif
270  .p.ch_layouts = ff_ac3_ch_layouts,
271  .defaults = ff_ac3_enc_defaults,
272  .caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
273 };
FF_ENABLE_DEPRECATION_WARNINGS
#define FF_ENABLE_DEPRECATION_WARNINGS
Definition: internal.h:82
AV_SAMPLE_FMT_FLTP
@ AV_SAMPLE_FMT_FLTP
float, planar
Definition: samplefmt.h:66
AC3EncOptions::mixing_level
int mixing_level
Definition: ac3enc.h:102
FF_CODEC_CAP_INIT_CLEANUP
#define FF_CODEC_CAP_INIT_CLEANUP
The codec allows calling the close function for deallocation even if the init function returned a fai...
Definition: codec_internal.h:42
AC3EncOptions::dolby_headphone_mode
int dolby_headphone_mode
Definition: ac3enc.h:114
ff_eac3_frm_expstr
const uint8_t ff_eac3_frm_expstr[32][6]
Table E2.14 Frame Exponent Strategy Combinations.
Definition: eac3_data.c:1064
AC3EncOptions::dialogue_level
int dialogue_level
Definition: ac3enc.h:96
put_bits
static void put_bits(Jpeg2000EncoderContext *s, int val, int n)
put n times val bit
Definition: j2kenc.c:221
AC3EncOptions::dolby_surround_mode
int dolby_surround_mode
Definition: ac3enc.h:100
FFCodec
Definition: codec_internal.h:119
ff_eac3_get_frame_exp_strategy
void ff_eac3_get_frame_exp_strategy(AC3EncodeContext *s)
Determine frame exponent strategy use and indices.
Definition: eac3enc.c:66
eac3enc_class
static const AVClass eac3enc_class
Definition: eac3enc.c:36
ff_ac3_float_encode_frame
int ff_ac3_float_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame, int *got_packet_ptr)
ff_eac3_set_cpl_states
void ff_eac3_set_cpl_states(AC3EncodeContext *s)
Set coupling states.
Definition: eac3enc.c:93
init
static int init
Definition: av_tx.c:47
ff_ac3_enc_options
const AVOption ff_ac3_enc_options[]
Definition: ac3enc.c:81
FFCodec::p
AVCodec p
The public AVCodec.
Definition: codec_internal.h:123
ff_ac3_float_encode_init
int ff_ac3_float_encode_init(AVCodecContext *avctx)
Definition: ac3enc_float.c:114
FF_CODEC_ENCODE_CB
#define FF_CODEC_ENCODE_CB(func)
Definition: codec_internal.h:288
eac3_frame_expstr_index_tab
static int8_t eac3_frame_expstr_index_tab[3][4][4][4][4][4]
LUT for finding a matching frame exponent strategy index from a set of exponent strategies for a sing...
Definition: eac3enc.c:47
ff_ac3_ch_layouts
const AVChannelLayout ff_ac3_ch_layouts[19]
List of supported channel layouts.
Definition: ac3enc.c:177
AC3EncOptions::eac3_mixing_metadata
int eac3_mixing_metadata
Definition: ac3enc.h:116
av_cold
#define av_cold
Definition: attributes.h:90
s
#define s(width, name)
Definition: cbs_vp9.c:256
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
eac3_data.h
ff_eac3_encoder
const FF_DISABLE_DEPRECATION_WARNINGS FFCodec ff_eac3_encoder
Definition: eac3enc.c:253
AC3EncOptions::audio_production_info
int audio_production_info
Definition: ac3enc.h:101
blk
#define blk(i)
Definition: sha.c:186
CODEC_LONG_NAME
#define CODEC_LONG_NAME(str)
Definition: codec_internal.h:264
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
AC3EncOptions::ad_converter_type
int ad_converter_type
Definition: ac3enc.h:115
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:66
ac3enc.h
av_default_item_name
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:237
AC3EncodeContext
AC-3 encoder private context.
Definition: ac3enc.h:157
AC3_MAX_CHANNELS
#define AC3_MAX_CHANNELS
maximum number of channels, including coupling channel
Definition: ac3defs.h:26
AC3EncOptions::copyright
int copyright
Definition: ac3enc.h:104
AC3Block
Data for a single audio block.
Definition: ac3enc.h:129
AV_CODEC_ID_EAC3
@ AV_CODEC_ID_EAC3
Definition: codec_id.h:473
AV_CODEC_CAP_DR1
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
AC3_CHMODE_STEREO
@ AC3_CHMODE_STEREO
Definition: ac3defs.h:57
AC3EncOptions::eac3_info_metadata
int eac3_info_metadata
Definition: ac3enc.h:117
AC3EncOptions::dolby_surround_ex_mode
int dolby_surround_ex_mode
Definition: ac3enc.h:113
codec_internal.h
ff_eac3_output_frame_header
void ff_eac3_output_frame_header(AC3EncodeContext *s)
Write the E-AC-3 frame header to the output bitstream.
Definition: eac3enc.c:126
AV_SAMPLE_FMT_NONE
@ AV_SAMPLE_FMT_NONE
Definition: samplefmt.h:56
AC3EncOptions::room_type
int room_type
Definition: ac3enc.h:103
AC3EncOptions
Encoding Options used by AVOption.
Definition: ac3enc.h:94
attributes.h
eac3enc.h
ff_ac3_sample_rate_tab
const int ff_ac3_sample_rate_tab[]
Definition: ac3tab.c:95
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
AVSampleFormat
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:55
AC3EncOptions::original
int original
Definition: ac3enc.h:105
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:211
AC3_CHMODE_MONO
@ AC3_CHMODE_MONO
Definition: ac3defs.h:56
AVClass::class_name
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:71
AC3_CHMODE_2F2R
@ AC3_CHMODE_2F2R
Definition: ac3defs.h:61
ff_eac3_exponent_init
av_cold void ff_eac3_exponent_init(void)
Initialize E-AC-3 exponent tables.
Definition: eac3enc.c:50
AC3EncOptions::preferred_stereo_downmix
int preferred_stereo_downmix
Definition: ac3enc.h:107
FF_DISABLE_DEPRECATION_WARNINGS
#define FF_DISABLE_DEPRECATION_WARNINGS
Definition: internal.h:81
ff_ac3_enc_defaults
const FFCodecDefault ff_ac3_enc_defaults[]
Definition: ac3enc.c:138
ff_ac3_encode_close
av_cold int ff_ac3_encode_close(AVCodecContext *avctx)
Finalize encoding and free any memory allocated by the encoder.
Definition: ac3enc.c:2168
block
The exact code depends on how similar the blocks are and how related they are to the block
Definition: filter_design.txt:207