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 "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 static av_cold void eac3_exponent_init(void)
56 {
57  int i;
58 
60  for (i = 0; i < 32; i++) {
62  [ff_eac3_frm_expstr[i][1]]
63  [ff_eac3_frm_expstr[i][2]]
64  [ff_eac3_frm_expstr[i][3]]
65  [ff_eac3_frm_expstr[i][4]]
66  [ff_eac3_frm_expstr[i][5]] = i;
67  }
68 }
69 
70 
72 {
73  int ch;
74 
75  if (s->num_blocks < 6) {
76  s->use_frame_exp_strategy = 0;
77  return;
78  }
79 
80  s->use_frame_exp_strategy = 1;
81  for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++) {
82  int expstr = eac3_frame_expstr_index_tab[s->exp_strategy[ch][0]-1]
83  [s->exp_strategy[ch][1]]
84  [s->exp_strategy[ch][2]]
85  [s->exp_strategy[ch][3]]
86  [s->exp_strategy[ch][4]]
87  [s->exp_strategy[ch][5]];
88  if (expstr < 0) {
89  s->use_frame_exp_strategy = 0;
90  break;
91  }
92  s->frame_exp_strategy[ch] = expstr;
93  }
94 }
95 
96 
97 
99 {
100  int ch, blk;
101  int first_cpl_coords[AC3_MAX_CHANNELS];
102 
103  /* set first cpl coords */
104  for (ch = 1; ch <= s->fbw_channels; ch++)
105  first_cpl_coords[ch] = 1;
106  for (blk = 0; blk < s->num_blocks; blk++) {
107  AC3Block *block = &s->blocks[blk];
108  for (ch = 1; ch <= s->fbw_channels; ch++) {
109  if (block->channel_in_cpl[ch]) {
110  if (first_cpl_coords[ch]) {
111  block->new_cpl_coords[ch] = 2;
112  first_cpl_coords[ch] = 0;
113  }
114  } else {
115  first_cpl_coords[ch] = 1;
116  }
117  }
118  }
119 
120  /* set first cpl leak */
121  for (blk = 0; blk < s->num_blocks; blk++) {
122  AC3Block *block = &s->blocks[blk];
123  if (block->cpl_in_use) {
124  block->new_cpl_leak = 2;
125  break;
126  }
127  }
128 }
129 
130 /**
131  * Write the E-AC-3 frame header to the output bitstream.
132  */
134 {
135  int blk, ch;
136  AC3EncOptions *opt = &s->options;
137 
138  put_bits(pb, 16, 0x0b77); /* sync word */
139 
140  /* BSI header */
141  put_bits(pb, 2, 0); /* stream type = independent */
142  put_bits(pb, 3, 0); /* substream id = 0 */
143  put_bits(pb, 11, (s->frame_size / 2) - 1); /* frame size */
144  put_bits(pb, 2, s->bit_alloc.sr_code); /* sample rate code */
145  put_bits(pb, 2, s->num_blks_code); /* number of blocks */
146  put_bits(pb, 3, s->channel_mode); /* audio coding mode */
147  put_bits(pb, 1, s->lfe_on); /* LFE channel indicator */
148  put_bits(pb, 5, s->bitstream_id); /* bitstream id (EAC3=16) */
149  put_bits(pb, 5, -opt->dialogue_level); /* dialogue normalization level */
150  put_bits(pb, 1, 0); /* no compression gain */
151  /* mixing metadata*/
152  put_bits(pb, 1, opt->eac3_mixing_metadata);
153  if (opt->eac3_mixing_metadata) {
154  if (s->channel_mode > AC3_CHMODE_STEREO)
155  put_bits(pb, 2, opt->preferred_stereo_downmix);
156  if (s->has_center) {
157  put_bits(pb, 3, s->ltrt_center_mix_level);
158  put_bits(pb, 3, s->loro_center_mix_level);
159  }
160  if (s->has_surround) {
161  put_bits(pb, 3, s->ltrt_surround_mix_level);
162  put_bits(pb, 3, s->loro_surround_mix_level);
163  }
164  if (s->lfe_on)
165  put_bits(pb, 1, 0);
166  put_bits(pb, 1, 0); /* no program scale */
167  put_bits(pb, 1, 0); /* no ext program scale */
168  put_bits(pb, 2, 0); /* no mixing parameters */
169  if (s->channel_mode < AC3_CHMODE_STEREO)
170  put_bits(pb, 1, 0); /* no pan info */
171  put_bits(pb, 1, 0); /* no frame mix config info */
172  }
173  /* info metadata*/
174  put_bits(pb, 1, opt->eac3_info_metadata);
175  if (opt->eac3_info_metadata) {
176  put_bits(pb, 3, s->bitstream_mode);
177  put_bits(pb, 1, opt->copyright);
178  put_bits(pb, 1, opt->original);
179  if (s->channel_mode == AC3_CHMODE_STEREO) {
180  put_bits(pb, 2, opt->dolby_surround_mode);
181  put_bits(pb, 2, opt->dolby_headphone_mode);
182  }
183  if (s->channel_mode >= AC3_CHMODE_2F2R)
184  put_bits(pb, 2, opt->dolby_surround_ex_mode);
185  put_bits(pb, 1, opt->audio_production_info);
186  if (opt->audio_production_info) {
187  put_bits(pb, 5, opt->mixing_level - 80);
188  put_bits(pb, 2, opt->room_type);
189  put_bits(pb, 1, opt->ad_converter_type);
190  }
191  put_bits(pb, 1, 0);
192  }
193  if (s->num_blocks != 6)
194  put_bits(pb, 1, !(s->avctx->frame_num % 6)); /* converter sync flag */
195  put_bits(pb, 1, 0); /* no additional bit stream info */
196 
197  /* frame header */
198  if (s->num_blocks == 6) {
199  put_bits(pb, 1, !s->use_frame_exp_strategy); /* exponent strategy syntax */
200  put_bits(pb, 1, 0); /* aht enabled = no */
201  }
202  put_bits(pb, 2, 0); /* snr offset strategy = 1 */
203  put_bits(pb, 1, 0); /* transient pre-noise processing enabled = no */
204  put_bits(pb, 1, 0); /* block switch syntax enabled = no */
205  put_bits(pb, 1, 0); /* dither flag syntax enabled = no */
206  put_bits(pb, 1, 0); /* bit allocation model syntax enabled = no */
207  put_bits(pb, 1, 0); /* fast gain codes enabled = no */
208  put_bits(pb, 1, 0); /* dba syntax enabled = no */
209  put_bits(pb, 1, 0); /* skip field syntax enabled = no */
210  put_bits(pb, 1, 0); /* spx enabled = no */
211  /* coupling strategy use flags */
212  if (s->channel_mode > AC3_CHMODE_MONO) {
213  put_bits(pb, 1, s->blocks[0].cpl_in_use);
214  for (blk = 1; blk < s->num_blocks; blk++) {
215  AC3Block *block = &s->blocks[blk];
216  put_bits(pb, 1, block->new_cpl_strategy);
217  if (block->new_cpl_strategy)
218  put_bits(pb, 1, block->cpl_in_use);
219  }
220  }
221  /* exponent strategy */
222  if (s->use_frame_exp_strategy) {
223  for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++)
224  put_bits(pb, 5, s->frame_exp_strategy[ch]);
225  } else {
226  for (blk = 0; blk < s->num_blocks; blk++)
227  for (ch = !s->blocks[blk].cpl_in_use; ch <= s->fbw_channels; ch++)
228  put_bits(pb, 2, s->exp_strategy[ch][blk]);
229  }
230  if (s->lfe_on) {
231  for (blk = 0; blk < s->num_blocks; blk++)
232  put_bits(pb, 1, s->exp_strategy[s->lfe_channel][blk]);
233  }
234  /* E-AC-3 to AC-3 converter exponent strategy (not optional when num blocks == 6) */
235  if (s->num_blocks != 6) {
236  put_bits(pb, 1, 0);
237  } else {
238  for (ch = 1; ch <= s->fbw_channels; ch++) {
239  if (s->use_frame_exp_strategy)
240  put_bits(pb, 5, s->frame_exp_strategy[ch]);
241  else
242  put_bits(pb, 5, 0);
243  }
244  }
245  /* snr offsets */
246  put_bits(pb, 6, s->coarse_snr_offset);
247  put_bits(pb, 4, s->fine_snr_offset[1]);
248  /* block start info */
249  if (s->num_blocks > 1)
250  put_bits(pb, 1, 0);
251 }
252 
254 {
255  static AVOnce init_static_once = AV_ONCE_INIT;
256  AC3EncodeContext *s = avctx->priv_data;
257 
258  s->eac3 = 1;
259  s->output_frame_header = eac3_output_frame_header;
260 
261  ff_thread_once(&init_static_once, eac3_exponent_init);
262 
263  return ff_ac3_float_encode_init(avctx);
264 }
265 
267  .p.name = "eac3",
268  CODEC_LONG_NAME("ATSC A/52 E-AC-3"),
269  .p.type = AVMEDIA_TYPE_AUDIO,
270  .p.id = AV_CODEC_ID_EAC3,
272  .priv_data_size = sizeof(AC3EncodeContext),
275  .close = ff_ac3_encode_close,
276  .p.sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_FLTP,
278  .p.priv_class = &eac3enc_class,
279  .p.supported_samplerates = ff_ac3_sample_rate_tab,
280  .p.ch_layouts = ff_ac3_ch_layouts,
281  .defaults = ff_ac3_enc_defaults,
282  .caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
283 };
AV_SAMPLE_FMT_FLTP
@ AV_SAMPLE_FMT_FLTP
float, planar
Definition: samplefmt.h:66
AC3EncOptions::mixing_level
int mixing_level
Definition: ac3enc.h:101
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:113
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
thread.h
AC3EncOptions::dialogue_level
int dialogue_level
Definition: ac3enc.h:95
put_bits
static void put_bits(Jpeg2000EncoderContext *s, int val, int n)
put n times val bit
Definition: j2kenc.c:223
AC3EncOptions::dolby_surround_mode
int dolby_surround_mode
Definition: ac3enc.h:99
FFCodec
Definition: codec_internal.h:126
ff_ac3_encode_frame
int ff_ac3_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame, int *got_packet_ptr)
Definition: ac3enc.c:1985
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:71
eac3enc_class
static const AVClass eac3enc_class
Definition: eac3enc.c:38
ff_eac3_set_cpl_states
void ff_eac3_set_cpl_states(AC3EncodeContext *s)
Set coupling states.
Definition: eac3enc.c:98
ff_ac3_enc_options
const AVOption ff_ac3_enc_options[]
Definition: ac3enc.c:84
FFCodec::p
AVCodec p
The public AVCodec.
Definition: codec_internal.h:130
ff_ac3_float_encode_init
int ff_ac3_float_encode_init(AVCodecContext *avctx)
Definition: ac3enc_float.c:97
eac3_exponent_init
static av_cold void eac3_exponent_init(void)
Initialize E-AC-3 exponent tables.
Definition: eac3enc.c:55
FF_CODEC_ENCODE_CB
#define FF_CODEC_ENCODE_CB(func)
Definition: codec_internal.h:295
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:49
ff_ac3_ch_layouts
const AVChannelLayout ff_ac3_ch_layouts[19]
List of supported channel layouts.
Definition: ac3enc.c:156
ff_thread_once
static int ff_thread_once(char *control, void(*routine)(void))
Definition: thread.h:205
AC3EncOptions::eac3_mixing_metadata
int eac3_mixing_metadata
Definition: ac3enc.h:115
av_cold
#define av_cold
Definition: attributes.h:90
s
#define s(width, name)
Definition: cbs_vp9.c:198
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
eac3_data.h
AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE
#define AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE
This encoder can reorder user opaque values from input AVFrames and return them with corresponding ou...
Definition: codec.h:159
AC3EncOptions::audio_production_info
int audio_production_info
Definition: ac3enc.h:100
blk
#define blk(i)
Definition: sha.c:186
eac3_output_frame_header
static void eac3_output_frame_header(AC3EncodeContext *s, PutBitContext *pb)
Write the E-AC-3 frame header to the output bitstream.
Definition: eac3enc.c:133
PutBitContext
Definition: put_bits.h:50
CODEC_LONG_NAME
#define CODEC_LONG_NAME(str)
Definition: codec_internal.h:271
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
AV_ONCE_INIT
#define AV_ONCE_INIT
Definition: thread.h:203
AC3EncOptions::ad_converter_type
int ad_converter_type
Definition: ac3enc.h:114
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:158
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:103
AVOnce
#define AVOnce
Definition: thread.h:202
AC3Block
Data for a single audio block.
Definition: ac3enc.h:128
ff_eac3_encoder
const FFCodec ff_eac3_encoder
Definition: eac3enc.c:266
AV_CODEC_ID_EAC3
@ AV_CODEC_ID_EAC3
Definition: codec_id.h:480
init
int(* init)(AVBSFContext *ctx)
Definition: dts2pts.c:366
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:116
AC3EncOptions::dolby_surround_ex_mode
int dolby_surround_ex_mode
Definition: ac3enc.h:112
codec_internal.h
AV_SAMPLE_FMT_NONE
@ AV_SAMPLE_FMT_NONE
Definition: samplefmt.h:56
eac3_encode_init
static av_cold int eac3_encode_init(AVCodecContext *avctx)
Definition: eac3enc.c:253
AC3EncOptions::room_type
int room_type
Definition: ac3enc.h:102
AC3EncOptions
Encoding Options used by AVOption.
Definition: ac3enc.h:93
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:256
AVSampleFormat
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:55
AC3EncOptions::original
int original
Definition: ac3enc.h:104
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:194
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
AC3EncOptions::preferred_stereo_downmix
int preferred_stereo_downmix
Definition: ac3enc.h:106
AVCodecContext
main external API structure.
Definition: avcodec.h:445
ff_ac3_enc_defaults
const FFCodecDefault ff_ac3_enc_defaults[]
Definition: ac3enc.c:141
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:472
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:2158
block
The exact code depends on how similar the blocks are and how related they are to the block
Definition: filter_design.txt:207
put_bits.h