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 "eac3enc.h"
32 #include "eac3_data.h"
33 
34 
35 static const AVClass eac3enc_class = {
36  .class_name = "E-AC-3 Encoder",
37  .item_name = av_default_item_name,
38  .option = &ff_ac3_enc_options[2], /* First two options are AC-3 only. */
39  .version = LIBAVUTIL_VERSION_INT,
40 };
41 
42 /**
43  * LUT for finding a matching frame exponent strategy index from a set of
44  * exponent strategies for a single channel across all 6 blocks.
45  */
46 static int8_t eac3_frame_expstr_index_tab[3][4][4][4][4][4];
47 
48 
50 {
51  int i;
52 
54  for (i = 0; i < 32; i++) {
56  [ff_eac3_frm_expstr[i][1]]
57  [ff_eac3_frm_expstr[i][2]]
58  [ff_eac3_frm_expstr[i][3]]
59  [ff_eac3_frm_expstr[i][4]]
60  [ff_eac3_frm_expstr[i][5]] = i;
61  }
62 }
63 
64 
66 {
67  int ch;
68 
69  if (s->num_blocks < 6) {
70  s->use_frame_exp_strategy = 0;
71  return;
72  }
73 
74  s->use_frame_exp_strategy = 1;
75  for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++) {
76  int expstr = eac3_frame_expstr_index_tab[s->exp_strategy[ch][0]-1]
77  [s->exp_strategy[ch][1]]
78  [s->exp_strategy[ch][2]]
79  [s->exp_strategy[ch][3]]
80  [s->exp_strategy[ch][4]]
81  [s->exp_strategy[ch][5]];
82  if (expstr < 0) {
83  s->use_frame_exp_strategy = 0;
84  break;
85  }
86  s->frame_exp_strategy[ch] = expstr;
87  }
88 }
89 
90 
91 
93 {
94  int ch, blk;
95  int first_cpl_coords[AC3_MAX_CHANNELS];
96 
97  /* set first cpl coords */
98  for (ch = 1; ch <= s->fbw_channels; ch++)
99  first_cpl_coords[ch] = 1;
100  for (blk = 0; blk < s->num_blocks; blk++) {
101  AC3Block *block = &s->blocks[blk];
102  for (ch = 1; ch <= s->fbw_channels; ch++) {
103  if (block->channel_in_cpl[ch]) {
104  if (first_cpl_coords[ch]) {
105  block->new_cpl_coords[ch] = 2;
106  first_cpl_coords[ch] = 0;
107  }
108  } else {
109  first_cpl_coords[ch] = 1;
110  }
111  }
112  }
113 
114  /* set first cpl leak */
115  for (blk = 0; blk < s->num_blocks; blk++) {
116  AC3Block *block = &s->blocks[blk];
117  if (block->cpl_in_use) {
118  block->new_cpl_leak = 2;
119  break;
120  }
121  }
122 }
123 
124 
126 {
127  int blk, ch;
128  AC3EncOptions *opt = &s->options;
129 
130  put_bits(&s->pb, 16, 0x0b77); /* sync word */
131 
132  /* BSI header */
133  put_bits(&s->pb, 2, 0); /* stream type = independent */
134  put_bits(&s->pb, 3, 0); /* substream id = 0 */
135  put_bits(&s->pb, 11, (s->frame_size / 2) - 1); /* frame size */
136  if (s->bit_alloc.sr_shift) {
137  put_bits(&s->pb, 2, 0x3); /* fscod2 */
138  put_bits(&s->pb, 2, s->bit_alloc.sr_code); /* sample rate code */
139  } else {
140  put_bits(&s->pb, 2, s->bit_alloc.sr_code); /* sample rate code */
141  put_bits(&s->pb, 2, s->num_blks_code); /* number of blocks */
142  }
143  put_bits(&s->pb, 3, s->channel_mode); /* audio coding mode */
144  put_bits(&s->pb, 1, s->lfe_on); /* LFE channel indicator */
145  put_bits(&s->pb, 5, s->bitstream_id); /* bitstream id (EAC3=16) */
146  put_bits(&s->pb, 5, -opt->dialogue_level); /* dialogue normalization level */
147  put_bits(&s->pb, 1, 0); /* no compression gain */
148  /* mixing metadata*/
149  put_bits(&s->pb, 1, opt->eac3_mixing_metadata);
150  if (opt->eac3_mixing_metadata) {
151  if (s->channel_mode > AC3_CHMODE_STEREO)
152  put_bits(&s->pb, 2, opt->preferred_stereo_downmix);
153  if (s->has_center) {
154  put_bits(&s->pb, 3, s->ltrt_center_mix_level);
155  put_bits(&s->pb, 3, s->loro_center_mix_level);
156  }
157  if (s->has_surround) {
158  put_bits(&s->pb, 3, s->ltrt_surround_mix_level);
159  put_bits(&s->pb, 3, s->loro_surround_mix_level);
160  }
161  if (s->lfe_on)
162  put_bits(&s->pb, 1, 0);
163  put_bits(&s->pb, 1, 0); /* no program scale */
164  put_bits(&s->pb, 1, 0); /* no ext program scale */
165  put_bits(&s->pb, 2, 0); /* no mixing parameters */
166  if (s->channel_mode < AC3_CHMODE_STEREO)
167  put_bits(&s->pb, 1, 0); /* no pan info */
168  put_bits(&s->pb, 1, 0); /* no frame mix config info */
169  }
170  /* info metadata*/
171  put_bits(&s->pb, 1, opt->eac3_info_metadata);
172  if (opt->eac3_info_metadata) {
173  put_bits(&s->pb, 3, s->bitstream_mode);
174  put_bits(&s->pb, 1, opt->copyright);
175  put_bits(&s->pb, 1, opt->original);
176  if (s->channel_mode == AC3_CHMODE_STEREO) {
177  put_bits(&s->pb, 2, opt->dolby_surround_mode);
178  put_bits(&s->pb, 2, opt->dolby_headphone_mode);
179  }
180  if (s->channel_mode >= AC3_CHMODE_2F2R)
181  put_bits(&s->pb, 2, opt->dolby_surround_ex_mode);
182  put_bits(&s->pb, 1, opt->audio_production_info);
183  if (opt->audio_production_info) {
184  put_bits(&s->pb, 5, opt->mixing_level - 80);
185  put_bits(&s->pb, 2, opt->room_type);
186  put_bits(&s->pb, 1, opt->ad_converter_type);
187  }
188  put_bits(&s->pb, 1, 0);
189  }
190  if (s->num_blocks != 6)
191  put_bits(&s->pb, 1, !(s->avctx->frame_number % 6)); /* converter sync flag */
192  put_bits(&s->pb, 1, 0); /* no additional bit stream info */
193 
194  /* frame header */
195  if (s->num_blocks == 6) {
196  put_bits(&s->pb, 1, !s->use_frame_exp_strategy); /* exponent strategy syntax */
197  put_bits(&s->pb, 1, 0); /* aht enabled = no */
198  }
199  put_bits(&s->pb, 2, 0); /* snr offset strategy = 1 */
200  put_bits(&s->pb, 1, 0); /* transient pre-noise processing enabled = no */
201  put_bits(&s->pb, 1, 0); /* block switch syntax enabled = no */
202  put_bits(&s->pb, 1, 0); /* dither flag syntax enabled = no */
203  put_bits(&s->pb, 1, 0); /* bit allocation model syntax enabled = no */
204  put_bits(&s->pb, 1, 0); /* fast gain codes enabled = no */
205  put_bits(&s->pb, 1, 0); /* dba syntax enabled = no */
206  put_bits(&s->pb, 1, 0); /* skip field syntax enabled = no */
207  put_bits(&s->pb, 1, 0); /* spx enabled = no */
208  /* coupling strategy use flags */
209  if (s->channel_mode > AC3_CHMODE_MONO) {
210  put_bits(&s->pb, 1, s->blocks[0].cpl_in_use);
211  for (blk = 1; blk < s->num_blocks; blk++) {
212  AC3Block *block = &s->blocks[blk];
213  put_bits(&s->pb, 1, block->new_cpl_strategy);
214  if (block->new_cpl_strategy)
215  put_bits(&s->pb, 1, block->cpl_in_use);
216  }
217  }
218  /* exponent strategy */
219  if (s->use_frame_exp_strategy) {
220  for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++)
221  put_bits(&s->pb, 5, s->frame_exp_strategy[ch]);
222  } else {
223  for (blk = 0; blk < s->num_blocks; blk++)
224  for (ch = !s->blocks[blk].cpl_in_use; ch <= s->fbw_channels; ch++)
225  put_bits(&s->pb, 2, s->exp_strategy[ch][blk]);
226  }
227  if (s->lfe_on) {
228  for (blk = 0; blk < s->num_blocks; blk++)
229  put_bits(&s->pb, 1, s->exp_strategy[s->lfe_channel][blk]);
230  }
231  /* E-AC-3 to AC-3 converter exponent strategy (not optional when num blocks == 6) */
232  if (s->num_blocks != 6) {
233  put_bits(&s->pb, 1, 0);
234  } else {
235  for (ch = 1; ch <= s->fbw_channels; ch++) {
236  if (s->use_frame_exp_strategy)
237  put_bits(&s->pb, 5, s->frame_exp_strategy[ch]);
238  else
239  put_bits(&s->pb, 5, 0);
240  }
241  }
242  /* snr offsets */
243  put_bits(&s->pb, 6, s->coarse_snr_offset);
244  put_bits(&s->pb, 4, s->fine_snr_offset[1]);
245  /* block start info */
246  if (s->num_blocks > 1)
247  put_bits(&s->pb, 1, 0);
248 }
249 
250 
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  .capabilities = AV_CODEC_CAP_DR1,
257  .priv_data_size = sizeof(AC3EncodeContext),
259  .encode2 = ff_ac3_float_encode_frame,
260  .close = ff_ac3_encode_close,
261  .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_FLTP,
263  .priv_class = &eac3enc_class,
264  .supported_samplerates = ff_ac3_sample_rate_tab,
265  .channel_layouts = ff_ac3_channel_layouts,
266  .defaults = ff_ac3_enc_defaults,
268 };
AVCodec
AVCodec.
Definition: codec.h:197
AV_SAMPLE_FMT_FLTP
@ AV_SAMPLE_FMT_FLTP
float, planar
Definition: samplefmt.h:69
FF_CODEC_CAP_INIT_THREADSAFE
#define FF_CODEC_CAP_INIT_THREADSAFE
The codec does not modify any global variables in the init function, allowing to call the init functi...
Definition: internal.h:41
AC3EncOptions::mixing_level
int mixing_level
Definition: ac3enc.h:99
init
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:31
AC3EncOptions::dolby_headphone_mode
int dolby_headphone_mode
Definition: ac3enc.h:111
ff_ac3_enc_defaults
const AVCodecDefault ff_ac3_enc_defaults[]
Definition: ac3enc.c:128
AC3_CHMODE_MONO
@ AC3_CHMODE_MONO
Definition: ac3.h:124
ff_eac3_frm_expstr
const uint8_t ff_eac3_frm_expstr[32][6]
Table E2.14 Frame Exponent Strategy Combinations.
Definition: eac3_data.c:1062
sample_fmts
static enum AVSampleFormat sample_fmts[]
Definition: adpcmenc.c:953
AC3EncOptions::dialogue_level
int dialogue_level
Definition: ac3enc.h:93
put_bits
static void put_bits(Jpeg2000EncoderContext *s, int val, int n)
put n times val bit
Definition: j2kenc.c:218
AC3EncOptions::dolby_surround_mode
int dolby_surround_mode
Definition: ac3enc.h:97
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:65
eac3enc_class
static const AVClass eac3enc_class
Definition: eac3enc.c:35
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:92
ff_ac3_enc_options
const AVOption ff_ac3_enc_options[]
Definition: ac3enc.c:78
ff_ac3_float_encode_init
int ff_ac3_float_encode_init(AVCodecContext *avctx)
Definition: ac3enc_float.c:122
AC3_MAX_CHANNELS
#define AC3_MAX_CHANNELS
maximum number of channels, including coupling channel
Definition: ac3.h:31
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:46
AC3EncOptions::eac3_mixing_metadata
int eac3_mixing_metadata
Definition: ac3enc.h:113
av_cold
#define av_cold
Definition: attributes.h:90
s
#define s(width, name)
Definition: cbs_vp9.c:257
ff_ac3_channel_layouts
const uint64_t ff_ac3_channel_layouts[19]
List of supported channel layouts.
Definition: ac3enc.c:143
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
eac3_data.h
AC3EncOptions::audio_production_info
int audio_production_info
Definition: ac3enc.h:98
blk
#define blk(i)
Definition: sha.c:185
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
AC3EncOptions::ad_converter_type
int ad_converter_type
Definition: ac3enc.h:112
AVClass
Describe the class of an AVClass context structure.
Definition: log.h:67
ac3enc.h
av_default_item_name
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235
AC3_CHMODE_STEREO
@ AC3_CHMODE_STEREO
Definition: ac3.h:125
AC3EncodeContext
AC-3 encoder private context.
Definition: ac3enc.h:154
AC3EncOptions::copyright
int copyright
Definition: ac3enc.h:101
AC3Block
Data for a single audio block.
Definition: ac3enc.h:126
AV_CODEC_ID_EAC3
@ AV_CODEC_ID_EAC3
Definition: codec_id.h:460
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
AC3EncOptions::eac3_info_metadata
int eac3_info_metadata
Definition: ac3enc.h:114
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
AC3EncOptions::dolby_surround_ex_mode
int dolby_surround_ex_mode
Definition: ac3enc.h:110
ff_eac3_encoder
const AVCodec ff_eac3_encoder
Definition: eac3enc.c:251
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:125
AV_SAMPLE_FMT_NONE
@ AV_SAMPLE_FMT_NONE
Definition: samplefmt.h:59
AC3EncOptions::room_type
int room_type
Definition: ac3enc.h:100
AC3EncOptions
Encoding Options used by AVOption.
Definition: ac3enc.h:91
attributes.h
eac3enc.h
ff_ac3_sample_rate_tab
const int ff_ac3_sample_rate_tab[]
Definition: ac3tab.c:111
i
int i
Definition: input.c:407
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: internal.h:49
AVSampleFormat
AVSampleFormat
Audio sample formats.
Definition: samplefmt.h:58
AC3EncOptions::original
int original
Definition: ac3enc.h:102
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:204
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:72
ff_eac3_exponent_init
av_cold void ff_eac3_exponent_init(void)
Initialize E-AC-3 exponent tables.
Definition: eac3enc.c:49
AC3EncOptions::preferred_stereo_downmix
int preferred_stereo_downmix
Definition: ac3enc.h:104
AC3_CHMODE_2F2R
@ AC3_CHMODE_2F2R
Definition: ac3.h:129
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:2116
block
The exact code depends on how similar the blocks are and how related they are to the block
Definition: filter_design.txt:207