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ffmpeg/libavcodec/eac3enc.c

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/*
* E-AC-3 encoder
* Copyright (c) 2011 Justin Ruggles <justin.ruggles@gmail.com>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* E-AC-3 encoder
*/
#define AC3ENC_FLOAT 1
#include "libavutil/attributes.h"
#include "libavutil/thread.h"
#include "ac3enc.h"
#include "codec_internal.h"
#include "eac3enc.h"
#include "eac3_data.h"
#include "put_bits.h"
static const AVClass eac3enc_class = {
.class_name = "E-AC-3 Encoder",
.item_name = av_default_item_name,
.option = &ff_ac3_enc_options[2], /* First two options are AC-3 only. */
.version = LIBAVUTIL_VERSION_INT,
};
/**
* LUT for finding a matching frame exponent strategy index from a set of
* exponent strategies for a single channel across all 6 blocks.
*/
static int8_t eac3_frame_expstr_index_tab[3][4][4][4][4][4];
/**
* Initialize E-AC-3 exponent tables.
*/
static av_cold void eac3_exponent_init(void)
{
int i;
memset(eac3_frame_expstr_index_tab, -1, sizeof(eac3_frame_expstr_index_tab));
for (i = 0; i < 32; i++) {
eac3_frame_expstr_index_tab[ff_eac3_frm_expstr[i][0]-1]
[ff_eac3_frm_expstr[i][1]]
[ff_eac3_frm_expstr[i][2]]
[ff_eac3_frm_expstr[i][3]]
[ff_eac3_frm_expstr[i][4]]
[ff_eac3_frm_expstr[i][5]] = i;
}
}
void ff_eac3_get_frame_exp_strategy(AC3EncodeContext *s)
{
int ch;
if (s->num_blocks < 6) {
s->use_frame_exp_strategy = 0;
return;
}
s->use_frame_exp_strategy = 1;
for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++) {
int expstr = eac3_frame_expstr_index_tab[s->exp_strategy[ch][0]-1]
[s->exp_strategy[ch][1]]
[s->exp_strategy[ch][2]]
[s->exp_strategy[ch][3]]
[s->exp_strategy[ch][4]]
[s->exp_strategy[ch][5]];
if (expstr < 0) {
s->use_frame_exp_strategy = 0;
break;
}
s->frame_exp_strategy[ch] = expstr;
}
}
void ff_eac3_set_cpl_states(AC3EncodeContext *s)
{
int ch, blk;
int first_cpl_coords[AC3_MAX_CHANNELS];
/* set first cpl coords */
for (ch = 1; ch <= s->fbw_channels; ch++)
first_cpl_coords[ch] = 1;
for (blk = 0; blk < s->num_blocks; blk++) {
AC3Block *block = &s->blocks[blk];
for (ch = 1; ch <= s->fbw_channels; ch++) {
if (block->channel_in_cpl[ch]) {
if (first_cpl_coords[ch]) {
block->new_cpl_coords[ch] = 2;
first_cpl_coords[ch] = 0;
}
} else {
first_cpl_coords[ch] = 1;
}
}
}
/* set first cpl leak */
for (blk = 0; blk < s->num_blocks; blk++) {
AC3Block *block = &s->blocks[blk];
if (block->cpl_in_use) {
block->new_cpl_leak = 2;
break;
}
}
}
/**
* Write the E-AC-3 frame header to the output bitstream.
*/
static void eac3_output_frame_header(AC3EncodeContext *s, PutBitContext *pb)
{
int blk, ch;
AC3EncOptions *opt = &s->options;
put_bits(pb, 16, 0x0b77); /* sync word */
/* BSI header */
put_bits(pb, 2, 0); /* stream type = independent */
put_bits(pb, 3, 0); /* substream id = 0 */
put_bits(pb, 11, (s->frame_size / 2) - 1); /* frame size */
put_bits(pb, 2, s->bit_alloc.sr_code); /* sample rate code */
put_bits(pb, 2, s->num_blks_code); /* number of blocks */
put_bits(pb, 3, s->channel_mode); /* audio coding mode */
put_bits(pb, 1, s->lfe_on); /* LFE channel indicator */
put_bits(pb, 5, s->bitstream_id); /* bitstream id (EAC3=16) */
put_bits(pb, 5, -opt->dialogue_level); /* dialogue normalization level */
put_bits(pb, 1, 0); /* no compression gain */
/* mixing metadata*/
put_bits(pb, 1, opt->eac3_mixing_metadata);
if (opt->eac3_mixing_metadata) {
if (s->channel_mode > AC3_CHMODE_STEREO)
put_bits(pb, 2, opt->preferred_stereo_downmix);
if (s->has_center) {
put_bits(pb, 3, s->ltrt_center_mix_level);
put_bits(pb, 3, s->loro_center_mix_level);
}
if (s->has_surround) {
put_bits(pb, 3, s->ltrt_surround_mix_level);
put_bits(pb, 3, s->loro_surround_mix_level);
}
if (s->lfe_on)
put_bits(pb, 1, 0);
put_bits(pb, 1, 0); /* no program scale */
put_bits(pb, 1, 0); /* no ext program scale */
put_bits(pb, 2, 0); /* no mixing parameters */
if (s->channel_mode < AC3_CHMODE_STEREO)
put_bits(pb, 1, 0); /* no pan info */
put_bits(pb, 1, 0); /* no frame mix config info */
}
/* info metadata*/
put_bits(pb, 1, opt->eac3_info_metadata);
if (opt->eac3_info_metadata) {
put_bits(pb, 3, s->bitstream_mode);
put_bits(pb, 1, opt->copyright);
put_bits(pb, 1, opt->original);
if (s->channel_mode == AC3_CHMODE_STEREO) {
put_bits(pb, 2, opt->dolby_surround_mode);
put_bits(pb, 2, opt->dolby_headphone_mode);
}
if (s->channel_mode >= AC3_CHMODE_2F2R)
put_bits(pb, 2, opt->dolby_surround_ex_mode);
put_bits(pb, 1, opt->audio_production_info);
if (opt->audio_production_info) {
put_bits(pb, 5, opt->mixing_level - 80);
put_bits(pb, 2, opt->room_type);
put_bits(pb, 1, opt->ad_converter_type);
}
put_bits(pb, 1, 0);
}
if (s->num_blocks != 6)
put_bits(pb, 1, !(s->avctx->frame_num % 6)); /* converter sync flag */
put_bits(pb, 1, 0); /* no additional bit stream info */
/* frame header */
if (s->num_blocks == 6) {
put_bits(pb, 1, !s->use_frame_exp_strategy); /* exponent strategy syntax */
put_bits(pb, 1, 0); /* aht enabled = no */
}
put_bits(pb, 2, 0); /* snr offset strategy = 1 */
put_bits(pb, 1, 0); /* transient pre-noise processing enabled = no */
put_bits(pb, 1, 0); /* block switch syntax enabled = no */
put_bits(pb, 1, 0); /* dither flag syntax enabled = no */
put_bits(pb, 1, 0); /* bit allocation model syntax enabled = no */
put_bits(pb, 1, 0); /* fast gain codes enabled = no */
put_bits(pb, 1, 0); /* dba syntax enabled = no */
put_bits(pb, 1, 0); /* skip field syntax enabled = no */
put_bits(pb, 1, 0); /* spx enabled = no */
/* coupling strategy use flags */
if (s->channel_mode > AC3_CHMODE_MONO) {
put_bits(pb, 1, s->blocks[0].cpl_in_use);
for (blk = 1; blk < s->num_blocks; blk++) {
AC3Block *block = &s->blocks[blk];
put_bits(pb, 1, block->new_cpl_strategy);
if (block->new_cpl_strategy)
put_bits(pb, 1, block->cpl_in_use);
}
}
/* exponent strategy */
if (s->use_frame_exp_strategy) {
for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++)
put_bits(pb, 5, s->frame_exp_strategy[ch]);
} else {
for (blk = 0; blk < s->num_blocks; blk++)
for (ch = !s->blocks[blk].cpl_in_use; ch <= s->fbw_channels; ch++)
put_bits(pb, 2, s->exp_strategy[ch][blk]);
}
if (s->lfe_on) {
for (blk = 0; blk < s->num_blocks; blk++)
put_bits(pb, 1, s->exp_strategy[s->lfe_channel][blk]);
}
/* E-AC-3 to AC-3 converter exponent strategy (not optional when num blocks == 6) */
if (s->num_blocks != 6) {
put_bits(pb, 1, 0);
} else {
for (ch = 1; ch <= s->fbw_channels; ch++) {
if (s->use_frame_exp_strategy)
put_bits(pb, 5, s->frame_exp_strategy[ch]);
else
put_bits(pb, 5, 0);
}
}
/* snr offsets */
put_bits(pb, 6, s->coarse_snr_offset);
put_bits(pb, 4, s->fine_snr_offset[1]);
/* block start info */
if (s->num_blocks > 1)
put_bits(pb, 1, 0);
}
static av_cold int eac3_encode_init(AVCodecContext *avctx)
{
static AVOnce init_static_once = AV_ONCE_INIT;
AC3EncodeContext *s = avctx->priv_data;
s->eac3 = 1;
s->output_frame_header = eac3_output_frame_header;
ff_thread_once(&init_static_once, eac3_exponent_init);
return ff_ac3_float_encode_init(avctx);
}
const FFCodec ff_eac3_encoder = {
.p.name = "eac3",
CODEC_LONG_NAME("ATSC A/52 E-AC-3"),
.p.type = AVMEDIA_TYPE_AUDIO,
.p.id = AV_CODEC_ID_EAC3,
.p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,
.priv_data_size = sizeof(AC3EncodeContext),
.init = eac3_encode_init,
FF_CODEC_ENCODE_CB(ff_ac3_encode_frame),
.close = ff_ac3_encode_close,
.p.sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_FLTP,
AV_SAMPLE_FMT_NONE },
.p.priv_class = &eac3enc_class,
.p.supported_samplerates = ff_ac3_sample_rate_tab,
.p.ch_layouts = ff_ac3_ch_layouts,
.defaults = ff_ac3_enc_defaults,
.caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
};
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