225 lines
8.2 KiB
C
225 lines
8.2 KiB
C
/*
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* E-AC-3 encoder
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* Copyright (c) 2011 Justin Ruggles <justin.ruggles@gmail.com>
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* E-AC-3 encoder
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*/
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#define CONFIG_AC3ENC_FLOAT 1
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#include "ac3enc.h"
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#include "eac3enc.h"
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#include "eac3_data.h"
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#define AC3ENC_TYPE AC3ENC_TYPE_EAC3
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#include "ac3enc_opts_template.c"
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static const AVClass eac3enc_class = { "E-AC-3 Encoder", av_default_item_name,
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eac3_options, LIBAVUTIL_VERSION_INT };
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/**
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* LUT for finding a matching frame exponent strategy index from a set of
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* exponent strategies for a single channel across all 6 blocks.
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*/
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static int8_t eac3_frame_expstr_index_tab[3][4][4][4][4][4];
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void ff_eac3_exponent_init(void)
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{
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int i;
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memset(eac3_frame_expstr_index_tab, -1, sizeof(eac3_frame_expstr_index_tab));
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for (i = 0; i < 32; i++) {
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eac3_frame_expstr_index_tab[ff_eac3_frm_expstr[i][0]-1]
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[ff_eac3_frm_expstr[i][1]]
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[ff_eac3_frm_expstr[i][2]]
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[ff_eac3_frm_expstr[i][3]]
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[ff_eac3_frm_expstr[i][4]]
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[ff_eac3_frm_expstr[i][5]] = i;
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}
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}
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void ff_eac3_get_frame_exp_strategy(AC3EncodeContext *s)
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{
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int ch;
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if (s->num_blocks < 6) {
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s->use_frame_exp_strategy = 0;
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return;
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}
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s->use_frame_exp_strategy = 1;
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for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++) {
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int expstr = eac3_frame_expstr_index_tab[s->exp_strategy[ch][0]-1]
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[s->exp_strategy[ch][1]]
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[s->exp_strategy[ch][2]]
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[s->exp_strategy[ch][3]]
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[s->exp_strategy[ch][4]]
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[s->exp_strategy[ch][5]];
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if (expstr < 0) {
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s->use_frame_exp_strategy = 0;
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break;
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}
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s->frame_exp_strategy[ch] = expstr;
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}
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}
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void ff_eac3_set_cpl_states(AC3EncodeContext *s)
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{
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int ch, blk;
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int first_cpl_coords[AC3_MAX_CHANNELS];
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/* set first cpl coords */
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for (ch = 1; ch <= s->fbw_channels; ch++)
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first_cpl_coords[ch] = 1;
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for (blk = 0; blk < s->num_blocks; blk++) {
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AC3Block *block = &s->blocks[blk];
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for (ch = 1; ch <= s->fbw_channels; ch++) {
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if (block->channel_in_cpl[ch]) {
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if (first_cpl_coords[ch]) {
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block->new_cpl_coords = 2;
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first_cpl_coords[ch] = 0;
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}
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} else {
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first_cpl_coords[ch] = 1;
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}
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}
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}
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/* set first cpl leak */
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for (blk = 0; blk < s->num_blocks; blk++) {
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AC3Block *block = &s->blocks[blk];
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if (block->cpl_in_use) {
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block->new_cpl_leak = 2;
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break;
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}
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}
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}
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void ff_eac3_output_frame_header(AC3EncodeContext *s)
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{
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int blk, ch;
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AC3EncOptions *opt = &s->options;
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put_bits(&s->pb, 16, 0x0b77); /* sync word */
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/* BSI header */
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put_bits(&s->pb, 2, 0); /* stream type = independent */
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put_bits(&s->pb, 3, 0); /* substream id = 0 */
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put_bits(&s->pb, 11, (s->frame_size / 2) - 1); /* frame size */
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if (s->bit_alloc.sr_shift) {
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put_bits(&s->pb, 2, 0x3); /* fscod2 */
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put_bits(&s->pb, 2, s->bit_alloc.sr_code); /* sample rate code */
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} else {
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put_bits(&s->pb, 2, s->bit_alloc.sr_code); /* sample rate code */
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put_bits(&s->pb, 2, s->num_blks_code); /* number of blocks */
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}
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put_bits(&s->pb, 3, s->channel_mode); /* audio coding mode */
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put_bits(&s->pb, 1, s->lfe_on); /* LFE channel indicator */
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put_bits(&s->pb, 5, s->bitstream_id); /* bitstream id (EAC3=16) */
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put_bits(&s->pb, 5, -opt->dialogue_level); /* dialogue normalization level */
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put_bits(&s->pb, 1, 0); /* no compression gain */
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put_bits(&s->pb, 1, 0); /* no mixing metadata */
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/* TODO: mixing metadata */
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put_bits(&s->pb, 1, 0); /* no info metadata */
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/* TODO: info metadata */
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if (s->num_blocks != 6)
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put_bits(&s->pb, 1, !(s->avctx->frame_number % 6)); /* converter sync flag */
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put_bits(&s->pb, 1, 0); /* no additional bit stream info */
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/* frame header */
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if (s->num_blocks == 6) {
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put_bits(&s->pb, 1, !s->use_frame_exp_strategy);/* exponent strategy syntax */
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put_bits(&s->pb, 1, 0); /* aht enabled = no */
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}
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put_bits(&s->pb, 2, 0); /* snr offset strategy = 1 */
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put_bits(&s->pb, 1, 0); /* transient pre-noise processing enabled = no */
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put_bits(&s->pb, 1, 0); /* block switch syntax enabled = no */
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put_bits(&s->pb, 1, 0); /* dither flag syntax enabled = no */
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put_bits(&s->pb, 1, 0); /* bit allocation model syntax enabled = no */
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put_bits(&s->pb, 1, 0); /* fast gain codes enabled = no */
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put_bits(&s->pb, 1, 0); /* dba syntax enabled = no */
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put_bits(&s->pb, 1, 0); /* skip field syntax enabled = no */
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put_bits(&s->pb, 1, 0); /* spx enabled = no */
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/* coupling strategy use flags */
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if (s->channel_mode > AC3_CHMODE_MONO) {
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put_bits(&s->pb, 1, s->blocks[0].cpl_in_use);
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for (blk = 1; blk < s->num_blocks; blk++) {
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AC3Block *block = &s->blocks[blk];
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put_bits(&s->pb, 1, block->new_cpl_strategy);
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if (block->new_cpl_strategy)
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put_bits(&s->pb, 1, block->cpl_in_use);
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}
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}
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/* exponent strategy */
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if (s->use_frame_exp_strategy) {
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for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++)
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put_bits(&s->pb, 5, s->frame_exp_strategy[ch]);
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} else {
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for (blk = 0; blk < s->num_blocks; blk++)
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for (ch = !s->blocks[blk].cpl_in_use; ch <= s->fbw_channels; ch++)
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put_bits(&s->pb, 2, s->exp_strategy[ch][blk]);
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}
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if (s->lfe_on) {
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for (blk = 0; blk < s->num_blocks; blk++)
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put_bits(&s->pb, 1, s->exp_strategy[s->lfe_channel][blk]);
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}
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/* E-AC-3 to AC-3 converter exponent strategy (not optional when num blocks == 6) */
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if (s->num_blocks != 6) {
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put_bits(&s->pb, 1, 0);
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} else {
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for (ch = 1; ch <= s->fbw_channels; ch++) {
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if (s->use_frame_exp_strategy)
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put_bits(&s->pb, 5, s->frame_exp_strategy[ch]);
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else
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put_bits(&s->pb, 5, 0);
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}
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}
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/* snr offsets */
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put_bits(&s->pb, 6, s->coarse_snr_offset);
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put_bits(&s->pb, 4, s->fine_snr_offset[1]);
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/* block start info */
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if (s->num_blocks > 1)
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put_bits(&s->pb, 1, 0);
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}
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#if CONFIG_EAC3_ENCODER
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AVCodec ff_eac3_encoder = {
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.name = "eac3",
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.type = AVMEDIA_TYPE_AUDIO,
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.id = CODEC_ID_EAC3,
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.priv_data_size = sizeof(AC3EncodeContext),
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.init = ff_ac3_encode_init,
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.encode = ff_ac3_float_encode_frame,
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.close = ff_ac3_encode_close,
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.sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_FLT,AV_SAMPLE_FMT_NONE},
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.long_name = NULL_IF_CONFIG_SMALL("ATSC A/52 E-AC-3"),
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.priv_class = &eac3enc_class,
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.channel_layouts = ff_ac3_channel_layouts,
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};
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#endif
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