mirror of https://git.ffmpeg.org/ffmpeg.git
132 lines
5.3 KiB
C
132 lines
5.3 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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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 < AC3_MAX_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 < AC3_MAX_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, 0x3); /* number of blocks = 6 */
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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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put_bits(&s->pb, 1, 0); /* no additional bit stream info */
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/* frame header */
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put_bits(&s->pb, 1, 1); /* exponent strategy syntax = each block */
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put_bits(&s->pb, 1, 0); /* aht enabled = no */
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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 < AC3_MAX_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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for (blk = 0; blk < AC3_MAX_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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if (s->lfe_on) {
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for (blk = 0; blk < AC3_MAX_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 (unfortunately not optional...) */
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for (ch = 1; ch <= s->fbw_channels; ch++)
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put_bits(&s->pb, 5, 0);
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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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put_bits(&s->pb, 1, 0);
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}
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