3 * Copyright (c) 2011 Justin Ruggles <justin.ruggles@gmail.com>
5 * This file is part of Libav.
7 * Libav 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.
12 * Libav 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.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
27 #define CONFIG_AC3ENC_FLOAT 1
30 #include "eac3_data.h"
33 #define AC3ENC_TYPE AC3ENC_TYPE_EAC3
34 #include "ac3enc_opts_template.c"
35 static const AVClass eac3enc_class = { "E-AC-3 Encoder", av_default_item_name,
36 eac3_options, LIBAVUTIL_VERSION_INT };
40 * LUT for finding a matching frame exponent strategy index from a set of
41 * exponent strategies for a single channel across all 6 blocks.
43 static int8_t eac3_frame_expstr_index_tab[3][4][4][4][4][4];
46 void ff_eac3_exponent_init(void)
50 memset(eac3_frame_expstr_index_tab, -1, sizeof(eac3_frame_expstr_index_tab));
51 for (i = 0; i < 32; i++) {
52 eac3_frame_expstr_index_tab[ff_eac3_frm_expstr[i][0]-1]
53 [ff_eac3_frm_expstr[i][1]]
54 [ff_eac3_frm_expstr[i][2]]
55 [ff_eac3_frm_expstr[i][3]]
56 [ff_eac3_frm_expstr[i][4]]
57 [ff_eac3_frm_expstr[i][5]] = i;
62 void ff_eac3_get_frame_exp_strategy(AC3EncodeContext *s)
66 if (s->num_blocks < 6) {
67 s->use_frame_exp_strategy = 0;
71 s->use_frame_exp_strategy = 1;
72 for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++) {
73 int expstr = eac3_frame_expstr_index_tab[s->exp_strategy[ch][0]-1]
74 [s->exp_strategy[ch][1]]
75 [s->exp_strategy[ch][2]]
76 [s->exp_strategy[ch][3]]
77 [s->exp_strategy[ch][4]]
78 [s->exp_strategy[ch][5]];
80 s->use_frame_exp_strategy = 0;
83 s->frame_exp_strategy[ch] = expstr;
89 void ff_eac3_set_cpl_states(AC3EncodeContext *s)
92 int first_cpl_coords[AC3_MAX_CHANNELS];
94 /* set first cpl coords */
95 for (ch = 1; ch <= s->fbw_channels; ch++)
96 first_cpl_coords[ch] = 1;
97 for (blk = 0; blk < s->num_blocks; blk++) {
98 AC3Block *block = &s->blocks[blk];
99 for (ch = 1; ch <= s->fbw_channels; ch++) {
100 if (block->channel_in_cpl[ch]) {
101 if (first_cpl_coords[ch]) {
102 block->new_cpl_coords = 2;
103 first_cpl_coords[ch] = 0;
106 first_cpl_coords[ch] = 1;
111 /* set first cpl leak */
112 for (blk = 0; blk < s->num_blocks; blk++) {
113 AC3Block *block = &s->blocks[blk];
114 if (block->cpl_in_use) {
115 block->new_cpl_leak = 2;
122 void ff_eac3_output_frame_header(AC3EncodeContext *s)
125 AC3EncOptions *opt = &s->options;
127 put_bits(&s->pb, 16, 0x0b77); /* sync word */
130 put_bits(&s->pb, 2, 0); /* stream type = independent */
131 put_bits(&s->pb, 3, 0); /* substream id = 0 */
132 put_bits(&s->pb, 11, (s->frame_size / 2) - 1); /* frame size */
133 if (s->bit_alloc.sr_shift) {
134 put_bits(&s->pb, 2, 0x3); /* fscod2 */
135 put_bits(&s->pb, 2, s->bit_alloc.sr_code); /* sample rate code */
137 put_bits(&s->pb, 2, s->bit_alloc.sr_code); /* sample rate code */
138 put_bits(&s->pb, 2, s->num_blks_code); /* number of blocks */
140 put_bits(&s->pb, 3, s->channel_mode); /* audio coding mode */
141 put_bits(&s->pb, 1, s->lfe_on); /* LFE channel indicator */
142 put_bits(&s->pb, 5, s->bitstream_id); /* bitstream id (EAC3=16) */
143 put_bits(&s->pb, 5, -opt->dialogue_level); /* dialogue normalization level */
144 put_bits(&s->pb, 1, 0); /* no compression gain */
145 put_bits(&s->pb, 1, 0); /* no mixing metadata */
146 /* TODO: mixing metadata */
147 put_bits(&s->pb, 1, 0); /* no info metadata */
148 /* TODO: info metadata */
149 if (s->num_blocks != 6)
150 put_bits(&s->pb, 1, !(s->avctx->frame_number % 6)); /* converter sync flag */
151 put_bits(&s->pb, 1, 0); /* no additional bit stream info */
154 if (s->num_blocks == 6) {
155 put_bits(&s->pb, 1, !s->use_frame_exp_strategy);/* exponent strategy syntax */
156 put_bits(&s->pb, 1, 0); /* aht enabled = no */
158 put_bits(&s->pb, 2, 0); /* snr offset strategy = 1 */
159 put_bits(&s->pb, 1, 0); /* transient pre-noise processing enabled = no */
160 put_bits(&s->pb, 1, 0); /* block switch syntax enabled = no */
161 put_bits(&s->pb, 1, 0); /* dither flag syntax enabled = no */
162 put_bits(&s->pb, 1, 0); /* bit allocation model syntax enabled = no */
163 put_bits(&s->pb, 1, 0); /* fast gain codes enabled = no */
164 put_bits(&s->pb, 1, 0); /* dba syntax enabled = no */
165 put_bits(&s->pb, 1, 0); /* skip field syntax enabled = no */
166 put_bits(&s->pb, 1, 0); /* spx enabled = no */
167 /* coupling strategy use flags */
168 if (s->channel_mode > AC3_CHMODE_MONO) {
169 put_bits(&s->pb, 1, s->blocks[0].cpl_in_use);
170 for (blk = 1; blk < s->num_blocks; blk++) {
171 AC3Block *block = &s->blocks[blk];
172 put_bits(&s->pb, 1, block->new_cpl_strategy);
173 if (block->new_cpl_strategy)
174 put_bits(&s->pb, 1, block->cpl_in_use);
177 /* exponent strategy */
178 if (s->use_frame_exp_strategy) {
179 for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++)
180 put_bits(&s->pb, 5, s->frame_exp_strategy[ch]);
182 for (blk = 0; blk < s->num_blocks; blk++)
183 for (ch = !s->blocks[blk].cpl_in_use; ch <= s->fbw_channels; ch++)
184 put_bits(&s->pb, 2, s->exp_strategy[ch][blk]);
187 for (blk = 0; blk < s->num_blocks; blk++)
188 put_bits(&s->pb, 1, s->exp_strategy[s->lfe_channel][blk]);
190 /* E-AC-3 to AC-3 converter exponent strategy (not optional when num blocks == 6) */
191 if (s->num_blocks != 6) {
192 put_bits(&s->pb, 1, 0);
194 for (ch = 1; ch <= s->fbw_channels; ch++) {
195 if (s->use_frame_exp_strategy)
196 put_bits(&s->pb, 5, s->frame_exp_strategy[ch]);
198 put_bits(&s->pb, 5, 0);
202 put_bits(&s->pb, 6, s->coarse_snr_offset);
203 put_bits(&s->pb, 4, s->fine_snr_offset[1]);
204 /* block start info */
205 if (s->num_blocks > 1)
206 put_bits(&s->pb, 1, 0);
210 #if CONFIG_EAC3_ENCODER
211 AVCodec ff_eac3_encoder = {
213 .type = AVMEDIA_TYPE_AUDIO,
215 .priv_data_size = sizeof(AC3EncodeContext),
216 .init = ff_ac3_encode_init,
217 .encode = ff_ac3_float_encode_frame,
218 .close = ff_ac3_encode_close,
219 .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_FLT,AV_SAMPLE_FMT_NONE},
220 .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52 E-AC-3"),
221 .priv_class = &eac3enc_class,
222 .channel_layouts = ff_ac3_channel_layouts,