/src/ffmpeg/libavcodec/eac3enc.c

Source
/*
 * 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_assume_flushed(pb);

    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,
    CODEC_SAMPLEFMTS(AV_SAMPLE_FMT_FLTP),
    .p.priv_class    = &eac3enc_class,
    CODEC_SAMPLERATES_ARRAY(ff_ac3_sample_rate_tab),
    CODEC_CH_LAYOUTS_ARRAY(ff_ac3_ch_layouts),
    .defaults        = ff_ac3_enc_defaults,
    .caps_internal   = FF_CODEC_CAP_INIT_CLEANUP,
};

Coverage Report

Created: 2025-11-16 07:20

Line	Count	Source
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 "libavutil/thread.h"
31		#include "ac3enc.h"
32		#include "codec_internal.h"
33		#include "eac3enc.h"
34		#include "eac3_data.h"
35		#include "put_bits.h"
36
37
38		static const AVClass eac3enc_class = {
39		.class_name = "E-AC-3 Encoder",
40		.item_name = av_default_item_name,
41		.option = &ff_ac3_enc_options[2], /* First two options are AC-3 only. */
42		.version = LIBAVUTIL_VERSION_INT,
43		};
44
45		/**
46		* LUT for finding a matching frame exponent strategy index from a set of
47		* exponent strategies for a single channel across all 6 blocks.
48		*/
49		static int8_t eac3_frame_expstr_index_tab[3][4][4][4][4][4];
50
51
52		/**
53		* Initialize E-AC-3 exponent tables.
54		*/
55		static av_cold void eac3_exponent_init(void)
56	0	{
57	0	int i;
58
59	0	memset(eac3_frame_expstr_index_tab, -1, sizeof(eac3_frame_expstr_index_tab));
60	0	for (i = 0; i < 32; i++) {
61	0	eac3_frame_expstr_index_tab[ff_eac3_frm_expstr[i][0]-1]
62	0	[ff_eac3_frm_expstr[i][1]]
63	0	[ff_eac3_frm_expstr[i][2]]
64	0	[ff_eac3_frm_expstr[i][3]]
65	0	[ff_eac3_frm_expstr[i][4]]
66	0	[ff_eac3_frm_expstr[i][5]] = i;
67	0	}
68	0	}
69
70
71		void ff_eac3_get_frame_exp_strategy(AC3EncodeContext *s)
72	0	{
73	0	int ch;
74
75	0	if (s->num_blocks < 6) {
76	0	s->use_frame_exp_strategy = 0;
77	0	return;
78	0	}
79
80	0	s->use_frame_exp_strategy = 1;
81	0	for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++) {
82	0	int expstr = eac3_frame_expstr_index_tab[s->exp_strategy[ch][0]-1]
83	0	[s->exp_strategy[ch][1]]
84	0	[s->exp_strategy[ch][2]]
85	0	[s->exp_strategy[ch][3]]
86	0	[s->exp_strategy[ch][4]]
87	0	[s->exp_strategy[ch][5]];
88	0	if (expstr < 0) {
89	0	s->use_frame_exp_strategy = 0;
90	0	break;
91	0	}
92	0	s->frame_exp_strategy[ch] = expstr;
93	0	}
94	0	}
95
96
97
98		void ff_eac3_set_cpl_states(AC3EncodeContext *s)
99	0	{
100	0	int ch, blk;
101	0	int first_cpl_coords[AC3_MAX_CHANNELS];
102
103		/* set first cpl coords */
104	0	for (ch = 1; ch <= s->fbw_channels; ch++)
105	0	first_cpl_coords[ch] = 1;
106	0	for (blk = 0; blk < s->num_blocks; blk++) {
107	0	AC3Block *block = &s->blocks[blk];
108	0	for (ch = 1; ch <= s->fbw_channels; ch++) {
109	0	if (block->channel_in_cpl[ch]) {
110	0	if (first_cpl_coords[ch]) {
111	0	block->new_cpl_coords[ch] = 2;
112	0	first_cpl_coords[ch] = 0;
113	0	}
114	0	} else {
115	0	first_cpl_coords[ch] = 1;
116	0	}
117	0	}
118	0	}
119
120		/* set first cpl leak */
121	0	for (blk = 0; blk < s->num_blocks; blk++) {
122	0	AC3Block *block = &s->blocks[blk];
123	0	if (block->cpl_in_use) {
124	0	block->new_cpl_leak = 2;
125	0	break;
126	0	}
127	0	}
128	0	}
129
130		/**
131		* Write the E-AC-3 frame header to the output bitstream.
132		*/
133		static void eac3_output_frame_header(AC3EncodeContext s, PutBitContext pb)
134	0	{
135	0	int blk, ch;
136	0	AC3EncOptions *opt = &s->options;
137
138	0	put_bits_assume_flushed(pb);
139
140	0	put_bits(pb, 16, 0x0b77); /* sync word */
141
142		/* BSI header */
143	0	put_bits(pb, 2, 0); /* stream type = independent */
144	0	put_bits(pb, 3, 0); /* substream id = 0 */
145	0	put_bits(pb, 11, (s->frame_size / 2) - 1); /* frame size */
146	0	put_bits(pb, 2, s->bit_alloc.sr_code); /* sample rate code */
147	0	put_bits(pb, 2, s->num_blks_code); /* number of blocks */
148	0	put_bits(pb, 3, s->channel_mode); /* audio coding mode */
149	0	put_bits(pb, 1, s->lfe_on); /* LFE channel indicator */
150	0	put_bits(pb, 5, s->bitstream_id); /* bitstream id (EAC3=16) */
151	0	put_bits(pb, 5, -opt->dialogue_level); /* dialogue normalization level */
152	0	put_bits(pb, 1, 0); /* no compression gain */
153		/* mixing metadata*/
154	0	put_bits(pb, 1, opt->eac3_mixing_metadata);
155	0	if (opt->eac3_mixing_metadata) {
156	0	if (s->channel_mode > AC3_CHMODE_STEREO)
157	0	put_bits(pb, 2, opt->preferred_stereo_downmix);
158	0	if (s->has_center) {
159	0	put_bits(pb, 3, s->ltrt_center_mix_level);
160	0	put_bits(pb, 3, s->loro_center_mix_level);
161	0	}
162	0	if (s->has_surround) {
163	0	put_bits(pb, 3, s->ltrt_surround_mix_level);
164	0	put_bits(pb, 3, s->loro_surround_mix_level);
165	0	}
166	0	if (s->lfe_on)
167	0	put_bits(pb, 1, 0);
168	0	put_bits(pb, 1, 0); /* no program scale */
169	0	put_bits(pb, 1, 0); /* no ext program scale */
170	0	put_bits(pb, 2, 0); /* no mixing parameters */
171	0	if (s->channel_mode < AC3_CHMODE_STEREO)
172	0	put_bits(pb, 1, 0); /* no pan info */
173	0	put_bits(pb, 1, 0); /* no frame mix config info */
174	0	}
175		/* info metadata*/
176	0	put_bits(pb, 1, opt->eac3_info_metadata);
177	0	if (opt->eac3_info_metadata) {
178	0	put_bits(pb, 3, s->bitstream_mode);
179	0	put_bits(pb, 1, opt->copyright);
180	0	put_bits(pb, 1, opt->original);
181	0	if (s->channel_mode == AC3_CHMODE_STEREO) {
182	0	put_bits(pb, 2, opt->dolby_surround_mode);
183	0	put_bits(pb, 2, opt->dolby_headphone_mode);
184	0	}
185	0	if (s->channel_mode >= AC3_CHMODE_2F2R)
186	0	put_bits(pb, 2, opt->dolby_surround_ex_mode);
187	0	put_bits(pb, 1, opt->audio_production_info);
188	0	if (opt->audio_production_info) {
189	0	put_bits(pb, 5, opt->mixing_level - 80);
190	0	put_bits(pb, 2, opt->room_type);
191	0	put_bits(pb, 1, opt->ad_converter_type);
192	0	}
193	0	put_bits(pb, 1, 0);
194	0	}
195	0	if (s->num_blocks != 6)
196	0	put_bits(pb, 1, !(s->avctx->frame_num % 6)); /* converter sync flag */
197	0	put_bits(pb, 1, 0); /* no additional bit stream info */
198
199		/* frame header */
200	0	if (s->num_blocks == 6) {
201	0	put_bits(pb, 1, !s->use_frame_exp_strategy); /* exponent strategy syntax */
202	0	put_bits(pb, 1, 0); /* aht enabled = no */
203	0	}
204	0	put_bits(pb, 2, 0); /* snr offset strategy = 1 */
205	0	put_bits(pb, 1, 0); /* transient pre-noise processing enabled = no */
206	0	put_bits(pb, 1, 0); /* block switch syntax enabled = no */
207	0	put_bits(pb, 1, 0); /* dither flag syntax enabled = no */
208	0	put_bits(pb, 1, 0); /* bit allocation model syntax enabled = no */
209	0	put_bits(pb, 1, 0); /* fast gain codes enabled = no */
210	0	put_bits(pb, 1, 0); /* dba syntax enabled = no */
211	0	put_bits(pb, 1, 0); /* skip field syntax enabled = no */
212	0	put_bits(pb, 1, 0); /* spx enabled = no */
213		/* coupling strategy use flags */
214	0	if (s->channel_mode > AC3_CHMODE_MONO) {
215	0	put_bits(pb, 1, s->blocks[0].cpl_in_use);
216	0	for (blk = 1; blk < s->num_blocks; blk++) {
217	0	AC3Block *block = &s->blocks[blk];
218	0	put_bits(pb, 1, block->new_cpl_strategy);
219	0	if (block->new_cpl_strategy)
220	0	put_bits(pb, 1, block->cpl_in_use);
221	0	}
222	0	}
223		/* exponent strategy */
224	0	if (s->use_frame_exp_strategy) {
225	0	for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++)
226	0	put_bits(pb, 5, s->frame_exp_strategy[ch]);
227	0	} else {
228	0	for (blk = 0; blk < s->num_blocks; blk++)
229	0	for (ch = !s->blocks[blk].cpl_in_use; ch <= s->fbw_channels; ch++)
230	0	put_bits(pb, 2, s->exp_strategy[ch][blk]);
231	0	}
232	0	if (s->lfe_on) {
233	0	for (blk = 0; blk < s->num_blocks; blk++)
234	0	put_bits(pb, 1, s->exp_strategy[s->lfe_channel][blk]);
235	0	}
236		/* E-AC-3 to AC-3 converter exponent strategy (not optional when num blocks == 6) */
237	0	if (s->num_blocks != 6) {
238	0	put_bits(pb, 1, 0);
239	0	} else {
240	0	for (ch = 1; ch <= s->fbw_channels; ch++) {
241	0	if (s->use_frame_exp_strategy)
242	0	put_bits(pb, 5, s->frame_exp_strategy[ch]);
243	0	else
244	0	put_bits(pb, 5, 0);
245	0	}
246	0	}
247		/* snr offsets */
248	0	put_bits(pb, 6, s->coarse_snr_offset);
249	0	put_bits(pb, 4, s->fine_snr_offset[1]);
250		/* block start info */
251	0	if (s->num_blocks > 1)
252	0	put_bits(pb, 1, 0);
253	0	}
254
255		static av_cold int eac3_encode_init(AVCodecContext *avctx)
256	0	{
257	0	static AVOnce init_static_once = AV_ONCE_INIT;
258	0	AC3EncodeContext *s = avctx->priv_data;
259
260	0	s->eac3 = 1;
261	0	s->output_frame_header = eac3_output_frame_header;
262
263	0	ff_thread_once(&init_static_once, eac3_exponent_init);
264
265	0	return ff_ac3_float_encode_init(avctx);
266	0	}
267
268		const FFCodec ff_eac3_encoder = {
269		.p.name = "eac3",
270		CODEC_LONG_NAME("ATSC A/52 E-AC-3"),
271		.p.type = AVMEDIA_TYPE_AUDIO,
272		.p.id = AV_CODEC_ID_EAC3,
273		.p.capabilities = AV_CODEC_CAP_DR1 \| AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,
274		.priv_data_size = sizeof(AC3EncodeContext),
275		.init = eac3_encode_init,
276		FF_CODEC_ENCODE_CB(ff_ac3_encode_frame),
277		.close = ff_ac3_encode_close,
278		CODEC_SAMPLEFMTS(AV_SAMPLE_FMT_FLTP),
279		.p.priv_class = &eac3enc_class,
280		CODEC_SAMPLERATES_ARRAY(ff_ac3_sample_rate_tab),
281		CODEC_CH_LAYOUTS_ARRAY(ff_ac3_ch_layouts),
282		.defaults = ff_ac3_enc_defaults,
283		.caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
284		};