1 /*
2 * The simplest AC-3 encoder
3 * Copyright (c) 2000 Fabrice Bellard
4 * Copyright (c) 2006-2010 Justin Ruggles <justin.ruggles@gmail.com>
5 * Copyright (c) 2006-2010 Prakash Punnoor <prakash@punnoor.de>
6 *
7 * This file is part of FFmpeg.
8 *
9 * FFmpeg is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
13 *
14 * FFmpeg is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with FFmpeg; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24 /**
25 * @file
26 * fixed-point AC-3 encoder.
27 */
28
29 #define AC3ENC_FLOAT 0
30 #define FFT_FLOAT 0
31 #include "audiodsp.h"
32 #include "ac3enc.h"
33 #include "codec_internal.h"
34 #include "eac3enc.h"
35 #include "kbdwin.h"
36
sum_square_butterfly(AC3EncodeContext *s, int64_t sum[4], const int32_t *coef0, const int32_t *coef1, int len)37 static void sum_square_butterfly(AC3EncodeContext *s, int64_t sum[4],
38 const int32_t *coef0, const int32_t *coef1,
39 int len)
40 {
41 s->ac3dsp.sum_square_butterfly_int32(sum, coef0, coef1, len);
42 }
43
44 /*
45 * Clip MDCT coefficients to allowable range.
46 */
clip_coefficients(AudioDSPContext *adsp, int32_t *coef, unsigned int len)47 static void clip_coefficients(AudioDSPContext *adsp, int32_t *coef,
48 unsigned int len)
49 {
50 adsp->vector_clip_int32(coef, coef, COEF_MIN, COEF_MAX, len);
51 }
52
53
54 /*
55 * Calculate a single coupling coordinate.
56 */
calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl)57 static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl)
58 {
59 if (energy_cpl <= COEF_MAX) {
60 return 1048576;
61 } else {
62 uint64_t coord = energy_ch / (energy_cpl >> 24);
63 uint32_t coord32 = FFMIN(coord, 1073741824);
64 coord32 = ff_sqrt(coord32) << 9;
65 return FFMIN(coord32, COEF_MAX);
66 }
67 }
68
69
70 #include "ac3enc_template.c"
71
72
73 /**
74 * Finalize MDCT and free allocated memory.
75 *
76 * @param s AC-3 encoder private context
77 */
ac3_fixed_mdct_end(AC3EncodeContext *s)78 static av_cold void ac3_fixed_mdct_end(AC3EncodeContext *s)
79 {
80 ff_mdct_end(&s->mdct);
81 }
82
83 /**
84 * Initialize MDCT tables.
85 *
86 * @param s AC-3 encoder private context
87 * @return 0 on success, negative error code on failure
88 */
ac3_fixed_mdct_init(AC3EncodeContext *s)89 static av_cold int ac3_fixed_mdct_init(AC3EncodeContext *s)
90 {
91 float fwin[AC3_BLOCK_SIZE];
92
93 int32_t *iwin = av_malloc_array(AC3_BLOCK_SIZE, sizeof(*iwin));
94 if (!iwin)
95 return AVERROR(ENOMEM);
96
97 ff_kbd_window_init(fwin, 5.0, AC3_BLOCK_SIZE);
98 for (int i = 0; i < AC3_BLOCK_SIZE; i++)
99 iwin[i] = lrintf(fwin[i] * (1 << 22));
100
101 s->mdct_window = iwin;
102
103 s->fdsp = avpriv_alloc_fixed_dsp(s->avctx->flags & AV_CODEC_FLAG_BITEXACT);
104 if (!s->fdsp)
105 return AVERROR(ENOMEM);
106
107 return ff_mdct_init(&s->mdct, 9, 0, -1.0);
108 }
109
110
ac3_fixed_encode_init(AVCodecContext *avctx)111 static av_cold int ac3_fixed_encode_init(AVCodecContext *avctx)
112 {
113 AC3EncodeContext *s = avctx->priv_data;
114 s->fixed_point = 1;
115 s->mdct_end = ac3_fixed_mdct_end;
116 s->mdct_init = ac3_fixed_mdct_init;
117 s->allocate_sample_buffers = allocate_sample_buffers;
118 return ff_ac3_encode_init(avctx);
119 }
120
121
122 FF_DISABLE_DEPRECATION_WARNINGS
123 const FFCodec ff_ac3_fixed_encoder = {
124 .p.name = "ac3_fixed",
125 .p.long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
126 .p.type = AVMEDIA_TYPE_AUDIO,
127 .p.id = AV_CODEC_ID_AC3,
128 .p.capabilities = AV_CODEC_CAP_DR1,
129 .priv_data_size = sizeof(AC3EncodeContext),
130 .init = ac3_fixed_encode_init,
131 FF_CODEC_ENCODE_CB(ff_ac3_fixed_encode_frame),
132 .close = ff_ac3_encode_close,
133 .p.sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S32P,
134 AV_SAMPLE_FMT_NONE },
135 .p.priv_class = &ff_ac3enc_class,
136 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
137 .p.supported_samplerates = ff_ac3_sample_rate_tab,
138 #if FF_API_OLD_CHANNEL_LAYOUT
139 .p.channel_layouts = ff_ac3_channel_layouts,
140 #endif
141 .p.ch_layouts = ff_ac3_ch_layouts,
142 .defaults = ff_ac3_enc_defaults,
143 };
144 FF_ENABLE_DEPRECATION_WARNINGS
145