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
37static 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 */
47static 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 */
57static 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 */
78static 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 */
89static 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
111static 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
122FF_DISABLE_DEPRECATION_WARNINGS
123const 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};
144FF_ENABLE_DEPRECATION_WARNINGS
145