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 * floating-point AC-3 encoder.
27 */
28
29#define AC3ENC_FLOAT 1
30#include "audiodsp.h"
31#include "ac3enc.h"
32#include "codec_internal.h"
33#include "eac3enc.h"
34#include "kbdwin.h"
35
36
37/*
38 * Scale MDCT coefficients from float to 24-bit fixed-point.
39 */
40static void scale_coefficients(AC3EncodeContext *s)
41{
42    int chan_size = AC3_MAX_COEFS * s->num_blocks;
43    int cpl       = s->cpl_on;
44    s->ac3dsp.float_to_fixed24(s->fixed_coef_buffer + (chan_size * !cpl),
45                               s->mdct_coef_buffer  + (chan_size * !cpl),
46                               chan_size * (s->channels + cpl));
47}
48
49
50/*
51 * Clip MDCT coefficients to allowable range.
52 */
53static void clip_coefficients(AudioDSPContext *adsp, float *coef,
54                              unsigned int len)
55{
56    adsp->vector_clipf(coef, coef, len, COEF_MIN, COEF_MAX);
57}
58
59
60/*
61 * Calculate a single coupling coordinate.
62 */
63static CoefType calc_cpl_coord(CoefSumType energy_ch, CoefSumType energy_cpl)
64{
65    float coord = 0.125;
66    if (energy_cpl > 0)
67        coord *= sqrtf(energy_ch / energy_cpl);
68    return FFMIN(coord, COEF_MAX);
69}
70
71static void sum_square_butterfly(AC3EncodeContext *s, float sum[4],
72                                 const float *coef0, const float *coef1,
73                                 int len)
74{
75    s->ac3dsp.sum_square_butterfly_float(sum, coef0, coef1, len);
76}
77
78
79#include "ac3enc_template.c"
80
81
82/**
83 * Finalize MDCT and free allocated memory.
84 *
85 * @param s  AC-3 encoder private context
86 */
87static av_cold void ac3_float_mdct_end(AC3EncodeContext *s)
88{
89    ff_mdct_end(&s->mdct);
90}
91
92
93/**
94 * Initialize MDCT tables.
95 *
96 * @param s  AC-3 encoder private context
97 * @return   0 on success, negative error code on failure
98 */
99static av_cold int ac3_float_mdct_init(AC3EncodeContext *s)
100{
101    float *window = av_malloc_array(AC3_BLOCK_SIZE, sizeof(*window));
102    if (!window) {
103        av_log(s->avctx, AV_LOG_ERROR, "Cannot allocate memory.\n");
104        return AVERROR(ENOMEM);
105    }
106
107    ff_kbd_window_init(window, 5.0, AC3_BLOCK_SIZE);
108    s->mdct_window = window;
109
110    return ff_mdct_init(&s->mdct, 9, 0, -2.0 / AC3_WINDOW_SIZE);
111}
112
113
114av_cold int ff_ac3_float_encode_init(AVCodecContext *avctx)
115{
116    AC3EncodeContext *s = avctx->priv_data;
117    s->mdct_end                = ac3_float_mdct_end;
118    s->mdct_init               = ac3_float_mdct_init;
119    s->allocate_sample_buffers = allocate_sample_buffers;
120    s->fdsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT);
121    if (!s->fdsp)
122        return AVERROR(ENOMEM);
123    return ff_ac3_encode_init(avctx);
124}
125
126FF_DISABLE_DEPRECATION_WARNINGS
127const FFCodec ff_ac3_encoder = {
128    .p.name          = "ac3",
129    .p.long_name     = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
130    .p.type          = AVMEDIA_TYPE_AUDIO,
131    .p.id            = AV_CODEC_ID_AC3,
132    .p.capabilities  = AV_CODEC_CAP_DR1,
133    .priv_data_size  = sizeof(AC3EncodeContext),
134    .init            = ff_ac3_float_encode_init,
135    FF_CODEC_ENCODE_CB(ff_ac3_float_encode_frame),
136    .close           = ff_ac3_encode_close,
137    .p.sample_fmts   = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_FLTP,
138                                                      AV_SAMPLE_FMT_NONE },
139    .p.priv_class    = &ff_ac3enc_class,
140    .p.supported_samplerates = ff_ac3_sample_rate_tab,
141#if FF_API_OLD_CHANNEL_LAYOUT
142    .p.channel_layouts = ff_ac3_channel_layouts,
143#endif
144    .p.ch_layouts    = ff_ac3_ch_layouts,
145    .defaults        = ff_ac3_enc_defaults,
146    .caps_internal   = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
147};
148FF_ENABLE_DEPRECATION_WARNINGS
149