1/*
2 * Copyright (c) 2011 Mans Rullgard
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21#include "config.h"
22#include "libavutil/attributes.h"
23#include "libavutil/thread.h"
24#include "mpegaudio.h"
25#include "mpegaudiodsp.h"
26#include "dct.h"
27#include "dct32.h"
28
29static AVOnce mpadsp_table_init = AV_ONCE_INIT;
30
31static av_cold void mpadsp_init_tabs(void)
32{
33    int i, j;
34    /* compute mdct windows */
35    for (i = 0; i < 36; i++) {
36        for (j = 0; j < 4; j++) {
37            double d;
38
39            if (j == 2 && i % 3 != 1)
40                continue;
41
42            d = sin(M_PI * (i + 0.5) / 36.0);
43            if (j == 1) {
44                if      (i >= 30) d = 0;
45                else if (i >= 24) d = sin(M_PI * (i - 18 + 0.5) / 12.0);
46                else if (i >= 18) d = 1;
47            } else if (j == 3) {
48                if      (i <   6) d = 0;
49                else if (i <  12) d = sin(M_PI * (i -  6 + 0.5) / 12.0);
50                else if (i <  18) d = 1;
51            }
52            //merge last stage of imdct into the window coefficients
53            d *= 0.5 * IMDCT_SCALAR / cos(M_PI * (2 * i + 19) / 72);
54
55            if (j == 2) {
56                ff_mdct_win_float[j][i/3] = d / (1 << 5);
57                ff_mdct_win_fixed[j][i/3] = d / (1 << 5) * (1LL << 32) + 0.5;
58            } else {
59                int idx = i < 18 ? i : i + (MDCT_BUF_SIZE/2 - 18);
60                ff_mdct_win_float[j][idx] = d / (1 << 5);
61                ff_mdct_win_fixed[j][idx] = d / (1 << 5) * (1LL << 32) + 0.5;
62            }
63        }
64    }
65
66    /* NOTE: we do frequency inversion after the MDCT by changing
67        the sign of the right window coefs */
68    for (j = 0; j < 4; j++) {
69        for (i = 0; i < MDCT_BUF_SIZE; i += 2) {
70            ff_mdct_win_float[j + 4][i    ] =  ff_mdct_win_float[j][i    ];
71            ff_mdct_win_float[j + 4][i + 1] = -ff_mdct_win_float[j][i + 1];
72            ff_mdct_win_fixed[j + 4][i    ] =  ff_mdct_win_fixed[j][i    ];
73            ff_mdct_win_fixed[j + 4][i + 1] = -ff_mdct_win_fixed[j][i + 1];
74        }
75    }
76
77#if ARCH_X86
78    ff_mpadsp_init_x86_tabs();
79#endif
80}
81
82av_cold void ff_mpadsp_init(MPADSPContext *s)
83{
84    DCTContext dct;
85
86    ff_dct_init(&dct, 5, DCT_II);
87    ff_thread_once(&mpadsp_table_init, &mpadsp_init_tabs);
88
89    s->apply_window_float = ff_mpadsp_apply_window_float;
90    s->apply_window_fixed = ff_mpadsp_apply_window_fixed;
91
92    s->dct32_float = dct.dct32;
93    s->dct32_fixed = ff_dct32_fixed;
94
95    s->imdct36_blocks_float = ff_imdct36_blocks_float;
96    s->imdct36_blocks_fixed = ff_imdct36_blocks_fixed;
97
98#if ARCH_AARCH64
99    ff_mpadsp_init_aarch64(s);
100#elif ARCH_ARM
101    ff_mpadsp_init_arm(s);
102#elif ARCH_PPC
103    ff_mpadsp_init_ppc(s);
104#elif ARCH_X86
105    ff_mpadsp_init_x86(s);
106#endif
107#if HAVE_MIPSFPU
108    ff_mpadsp_init_mipsfpu(s);
109#endif
110#if HAVE_MIPSDSP
111    ff_mpadsp_init_mipsdsp(s);
112#endif
113}
114