add more OKed parts of the E-AC-3 decoder
[libav.git] / libavcodec / eac3dec.c
CommitLineData
60203130
JR
1/*
2 * E-AC-3 decoder
3 * Copyright (c) 2007 Bartlomiej Wolowiec <bartek.wolowiec@gmail.com>
4 * Copyright (c) 2008 Justin Ruggles
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23#include "avcodec.h"
24#include "ac3.h"
25#include "ac3_parser.h"
26#include "ac3dec.h"
27#include "ac3dec_data.h"
28
29/** gain adaptive quantization mode */
30typedef enum {
31 EAC3_GAQ_NO =0,
32 EAC3_GAQ_12,
33 EAC3_GAQ_14,
34 EAC3_GAQ_124
35} EAC3GaqMode;
36
37#define EAC3_SR_CODE_REDUCED 3
38
39/** lrint(M_SQRT2*cos(2*M_PI/12)*(1<<23)) */
40#define COEFF_0 10273905LL
41
42/** lrint(M_SQRT2*cos(0*M_PI/12)*(1<<23)) = lrint(M_SQRT2*(1<<23)) */
43#define COEFF_1 11863283LL
44
45/** lrint(M_SQRT2*cos(5*M_PI/12)*(1<<23)) */
46#define COEFF_2 3070444LL
47
48/**
49 * Calculate 6-point IDCT of the pre-mantissas.
50 * All calculations are 24-bit fixed-point.
51 */
52static void idct6(int pre_mant[6])
53{
54 int tmp;
55 int even0, even1, even2, odd0, odd1, odd2;
56
57 odd1 = pre_mant[1] - pre_mant[3] - pre_mant[5];
58
59 even2 = ( pre_mant[2] * COEFF_0) >> 23;
60 tmp = ( pre_mant[4] * COEFF_1) >> 23;
61 odd0 = ((pre_mant[1] + pre_mant[5]) * COEFF_2) >> 23;
62
63 even0 = pre_mant[0] + (tmp >> 1);
64 even1 = pre_mant[0] - tmp;
65
66 tmp = even0;
67 even0 = tmp + even2;
68 even2 = tmp - even2;
69
70 tmp = odd0;
71 odd0 = tmp + pre_mant[1] + pre_mant[3];
72 odd2 = tmp + pre_mant[5] - pre_mant[3];
73
74 pre_mant[0] = even0 + odd0;
75 pre_mant[1] = even1 + odd1;
76 pre_mant[2] = even2 + odd2;
77 pre_mant[3] = even2 - odd2;
78 pre_mant[4] = even1 - odd1;
79 pre_mant[5] = even0 - odd0;
80}