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path: root/libavcodec/faanidct.c (plain)
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1/*
2 * Floating point AAN IDCT
3 * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21#include "faanidct.h"
22#include "libavutil/common.h"
23
24/* To allow switching to double. */
25typedef float FLOAT;
26
27#define B0 1.0000000000000000000000
28#define B1 1.3870398453221474618216 // cos(pi*1/16)sqrt(2)
29#define B2 1.3065629648763765278566 // cos(pi*2/16)sqrt(2)
30#define B3 1.1758756024193587169745 // cos(pi*3/16)sqrt(2)
31#define B4 1.0000000000000000000000 // cos(pi*4/16)sqrt(2)
32#define B5 0.7856949583871021812779 // cos(pi*5/16)sqrt(2)
33#define B6 0.5411961001461969843997 // cos(pi*6/16)sqrt(2)
34#define B7 0.2758993792829430123360 // cos(pi*7/16)sqrt(2)
35
36#define A4 0.70710678118654752438 // cos(pi*4/16)
37#define A2 0.92387953251128675613 // cos(pi*2/16)
38
39static const FLOAT prescale[64]={
40B0*B0/8, B0*B1/8, B0*B2/8, B0*B3/8, B0*B4/8, B0*B5/8, B0*B6/8, B0*B7/8,
41B1*B0/8, B1*B1/8, B1*B2/8, B1*B3/8, B1*B4/8, B1*B5/8, B1*B6/8, B1*B7/8,
42B2*B0/8, B2*B1/8, B2*B2/8, B2*B3/8, B2*B4/8, B2*B5/8, B2*B6/8, B2*B7/8,
43B3*B0/8, B3*B1/8, B3*B2/8, B3*B3/8, B3*B4/8, B3*B5/8, B3*B6/8, B3*B7/8,
44B4*B0/8, B4*B1/8, B4*B2/8, B4*B3/8, B4*B4/8, B4*B5/8, B4*B6/8, B4*B7/8,
45B5*B0/8, B5*B1/8, B5*B2/8, B5*B3/8, B5*B4/8, B5*B5/8, B5*B6/8, B5*B7/8,
46B6*B0/8, B6*B1/8, B6*B2/8, B6*B3/8, B6*B4/8, B6*B5/8, B6*B6/8, B6*B7/8,
47B7*B0/8, B7*B1/8, B7*B2/8, B7*B3/8, B7*B4/8, B7*B5/8, B7*B6/8, B7*B7/8,
48};
49
50static inline void p8idct(int16_t data[64], FLOAT temp[64], uint8_t *dest,
51 ptrdiff_t stride, int x, int y, int type)
52{
53 int i;
54 FLOAT s04, d04, s17, d17, s26, d26, s53, d53;
55 FLOAT os07, os16, os25, os34;
56 FLOAT od07, od16, od25, od34;
57
58 for(i=0; i<y*8; i+=y){
59 s17= temp[1*x + i] + temp[7*x + i];
60 d17= temp[1*x + i] - temp[7*x + i];
61 s53= temp[5*x + i] + temp[3*x + i];
62 d53= temp[5*x + i] - temp[3*x + i];
63
64 od07= s17 + s53;
65 od25= (s17 - s53)*(2*A4);
66
67 od34= d17*(2*(B6-A2)) - d53*(2*A2);
68 od16= d53*(2*(A2-B2)) + d17*(2*A2);
69
70 od16 -= od07;
71 od25 -= od16;
72 od34 += od25;
73
74 s26 = temp[2*x + i] + temp[6*x + i];
75 d26 = temp[2*x + i] - temp[6*x + i];
76 d26*= 2*A4;
77 d26-= s26;
78
79 s04= temp[0*x + i] + temp[4*x + i];
80 d04= temp[0*x + i] - temp[4*x + i];
81
82 os07= s04 + s26;
83 os34= s04 - s26;
84 os16= d04 + d26;
85 os25= d04 - d26;
86
87 if(type==0){
88 temp[0*x + i]= os07 + od07;
89 temp[7*x + i]= os07 - od07;
90 temp[1*x + i]= os16 + od16;
91 temp[6*x + i]= os16 - od16;
92 temp[2*x + i]= os25 + od25;
93 temp[5*x + i]= os25 - od25;
94 temp[3*x + i]= os34 - od34;
95 temp[4*x + i]= os34 + od34;
96 }else if(type==1){
97 data[0*x + i]= lrintf(os07 + od07);
98 data[7*x + i]= lrintf(os07 - od07);
99 data[1*x + i]= lrintf(os16 + od16);
100 data[6*x + i]= lrintf(os16 - od16);
101 data[2*x + i]= lrintf(os25 + od25);
102 data[5*x + i]= lrintf(os25 - od25);
103 data[3*x + i]= lrintf(os34 - od34);
104 data[4*x + i]= lrintf(os34 + od34);
105 }else if(type==2){
106 dest[0*stride + i]= av_clip_uint8(((int)dest[0*stride + i]) + lrintf(os07 + od07));
107 dest[7*stride + i]= av_clip_uint8(((int)dest[7*stride + i]) + lrintf(os07 - od07));
108 dest[1*stride + i]= av_clip_uint8(((int)dest[1*stride + i]) + lrintf(os16 + od16));
109 dest[6*stride + i]= av_clip_uint8(((int)dest[6*stride + i]) + lrintf(os16 - od16));
110 dest[2*stride + i]= av_clip_uint8(((int)dest[2*stride + i]) + lrintf(os25 + od25));
111 dest[5*stride + i]= av_clip_uint8(((int)dest[5*stride + i]) + lrintf(os25 - od25));
112 dest[3*stride + i]= av_clip_uint8(((int)dest[3*stride + i]) + lrintf(os34 - od34));
113 dest[4*stride + i]= av_clip_uint8(((int)dest[4*stride + i]) + lrintf(os34 + od34));
114 }else{
115 dest[0*stride + i]= av_clip_uint8(lrintf(os07 + od07));
116 dest[7*stride + i]= av_clip_uint8(lrintf(os07 - od07));
117 dest[1*stride + i]= av_clip_uint8(lrintf(os16 + od16));
118 dest[6*stride + i]= av_clip_uint8(lrintf(os16 - od16));
119 dest[2*stride + i]= av_clip_uint8(lrintf(os25 + od25));
120 dest[5*stride + i]= av_clip_uint8(lrintf(os25 - od25));
121 dest[3*stride + i]= av_clip_uint8(lrintf(os34 - od34));
122 dest[4*stride + i]= av_clip_uint8(lrintf(os34 + od34));
123 }
124 }
125}
126
127void ff_faanidct(int16_t block[64]){
128 FLOAT temp[64];
129 int i;
130
131 emms_c();
132
133 for(i=0; i<64; i++)
134 temp[i] = block[i] * prescale[i];
135
136 p8idct(block, temp, NULL, 0, 1, 8, 0);
137 p8idct(block, temp, NULL, 0, 8, 1, 1);
138}
139
140void ff_faanidct_add(uint8_t *dest, ptrdiff_t line_size, int16_t block[64])
141{
142 FLOAT temp[64];
143 int i;
144
145 emms_c();
146
147 for(i=0; i<64; i++)
148 temp[i] = block[i] * prescale[i];
149
150 p8idct(block, temp, NULL, 0, 1, 8, 0);
151 p8idct(NULL , temp, dest, line_size, 8, 1, 2);
152}
153
154void ff_faanidct_put(uint8_t *dest, ptrdiff_t line_size, int16_t block[64])
155{
156 FLOAT temp[64];
157 int i;
158
159 emms_c();
160
161 for(i=0; i<64; i++)
162 temp[i] = block[i] * prescale[i];
163
164 p8idct(block, temp, NULL, 0, 1, 8, 0);
165 p8idct(NULL , temp, dest, line_size, 8, 1, 3);
166}
167
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