FFmpeg
faanidct.c
Go to the documentation of this file.
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. */
25 typedef 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 
39 static const FLOAT prescale[64]={
40 B0*B0/8, B0*B1/8, B0*B2/8, B0*B3/8, B0*B4/8, B0*B5/8, B0*B6/8, B0*B7/8,
41 B1*B0/8, B1*B1/8, B1*B2/8, B1*B3/8, B1*B4/8, B1*B5/8, B1*B6/8, B1*B7/8,
42 B2*B0/8, B2*B1/8, B2*B2/8, B2*B3/8, B2*B4/8, B2*B5/8, B2*B6/8, B2*B7/8,
43 B3*B0/8, B3*B1/8, B3*B2/8, B3*B3/8, B3*B4/8, B3*B5/8, B3*B6/8, B3*B7/8,
44 B4*B0/8, B4*B1/8, B4*B2/8, B4*B3/8, B4*B4/8, B4*B5/8, B4*B6/8, B4*B7/8,
45 B5*B0/8, B5*B1/8, B5*B2/8, B5*B3/8, B5*B4/8, B5*B5/8, B5*B6/8, B5*B7/8,
46 B6*B0/8, B6*B1/8, B6*B2/8, B6*B3/8, B6*B4/8, B6*B5/8, B6*B6/8, B6*B7/8,
47 B7*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 
50 static 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 
127 void 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 
140 void 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 
154 void 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 }
stride
int stride
Definition: mace.c:144
p8idct
static void p8idct(int16_t data[64], FLOAT temp[64], uint8_t *dest, ptrdiff_t stride, int x, int y, int type)
Definition: faanidct.c:50
B0
#define B0
Definition: faanidct.c:27
data
const char data[16]
Definition: mxf.c:143
A2
#define A2
Definition: faanidct.c:37
type
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf type
Definition: writing_filters.txt:86
A4
#define A4
Definition: faanidct.c:36
ff_faanidct_add
void ff_faanidct_add(uint8_t *dest, ptrdiff_t line_size, int16_t block[64])
Definition: faanidct.c:140
ff_faanidct
void ff_faanidct(int16_t block[64])
Definition: faanidct.c:127
B2
#define B2
Definition: faanidct.c:29
prescale
static const FLOAT prescale[64]
Definition: faanidct.c:39
NULL
#define NULL
Definition: coverity.c:32
B3
#define B3
Definition: faanidct.c:30
B5
#define B5
Definition: faanidct.c:32
ff_faanidct_put
void ff_faanidct_put(uint8_t *dest, ptrdiff_t line_size, int16_t block[64])
Definition: faanidct.c:154
B7
#define B7
Definition: faanidct.c:34
faanidct.h
lrintf
#define lrintf(x)
Definition: libm_mips.h:72
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:271
common.h
FLOAT
float FLOAT
Definition: faandct.c:32
B6
#define B6
Definition: faanidct.c:33
temp
else temp
Definition: vf_mcdeint.c:248
av_clip_uint8
#define av_clip_uint8
Definition: common.h:102
FLOAT
float FLOAT
Definition: faanidct.c:25
block
The exact code depends on how similar the blocks are and how related they are to the block
Definition: filter_design.txt:207
B1
#define B1
Definition: faanidct.c:28
B4
#define B4
Definition: faanidct.c:31
Generated on Wed Aug 24 2022 21:37:33 for FFmpeg by   doxygen 1.8.17