FFmpeg: libavcodec/simple_idct.c Source File

FFmpeg
simple_idct.c
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1 /*
2  * Simple IDCT
3  *
4  * Copyright (c) 2001 Michael Niedermayer <michaelni@gmx.at>
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 Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 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  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser 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 /**
24  * @file
25  * simpleidct in C.
26  */
27 
28 #include "libavutil/intreadwrite.h"
29 #include "mathops.h"
30 #include "simple_idct.h"
31 
32 #define IN_IDCT_DEPTH 16
33 
34 #define BIT_DEPTH 8
35 #include "simple_idct_template.c"
36 #undef BIT_DEPTH
37 
38 #define BIT_DEPTH 10
39 #include "simple_idct_template.c"
40 #undef BIT_DEPTH
41 
42 #define BIT_DEPTH 12
43 #include "simple_idct_template.c"
44 #undef BIT_DEPTH
45 #undef IN_IDCT_DEPTH
46 
47  #define IN_IDCT_DEPTH 32
48  #define BIT_DEPTH 10
49 #include "simple_idct_template.c"
50 #undef BIT_DEPTH
51 #undef IN_IDCT_DEPTH
52 
53 /* 2x4x8 idct */
54 
55 #define CN_SHIFT 12
56 #define C_FIX(x) ((int)((x) * (1 << CN_SHIFT) + 0.5))
57 #define C1 C_FIX(0.6532814824)
58 #define C2 C_FIX(0.2705980501)
59 
60 /* row idct is multiple by 16 * sqrt(2.0), col idct4 is normalized,
61  and the butterfly must be multiplied by 0.5 * sqrt(2.0) */
62 #define C_SHIFT (4+1+12)
63 
64  static inline void idct4col_put(uint8_t *dest, ptrdiff_t line_size, const int16_t *col)
65 {
66  int c0, c1, c2, c3, a0, a1, a2, a3;
67 
68  a0 = col[8*0];
69  a1 = col[8*2];
70  a2 = col[8*4];
71  a3 = col[8*6];
72  c0 = ((a0 + a2) * (1 << CN_SHIFT - 1)) + (1 << (C_SHIFT - 1));
73  c2 = ((a0 - a2) * (1 << CN_SHIFT - 1)) + (1 << (C_SHIFT - 1));
74  c1 = a1 * C1 + a3 * C2;
75  c3 = a1 * C2 - a3 * C1;
76  dest[0] = av_clip_uint8((c0 + c1) >> C_SHIFT);
77  dest += line_size;
78  dest[0] = av_clip_uint8((c2 + c3) >> C_SHIFT);
79  dest += line_size;
80  dest[0] = av_clip_uint8((c2 - c3) >> C_SHIFT);
81  dest += line_size;
82  dest[0] = av_clip_uint8((c0 - c1) >> C_SHIFT);
83 }
84 
85  #define BF(k) \
86 {\
87  int a0, a1;\
88  a0 = ptr[k];\
89  a1 = ptr[8 + k];\
90  ptr[k] = a0 + a1;\
91  ptr[8 + k] = a0 - a1;\
92 }
93 
94 /* only used by DV codec. The input must be interlaced. 128 is added
95  to the pixels before clamping to avoid systematic error
96  (1024*sqrt(2)) offset would be needed otherwise. */
97 /* XXX: I think a 1.0/sqrt(2) normalization should be needed to
98  compensate the extra butterfly stage - I don't have the full DV
99  specification */
100  void ff_simple_idct248_put(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
101 {
102  int i;
103  int16_t *ptr;
104 
105  /* butterfly */
106  ptr = block;
107  for(i=0;i<4;i++) {
108  BF(0);
109  BF(1);
110  BF(2);
111  BF(3);
112  BF(4);
113  BF(5);
114  BF(6);
115  BF(7);
116  ptr += 2 * 8;
117  }
118 
119  /* IDCT8 on each line */
120  for(i=0; i<8; i++) {
121  idctRowCondDC_int16_8bit(block + i*8, 0);
122  }
123 
124  /* IDCT4 and store */
125  for(i=0;i<8;i++) {
126  idct4col_put(dest + i, 2 * line_size, block + i);
127  idct4col_put(dest + line_size + i, 2 * line_size, block + 8 + i);
128  }
129 }
130 
131 /* 8x4 & 4x8 WMV2 IDCT */
132 #undef CN_SHIFT
133 #undef C_SHIFT
134 #undef C_FIX
135 #undef C1
136 #undef C2
137  #define CN_SHIFT 12
138  #define C_FIX(x) ((int)((x) * M_SQRT2 * (1 << CN_SHIFT) + 0.5))
139  #define C1 C_FIX(0.6532814824)
140  #define C2 C_FIX(0.2705980501)
141  #define C3 C_FIX(0.5)
142  #define C_SHIFT (4+1+12)
143  static inline void idct4col_add(uint8_t *dest, ptrdiff_t line_size, const int16_t *col)
144 {
145  int c0, c1, c2, c3, a0, a1, a2, a3;
146 
147  a0 = col[8*0];
148  a1 = col[8*1];
149  a2 = col[8*2];
150  a3 = col[8*3];
151  c0 = (a0 + a2)*C3 + (1 << (C_SHIFT - 1));
152  c2 = (a0 - a2)*C3 + (1 << (C_SHIFT - 1));
153  c1 = a1 * C1 + a3 * C2;
154  c3 = a1 * C2 - a3 * C1;
155  dest[0] = av_clip_uint8(dest[0] + ((c0 + c1) >> C_SHIFT));
156  dest += line_size;
157  dest[0] = av_clip_uint8(dest[0] + ((c2 + c3) >> C_SHIFT));
158  dest += line_size;
159  dest[0] = av_clip_uint8(dest[0] + ((c2 - c3) >> C_SHIFT));
160  dest += line_size;
161  dest[0] = av_clip_uint8(dest[0] + ((c0 - c1) >> C_SHIFT));
162 }
163 
164  #define RN_SHIFT 15
165  #define R_FIX(x) ((int)((x) * M_SQRT2 * (1 << RN_SHIFT) + 0.5))
166  #define R1 R_FIX(0.6532814824)
167  #define R2 R_FIX(0.2705980501)
168  #define R3 R_FIX(0.5)
169  #define R_SHIFT 11
170  static inline void idct4row(int16_t *row)
171 {
172  unsigned c0, c1, c2, c3;
173  int a0, a1, a2, a3;
174 
175  a0 = row[0];
176  a1 = row[1];
177  a2 = row[2];
178  a3 = row[3];
179  c0 = (a0 + a2)*R3 + (1 << (R_SHIFT - 1));
180  c2 = (a0 - a2)*R3 + (1 << (R_SHIFT - 1));
181  c1 = a1 * R1 + a3 * R2;
182  c3 = a1 * R2 - a3 * R1;
183  row[0]= (c0 + c1) >> R_SHIFT;
184  row[1]= (c2 + c3) >> R_SHIFT;
185  row[2]= (c2 - c3) >> R_SHIFT;
186  row[3]= (c0 - c1) >> R_SHIFT;
187 }
188 
189  void ff_simple_idct84_add(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
190 {
191  int i;
192 
193  /* IDCT8 on each line */
194  for(i=0; i<4; i++) {
195  idctRowCondDC_int16_8bit(block + i*8, 0);
196  }
197 
198  /* IDCT4 and store */
199  for(i=0;i<8;i++) {
200  idct4col_add(dest + i, line_size, block + i);
201  }
202 }
203 
204  void ff_simple_idct48_add(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
205 {
206  int i;
207 
208  /* IDCT4 on each line */
209  for(i=0; i<8; i++) {
210  idct4row(block + i*8);
211  }
212 
213  /* IDCT8 and store */
214  for(i=0; i<4; i++){
215  idctSparseColAdd_int16_8bit(dest + i, line_size, block + i);
216  }
217 }
218 
219  void ff_simple_idct44_add(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
220 {
221  int i;
222 
223  /* IDCT4 on each line */
224  for(i=0; i<4; i++) {
225  idct4row(block + i*8);
226  }
227 
228  /* IDCT4 and store */
229  for(i=0; i<4; i++){
230  idct4col_add(dest + i, line_size, block + i);
231  }
232 }
idct4col_put
static void idct4col_put(uint8_t *dest, ptrdiff_t line_size, const int16_t *col)
Definition: simple_idct.c:64
idct4row
static void idct4row(int16_t *row)
Definition: simple_idct.c:170
ff_simple_idct44_add
void ff_simple_idct44_add(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
Definition: simple_idct.c:219
R3
#define R3
Definition: simple_idct.c:168
ff_simple_idct84_add
void ff_simple_idct84_add(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
Definition: simple_idct.c:189
R1
#define R1
Definition: simple_idct.c:166
c1
static const uint64_t c1
Definition: murmur3.c:52
C3
#define C3
Definition: simple_idct.c:141
BF
#define BF(k)
Definition: simple_idct.c:85
ff_simple_idct248_put
void ff_simple_idct248_put(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
Definition: simple_idct.c:100
a2
static double a2(void *priv, double x, double y)
Definition: vf_xfade.c:2030
intreadwrite.h
R_SHIFT
#define R_SHIFT
Definition: simple_idct.c:169
idct4col_add
static void idct4col_add(uint8_t *dest, ptrdiff_t line_size, const int16_t *col)
Definition: simple_idct.c:143
ff_simple_idct48_add
void ff_simple_idct48_add(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
Definition: simple_idct.c:204
simple_idct.h
a3
static double a3(void *priv, double x, double y)
Definition: vf_xfade.c:2031
mathops.h
R2
#define R2
Definition: simple_idct.c:167
a0
static double a0(void *priv, double x, double y)
Definition: vf_xfade.c:2028
CN_SHIFT
#define CN_SHIFT
Definition: simple_idct.c:137
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:256
C2
#define C2
Definition: simple_idct.c:140
c2
static const uint64_t c2
Definition: murmur3.c:53
C_SHIFT
#define C_SHIFT
Definition: simple_idct.c:142
av_clip_uint8
#define av_clip_uint8
Definition: common.h:106
C1
#define C1
Definition: simple_idct.c:139
block
The exact code depends on how similar the blocks are and how related they are to the block
Definition: filter_design.txt:207
a1
static double a1(void *priv, double x, double y)
Definition: vf_xfade.c:2029
simple_idct_template.c
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