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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 "avcodec.h"
30 #include "mathops.h"
31 #include "simple_idct.h"
32 
33 #define BIT_DEPTH 8
34 #include "simple_idct_template.c"
35 #undef BIT_DEPTH
36 
37 #define BIT_DEPTH 10
38 #include "simple_idct_template.c"
39 
40 #define EXTRA_SHIFT 2
41 #include "simple_idct_template.c"
42 
43 #undef EXTRA_SHIFT
44 #undef BIT_DEPTH
45 
46 #define BIT_DEPTH 12
47 #include "simple_idct_template.c"
48 #undef BIT_DEPTH
49 
50 /* 2x4x8 idct */
51 
52 #define CN_SHIFT 12
53 #define C_FIX(x) ((int)((x) * (1 << CN_SHIFT) + 0.5))
54 #define C1 C_FIX(0.6532814824)
55 #define C2 C_FIX(0.2705980501)
56 
57 /* row idct is multiple by 16 * sqrt(2.0), col idct4 is normalized,
58  and the butterfly must be multiplied by 0.5 * sqrt(2.0) */
59 #define C_SHIFT (4+1+12)
60 
61 static inline void idct4col_put(uint8_t *dest, ptrdiff_t line_size, const int16_t *col)
62 {
63  int c0, c1, c2, c3, a0, a1, a2, a3;
64 
65  a0 = col[8*0];
66  a1 = col[8*2];
67  a2 = col[8*4];
68  a3 = col[8*6];
69  c0 = ((a0 + a2) * (1 << CN_SHIFT - 1)) + (1 << (C_SHIFT - 1));
70  c2 = ((a0 - a2) * (1 << CN_SHIFT - 1)) + (1 << (C_SHIFT - 1));
71  c1 = a1 * C1 + a3 * C2;
72  c3 = a1 * C2 - a3 * C1;
73  dest[0] = av_clip_uint8((c0 + c1) >> C_SHIFT);
74  dest += line_size;
75  dest[0] = av_clip_uint8((c2 + c3) >> C_SHIFT);
76  dest += line_size;
77  dest[0] = av_clip_uint8((c2 - c3) >> C_SHIFT);
78  dest += line_size;
79  dest[0] = av_clip_uint8((c0 - c1) >> C_SHIFT);
80 }
81 
82 #define BF(k) \
83 {\
84  int a0, a1;\
85  a0 = ptr[k];\
86  a1 = ptr[8 + k];\
87  ptr[k] = a0 + a1;\
88  ptr[8 + k] = a0 - a1;\
89 }
90 
91 /* only used by DV codec. The input must be interlaced. 128 is added
92  to the pixels before clamping to avoid systematic error
93  (1024*sqrt(2)) offset would be needed otherwise. */
94 /* XXX: I think a 1.0/sqrt(2) normalization should be needed to
95  compensate the extra butterfly stage - I don't have the full DV
96  specification */
97 void ff_simple_idct248_put(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
98 {
99  int i;
100  int16_t *ptr;
101 
102  /* butterfly */
103  ptr = block;
104  for(i=0;i<4;i++) {
105  BF(0);
106  BF(1);
107  BF(2);
108  BF(3);
109  BF(4);
110  BF(5);
111  BF(6);
112  BF(7);
113  ptr += 2 * 8;
114  }
115 
116  /* IDCT8 on each line */
117  for(i=0; i<8; i++) {
118  idctRowCondDC_8(block + i*8, 0);
119  }
120 
121  /* IDCT4 and store */
122  for(i=0;i<8;i++) {
123  idct4col_put(dest + i, 2 * line_size, block + i);
124  idct4col_put(dest + line_size + i, 2 * line_size, block + 8 + i);
125  }
126 }
127 
128 /* 8x4 & 4x8 WMV2 IDCT */
129 #undef CN_SHIFT
130 #undef C_SHIFT
131 #undef C_FIX
132 #undef C1
133 #undef C2
134 #define CN_SHIFT 12
135 #define C_FIX(x) ((int)((x) * M_SQRT2 * (1 << CN_SHIFT) + 0.5))
136 #define C1 C_FIX(0.6532814824)
137 #define C2 C_FIX(0.2705980501)
138 #define C3 C_FIX(0.5)
139 #define C_SHIFT (4+1+12)
140 static inline void idct4col_add(uint8_t *dest, ptrdiff_t line_size, const int16_t *col)
141 {
142  int c0, c1, c2, c3, a0, a1, a2, a3;
143 
144  a0 = col[8*0];
145  a1 = col[8*1];
146  a2 = col[8*2];
147  a3 = col[8*3];
148  c0 = (a0 + a2)*C3 + (1 << (C_SHIFT - 1));
149  c2 = (a0 - a2)*C3 + (1 << (C_SHIFT - 1));
150  c1 = a1 * C1 + a3 * C2;
151  c3 = a1 * C2 - a3 * C1;
152  dest[0] = av_clip_uint8(dest[0] + ((c0 + c1) >> C_SHIFT));
153  dest += line_size;
154  dest[0] = av_clip_uint8(dest[0] + ((c2 + c3) >> C_SHIFT));
155  dest += line_size;
156  dest[0] = av_clip_uint8(dest[0] + ((c2 - c3) >> C_SHIFT));
157  dest += line_size;
158  dest[0] = av_clip_uint8(dest[0] + ((c0 - c1) >> C_SHIFT));
159 }
160 
161 #define RN_SHIFT 15
162 #define R_FIX(x) ((int)((x) * M_SQRT2 * (1 << RN_SHIFT) + 0.5))
163 #define R1 R_FIX(0.6532814824)
164 #define R2 R_FIX(0.2705980501)
165 #define R3 R_FIX(0.5)
166 #define R_SHIFT 11
167 static inline void idct4row(int16_t *row)
168 {
169  int c0, c1, c2, c3, a0, a1, a2, a3;
170 
171  a0 = row[0];
172  a1 = row[1];
173  a2 = row[2];
174  a3 = row[3];
175  c0 = (a0 + a2)*R3 + (1 << (R_SHIFT - 1));
176  c2 = (a0 - a2)*R3 + (1 << (R_SHIFT - 1));
177  c1 = a1 * R1 + a3 * R2;
178  c3 = a1 * R2 - a3 * R1;
179  row[0]= (c0 + c1) >> R_SHIFT;
180  row[1]= (c2 + c3) >> R_SHIFT;
181  row[2]= (c2 - c3) >> R_SHIFT;
182  row[3]= (c0 - c1) >> R_SHIFT;
183 }
184 
185 void ff_simple_idct84_add(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
186 {
187  int i;
188 
189  /* IDCT8 on each line */
190  for(i=0; i<4; i++) {
191  idctRowCondDC_8(block + i*8, 0);
192  }
193 
194  /* IDCT4 and store */
195  for(i=0;i<8;i++) {
196  idct4col_add(dest + i, line_size, block + i);
197  }
198 }
199 
200 void ff_simple_idct48_add(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
201 {
202  int i;
203 
204  /* IDCT4 on each line */
205  for(i=0; i<8; i++) {
206  idct4row(block + i*8);
207  }
208 
209  /* IDCT8 and store */
210  for(i=0; i<4; i++){
211  idctSparseColAdd_8(dest + i, line_size, block + i);
212  }
213 }
214 
215 void ff_simple_idct44_add(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
216 {
217  int i;
218 
219  /* IDCT4 on each line */
220  for(i=0; i<4; i++) {
221  idct4row(block + i*8);
222  }
223 
224  /* IDCT4 and store */
225  for(i=0; i<4; i++){
226  idct4col_add(dest + i, line_size, block + i);
227  }
228 }
229 
230 void ff_prores_idct(int16_t *block, const int16_t *qmat)
231 {
232  int i;
233 
234  for (i = 0; i < 64; i++)
235  block[i] *= qmat[i];
236 
237  for (i = 0; i < 8; i++)
238  idctRowCondDC_extrashift_10(block + i*8, 2);
239 
240  for (i = 0; i < 8; i++) {
241  block[i] += 8192;
242  idctSparseCol_extrashift_10(block + i);
243  }
244 }
#define a0
Definition: regdef.h:46
#define R2
Definition: simple_idct.c:164
#define a1
Definition: regdef.h:47
#define C2
Definition: simple_idct.c:137
#define CN_SHIFT
Definition: simple_idct.c:134
static int16_t block[64]
Definition: dct.c:115
#define a3
Definition: regdef.h:49
uint8_t
static const uint64_t c1
Definition: murmur3.c:49
void ff_prores_idct(int16_t *block, const int16_t *qmat)
Special version of ff_simple_idct_10() which does dequantization and scales by a factor of 2 more bet...
Definition: simple_idct.c:230
#define C1
Definition: simple_idct.c:136
#define C_SHIFT
Definition: simple_idct.c:139
static void idct4row(int16_t *row)
Definition: simple_idct.c:167
void ff_simple_idct44_add(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
Definition: simple_idct.c:215
simpleidct in C.
#define a2
Definition: regdef.h:48
static void idct4col_put(uint8_t *dest, ptrdiff_t line_size, const int16_t *col)
Definition: simple_idct.c:61
#define R1
Definition: simple_idct.c:163
#define R3
Definition: simple_idct.c:165
Libavcodec external API header.
void ff_simple_idct84_add(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
Definition: simple_idct.c:185
#define C3
Definition: simple_idct.c:138
void ff_simple_idct248_put(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
Definition: simple_idct.c:97
#define BF(k)
Definition: simple_idct.c:82
static const uint64_t c2
Definition: murmur3.c:50
simple idct header.
#define R_SHIFT
Definition: simple_idct.c:166
static void idct4col_add(uint8_t *dest, ptrdiff_t line_size, const int16_t *col)
Definition: simple_idct.c:140
void ff_simple_idct48_add(uint8_t *dest, ptrdiff_t line_size, int16_t *block)
Definition: simple_idct.c:200