FFmpeg
hqxdsp.c
Go to the documentation of this file.
1 /*
2  * HQX DSP routines
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include <stdint.h>
22 
23 #include "libavutil/common.h"
24 
25 #include "hqxdsp.h"
26 
27 static inline void idct_col(int16_t *blk, const uint8_t *quant)
28 {
29  int t0, t1, t2, t3, t4, t5, t6, t7, t8, t9, tA, tB, tC, tD, tE, tF;
30  int t10, t11, t12, t13;
31  int s0, s1, s2, s3, s4, s5, s6, s7;
32 
33  s0 = (int) blk[0 * 8] * quant[0 * 8];
34  s1 = (int) blk[1 * 8] * quant[1 * 8];
35  s2 = (int) blk[2 * 8] * quant[2 * 8];
36  s3 = (int) blk[3 * 8] * quant[3 * 8];
37  s4 = (int) blk[4 * 8] * quant[4 * 8];
38  s5 = (int) blk[5 * 8] * quant[5 * 8];
39  s6 = (int) blk[6 * 8] * quant[6 * 8];
40  s7 = (int) blk[7 * 8] * quant[7 * 8];
41 
42  t0 = (int)(s3 * 19266U + s5 * 12873U) >> 15;
43  t1 = (int)(s5 * 19266U - s3 * 12873U) >> 15;
44  t2 = ((int)(s7 * 4520U + s1 * 22725U) >> 15) - t0;
45  t3 = ((int)(s1 * 4520U - s7 * 22725U) >> 15) - t1;
46  t4 = t0 * 2 + t2;
47  t5 = t1 * 2 + t3;
48  t6 = t2 - t3;
49  t7 = t3 * 2 + t6;
50  t8 = (int)(t6 * 11585U) >> 14;
51  t9 = (int)(t7 * 11585U) >> 14;
52  tA = (int)(s2 * 8867U - s6 * 21407U) >> 14;
53  tB = (int)(s6 * 8867U + s2 * 21407U) >> 14;
54  tC = (s0 >> 1) - (s4 >> 1);
55  tD = (s4 >> 1) * 2 + tC;
56  tE = tC - (tA >> 1);
57  tF = tD - (tB >> 1);
58  t10 = tF - t5;
59  t11 = tE - t8;
60  t12 = tE + (tA >> 1) * 2 - t9;
61  t13 = tF + (tB >> 1) * 2 - t4;
62 
63  blk[0 * 8] = t13 + t4 * 2;
64  blk[1 * 8] = t12 + t9 * 2;
65  blk[2 * 8] = t11 + t8 * 2;
66  blk[3 * 8] = t10 + t5 * 2;
67  blk[4 * 8] = t10;
68  blk[5 * 8] = t11;
69  blk[6 * 8] = t12;
70  blk[7 * 8] = t13;
71 }
72 
73 static inline void idct_row(int16_t *blk)
74 {
75  int t0, t1, t2, t3, t4, t5, t6, t7, t8, t9, tA, tB, tC, tD, tE, tF;
76  int t10, t11, t12, t13;
77 
78  t0 = (blk[3] * 19266 + blk[5] * 12873) >> 14;
79  t1 = (blk[5] * 19266 - blk[3] * 12873) >> 14;
80  t2 = ((blk[7] * 4520 + blk[1] * 22725) >> 14) - t0;
81  t3 = ((blk[1] * 4520 - blk[7] * 22725) >> 14) - t1;
82  t4 = t0 * 2 + t2;
83  t5 = t1 * 2 + t3;
84  t6 = t2 - t3;
85  t7 = t3 * 2 + t6;
86  t8 = (t6 * 11585) >> 14;
87  t9 = (t7 * 11585) >> 14;
88  tA = (blk[2] * 8867 - blk[6] * 21407) >> 14;
89  tB = (blk[6] * 8867 + blk[2] * 21407) >> 14;
90  tC = blk[0] - blk[4];
91  tD = blk[4] * 2 + tC;
92  tE = tC - tA;
93  tF = tD - tB;
94  t10 = tF - t5;
95  t11 = tE - t8;
96  t12 = tE + tA * 2 - t9;
97  t13 = tF + tB * 2 - t4;
98 
99  blk[0] = (t13 + t4 * 2 + 4) >> 3;
100  blk[1] = (t12 + t9 * 2 + 4) >> 3;
101  blk[2] = (t11 + t8 * 2 + 4) >> 3;
102  blk[3] = (t10 + t5 * 2 + 4) >> 3;
103  blk[4] = (t10 + 4) >> 3;
104  blk[5] = (t11 + 4) >> 3;
105  blk[6] = (t12 + 4) >> 3;
106  blk[7] = (t13 + 4) >> 3;
107 }
108 
109 static void hqx_idct_put(uint16_t *dst, ptrdiff_t stride,
110  int16_t *block, const uint8_t *quant)
111 {
112  int i, j;
113 
114  for (i = 0; i < 8; i++)
115  idct_col(block + i, quant + i);
116  for (i = 0; i < 8; i++)
117  idct_row(block + i * 8);
118 
119  for (i = 0; i < 8; i++) {
120  for (j = 0; j < 8; j++) {
121  int v = av_clip_uintp2(block[j + i * 8] + 0x800, 12);
122  dst[j] = (v << 4) | (v >> 8);
123  }
124  dst += stride >> 1;
125  }
126 }
127 
129 {
130  c->idct_put = hqx_idct_put;
131 }
#define t9
Definition: regdef.h:54
#define t8
Definition: regdef.h:53
#define blk(i)
Definition: sha.c:185
#define t7
Definition: regdef.h:35
#define t12
Definition: regdef.h:58
The exact code depends on how similar the blocks are and how related they are to the block
uint8_t
#define av_cold
Definition: attributes.h:82
static void hqx_idct_put(uint16_t *dst, ptrdiff_t stride, int16_t *block, const uint8_t *quant)
Definition: hqxdsp.c:109
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
#define t11
Definition: regdef.h:56
#define t0
Definition: regdef.h:28
static void idct_row(int16_t *blk)
Definition: hqxdsp.c:73
#define U(x)
Definition: vp56_arith.h:37
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
#define s2
Definition: regdef.h:39
#define t10
Definition: regdef.h:55
#define s0
Definition: regdef.h:37
#define t1
Definition: regdef.h:29
#define t3
Definition: regdef.h:31
#define s5
Definition: regdef.h:42
HQX DSP routines.
#define s4
Definition: regdef.h:41
static void idct_col(int16_t *blk, const uint8_t *quant)
Definition: hqxdsp.c:27
#define s3
Definition: regdef.h:40
#define t5
Definition: regdef.h:33
#define s1
Definition: regdef.h:38
const uint8_t * quant
GLint GLenum GLboolean GLsizei stride
Definition: opengl_enc.c:104
int
common internal and external API header
#define t6
Definition: regdef.h:34
av_cold void ff_hqxdsp_init(HQXDSPContext *c)
Definition: hqxdsp.c:128
#define t4
Definition: regdef.h:32
void(* idct_put)(uint16_t *dst, ptrdiff_t stride, int16_t *block, const uint8_t *quant)
Definition: hqxdsp.h:33
#define s6
Definition: regdef.h:43
#define t2
Definition: regdef.h:30