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transform.c
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1 /*
2  * Copyright (C) 2010 Georg Martius <georg.martius@web.de>
3  * Copyright (C) 2010 Daniel G. Taylor <dan@programmer-art.org>
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 
22 /**
23  * @file
24  * transform input video
25  */
26 
27 #include "libavutil/common.h"
28 #include "libavutil/avassert.h"
29 
30 #include "transform.h"
31 
32 #define INTERPOLATE_METHOD(name) \
33  static uint8_t name(float x, float y, const uint8_t *src, \
34  int width, int height, int stride, uint8_t def)
35 
36 #define PIXEL(img, x, y, w, h, stride, def) \
37  ((x) < 0 || (y) < 0) ? (def) : \
38  (((x) >= (w) || (y) >= (h)) ? (def) : \
39  img[(x) + (y) * (stride)])
40 
41 /**
42  * Nearest neighbor interpolation
43  */
44 INTERPOLATE_METHOD(interpolate_nearest)
45 {
46  return PIXEL(src, (int)(x + 0.5), (int)(y + 0.5), width, height, stride, def);
47 }
48 
49 /**
50  * Bilinear interpolation
51  */
52 INTERPOLATE_METHOD(interpolate_bilinear)
53 {
54  int x_c, x_f, y_c, y_f;
55  int v1, v2, v3, v4;
56 
57  if (x < -1 || x > width || y < -1 || y > height) {
58  return def;
59  } else {
60  x_f = (int)x;
61  x_c = x_f + 1;
62 
63  y_f = (int)y;
64  y_c = y_f + 1;
65 
66  v1 = PIXEL(src, x_c, y_c, width, height, stride, def);
67  v2 = PIXEL(src, x_c, y_f, width, height, stride, def);
68  v3 = PIXEL(src, x_f, y_c, width, height, stride, def);
69  v4 = PIXEL(src, x_f, y_f, width, height, stride, def);
70 
71  return (v1*(x - x_f)*(y - y_f) + v2*((x - x_f)*(y_c - y)) +
72  v3*(x_c - x)*(y - y_f) + v4*((x_c - x)*(y_c - y)));
73  }
74 }
75 
76 /**
77  * Biquadratic interpolation
78  */
79 INTERPOLATE_METHOD(interpolate_biquadratic)
80 {
81  int x_c, x_f, y_c, y_f;
82  uint8_t v1, v2, v3, v4;
83  float f1, f2, f3, f4;
84 
85  if (x < - 1 || x > width || y < -1 || y > height)
86  return def;
87  else {
88  x_f = (int)x;
89  x_c = x_f + 1;
90  y_f = (int)y;
91  y_c = y_f + 1;
92 
93  v1 = PIXEL(src, x_c, y_c, width, height, stride, def);
94  v2 = PIXEL(src, x_c, y_f, width, height, stride, def);
95  v3 = PIXEL(src, x_f, y_c, width, height, stride, def);
96  v4 = PIXEL(src, x_f, y_f, width, height, stride, def);
97 
98  f1 = 1 - sqrt((x_c - x) * (y_c - y));
99  f2 = 1 - sqrt((x_c - x) * (y - y_f));
100  f3 = 1 - sqrt((x - x_f) * (y_c - y));
101  f4 = 1 - sqrt((x - x_f) * (y - y_f));
102  return (v1 * f1 + v2 * f2 + v3 * f3 + v4 * f4) / (f1 + f2 + f3 + f4);
103  }
104 }
105 
106 void avfilter_get_matrix(float x_shift, float y_shift, float angle, float zoom, float *matrix) {
107  matrix[0] = zoom * cos(angle);
108  matrix[1] = -sin(angle);
109  matrix[2] = x_shift;
110  matrix[3] = -matrix[1];
111  matrix[4] = matrix[0];
112  matrix[5] = y_shift;
113  matrix[6] = 0;
114  matrix[7] = 0;
115  matrix[8] = 1;
116 }
117 
118 void avfilter_add_matrix(const float *m1, const float *m2, float *result)
119 {
120  int i;
121  for (i = 0; i < 9; i++)
122  result[i] = m1[i] + m2[i];
123 }
124 
125 void avfilter_sub_matrix(const float *m1, const float *m2, float *result)
126 {
127  int i;
128  for (i = 0; i < 9; i++)
129  result[i] = m1[i] - m2[i];
130 }
131 
132 void avfilter_mul_matrix(const float *m1, float scalar, float *result)
133 {
134  int i;
135  for (i = 0; i < 9; i++)
136  result[i] = m1[i] * scalar;
137 }
138 
140  int src_stride, int dst_stride,
141  int width, int height, const float *matrix,
143  enum FillMethod fill)
144 {
145  int x, y;
146  float x_s, y_s;
147  uint8_t def = 0;
148  uint8_t (*func)(float, float, const uint8_t *, int, int, int, uint8_t) = NULL;
149 
150  switch(interpolate) {
151  case INTERPOLATE_NEAREST:
152  func = interpolate_nearest;
153  break;
155  func = interpolate_bilinear;
156  break;
158  func = interpolate_biquadratic;
159  break;
160  default:
161  return AVERROR(EINVAL);
162  }
163 
164  for (y = 0; y < height; y++) {
165  for(x = 0; x < width; x++) {
166  x_s = x * matrix[0] + y * matrix[1] + matrix[2];
167  y_s = x * matrix[3] + y * matrix[4] + matrix[5];
168 
169  switch(fill) {
170  case FILL_ORIGINAL:
171  def = src[y * src_stride + x];
172  break;
173  case FILL_CLAMP:
174  y_s = av_clipf(y_s, 0, height - 1);
175  x_s = av_clipf(x_s, 0, width - 1);
176  def = src[(int)y_s * src_stride + (int)x_s];
177  break;
178  case FILL_MIRROR:
179  x_s = avpriv_mirror(x_s, width-1);
180  y_s = avpriv_mirror(y_s, height-1);
181 
182  av_assert2(x_s >= 0 && y_s >= 0);
183  av_assert2(x_s < width && y_s < height);
184  def = src[(int)y_s * src_stride + (int)x_s];
185  }
186 
187  dst[y * dst_stride + x] = func(x_s, y_s, src, width, height, src_stride, def);
188  }
189  }
190  return 0;
191 }
#define NULL
Definition: coverity.c:32
void avfilter_sub_matrix(const float *m1, const float *m2, float *result)
Subtract one matrix from another.
Definition: transform.c:125
InterpolateMethod
Definition: transform.h:39
#define INTERPOLATE_METHOD(name)
Definition: transform.c:32
uint8_t
#define av_assert2(cond)
assert() equivalent, that does lie in speed critical code.
Definition: avassert.h:63
int avfilter_transform(const uint8_t *src, uint8_t *dst, int src_stride, int dst_stride, int width, int height, const float *matrix, enum InterpolateMethod interpolate, enum FillMethod fill)
Do an affine transformation with the given interpolation method.
Definition: transform.c:139
void avfilter_add_matrix(const float *m1, const float *m2, float *result)
Add two matrices together.
Definition: transform.c:118
static void interpolate(float *out, float v1, float v2, int size)
Definition: twinvq.c:84
#define height
#define AVERROR(e)
Definition: error.h:43
simple assert() macros that are a bit more flexible than ISO C assert().
FillMethod
Definition: transform.h:51
#define width
#define src
Definition: vp9dsp.c:530
static av_always_inline av_const int avpriv_mirror(int x, int w)
Definition: internal.h:318
transform input video
#define PIXEL(img, x, y, w, h, stride, def)
Definition: transform.c:36
int(* func)(AVBPrint *dst, const char *in, const char *arg)
Definition: jacosubdec.c:67
void avfilter_mul_matrix(const float *m1, float scalar, float *result)
Multiply a matrix by a scalar value.
Definition: transform.c:132
GLint GLenum GLboolean GLsizei stride
Definition: opengl_enc.c:105
common internal and external API header
void avfilter_get_matrix(float x_shift, float y_shift, float angle, float zoom, float *matrix)
Get an affine transformation matrix from a given translation, rotation, and zoom factor.
Definition: transform.c:106