FFmpeg
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
#define src
Definition: vp8dsp.c:254
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:64
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
simple assert() macros that are a bit more flexible than ISO C assert().
FillMethod
Definition: transform.h:51
#define width
static av_always_inline av_const int avpriv_mirror(int x, int w)
Definition: internal.h:338
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
int
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
and forward the result(frame or status change) to the corresponding input.If nothing is possible
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions