FFmpeg
transform.c
Go to the documentation of this file.
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 
107  float x_shift,
108  float y_shift,
109  float angle,
110  float scale_x,
111  float scale_y,
112  float *matrix
113 ) {
114  matrix[0] = scale_x * cos(angle);
115  matrix[1] = -sin(angle);
116  matrix[2] = x_shift;
117  matrix[3] = -matrix[1];
118  matrix[4] = scale_y * cos(angle);
119  matrix[5] = y_shift;
120  matrix[6] = 0;
121  matrix[7] = 0;
122  matrix[8] = 1;
123 }
124 
125 void avfilter_add_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_sub_matrix(const float *m1, const float *m2, float *result)
133 {
134  int i;
135  for (i = 0; i < 9; i++)
136  result[i] = m1[i] - m2[i];
137 }
138 
139 void avfilter_mul_matrix(const float *m1, float scalar, float *result)
140 {
141  int i;
142  for (i = 0; i < 9; i++)
143  result[i] = m1[i] * scalar;
144 }
145 
147  int src_stride, int dst_stride,
148  int width, int height, const float *matrix,
150  enum FillMethod fill)
151 {
152  int x, y;
153  float x_s, y_s;
154  uint8_t def = 0;
155  uint8_t (*func)(float, float, const uint8_t *, int, int, int, uint8_t) = NULL;
156 
157  switch(interpolate) {
158  case INTERPOLATE_NEAREST:
159  func = interpolate_nearest;
160  break;
162  func = interpolate_bilinear;
163  break;
165  func = interpolate_biquadratic;
166  break;
167  default:
168  return AVERROR(EINVAL);
169  }
170 
171  for (y = 0; y < height; y++) {
172  for(x = 0; x < width; x++) {
173  x_s = x * matrix[0] + y * matrix[1] + matrix[2];
174  y_s = x * matrix[3] + y * matrix[4] + matrix[5];
175 
176  switch(fill) {
177  case FILL_ORIGINAL:
178  def = src[y * src_stride + x];
179  break;
180  case FILL_CLAMP:
181  y_s = av_clipf(y_s, 0, height - 1);
182  x_s = av_clipf(x_s, 0, width - 1);
183  def = src[(int)y_s * src_stride + (int)x_s];
184  break;
185  case FILL_MIRROR:
186  x_s = avpriv_mirror(x_s, width-1);
187  y_s = avpriv_mirror(y_s, height-1);
188 
189  av_assert2(x_s >= 0 && y_s >= 0);
190  av_assert2(x_s < width && y_s < height);
191  def = src[(int)y_s * src_stride + (int)x_s];
192  }
193 
194  dst[y * dst_stride + x] = func(x_s, y_s, src, width, height, src_stride, def);
195  }
196  }
197  return 0;
198 }
func
int(* func)(AVBPrint *dst, const char *in, const char *arg)
Definition: jacosubdec.c:67
stride
int stride
Definition: mace.c:144
AVERROR
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
FILL_CLAMP
@ FILL_CLAMP
Definition: transform.h:54
INTERPOLATE_NEAREST
@ INTERPOLATE_NEAREST
Definition: transform.h:40
InterpolateMethod
InterpolateMethod
Definition: transform.h:39
FILL_ORIGINAL
@ FILL_ORIGINAL
Definition: transform.h:53
avassert.h
avfilter_add_matrix
void avfilter_add_matrix(const float *m1, const float *m2, float *result)
Add two matrices together.
Definition: transform.c:125
width
#define width
result
and forward the result(frame or status change) to the corresponding input. If nothing is possible
INTERPOLATE_METHOD
#define INTERPOLATE_METHOD(name)
Definition: transform.c:32
NULL
#define NULL
Definition: coverity.c:32
av_clipf
#define av_clipf
Definition: common.h:170
src
#define src
Definition: vp8dsp.c:255
avpriv_mirror
static av_always_inline av_const int avpriv_mirror(int x, int w)
Definition: internal.h:269
PIXEL
#define PIXEL(img, x, y, w, h, stride, def)
Definition: transform.c:36
FILL_MIRROR
@ FILL_MIRROR
Definition: transform.h:55
height
#define height
INTERPOLATE_BILINEAR
@ INTERPOLATE_BILINEAR
Definition: transform.h:41
interpolate
static void interpolate(float *out, float v1, float v2, int size)
Definition: twinvq.c:84
av_assert2
#define av_assert2(cond)
assert() equivalent, that does lie in speed critical code.
Definition: avassert.h:64
i
int i
Definition: input.c:407
ff_get_matrix
void ff_get_matrix(float x_shift, float y_shift, float angle, float scale_x, float scale_y, float *matrix)
Get an affine transformation matrix from given translation, rotation, and zoom factors.
Definition: transform.c:106
common.h
uint8_t
uint8_t
Definition: audio_convert.c:194
transform.h
avfilter_mul_matrix
void avfilter_mul_matrix(const float *m1, float scalar, float *result)
Multiply a matrix by a scalar value.
Definition: transform.c:139
avfilter_transform
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:146
avfilter_sub_matrix
void avfilter_sub_matrix(const float *m1, const float *m2, float *result)
Subtract one matrix from another.
Definition: transform.c:132
FillMethod
FillMethod
Definition: transform.h:51
int
int
Definition: ffmpeg_filter.c:158
INTERPOLATE_BIQUADRATIC
@ INTERPOLATE_BIQUADRATIC
Definition: transform.h:42