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vf_lenscorrection.c
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1 /*
2  * Copyright (C) 2007 Richard Spindler (author of frei0r plugin from which this was derived)
3  * Copyright (C) 2014 Daniel Oberhoff
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  * Lenscorrection filter, algorithm from the frei0r plugin with the same name
25 */
26 #include <stdlib.h>
27 #include <math.h>
28 
29 #include "libavutil/opt.h"
30 #include "libavutil/intreadwrite.h"
31 #include "libavutil/pixdesc.h"
32 
33 #include "avfilter.h"
34 #include "internal.h"
35 #include "video.h"
36 
37 typedef struct LenscorrectionCtx {
38  const AVClass *av_class;
39  unsigned int width;
40  unsigned int height;
41  int hsub, vsub;
42  int nb_planes;
43  double cx, cy, k1, k2;
46 
47 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
48 static const AVOption lenscorrection_options[] = {
49  { "cx", "set relative center x", offsetof(LenscorrectionCtx, cx), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 1, .flags=FLAGS },
50  { "cy", "set relative center y", offsetof(LenscorrectionCtx, cy), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 1, .flags=FLAGS },
51  { "k1", "set quadratic distortion factor", offsetof(LenscorrectionCtx, k1), AV_OPT_TYPE_DOUBLE, {.dbl=0.0}, -1, 1, .flags=FLAGS },
52  { "k2", "set double quadratic distortion factor", offsetof(LenscorrectionCtx, k2), AV_OPT_TYPE_DOUBLE, {.dbl=0.0}, -1, 1, .flags=FLAGS },
53  { NULL }
54 };
55 
56 AVFILTER_DEFINE_CLASS(lenscorrection);
57 
58 typedef struct ThreadData {
59  AVFrame *in, *out;
60  int w, h;
61  int plane;
64 } ThreadData;
65 
66 static int filter_slice(AVFilterContext *ctx, void *arg, int job, int nb_jobs)
67 {
68  ThreadData *td = (ThreadData*)arg;
69  AVFrame *in = td->in;
70  AVFrame *out = td->out;
71 
72  const int w = td->w, h = td->h;
73  const int xcenter = td->xcenter;
74  const int ycenter = td->ycenter;
75  const int start = (h * job ) / nb_jobs;
76  const int end = (h * (job+1)) / nb_jobs;
77  const int plane = td->plane;
78  const int inlinesize = in->linesize[plane];
79  const int outlinesize = out->linesize[plane];
80  const uint8_t *indata = in->data[plane];
81  uint8_t *outrow = out->data[plane] + start * outlinesize;
82  int i;
83  for (i = start; i < end; i++, outrow += outlinesize) {
84  const int off_y = i - ycenter;
85  uint8_t *out = outrow;
86  int j;
87  for (j = 0; j < w; j++) {
88  const int off_x = j - xcenter;
89  const int64_t radius_mult = td->correction[j + i*w];
90  const int x = xcenter + ((radius_mult * off_x + (1<<23))>>24);
91  const int y = ycenter + ((radius_mult * off_y + (1<<23))>>24);
92  const char isvalid = x > 0 && x < w - 1 && y > 0 && y < h - 1;
93  *out++ = isvalid ? indata[y * inlinesize + x] : 0;
94  }
95  }
96  return 0;
97 }
98 
100 {
101  static const enum AVPixelFormat pix_fmts[] = {
108  };
109 
111  return 0;
112 }
113 
114 static av_cold void uninit(AVFilterContext *ctx)
115 {
116  LenscorrectionCtx *rect = ctx->priv;
117  int i;
118 
119  for (i = 0; i < FF_ARRAY_ELEMS(rect->correction); i++) {
120  av_freep(&rect->correction[i]);
121  }
122 }
123 
124 static int config_props(AVFilterLink *outlink)
125 {
126  AVFilterContext *ctx = outlink->src;
127  LenscorrectionCtx *rect = ctx->priv;
128  AVFilterLink *inlink = ctx->inputs[0];
129  const AVPixFmtDescriptor *pixdesc = av_pix_fmt_desc_get(inlink->format);
130  rect->hsub = pixdesc->log2_chroma_w;
131  rect->vsub = pixdesc->log2_chroma_h;
132  outlink->w = rect->width = inlink->w;
133  outlink->h = rect->height = inlink->h;
134  rect->nb_planes = av_pix_fmt_count_planes(inlink->format);
135  return 0;
136 }
137 
138 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
139 {
140  AVFilterContext *ctx = inlink->dst;
141  AVFilterLink *outlink = ctx->outputs[0];
143  AVFrame *out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
144  int plane;
145 
146  if (!out) {
147  av_frame_free(&in);
148  return AVERROR(ENOMEM);
149  }
150 
152 
153  for (plane = 0; plane < rect->nb_planes; ++plane) {
154  int hsub = plane == 1 || plane == 2 ? rect->hsub : 0;
155  int vsub = plane == 1 || plane == 2 ? rect->vsub : 0;
156  int hdiv = 1 << hsub;
157  int vdiv = 1 << vsub;
158  int w = rect->width / hdiv;
159  int h = rect->height / vdiv;
160  int xcenter = rect->cx * w;
161  int ycenter = rect->cy * h;
162  int k1 = rect->k1 * (1<<24);
163  int k2 = rect->k2 * (1<<24);
164  ThreadData td = {
165  .in = in,
166  .out = out,
167  .w = w,
168  .h = h,
169  .xcenter = xcenter,
170  .ycenter = ycenter,
171  .plane = plane};
172 
173  if (!rect->correction[plane]) {
174  int i,j;
175  const int64_t r2inv = (4LL<<60) / (w * w + h * h);
176 
177  rect->correction[plane] = av_malloc_array(w, h * sizeof(**rect->correction));
178  if (!rect->correction[plane])
179  return AVERROR(ENOMEM);
180  for (j = 0; j < h; j++) {
181  const int off_y = j - ycenter;
182  const int off_y2 = off_y * off_y;
183  for (i = 0; i < w; i++) {
184  const int off_x = i - xcenter;
185  const int64_t r2 = ((off_x * off_x + off_y2) * r2inv + (1LL<<31)) >> 32;
186  const int64_t r4 = (r2 * r2 + (1<<27)) >> 28;
187  const int radius_mult = (r2 * k1 + r4 * k2 + (1LL<<27) + (1LL<<52))>>28;
188  rect->correction[plane][j * w + i] = radius_mult;
189  }
190  }
191  }
192 
193  td.correction = rect->correction[plane];
194  ctx->internal->execute(ctx, filter_slice, &td, NULL, FFMIN(h, ctx->graph->nb_threads));
195  }
196 
197  av_frame_free(&in);
198  return ff_filter_frame(outlink, out);
199 }
200 
202  {
203  .name = "default",
204  .type = AVMEDIA_TYPE_VIDEO,
205  .filter_frame = filter_frame,
206  },
207  { NULL }
208 };
209 
211  {
212  .name = "default",
213  .type = AVMEDIA_TYPE_VIDEO,
214  .config_props = config_props,
215  },
216  { NULL }
217 };
218 
220  .name = "lenscorrection",
221  .description = NULL_IF_CONFIG_SMALL("Rectify the image by correcting for lens distortion."),
222  .priv_size = sizeof(LenscorrectionCtx),
224  .inputs = lenscorrection_inputs,
225  .outputs = lenscorrection_outputs,
226  .priv_class = &lenscorrection_class,
227  .uninit = uninit,
229 };