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vf_boxblur.c
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1 /*
2  * Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
3  * Copyright (c) 2011 Stefano Sabatini
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (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
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License along
18  * with FFmpeg; if not, write to the Free Software Foundation, Inc.,
19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
20  */
21 
22 /**
23  * @file
24  * Apply a boxblur filter to the input video.
25  * Ported from MPlayer libmpcodecs/vf_boxblur.c.
26  */
27 
28 #include "libavutil/avstring.h"
29 #include "libavutil/common.h"
30 #include "libavutil/eval.h"
31 #include "libavutil/opt.h"
32 #include "libavutil/pixdesc.h"
33 #include "avfilter.h"
34 #include "formats.h"
35 #include "internal.h"
36 #include "video.h"
37 
38 static const char *const var_names[] = {
39  "w",
40  "h",
41  "cw",
42  "ch",
43  "hsub",
44  "vsub",
45  NULL
46 };
47 
48 enum var_name {
56 };
57 
58 typedef struct {
59  int radius;
60  int power;
61  char *radius_expr;
62 } FilterParam;
63 
64 typedef struct {
65  const AVClass *class;
69 
70  int hsub, vsub;
71  int radius[4];
72  int power[4];
73  uint8_t *temp[2]; ///< temporary buffer used in blur_power()
75 
76 #define Y 0
77 #define U 1
78 #define V 2
79 #define A 3
80 
81 static av_cold int init(AVFilterContext *ctx)
82 {
83  BoxBlurContext *s = ctx->priv;
84 
85  if (!s->luma_param.radius_expr) {
86  av_log(ctx, AV_LOG_ERROR, "Luma radius expression is not set.\n");
87  return AVERROR(EINVAL);
88  }
89 
90  /* fill missing params */
91  if (!s->chroma_param.radius_expr) {
93  if (!s->chroma_param.radius_expr)
94  return AVERROR(ENOMEM);
95  }
96  if (s->chroma_param.power < 0)
98 
99  if (!s->alpha_param.radius_expr) {
101  if (!s->alpha_param.radius_expr)
102  return AVERROR(ENOMEM);
103  }
104  if (s->alpha_param.power < 0)
106 
107  return 0;
108 }
109 
110 static av_cold void uninit(AVFilterContext *ctx)
111 {
112  BoxBlurContext *s = ctx->priv;
113 
114  av_freep(&s->temp[0]);
115  av_freep(&s->temp[1]);
116 }
117 
119 {
120  static const enum AVPixelFormat pix_fmts[] = {
127  };
128 
130  return 0;
131 }
132 
133 static int config_input(AVFilterLink *inlink)
134 {
135  const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
136  AVFilterContext *ctx = inlink->dst;
137  BoxBlurContext *s = ctx->priv;
138  int w = inlink->w, h = inlink->h;
139  int cw, ch;
140  double var_values[VARS_NB], res;
141  char *expr;
142  int ret;
143 
144  if (!(s->temp[0] = av_malloc(FFMAX(w, h))) ||
145  !(s->temp[1] = av_malloc(FFMAX(w, h))))
146  return AVERROR(ENOMEM);
147 
148  s->hsub = desc->log2_chroma_w;
149  s->vsub = desc->log2_chroma_h;
150 
151  var_values[VAR_W] = inlink->w;
152  var_values[VAR_H] = inlink->h;
153  var_values[VAR_CW] = cw = w>>s->hsub;
154  var_values[VAR_CH] = ch = h>>s->vsub;
155  var_values[VAR_HSUB] = 1<<s->hsub;
156  var_values[VAR_VSUB] = 1<<s->vsub;
157 
158 #define EVAL_RADIUS_EXPR(comp) \
159  expr = s->comp##_param.radius_expr; \
160  ret = av_expr_parse_and_eval(&res, expr, var_names, var_values, \
161  NULL, NULL, NULL, NULL, NULL, 0, ctx); \
162  s->comp##_param.radius = res; \
163  if (ret < 0) { \
164  av_log(NULL, AV_LOG_ERROR, \
165  "Error when evaluating " #comp " radius expression '%s'\n", expr); \
166  return ret; \
167  }
168  EVAL_RADIUS_EXPR(luma);
169  EVAL_RADIUS_EXPR(chroma);
171 
172  av_log(ctx, AV_LOG_VERBOSE,
173  "luma_radius:%d luma_power:%d "
174  "chroma_radius:%d chroma_power:%d "
175  "alpha_radius:%d alpha_power:%d "
176  "w:%d chroma_w:%d h:%d chroma_h:%d\n",
180  w, cw, h, ch);
181 
182 #define CHECK_RADIUS_VAL(w_, h_, comp) \
183  if (s->comp##_param.radius < 0 || \
184  2*s->comp##_param.radius > FFMIN(w_, h_)) { \
185  av_log(ctx, AV_LOG_ERROR, \
186  "Invalid " #comp " radius value %d, must be >= 0 and <= %d\n", \
187  s->comp##_param.radius, FFMIN(w_, h_)/2); \
188  return AVERROR(EINVAL); \
189  }
190  CHECK_RADIUS_VAL(w, h, luma);
191  CHECK_RADIUS_VAL(cw, ch, chroma);
192  CHECK_RADIUS_VAL(w, h, alpha);
193 
194  s->radius[Y] = s->luma_param.radius;
195  s->radius[U] = s->radius[V] = s->chroma_param.radius;
196  s->radius[A] = s->alpha_param.radius;
197 
198  s->power[Y] = s->luma_param.power;
199  s->power[U] = s->power[V] = s->chroma_param.power;
200  s->power[A] = s->alpha_param.power;
201 
202  return 0;
203 }
204 
205 static inline void blur(uint8_t *dst, int dst_step, const uint8_t *src, int src_step,
206  int len, int radius)
207 {
208  /* Naive boxblur would sum source pixels from x-radius .. x+radius
209  * for destination pixel x. That would be O(radius*width).
210  * If you now look at what source pixels represent 2 consecutive
211  * output pixels, then you see they are almost identical and only
212  * differ by 2 pixels, like:
213  * src0 111111111
214  * dst0 1
215  * src1 111111111
216  * dst1 1
217  * src0-src1 1 -1
218  * so when you know one output pixel you can find the next by just adding
219  * and subtracting 1 input pixel.
220  * The following code adopts this faster variant.
221  */
222  const int length = radius*2 + 1;
223  const int inv = ((1<<16) + length/2)/length;
224  int x, sum = 0;
225 
226  for (x = 0; x < radius; x++)
227  sum += src[x*src_step]<<1;
228  sum += src[radius*src_step];
229 
230  for (x = 0; x <= radius; x++) {
231  sum += src[(radius+x)*src_step] - src[(radius-x)*src_step];
232  dst[x*dst_step] = (sum*inv + (1<<15))>>16;
233  }
234 
235  for (; x < len-radius; x++) {
236  sum += src[(radius+x)*src_step] - src[(x-radius-1)*src_step];
237  dst[x*dst_step] = (sum*inv + (1<<15))>>16;
238  }
239 
240  for (; x < len; x++) {
241  sum += src[(2*len-radius-x-1)*src_step] - src[(x-radius-1)*src_step];
242  dst[x*dst_step] = (sum*inv + (1<<15))>>16;
243  }
244 }
245 
246 static inline void blur_power(uint8_t *dst, int dst_step, const uint8_t *src, int src_step,
247  int len, int radius, int power, uint8_t *temp[2])
248 {
249  uint8_t *a = temp[0], *b = temp[1];
250 
251  if (radius && power) {
252  blur(a, 1, src, src_step, len, radius);
253  for (; power > 2; power--) {
254  uint8_t *c;
255  blur(b, 1, a, 1, len, radius);
256  c = a; a = b; b = c;
257  }
258  if (power > 1) {
259  blur(dst, dst_step, a, 1, len, radius);
260  } else {
261  int i;
262  for (i = 0; i < len; i++)
263  dst[i*dst_step] = a[i];
264  }
265  } else {
266  int i;
267  for (i = 0; i < len; i++)
268  dst[i*dst_step] = src[i*src_step];
269  }
270 }
271 
272 static void hblur(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize,
273  int w, int h, int radius, int power, uint8_t *temp[2])
274 {
275  int y;
276 
277  if (radius == 0 && dst == src)
278  return;
279 
280  for (y = 0; y < h; y++)
281  blur_power(dst + y*dst_linesize, 1, src + y*src_linesize, 1,
282  w, radius, power, temp);
283 }
284 
285 static void vblur(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize,
286  int w, int h, int radius, int power, uint8_t *temp[2])
287 {
288  int x;
289 
290  if (radius == 0 && dst == src)
291  return;
292 
293  for (x = 0; x < w; x++)
294  blur_power(dst + x, dst_linesize, src + x, src_linesize,
295  h, radius, power, temp);
296 }
297 
298 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
299 {
300  AVFilterContext *ctx = inlink->dst;
301  BoxBlurContext *s = ctx->priv;
302  AVFilterLink *outlink = inlink->dst->outputs[0];
303  AVFrame *out;
304  int plane;
305  int cw = FF_CEIL_RSHIFT(inlink->w, s->hsub), ch = FF_CEIL_RSHIFT(in->height, s->vsub);
306  int w[4] = { inlink->w, cw, cw, inlink->w };
307  int h[4] = { in->height, ch, ch, in->height };
308 
309  out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
310  if (!out) {
311  av_frame_free(&in);
312  return AVERROR(ENOMEM);
313  }
314  av_frame_copy_props(out, in);
315 
316  for (plane = 0; plane < 4 && in->data[plane] && in->linesize[plane]; plane++)
317  hblur(out->data[plane], out->linesize[plane],
318  in ->data[plane], in ->linesize[plane],
319  w[plane], h[plane], s->radius[plane], s->power[plane],
320  s->temp);
321 
322  for (plane = 0; plane < 4 && in->data[plane] && in->linesize[plane]; plane++)
323  vblur(out->data[plane], out->linesize[plane],
324  out->data[plane], out->linesize[plane],
325  w[plane], h[plane], s->radius[plane], s->power[plane],
326  s->temp);
327 
328  av_frame_free(&in);
329 
330  return ff_filter_frame(outlink, out);
331 }
332 
333 #define OFFSET(x) offsetof(BoxBlurContext, x)
334 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
335 
336 static const AVOption boxblur_options[] = {
337  { "luma_radius", "Radius of the luma blurring box", OFFSET(luma_param.radius_expr), AV_OPT_TYPE_STRING, {.str="2"}, .flags = FLAGS },
338  { "lr", "Radius of the luma blurring box", OFFSET(luma_param.radius_expr), AV_OPT_TYPE_STRING, {.str="2"}, .flags = FLAGS },
339  { "luma_power", "How many times should the boxblur be applied to luma", OFFSET(luma_param.power), AV_OPT_TYPE_INT, {.i64=2}, 0, INT_MAX, .flags = FLAGS },
340  { "lp", "How many times should the boxblur be applied to luma", OFFSET(luma_param.power), AV_OPT_TYPE_INT, {.i64=2}, 0, INT_MAX, .flags = FLAGS },
341 
342  { "chroma_radius", "Radius of the chroma blurring box", OFFSET(chroma_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
343  { "cr", "Radius of the chroma blurring box", OFFSET(chroma_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
344  { "chroma_power", "How many times should the boxblur be applied to chroma", OFFSET(chroma_param.power), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, .flags = FLAGS },
345  { "cp", "How many times should the boxblur be applied to chroma", OFFSET(chroma_param.power), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, .flags = FLAGS },
346 
347  { "alpha_radius", "Radius of the alpha blurring box", OFFSET(alpha_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
348  { "ar", "Radius of the alpha blurring box", OFFSET(alpha_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
349  { "alpha_power", "How many times should the boxblur be applied to alpha", OFFSET(alpha_param.power), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, .flags = FLAGS },
350  { "ap", "How many times should the boxblur be applied to alpha", OFFSET(alpha_param.power), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, .flags = FLAGS },
351 
352  { NULL }
353 };
354 
355 AVFILTER_DEFINE_CLASS(boxblur);
356 
358  {
359  .name = "default",
360  .type = AVMEDIA_TYPE_VIDEO,
361  .config_props = config_input,
362  .filter_frame = filter_frame,
363  },
364  { NULL }
365 };
366 
368  {
369  .name = "default",
370  .type = AVMEDIA_TYPE_VIDEO,
371  },
372  { NULL }
373 };
374 
376  .name = "boxblur",
377  .description = NULL_IF_CONFIG_SMALL("Blur the input."),
378  .priv_size = sizeof(BoxBlurContext),
379  .priv_class = &boxblur_class,
380  .init = init,
381  .uninit = uninit,
383  .inputs = avfilter_vf_boxblur_inputs,
384  .outputs = avfilter_vf_boxblur_outputs,
386 };