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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 FilterParam {
59  int radius;
60  int power;
61  char *radius_expr;
62 } FilterParam;
63 
64 typedef struct BoxBlurContext {
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[] = {
131  };
132 
134  return 0;
135 }
136 
137 static int config_input(AVFilterLink *inlink)
138 {
139  const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
140  AVFilterContext *ctx = inlink->dst;
141  BoxBlurContext *s = ctx->priv;
142  int w = inlink->w, h = inlink->h;
143  int cw, ch;
144  double var_values[VARS_NB], res;
145  char *expr;
146  int ret;
147 
148  if (!(s->temp[0] = av_malloc(2*FFMAX(w, h))) ||
149  !(s->temp[1] = av_malloc(2*FFMAX(w, h))))
150  return AVERROR(ENOMEM);
151 
152  s->hsub = desc->log2_chroma_w;
153  s->vsub = desc->log2_chroma_h;
154 
155  var_values[VAR_W] = inlink->w;
156  var_values[VAR_H] = inlink->h;
157  var_values[VAR_CW] = cw = w>>s->hsub;
158  var_values[VAR_CH] = ch = h>>s->vsub;
159  var_values[VAR_HSUB] = 1<<s->hsub;
160  var_values[VAR_VSUB] = 1<<s->vsub;
161 
162 #define EVAL_RADIUS_EXPR(comp) \
163  expr = s->comp##_param.radius_expr; \
164  ret = av_expr_parse_and_eval(&res, expr, var_names, var_values, \
165  NULL, NULL, NULL, NULL, NULL, 0, ctx); \
166  s->comp##_param.radius = res; \
167  if (ret < 0) { \
168  av_log(NULL, AV_LOG_ERROR, \
169  "Error when evaluating " #comp " radius expression '%s'\n", expr); \
170  return ret; \
171  }
172  EVAL_RADIUS_EXPR(luma);
173  EVAL_RADIUS_EXPR(chroma);
175 
176  av_log(ctx, AV_LOG_VERBOSE,
177  "luma_radius:%d luma_power:%d "
178  "chroma_radius:%d chroma_power:%d "
179  "alpha_radius:%d alpha_power:%d "
180  "w:%d chroma_w:%d h:%d chroma_h:%d\n",
184  w, cw, h, ch);
185 
186 #define CHECK_RADIUS_VAL(w_, h_, comp) \
187  if (s->comp##_param.radius < 0 || \
188  2*s->comp##_param.radius > FFMIN(w_, h_)) { \
189  av_log(ctx, AV_LOG_ERROR, \
190  "Invalid " #comp " radius value %d, must be >= 0 and <= %d\n", \
191  s->comp##_param.radius, FFMIN(w_, h_)/2); \
192  return AVERROR(EINVAL); \
193  }
194  CHECK_RADIUS_VAL(w, h, luma);
195  CHECK_RADIUS_VAL(cw, ch, chroma);
196  CHECK_RADIUS_VAL(w, h, alpha);
197 
198  s->radius[Y] = s->luma_param.radius;
199  s->radius[U] = s->radius[V] = s->chroma_param.radius;
200  s->radius[A] = s->alpha_param.radius;
201 
202  s->power[Y] = s->luma_param.power;
203  s->power[U] = s->power[V] = s->chroma_param.power;
204  s->power[A] = s->alpha_param.power;
205 
206  return 0;
207 }
208 
209 static inline void blur8(uint8_t *dst, int dst_step, const uint8_t *src, int src_step,
210  int len, int radius)
211 {
212  /* Naive boxblur would sum source pixels from x-radius .. x+radius
213  * for destination pixel x. That would be O(radius*width).
214  * If you now look at what source pixels represent 2 consecutive
215  * output pixels, then you see they are almost identical and only
216  * differ by 2 pixels, like:
217  * src0 111111111
218  * dst0 1
219  * src1 111111111
220  * dst1 1
221  * src0-src1 1 -1
222  * so when you know one output pixel you can find the next by just adding
223  * and subtracting 1 input pixel.
224  * The following code adopts this faster variant.
225  */
226  const int length = radius*2 + 1;
227  const int inv = ((1<<16) + length/2)/length;
228  int x, sum = src[radius*src_step];
229 
230  for (x = 0; x < radius; x++)
231  sum += src[x*src_step]<<1;
232 
233  sum = sum*inv + (1<<15);
234 
235  for (x = 0; x <= radius; x++) {
236  sum += (src[(radius+x)*src_step] - src[(radius-x)*src_step])*inv;
237  dst[x*dst_step] = sum>>16;
238  }
239 
240  for (; x < len-radius; x++) {
241  sum += (src[(radius+x)*src_step] - src[(x-radius-1)*src_step])*inv;
242  dst[x*dst_step] = sum >>16;
243  }
244 
245  for (; x < len; x++) {
246  sum += (src[(2*len-radius-x-1)*src_step] - src[(x-radius-1)*src_step])*inv;
247  dst[x*dst_step] = sum>>16;
248  }
249 }
250 
251 static inline void blur16(uint16_t *dst, int dst_step, const uint16_t *src, int src_step,
252  int len, int radius)
253 {
254  const int length = radius*2 + 1;
255  const int inv = ((1<<16) + length/2)/length;
256  int x, sum = src[radius*src_step];
257 
258  for (x = 0; x < radius; x++)
259  sum += src[x*src_step]<<1;
260 
261  sum = sum*inv + (1<<15);
262 
263  for (x = 0; x <= radius; x++) {
264  sum += (src[(radius+x)*src_step] - src[(radius-x)*src_step])*inv;
265  dst[x*dst_step] = sum>>16;
266  }
267 
268  for (; x < len-radius; x++) {
269  sum += (src[(radius+x)*src_step] - src[(x-radius-1)*src_step])*inv;
270  dst[x*dst_step] = sum >>16;
271  }
272 
273  for (; x < len; x++) {
274  sum += (src[(2*len-radius-x-1)*src_step] - src[(x-radius-1)*src_step])*inv;
275  dst[x*dst_step] = sum>>16;
276  }
277 }
278 
279 static inline void blur(uint8_t *dst, int dst_step, const uint8_t *src, int src_step,
280  int len, int radius, int pixsize)
281 {
282  if (pixsize == 1) blur8 (dst, dst_step , src, src_step , len, radius);
283  else blur16((uint16_t*)dst, dst_step>>1, (const uint16_t*)src, src_step>>1, len, radius);
284 }
285 
286 static inline void blur_power(uint8_t *dst, int dst_step, const uint8_t *src, int src_step,
287  int len, int radius, int power, uint8_t *temp[2], int pixsize)
288 {
289  uint8_t *a = temp[0], *b = temp[1];
290 
291  if (radius && power) {
292  blur(a, pixsize, src, src_step, len, radius, pixsize);
293  for (; power > 2; power--) {
294  uint8_t *c;
295  blur(b, pixsize, a, pixsize, len, radius, pixsize);
296  c = a; a = b; b = c;
297  }
298  if (power > 1) {
299  blur(dst, dst_step, a, pixsize, len, radius, pixsize);
300  } else {
301  int i;
302  if (pixsize == 1) {
303  for (i = 0; i < len; i++)
304  dst[i*dst_step] = a[i];
305  } else
306  for (i = 0; i < len; i++)
307  *(uint16_t*)(dst + i*dst_step) = ((uint16_t*)a)[i];
308  }
309  } else {
310  int i;
311  if (pixsize == 1) {
312  for (i = 0; i < len; i++)
313  dst[i*dst_step] = src[i*src_step];
314  } else
315  for (i = 0; i < len; i++)
316  *(uint16_t*)(dst + i*dst_step) = *(uint16_t*)(src + i*src_step);
317  }
318 }
319 
320 static void hblur(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize,
321  int w, int h, int radius, int power, uint8_t *temp[2], int pixsize)
322 {
323  int y;
324 
325  if (radius == 0 && dst == src)
326  return;
327 
328  for (y = 0; y < h; y++)
329  blur_power(dst + y*dst_linesize, pixsize, src + y*src_linesize, pixsize,
330  w, radius, power, temp, pixsize);
331 }
332 
333 static void vblur(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize,
334  int w, int h, int radius, int power, uint8_t *temp[2], int pixsize)
335 {
336  int x;
337 
338  if (radius == 0 && dst == src)
339  return;
340 
341  for (x = 0; x < w; x++)
342  blur_power(dst + x*pixsize, dst_linesize, src + x*pixsize, src_linesize,
343  h, radius, power, temp, pixsize);
344 }
345 
346 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
347 {
348  AVFilterContext *ctx = inlink->dst;
349  BoxBlurContext *s = ctx->priv;
350  AVFilterLink *outlink = inlink->dst->outputs[0];
351  AVFrame *out;
352  int plane;
353  int cw = FF_CEIL_RSHIFT(inlink->w, s->hsub), ch = FF_CEIL_RSHIFT(in->height, s->vsub);
354  int w[4] = { inlink->w, cw, cw, inlink->w };
355  int h[4] = { in->height, ch, ch, in->height };
356  const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
357  const int depth = desc->comp[0].depth_minus1 + 1;
358  const int pixsize = (depth+7)/8;
359 
360  out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
361  if (!out) {
362  av_frame_free(&in);
363  return AVERROR(ENOMEM);
364  }
365  av_frame_copy_props(out, in);
366 
367  for (plane = 0; plane < 4 && in->data[plane] && in->linesize[plane]; plane++)
368  hblur(out->data[plane], out->linesize[plane],
369  in ->data[plane], in ->linesize[plane],
370  w[plane], h[plane], s->radius[plane], s->power[plane],
371  s->temp, pixsize);
372 
373  for (plane = 0; plane < 4 && in->data[plane] && in->linesize[plane]; plane++)
374  vblur(out->data[plane], out->linesize[plane],
375  out->data[plane], out->linesize[plane],
376  w[plane], h[plane], s->radius[plane], s->power[plane],
377  s->temp, pixsize);
378 
379  av_frame_free(&in);
380 
381  return ff_filter_frame(outlink, out);
382 }
383 
384 #define OFFSET(x) offsetof(BoxBlurContext, x)
385 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
386 
387 static const AVOption boxblur_options[] = {
388  { "luma_radius", "Radius of the luma blurring box", OFFSET(luma_param.radius_expr), AV_OPT_TYPE_STRING, {.str="2"}, .flags = FLAGS },
389  { "lr", "Radius of the luma blurring box", OFFSET(luma_param.radius_expr), AV_OPT_TYPE_STRING, {.str="2"}, .flags = FLAGS },
390  { "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 },
391  { "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 },
392 
393  { "chroma_radius", "Radius of the chroma blurring box", OFFSET(chroma_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
394  { "cr", "Radius of the chroma blurring box", OFFSET(chroma_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
395  { "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 },
396  { "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 },
397 
398  { "alpha_radius", "Radius of the alpha blurring box", OFFSET(alpha_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
399  { "ar", "Radius of the alpha blurring box", OFFSET(alpha_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
400  { "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 },
401  { "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 },
402 
403  { NULL }
404 };
405 
406 AVFILTER_DEFINE_CLASS(boxblur);
407 
409  {
410  .name = "default",
411  .type = AVMEDIA_TYPE_VIDEO,
412  .config_props = config_input,
413  .filter_frame = filter_frame,
414  },
415  { NULL }
416 };
417 
419  {
420  .name = "default",
421  .type = AVMEDIA_TYPE_VIDEO,
422  },
423  { NULL }
424 };
425 
427  .name = "boxblur",
428  .description = NULL_IF_CONFIG_SMALL("Blur the input."),
429  .priv_size = sizeof(BoxBlurContext),
430  .priv_class = &boxblur_class,
431  .init = init,
432  .uninit = uninit,
434  .inputs = avfilter_vf_boxblur_inputs,
435  .outputs = avfilter_vf_boxblur_outputs,
437 };