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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  AVFilterFormats *formats = NULL;
121  int fmt;
122 
123  for (fmt = 0; av_pix_fmt_desc_get(fmt); fmt++) {
124  const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(fmt);
126  (desc->flags & AV_PIX_FMT_FLAG_PLANAR || desc->nb_components == 1) &&
127  (!(desc->flags & AV_PIX_FMT_FLAG_BE) == !HAVE_BIGENDIAN) || desc->comp[0].depth_minus1 == 7)
128  ff_add_format(&formats, fmt);
129  }
130 
131  ff_set_common_formats(ctx, formats);
132  return 0;
133 }
134 
135 static int config_input(AVFilterLink *inlink)
136 {
137  const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
138  AVFilterContext *ctx = inlink->dst;
139  BoxBlurContext *s = ctx->priv;
140  int w = inlink->w, h = inlink->h;
141  int cw, ch;
142  double var_values[VARS_NB], res;
143  char *expr;
144  int ret;
145 
146  if (!(s->temp[0] = av_malloc(2*FFMAX(w, h))) ||
147  !(s->temp[1] = av_malloc(2*FFMAX(w, h))))
148  return AVERROR(ENOMEM);
149 
150  s->hsub = desc->log2_chroma_w;
151  s->vsub = desc->log2_chroma_h;
152 
153  var_values[VAR_W] = inlink->w;
154  var_values[VAR_H] = inlink->h;
155  var_values[VAR_CW] = cw = w>>s->hsub;
156  var_values[VAR_CH] = ch = h>>s->vsub;
157  var_values[VAR_HSUB] = 1<<s->hsub;
158  var_values[VAR_VSUB] = 1<<s->vsub;
159 
160 #define EVAL_RADIUS_EXPR(comp) \
161  expr = s->comp##_param.radius_expr; \
162  ret = av_expr_parse_and_eval(&res, expr, var_names, var_values, \
163  NULL, NULL, NULL, NULL, NULL, 0, ctx); \
164  s->comp##_param.radius = res; \
165  if (ret < 0) { \
166  av_log(NULL, AV_LOG_ERROR, \
167  "Error when evaluating " #comp " radius expression '%s'\n", expr); \
168  return ret; \
169  }
170  EVAL_RADIUS_EXPR(luma);
171  EVAL_RADIUS_EXPR(chroma);
173 
174  av_log(ctx, AV_LOG_VERBOSE,
175  "luma_radius:%d luma_power:%d "
176  "chroma_radius:%d chroma_power:%d "
177  "alpha_radius:%d alpha_power:%d "
178  "w:%d chroma_w:%d h:%d chroma_h:%d\n",
182  w, cw, h, ch);
183 
184 #define CHECK_RADIUS_VAL(w_, h_, comp) \
185  if (s->comp##_param.radius < 0 || \
186  2*s->comp##_param.radius > FFMIN(w_, h_)) { \
187  av_log(ctx, AV_LOG_ERROR, \
188  "Invalid " #comp " radius value %d, must be >= 0 and <= %d\n", \
189  s->comp##_param.radius, FFMIN(w_, h_)/2); \
190  return AVERROR(EINVAL); \
191  }
192  CHECK_RADIUS_VAL(w, h, luma);
193  CHECK_RADIUS_VAL(cw, ch, chroma);
194  CHECK_RADIUS_VAL(w, h, alpha);
195 
196  s->radius[Y] = s->luma_param.radius;
197  s->radius[U] = s->radius[V] = s->chroma_param.radius;
198  s->radius[A] = s->alpha_param.radius;
199 
200  s->power[Y] = s->luma_param.power;
201  s->power[U] = s->power[V] = s->chroma_param.power;
202  s->power[A] = s->alpha_param.power;
203 
204  return 0;
205 }
206 
207 static inline void blur8(uint8_t *dst, int dst_step, const uint8_t *src, int src_step,
208  int len, int radius)
209 {
210  /* Naive boxblur would sum source pixels from x-radius .. x+radius
211  * for destination pixel x. That would be O(radius*width).
212  * If you now look at what source pixels represent 2 consecutive
213  * output pixels, then you see they are almost identical and only
214  * differ by 2 pixels, like:
215  * src0 111111111
216  * dst0 1
217  * src1 111111111
218  * dst1 1
219  * src0-src1 1 -1
220  * so when you know one output pixel you can find the next by just adding
221  * and subtracting 1 input pixel.
222  * The following code adopts this faster variant.
223  */
224  const int length = radius*2 + 1;
225  const int inv = ((1<<16) + length/2)/length;
226  int x, sum = src[radius*src_step];
227 
228  for (x = 0; x < radius; x++)
229  sum += src[x*src_step]<<1;
230 
231  sum = sum*inv + (1<<15);
232 
233  for (x = 0; x <= radius; x++) {
234  sum += (src[(radius+x)*src_step] - src[(radius-x)*src_step])*inv;
235  dst[x*dst_step] = sum>>16;
236  }
237 
238  for (; x < len-radius; x++) {
239  sum += (src[(radius+x)*src_step] - src[(x-radius-1)*src_step])*inv;
240  dst[x*dst_step] = sum >>16;
241  }
242 
243  for (; x < len; x++) {
244  sum += (src[(2*len-radius-x-1)*src_step] - src[(x-radius-1)*src_step])*inv;
245  dst[x*dst_step] = sum>>16;
246  }
247 }
248 
249 static inline void blur16(uint16_t *dst, int dst_step, const uint16_t *src, int src_step,
250  int len, int radius)
251 {
252  const int length = radius*2 + 1;
253  const int inv = ((1<<16) + length/2)/length;
254  int x, sum = src[radius*src_step];
255 
256  for (x = 0; x < radius; x++)
257  sum += src[x*src_step]<<1;
258 
259  sum = sum*inv + (1<<15);
260 
261  for (x = 0; x <= radius; x++) {
262  sum += (src[(radius+x)*src_step] - src[(radius-x)*src_step])*inv;
263  dst[x*dst_step] = sum>>16;
264  }
265 
266  for (; x < len-radius; x++) {
267  sum += (src[(radius+x)*src_step] - src[(x-radius-1)*src_step])*inv;
268  dst[x*dst_step] = sum >>16;
269  }
270 
271  for (; x < len; x++) {
272  sum += (src[(2*len-radius-x-1)*src_step] - src[(x-radius-1)*src_step])*inv;
273  dst[x*dst_step] = sum>>16;
274  }
275 }
276 
277 static inline void blur(uint8_t *dst, int dst_step, const uint8_t *src, int src_step,
278  int len, int radius, int pixsize)
279 {
280  if (pixsize == 1) blur8 (dst, dst_step , src, src_step , len, radius);
281  else blur16((uint16_t*)dst, dst_step>>1, (const uint16_t*)src, src_step>>1, len, radius);
282 }
283 
284 static inline void blur_power(uint8_t *dst, int dst_step, const uint8_t *src, int src_step,
285  int len, int radius, int power, uint8_t *temp[2], int pixsize)
286 {
287  uint8_t *a = temp[0], *b = temp[1];
288 
289  if (radius && power) {
290  blur(a, pixsize, src, src_step, len, radius, pixsize);
291  for (; power > 2; power--) {
292  uint8_t *c;
293  blur(b, pixsize, a, pixsize, len, radius, pixsize);
294  c = a; a = b; b = c;
295  }
296  if (power > 1) {
297  blur(dst, dst_step, a, pixsize, len, radius, pixsize);
298  } else {
299  int i;
300  if (pixsize == 1) {
301  for (i = 0; i < len; i++)
302  dst[i*dst_step] = a[i];
303  } else
304  for (i = 0; i < len; i++)
305  *(uint16_t*)(dst + i*dst_step) = ((uint16_t*)a)[i];
306  }
307  } else {
308  int i;
309  if (pixsize == 1) {
310  for (i = 0; i < len; i++)
311  dst[i*dst_step] = src[i*src_step];
312  } else
313  for (i = 0; i < len; i++)
314  *(uint16_t*)(dst + i*dst_step) = *(uint16_t*)(src + i*src_step);
315  }
316 }
317 
318 static void hblur(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize,
319  int w, int h, int radius, int power, uint8_t *temp[2], int pixsize)
320 {
321  int y;
322 
323  if (radius == 0 && dst == src)
324  return;
325 
326  for (y = 0; y < h; y++)
327  blur_power(dst + y*dst_linesize, pixsize, src + y*src_linesize, pixsize,
328  w, radius, power, temp, pixsize);
329 }
330 
331 static void vblur(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize,
332  int w, int h, int radius, int power, uint8_t *temp[2], int pixsize)
333 {
334  int x;
335 
336  if (radius == 0 && dst == src)
337  return;
338 
339  for (x = 0; x < w; x++)
340  blur_power(dst + x*pixsize, dst_linesize, src + x*pixsize, src_linesize,
341  h, radius, power, temp, pixsize);
342 }
343 
344 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
345 {
346  AVFilterContext *ctx = inlink->dst;
347  BoxBlurContext *s = ctx->priv;
348  AVFilterLink *outlink = inlink->dst->outputs[0];
349  AVFrame *out;
350  int plane;
351  int cw = FF_CEIL_RSHIFT(inlink->w, s->hsub), ch = FF_CEIL_RSHIFT(in->height, s->vsub);
352  int w[4] = { inlink->w, cw, cw, inlink->w };
353  int h[4] = { in->height, ch, ch, in->height };
354  const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
355  const int depth = desc->comp[0].depth_minus1 + 1;
356  const int pixsize = (depth+7)/8;
357 
358  out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
359  if (!out) {
360  av_frame_free(&in);
361  return AVERROR(ENOMEM);
362  }
363  av_frame_copy_props(out, in);
364 
365  for (plane = 0; plane < 4 && in->data[plane] && in->linesize[plane]; plane++)
366  hblur(out->data[plane], out->linesize[plane],
367  in ->data[plane], in ->linesize[plane],
368  w[plane], h[plane], s->radius[plane], s->power[plane],
369  s->temp, pixsize);
370 
371  for (plane = 0; plane < 4 && in->data[plane] && in->linesize[plane]; plane++)
372  vblur(out->data[plane], out->linesize[plane],
373  out->data[plane], out->linesize[plane],
374  w[plane], h[plane], s->radius[plane], s->power[plane],
375  s->temp, pixsize);
376 
377  av_frame_free(&in);
378 
379  return ff_filter_frame(outlink, out);
380 }
381 
382 #define OFFSET(x) offsetof(BoxBlurContext, x)
383 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
384 
385 static const AVOption boxblur_options[] = {
386  { "luma_radius", "Radius of the luma blurring box", OFFSET(luma_param.radius_expr), AV_OPT_TYPE_STRING, {.str="2"}, .flags = FLAGS },
387  { "lr", "Radius of the luma blurring box", OFFSET(luma_param.radius_expr), AV_OPT_TYPE_STRING, {.str="2"}, .flags = FLAGS },
388  { "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 },
389  { "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 },
390 
391  { "chroma_radius", "Radius of the chroma blurring box", OFFSET(chroma_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
392  { "cr", "Radius of the chroma blurring box", OFFSET(chroma_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
393  { "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 },
394  { "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 },
395 
396  { "alpha_radius", "Radius of the alpha blurring box", OFFSET(alpha_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
397  { "ar", "Radius of the alpha blurring box", OFFSET(alpha_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
398  { "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 },
399  { "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 },
400 
401  { NULL }
402 };
403 
404 AVFILTER_DEFINE_CLASS(boxblur);
405 
407  {
408  .name = "default",
409  .type = AVMEDIA_TYPE_VIDEO,
410  .config_props = config_input,
411  .filter_frame = filter_frame,
412  },
413  { NULL }
414 };
415 
417  {
418  .name = "default",
419  .type = AVMEDIA_TYPE_VIDEO,
420  },
421  { NULL }
422 };
423 
425  .name = "boxblur",
426  .description = NULL_IF_CONFIG_SMALL("Blur the input."),
427  .priv_size = sizeof(BoxBlurContext),
428  .priv_class = &boxblur_class,
429  .init = init,
430  .uninit = uninit,
432  .inputs = avfilter_vf_boxblur_inputs,
433  .outputs = avfilter_vf_boxblur_outputs,
435 };