FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavfilter/vf_blurdetect.c
Date: 2026-04-30 13:16:32
Exec Total Coverage
Lines: 143 147 97.3%
Functions: 7 8 87.5%
Branches: 66 127 52.0%
Line Branch Exec Source
1 /*
2 * Copyright (c) 2021 Thilo Borgmann <thilo.borgmann _at_ mail.de>
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 /**
22 * @file
23 * No-reference blurdetect filter
24 *
25 * Implementing:
26 * Marziliano, Pina, et al. "A no-reference perceptual blur metric." Proceedings.
27 * International conference on image processing. Vol. 3. IEEE, 2002.
28 * https://infoscience.epfl.ch/record/111802/files/14%20A%20no-reference%20perceptual%20blur%20metric.pdf
29 *
30 * @author Thilo Borgmann <thilo.borgmann _at_ mail.de>
31 */
32
33 #include "libavutil/mem.h"
34 #include "libavutil/opt.h"
35 #include "libavutil/pixdesc.h"
36 #include "libavutil/qsort.h"
37
38 #include "filters.h"
39 #include "edge_common.h"
40 #include "video.h"
41
42 ✗ static int comp(const float *a,const float *b)
43 {
44 ✗ return FFDIFFSIGN(*a, *b);
45 }
46
47 typedef struct BLRContext {
48 const AVClass *class;
49
50 int hsub, vsub;
51 int nb_planes;
52
53 float low, high;
54 uint8_t low_u8, high_u8;
55 int radius; // radius during local maxima detection
56 int block_pct; // percentage of "sharpest" blocks in the image to use for bluriness calculation
57 int block_width; // width for block abbreviation
58 int block_height; // height for block abbreviation
59 int planes; // number of planes to filter
60
61 double blur_total;
62 uint64_t nb_frames;
63
64 float *blks;
65 uint8_t *filterbuf;
66 uint8_t *tmpbuf;
67 uint16_t *gradients;
68 int8_t *directions;
69 } BLRContext;
70
71 #define OFFSET(x) offsetof(BLRContext, x)
72 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
73 static const AVOption blurdetect_options[] = {
74 { "high", "set high threshold", OFFSET(high), AV_OPT_TYPE_FLOAT, {.dbl=30/255.}, 0, 1, FLAGS },
75 { "low", "set low threshold", OFFSET(low), AV_OPT_TYPE_FLOAT, {.dbl=15/255.}, 0, 1, FLAGS },
76 { "radius", "search radius for maxima detection", OFFSET(radius), AV_OPT_TYPE_INT, {.i64=50}, 1, 100, FLAGS },
77 { "block_pct", "block pooling threshold when calculating blurriness", OFFSET(block_pct), AV_OPT_TYPE_INT, {.i64=80}, 1, 100, FLAGS },
78 { "block_width", "block size for block-based abbreviation of blurriness", OFFSET(block_width), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, FLAGS },
79 { "block_height", "block size for block-based abbreviation of blurriness", OFFSET(block_height), AV_OPT_TYPE_INT, {.i64=-1}, -1, INT_MAX, FLAGS },
80 { "planes", "set planes to filter", OFFSET(planes), AV_OPT_TYPE_INT, {.i64=1}, 0, 15, FLAGS },
81 { NULL }
82 };
83
84 AVFILTER_DEFINE_CLASS(blurdetect);
85
86 2 static av_cold int blurdetect_init(AVFilterContext *ctx)
87 {
88 2 BLRContext *s = ctx->priv;
89
90 2 s->low_u8 = s->low * 255. + .5;
91 2 s->high_u8 = s->high * 255. + .5;
92
93 2 return 0;
94 }
95
96 1 static int blurdetect_config_input(AVFilterLink *inlink)
97 {
98 1 AVFilterContext *ctx = inlink->dst;
99 1 BLRContext *s = ctx->priv;
100 1 const int bufsize = inlink->w * inlink->h;
101 const AVPixFmtDescriptor *pix_desc;
102
103 1 pix_desc = av_pix_fmt_desc_get(inlink->format);
104 1 s->hsub = pix_desc->log2_chroma_w;
105 1 s->vsub = pix_desc->log2_chroma_h;
106 1 s->nb_planes = av_pix_fmt_count_planes(inlink->format);
107
108
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 1 if (s->block_width < 1 || s->block_height < 1) {
109 1 s->block_width = inlink->w;
110 1 s->block_height = inlink->h;
111 }
112
113 1 s->tmpbuf = av_malloc(bufsize);
114 1 s->filterbuf = av_malloc(bufsize);
115 1 s->gradients = av_calloc(bufsize, sizeof(*s->gradients));
116 1 s->directions = av_malloc(bufsize);
117 1 s->blks = av_calloc((inlink->w / s->block_width) * (inlink->h / s->block_height),
118 sizeof(*s->blks));
119
120
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 1 if (!s->tmpbuf || !s->filterbuf || !s->gradients || !s->directions || !s->blks)
121 ✗ return AVERROR(ENOMEM);
122
123 1 return 0;
124 }
125
126 // edge width is defined as the distance between surrounding maxima of the edge pixel
127 9475 static float edge_width(BLRContext *blr, int i, int j, int8_t dir, int w, int h,
128 int edge, const uint8_t *src, int src_linesize)
129 {
130 9475 float width = 0;
131 int dX, dY;
132 int sign;
133 int tmp;
134 int p1;
135 int p2;
136 int k, x, y;
137 9475 int radius = blr->radius;
138
139
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 9475 switch(dir) {
140 2344 case DIRECTION_HORIZONTAL: dX = 1; dY = 0; break;
141 3412 case DIRECTION_VERTICAL: dX = 0; dY = 1; break;
142 1970 case DIRECTION_45UP: dX = 1; dY = -1; break;
143 1749 case DIRECTION_45DOWN: dX = 1; dY = 1; break;
144 ✗ default: dX = 1; dY = 1; break;
145 }
146
147 // determines if search in direction dX/dY is looking for a maximum or minimum
148
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 9475 sign = src[j * src_linesize + i] > src[(j - dY) * src_linesize + i - dX] ? 1 : -1;
149
150 // search in -(dX/dY) direction
151
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 34427 for (k = 0; k < radius; k++) {
152 34427 x = i - k*dX;
153 34427 y = j - k*dY;
154 34427 p1 = y * src_linesize + x;
155 34427 x -= dX;
156 34427 y -= dY;
157 34427 p2 = y * src_linesize + x;
158
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 34427 if (x < 0 || x >= w || y < 0 || y >= h)
159 1 return 0;
160
161 34426 tmp = (src[p1] - src[p2]) * sign;
162
163
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 34426 if (tmp <= 0) // local maximum found
164 9474 break;
165 }
166 9474 width += k;
167
168 // search in +(dX/dY) direction
169
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 34177 for (k = 0; k < radius; k++) {
170 34177 x = i + k * dX;
171 34177 y = j + k * dY;
172 34177 p1 = y * src_linesize + x;
173 34177 x += dX;
174 34177 y += dY;
175 34177 p2 = y * src_linesize + x;
176
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 34177 if (x < 0 || x >= w || y < 0 || y >= h)
177 10 return 0;
178
179 34167 tmp = (src[p1] - src[p2]) * sign;
180
181
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 34167 if (tmp >= 0) // local maximum found
182 9464 break;
183 }
184 9464 width += k;
185
186 // for 45 degree directions approximate edge width in pixel units: 0.7 ~= sqrt(2)/2
187
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 9464 if (dir == DIRECTION_45UP || dir == DIRECTION_45DOWN)
188 3708 width *= 0.7;
189
190 9464 return width;
191 }
192
193 5 static float calculate_blur(BLRContext *s, int w, int h, int hsub, int vsub,
194 int8_t* dir, int dir_linesize,
195 uint8_t* dst, int dst_linesize,
196 uint8_t* src, int src_linesize)
197 {
198 5 float total_width = 0.0;
199
200 5 int blkcnt = 0;
201
202 5 float *blks = s->blks;
203 5 float block_pool_threshold = s->block_pct / 100.0;
204
205 5 int block_width = AV_CEIL_RSHIFT(s->block_width, hsub);
206 5 int block_height = AV_CEIL_RSHIFT(s->block_height, vsub);
207 5 int brows = h / block_height;
208 5 int bcols = w / block_width;
209
210
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 10 for (int blkj = 0; blkj < brows; blkj++) {
211
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 10 for (int blki = 0; blki < bcols; blki++) {
212 5 double block_total_width = 0.0;
213 5 int block_count = 0;
214
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 1005 for (int inj = 0; inj < block_height; inj++) {
215
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 301000 for (int ini = 0; ini < block_width; ini++) {
216 300000 int i = blki * block_width + ini;
217 300000 int j = blkj * block_height + inj;
218
219
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 300000 if (dst[j * dst_linesize + i] > 0) {
220 9475 float width = edge_width(s, i, j, dir[j*dir_linesize+i],
221 9475 w, h, dst[j*dst_linesize+i],
222 src, src_linesize);
223
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 9475 if (width > 0.001) { // throw away zeros
224 9455 block_count++;
225 9455 block_total_width += width;
226 }
227 }
228 }
229 }
230 // if not enough edge pixels in a block, consider it smooth
231
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 5 if (block_total_width >= 2 && block_count) {
232 5 blks[blkcnt] = block_total_width / block_count;
233 5 blkcnt++;
234 }
235 }
236 }
237
238 // simple block pooling by sorting and keeping the sharper blocks
239
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 10 AV_QSORT(blks, blkcnt, float, comp);
240 5 blkcnt = ceil(blkcnt * block_pool_threshold);
241
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 10 for (int i = 0; i < blkcnt; i++) {
242 5 total_width += blks[i];
243 }
244
245 5 return total_width / blkcnt;
246 }
247
248 5 static void set_meta(AVDictionary **metadata, const char *key, float d)
249 {
250 char value[128];
251 5 snprintf(value, sizeof(value), "%f", d);
252 5 av_dict_set(metadata, key, value, 0);
253 5 }
254
255 5 static int blurdetect_filter_frame(AVFilterLink *inlink, AVFrame *in)
256 {
257 5 FilterLink *inl = ff_filter_link(inlink);
258 5 AVFilterContext *ctx = inlink->dst;
259 5 BLRContext *s = ctx->priv;
260 5 AVFilterLink *outlink = ctx->outputs[0];
261
262 5 const int inw = inlink->w;
263 5 const int inh = inlink->h;
264
265 5 uint8_t *tmpbuf = s->tmpbuf;
266 5 uint8_t *filterbuf = s->filterbuf;
267 5 uint16_t *gradients = s->gradients;
268 5 int8_t *directions = s->directions;
269
270 5 float blur = 0.0f;
271 5 int nplanes = 0;
272 AVDictionary **metadata;
273 5 metadata = &in->metadata;
274
275
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 20 for (int plane = 0; plane < s->nb_planes; plane++) {
276
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 15 int hsub = plane == 1 || plane == 2 ? s->hsub : 0;
277
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 15 int vsub = plane == 1 || plane == 2 ? s->vsub : 0;
278 15 int w = AV_CEIL_RSHIFT(inw, hsub);
279 15 int h = AV_CEIL_RSHIFT(inh, vsub);
280
281
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 15 if (!((1 << plane) & s->planes))
282 10 continue;
283
284 5 nplanes++;
285
286 // gaussian filter to reduce noise
287 5 ff_gaussian_blur_8(w, h,
288 filterbuf, w,
289 5 in->data[plane], in->linesize[plane], 1);
290
291 // compute the 16-bits gradients and directions for the next step
292 5 ff_sobel_8(w, h, gradients, w, directions, w, filterbuf, w, 1);
293
294 // non_maximum_suppression() will actually keep & clip what's necessary and
295 // ignore the rest, so we need a clean output buffer
296 5 memset(tmpbuf, 0, inw * inh);
297 5 ff_non_maximum_suppression(w, h, tmpbuf, w, directions, w, gradients, w);
298
299
300 // keep high values, or low values surrounded by high values
301 5 ff_double_threshold(s->low_u8, s->high_u8, w, h,
302 tmpbuf, w, tmpbuf, w);
303
304 5 blur += calculate_blur(s, w, h, hsub, vsub, directions, w,
305 tmpbuf, w, filterbuf, w);
306 }
307
308
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 5 if (nplanes)
309 5 blur /= nplanes;
310
311 5 s->blur_total += blur;
312
313 // write stats
314 5 av_log(ctx, AV_LOG_VERBOSE, "blur: %.7f\n", blur);
315
316 5 set_meta(metadata, "lavfi.blur", blur);
317
318 5 s->nb_frames = inl->frame_count_in;
319
320 5 return ff_filter_frame(outlink, in);
321 }
322
323 2 static av_cold void blurdetect_uninit(AVFilterContext *ctx)
324 {
325 2 BLRContext *s = ctx->priv;
326
327
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 2 if (s->nb_frames > 0) {
328 1 av_log(ctx, AV_LOG_INFO, "blur mean: %.7f\n",
329 1 s->blur_total / s->nb_frames);
330 }
331
332 2 av_freep(&s->tmpbuf);
333 2 av_freep(&s->filterbuf);
334 2 av_freep(&s->gradients);
335 2 av_freep(&s->directions);
336 2 av_freep(&s->blks);
337 2 }
338
339 static const enum AVPixelFormat pix_fmts[] = {
340 AV_PIX_FMT_GRAY8,
341 AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRAP,
342 AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV420P,
343 AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV440P,
344 AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV410P,
345 AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVJ411P, AV_PIX_FMT_YUVJ420P,
346 AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P,
347 AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUVA420P,
348 AV_PIX_FMT_NONE
349 };
350
351 static const AVFilterPad blurdetect_inputs[] = {
352 {
353 .name = "default",
354 .type = AVMEDIA_TYPE_VIDEO,
355 .config_props = blurdetect_config_input,
356 .filter_frame = blurdetect_filter_frame,
357 },
358 };
359
360 const FFFilter ff_vf_blurdetect = {
361 .p.name = "blurdetect",
362 .p.description = NULL_IF_CONFIG_SMALL("Blurdetect filter."),
363 .p.priv_class = &blurdetect_class,
364 .p.flags = AVFILTER_FLAG_METADATA_ONLY,
365 .priv_size = sizeof(BLRContext),
366 .init = blurdetect_init,
367 .uninit = blurdetect_uninit,
368 FILTER_PIXFMTS_ARRAY(pix_fmts),
369 FILTER_INPUTS(blurdetect_inputs),
370 FILTER_OUTPUTS(ff_video_default_filterpad),
371 };
372