FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavfilter/vf_boxblur.c
Date: 2026-08-26 10:34:04
Exec Total Coverage
Lines: 78 100 78.0%
Functions: 9 10 90.0%
Branches: 48 88 54.5%
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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/avassert.h"
29 #include "libavutil/common.h"
30 #include "libavutil/mem.h"
31 #include "libavutil/opt.h"
32 #include "avfilter.h"
33 #include "filters.h"
34 #include "formats.h"
35 #include "video.h"
36 #include "boxblur.h"
37
38
39 typedef struct BoxBlurContext {
40 const AVClass *class;
41 FilterParam luma_param;
42 FilterParam chroma_param;
43 FilterParam alpha_param;
44
45 int hsub, vsub;
46 int radius[4];
47 int power[4];
48 uint8_t *temp[2]; ///< temporary buffer used in blur_power()
49 } BoxBlurContext;
50
51 2 static av_cold void uninit(AVFilterContext *ctx)
52 {
53 2 BoxBlurContext *s = ctx->priv;
54
55 2 av_freep(&s->temp[0]);
56 2 av_freep(&s->temp[1]);
57 2 }
58
59 1 static int query_formats(const AVFilterContext *ctx,
60 AVFilterFormatsConfig **cfg_in,
61 AVFilterFormatsConfig **cfg_out)
62 {
63 1 AVFilterFormats *formats = NULL;
64 int fmt, ret;
65
66
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 269 for (fmt = 0; av_pix_fmt_desc_get(fmt); fmt++) {
67 268 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(fmt);
68
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 268 if (!(desc->flags & (AV_PIX_FMT_FLAG_HWACCEL | AV_PIX_FMT_FLAG_BITSTREAM | AV_PIX_FMT_FLAG_PAL)) &&
69
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 244 desc->comp[0].depth <= 16 &&
70
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 224 (desc->flags & AV_PIX_FMT_FLAG_PLANAR || desc->nb_components == 1) &&
71
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 221 (!(desc->flags & AV_PIX_FMT_FLAG_BE) == !HAVE_BIGENDIAN || desc->comp[0].depth == 8) &&
72 81 (ret = ff_add_format(&formats, fmt)) < 0)
73 ✗ return ret;
74 }
75
76 1 return ff_set_common_formats2(ctx, cfg_in, cfg_out, formats);
77 }
78
79 1 static int config_input(AVFilterLink *inlink)
80 {
81 1 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
82 1 AVFilterContext *ctx = inlink->dst;
83 1 BoxBlurContext *s = ctx->priv;
84 1 int w = inlink->w, h = inlink->h;
85 int ret;
86
87
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 1 if (!(s->temp[0] = av_malloc(2*FFMAX(w, h))) ||
88
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 1 !(s->temp[1] = av_malloc(2*FFMAX(w, h))))
89 ✗ return AVERROR(ENOMEM);
90
91 1 s->hsub = desc->log2_chroma_w;
92 1 s->vsub = desc->log2_chroma_h;
93
94 1 ret = ff_boxblur_eval_filter_params(inlink,
95 &s->luma_param,
96 &s->chroma_param,
97 &s->alpha_param);
98
99
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 1 if (ret != 0) {
100 ✗ av_log(ctx, AV_LOG_ERROR, "Failed to evaluate "
101 "filter params: %d.\n", ret);
102 ✗ return ret;
103 }
104
105 1 s->radius[Y] = s->luma_param.radius;
106 1 s->radius[U] = s->radius[V] = s->chroma_param.radius;
107 1 s->radius[A] = s->alpha_param.radius;
108
109 1 s->power[Y] = s->luma_param.power;
110 1 s->power[U] = s->power[V] = s->chroma_param.power;
111 1 s->power[A] = s->alpha_param.power;
112
113 1 return 0;
114 }
115
116 /* Naive boxblur would sum source pixels from x-radius .. x+radius
117 * for destination pixel x. That would be O(radius*width).
118 * If you now look at what source pixels represent 2 consecutive
119 * output pixels, then you see they are almost identical and only
120 * differ by 2 pixels, like:
121 * src0 111111111
122 * dst0 1
123 * src1 111111111
124 * dst1 1
125 * src0-src1 1 -1
126 * so when you know one output pixel you can find the next by just adding
127 * and subtracting 1 input pixel.
128 * The following code adopts this faster variant.
129 */
130 #define BLUR(type, depth) \
131 static inline void blur ## depth(type *dst, int dst_step, const type *src, \
132 int src_step, int len, int radius) \
133 { \
134 const int length = radius*2 + 1; \
135 const int inv = ((1<<16) + length/2)/length; \
136 int x, sum = src[radius*src_step]; \
137 \
138 for (x = 0; x < radius; x++) \
139 sum += src[x*src_step]<<1; \
140 \
141 sum = sum*inv + (1<<15); \
142 \
143 for (x = 0; x <= radius; x++) { \
144 sum += (src[(radius+x)*src_step] - src[(radius-x)*src_step])*inv; \
145 dst[x*dst_step] = sum>>16; \
146 } \
147 \
148 for (; x < len-radius; x++) { \
149 sum += (src[(radius+x)*src_step] - src[(x-radius-1)*src_step])*inv; \
150 dst[x*dst_step] = sum >>16; \
151 } \
152 \
153 for (; x < len; x++) { \
154 sum += (src[(2*len-radius-x-1)*src_step] - src[(x-radius-1)*src_step])*inv; \
155 dst[x*dst_step] = sum>>16; \
156 } \
157 }
158
159
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 15398400 BLUR(uint8_t, 8)
160 ✗ BLUR(uint16_t, 16)
161
162 #undef BLUR
163
164 64000 static inline void blur(uint8_t *dst, int dst_step, const uint8_t *src, int src_step,
165 int len, int radius, int pixsize)
166 {
167
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 64000 if (pixsize == 1) blur8 (dst, dst_step , src, src_step , len, radius);
168 ✗ else if (pixsize == 2)
169 ✗ blur16((uint16_t*)dst, dst_step>>1, (const uint16_t*)src, src_step>>1, len, radius);
170 else
171 ✗ av_assert0(0);
172 64000 }
173
174 64000 static inline void blur_power(uint8_t *dst, int dst_step, const uint8_t *src, int src_step,
175 int len, int radius, int power, uint8_t *temp[2], int pixsize)
176 {
177 64000 uint8_t *a = temp[0], *b = temp[1];
178
179
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 64000 if (radius && power) {
180 64000 blur(a, pixsize, src, src_step, len, radius, pixsize);
181
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 64000 for (; power > 2; power--) {
182 uint8_t *c;
183 ✗ blur(b, pixsize, a, pixsize, len, radius, pixsize);
184 ✗ c = a; a = b; b = c;
185 }
186
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 64000 if (power > 1) {
187 ✗ blur(dst, dst_step, a, pixsize, len, radius, pixsize);
188 } else {
189 int i;
190
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191
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 15270400 for (i = 0; i < len; i++)
192 15206400 dst[i*dst_step] = a[i];
193 } else
194 ✗ for (i = 0; i < len; i++)
195 ✗ *(uint16_t*)(dst + i*dst_step) = ((uint16_t*)a)[i];
196 }
197 } else {
198 int i;
199 ✗ if (pixsize == 1) {
200 ✗ for (i = 0; i < len; i++)
201 ✗ dst[i*dst_step] = src[i*src_step];
202 } else
203 ✗ for (i = 0; i < len; i++)
204 ✗ *(uint16_t*)(dst + i*dst_step) = *(uint16_t*)(src + i*src_step);
205 }
206 64000 }
207
208 150 static void hblur(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize,
209 int w, int h, int radius, int power, uint8_t *temp[2], int pixsize)
210 {
211 int y;
212
213
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 150 if (radius == 0 && dst == src)
214 ✗ return;
215
216
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 28950 for (y = 0; y < h; y++)
217 28800 blur_power(dst + y*dst_linesize, pixsize, src + y*src_linesize, pixsize,
218 w, radius, power, temp, pixsize);
219 }
220
221 150 static void vblur(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize,
222 int w, int h, int radius, int power, uint8_t *temp[2], int pixsize)
223 {
224 int x;
225
226
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 150 if (radius == 0 && dst == src)
227 ✗ return;
228
229
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 35350 for (x = 0; x < w; x++)
230 35200 blur_power(dst + x*pixsize, dst_linesize, src + x*pixsize, src_linesize,
231 h, radius, power, temp, pixsize);
232 }
233
234 50 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
235 {
236 50 AVFilterContext *ctx = inlink->dst;
237 50 BoxBlurContext *s = ctx->priv;
238 50 AVFilterLink *outlink = inlink->dst->outputs[0];
239 AVFrame *out;
240 int plane;
241 50 int cw = AV_CEIL_RSHIFT(inlink->w, s->hsub), ch = AV_CEIL_RSHIFT(in->height, s->vsub);
242 50 int w[4] = { inlink->w, cw, cw, inlink->w };
243 50 int h[4] = { in->height, ch, ch, in->height };
244 50 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
245 50 const int depth = desc->comp[0].depth;
246 50 const int pixsize = (depth+7)/8;
247
248 50 out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
249
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 50 if (!out) {
250 ✗ av_frame_free(&in);
251 ✗ return AVERROR(ENOMEM);
252 }
253 50 av_frame_copy_props(out, in);
254
255
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 200 for (plane = 0; plane < 4 && in->data[plane] && in->linesize[plane]; plane++)
256 150 hblur(out->data[plane], out->linesize[plane],
257 150 in ->data[plane], in ->linesize[plane],
258 w[plane], h[plane], s->radius[plane], s->power[plane],
259 150 s->temp, pixsize);
260
261
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 200 for (plane = 0; plane < 4 && in->data[plane] && in->linesize[plane]; plane++)
262 150 vblur(out->data[plane], out->linesize[plane],
263 150 out->data[plane], out->linesize[plane],
264 w[plane], h[plane], s->radius[plane], s->power[plane],
265 150 s->temp, pixsize);
266
267 50 av_frame_free(&in);
268
269 50 return ff_filter_frame(outlink, out);
270 }
271
272 #define OFFSET(x) offsetof(BoxBlurContext, x)
273 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
274
275 static const AVOption boxblur_options[] = {
276 { "luma_radius", "Radius of the luma blurring box", OFFSET(luma_param.radius_expr), AV_OPT_TYPE_STRING, {.str="2"}, .flags = FLAGS },
277 { "lr", "Radius of the luma blurring box", OFFSET(luma_param.radius_expr), AV_OPT_TYPE_STRING, {.str="2"}, .flags = FLAGS },
278 { "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 },
279 { "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 },
280
281 { "chroma_radius", "Radius of the chroma blurring box", OFFSET(chroma_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
282 { "cr", "Radius of the chroma blurring box", OFFSET(chroma_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
283 { "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 },
284 { "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 },
285
286 { "alpha_radius", "Radius of the alpha blurring box", OFFSET(alpha_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
287 { "ar", "Radius of the alpha blurring box", OFFSET(alpha_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
288 { "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 },
289 { "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 },
290
291 { NULL }
292 };
293
294 AVFILTER_DEFINE_CLASS(boxblur);
295
296 static const AVFilterPad avfilter_vf_boxblur_inputs[] = {
297 {
298 .name = "default",
299 .type = AVMEDIA_TYPE_VIDEO,
300 .config_props = config_input,
301 .filter_frame = filter_frame,
302 },
303 };
304
305 const FFFilter ff_vf_boxblur = {
306 .p.name = "boxblur",
307 .p.description = NULL_IF_CONFIG_SMALL("Blur the input."),
308 .p.priv_class = &boxblur_class,
309 .p.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
310 .priv_size = sizeof(BoxBlurContext),
311 .uninit = uninit,
312 FILTER_INPUTS(avfilter_vf_boxblur_inputs),
313 FILTER_OUTPUTS(ff_video_default_filterpad),
314 FILTER_QUERY_FUNC2(query_formats),
315 };
316