FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavfilter/vf_boxblur.c
Date: 2026-04-24 10:13:59
Exec Total Coverage
Lines: 77 97 79.4%
Functions: 9 10 90.0%
Branches: 46 84 54.8%
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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/common.h"
29 #include "libavutil/mem.h"
30 #include "libavutil/opt.h"
31 #include "avfilter.h"
32 #include "filters.h"
33 #include "formats.h"
34 #include "video.h"
35 #include "boxblur.h"
36
37
38 typedef struct BoxBlurContext {
39 const AVClass *class;
40 FilterParam luma_param;
41 FilterParam chroma_param;
42 FilterParam alpha_param;
43
44 int hsub, vsub;
45 int radius[4];
46 int power[4];
47 uint8_t *temp[2]; ///< temporary buffer used in blur_power()
48 } BoxBlurContext;
49
50 2 static av_cold void uninit(AVFilterContext *ctx)
51 {
52 2 BoxBlurContext *s = ctx->priv;
53
54 2 av_freep(&s->temp[0]);
55 2 av_freep(&s->temp[1]);
56 2 }
57
58 1 static int query_formats(const AVFilterContext *ctx,
59 AVFilterFormatsConfig **cfg_in,
60 AVFilterFormatsConfig **cfg_out)
61 {
62 1 AVFilterFormats *formats = NULL;
63 int fmt, ret;
64
65
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 268 for (fmt = 0; av_pix_fmt_desc_get(fmt); fmt++) {
66 267 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(fmt);
67
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 267 if (!(desc->flags & (AV_PIX_FMT_FLAG_HWACCEL | AV_PIX_FMT_FLAG_BITSTREAM | AV_PIX_FMT_FLAG_PAL)) &&
68
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 244 (desc->flags & AV_PIX_FMT_FLAG_PLANAR || desc->nb_components == 1) &&
69
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 236 (!(desc->flags & AV_PIX_FMT_FLAG_BE) == !HAVE_BIGENDIAN || desc->comp[0].depth == 8) &&
70 86 (ret = ff_add_format(&formats, fmt)) < 0)
71 ✗ return ret;
72 }
73
74 1 return ff_set_common_formats2(ctx, cfg_in, cfg_out, formats);
75 }
76
77 1 static int config_input(AVFilterLink *inlink)
78 {
79 1 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
80 1 AVFilterContext *ctx = inlink->dst;
81 1 BoxBlurContext *s = ctx->priv;
82 1 int w = inlink->w, h = inlink->h;
83 int ret;
84
85
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 1 if (!(s->temp[0] = av_malloc(2*FFMAX(w, h))) ||
86
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 1 !(s->temp[1] = av_malloc(2*FFMAX(w, h))))
87 ✗ return AVERROR(ENOMEM);
88
89 1 s->hsub = desc->log2_chroma_w;
90 1 s->vsub = desc->log2_chroma_h;
91
92 1 ret = ff_boxblur_eval_filter_params(inlink,
93 &s->luma_param,
94 &s->chroma_param,
95 &s->alpha_param);
96
97
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 1 if (ret != 0) {
98 ✗ av_log(ctx, AV_LOG_ERROR, "Failed to evaluate "
99 "filter params: %d.\n", ret);
100 ✗ return ret;
101 }
102
103 1 s->radius[Y] = s->luma_param.radius;
104 1 s->radius[U] = s->radius[V] = s->chroma_param.radius;
105 1 s->radius[A] = s->alpha_param.radius;
106
107 1 s->power[Y] = s->luma_param.power;
108 1 s->power[U] = s->power[V] = s->chroma_param.power;
109 1 s->power[A] = s->alpha_param.power;
110
111 1 return 0;
112 }
113
114 /* Naive boxblur would sum source pixels from x-radius .. x+radius
115 * for destination pixel x. That would be O(radius*width).
116 * If you now look at what source pixels represent 2 consecutive
117 * output pixels, then you see they are almost identical and only
118 * differ by 2 pixels, like:
119 * src0 111111111
120 * dst0 1
121 * src1 111111111
122 * dst1 1
123 * src0-src1 1 -1
124 * so when you know one output pixel you can find the next by just adding
125 * and subtracting 1 input pixel.
126 * The following code adopts this faster variant.
127 */
128 #define BLUR(type, depth) \
129 static inline void blur ## depth(type *dst, int dst_step, const type *src, \
130 int src_step, int len, int radius) \
131 { \
132 const int length = radius*2 + 1; \
133 const int inv = ((1<<16) + length/2)/length; \
134 int x, sum = src[radius*src_step]; \
135 \
136 for (x = 0; x < radius; x++) \
137 sum += src[x*src_step]<<1; \
138 \
139 sum = sum*inv + (1<<15); \
140 \
141 for (x = 0; x <= radius; x++) { \
142 sum += (src[(radius+x)*src_step] - src[(radius-x)*src_step])*inv; \
143 dst[x*dst_step] = sum>>16; \
144 } \
145 \
146 for (; x < len-radius; x++) { \
147 sum += (src[(radius+x)*src_step] - src[(x-radius-1)*src_step])*inv; \
148 dst[x*dst_step] = sum >>16; \
149 } \
150 \
151 for (; x < len; x++) { \
152 sum += (src[(2*len-radius-x-1)*src_step] - src[(x-radius-1)*src_step])*inv; \
153 dst[x*dst_step] = sum>>16; \
154 } \
155 }
156
157
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 15398400 BLUR(uint8_t, 8)
158 ✗ BLUR(uint16_t, 16)
159
160 #undef BLUR
161
162 64000 static inline void blur(uint8_t *dst, int dst_step, const uint8_t *src, int src_step,
163 int len, int radius, int pixsize)
164 {
165
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 64000 if (pixsize == 1) blur8 (dst, dst_step , src, src_step , len, radius);
166 ✗ else blur16((uint16_t*)dst, dst_step>>1, (const uint16_t*)src, src_step>>1, len, radius);
167 64000 }
168
169 64000 static inline void blur_power(uint8_t *dst, int dst_step, const uint8_t *src, int src_step,
170 int len, int radius, int power, uint8_t *temp[2], int pixsize)
171 {
172 64000 uint8_t *a = temp[0], *b = temp[1];
173
174
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 64000 if (radius && power) {
175 64000 blur(a, pixsize, src, src_step, len, radius, pixsize);
176
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 64000 for (; power > 2; power--) {
177 uint8_t *c;
178 ✗ blur(b, pixsize, a, pixsize, len, radius, pixsize);
179 ✗ c = a; a = b; b = c;
180 }
181
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 64000 if (power > 1) {
182 ✗ blur(dst, dst_step, a, pixsize, len, radius, pixsize);
183 } else {
184 int i;
185
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186
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 15270400 for (i = 0; i < len; i++)
187 15206400 dst[i*dst_step] = a[i];
188 } else
189 ✗ for (i = 0; i < len; i++)
190 ✗ *(uint16_t*)(dst + i*dst_step) = ((uint16_t*)a)[i];
191 }
192 } else {
193 int i;
194 ✗ if (pixsize == 1) {
195 ✗ for (i = 0; i < len; i++)
196 ✗ dst[i*dst_step] = src[i*src_step];
197 } else
198 ✗ for (i = 0; i < len; i++)
199 ✗ *(uint16_t*)(dst + i*dst_step) = *(uint16_t*)(src + i*src_step);
200 }
201 64000 }
202
203 150 static void hblur(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize,
204 int w, int h, int radius, int power, uint8_t *temp[2], int pixsize)
205 {
206 int y;
207
208
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 150 if (radius == 0 && dst == src)
209 ✗ return;
210
211
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 28950 for (y = 0; y < h; y++)
212 28800 blur_power(dst + y*dst_linesize, pixsize, src + y*src_linesize, pixsize,
213 w, radius, power, temp, pixsize);
214 }
215
216 150 static void vblur(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize,
217 int w, int h, int radius, int power, uint8_t *temp[2], int pixsize)
218 {
219 int x;
220
221
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 150 if (radius == 0 && dst == src)
222 ✗ return;
223
224
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 35350 for (x = 0; x < w; x++)
225 35200 blur_power(dst + x*pixsize, dst_linesize, src + x*pixsize, src_linesize,
226 h, radius, power, temp, pixsize);
227 }
228
229 50 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
230 {
231 50 AVFilterContext *ctx = inlink->dst;
232 50 BoxBlurContext *s = ctx->priv;
233 50 AVFilterLink *outlink = inlink->dst->outputs[0];
234 AVFrame *out;
235 int plane;
236 50 int cw = AV_CEIL_RSHIFT(inlink->w, s->hsub), ch = AV_CEIL_RSHIFT(in->height, s->vsub);
237 50 int w[4] = { inlink->w, cw, cw, inlink->w };
238 50 int h[4] = { in->height, ch, ch, in->height };
239 50 const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
240 50 const int depth = desc->comp[0].depth;
241 50 const int pixsize = (depth+7)/8;
242
243 50 out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
244
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 50 if (!out) {
245 ✗ av_frame_free(&in);
246 ✗ return AVERROR(ENOMEM);
247 }
248 50 av_frame_copy_props(out, in);
249
250
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 200 for (plane = 0; plane < 4 && in->data[plane] && in->linesize[plane]; plane++)
251 150 hblur(out->data[plane], out->linesize[plane],
252 150 in ->data[plane], in ->linesize[plane],
253 w[plane], h[plane], s->radius[plane], s->power[plane],
254 150 s->temp, pixsize);
255
256
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 200 for (plane = 0; plane < 4 && in->data[plane] && in->linesize[plane]; plane++)
257 150 vblur(out->data[plane], out->linesize[plane],
258 150 out->data[plane], out->linesize[plane],
259 w[plane], h[plane], s->radius[plane], s->power[plane],
260 150 s->temp, pixsize);
261
262 50 av_frame_free(&in);
263
264 50 return ff_filter_frame(outlink, out);
265 }
266
267 #define OFFSET(x) offsetof(BoxBlurContext, x)
268 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
269
270 static const AVOption boxblur_options[] = {
271 { "luma_radius", "Radius of the luma blurring box", OFFSET(luma_param.radius_expr), AV_OPT_TYPE_STRING, {.str="2"}, .flags = FLAGS },
272 { "lr", "Radius of the luma blurring box", OFFSET(luma_param.radius_expr), AV_OPT_TYPE_STRING, {.str="2"}, .flags = FLAGS },
273 { "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 },
274 { "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 },
275
276 { "chroma_radius", "Radius of the chroma blurring box", OFFSET(chroma_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
277 { "cr", "Radius of the chroma blurring box", OFFSET(chroma_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
278 { "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 },
279 { "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 },
280
281 { "alpha_radius", "Radius of the alpha blurring box", OFFSET(alpha_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
282 { "ar", "Radius of the alpha blurring box", OFFSET(alpha_param.radius_expr), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
283 { "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 },
284 { "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 },
285
286 { NULL }
287 };
288
289 AVFILTER_DEFINE_CLASS(boxblur);
290
291 static const AVFilterPad avfilter_vf_boxblur_inputs[] = {
292 {
293 .name = "default",
294 .type = AVMEDIA_TYPE_VIDEO,
295 .config_props = config_input,
296 .filter_frame = filter_frame,
297 },
298 };
299
300 const FFFilter ff_vf_boxblur = {
301 .p.name = "boxblur",
302 .p.description = NULL_IF_CONFIG_SMALL("Blur the input."),
303 .p.priv_class = &boxblur_class,
304 .p.flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
305 .priv_size = sizeof(BoxBlurContext),
306 .uninit = uninit,
307 FILTER_INPUTS(avfilter_vf_boxblur_inputs),
308 FILTER_OUTPUTS(ff_video_default_filterpad),
309 FILTER_QUERY_FUNC2(query_formats),
310 };
311