lavfi: port boxblur filter from libmpcodecs
[libav.git] / libavfilter / vf_boxblur.c
1 /*
2 * Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
3 * Copyright (c) 2011 Stefano Sabatini
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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 * Libav 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 Libav; 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/eval.h"
30 #include "libavutil/pixdesc.h"
31 #include "avfilter.h"
32
33 static const char *var_names[] = {
34 "w",
35 "h",
36 "cw",
37 "ch",
38 "hsub",
39 "vsub",
40 NULL
41 };
42
43 enum var_name {
44 VAR_W,
45 VAR_H,
46 VAR_CW,
47 VAR_CH,
48 VAR_HSUB,
49 VAR_VSUB,
50 VARS_NB
51 };
52
53 typedef struct {
54 int radius;
55 int power;
56 } FilterParam;
57
58 typedef struct {
59 FilterParam luma_param;
60 FilterParam chroma_param;
61 FilterParam alpha_param;
62 char luma_radius_expr [256];
63 char chroma_radius_expr[256];
64 char alpha_radius_expr [256];
65
66 int hsub, vsub;
67 int radius[4];
68 int power[4];
69 uint8_t *temp[2]; ///< temporary buffer used in blur_power()
70 } BoxBlurContext;
71
72 #define Y 0
73 #define U 1
74 #define V 2
75 #define A 3
76
77 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
78 {
79 BoxBlurContext *boxblur = ctx->priv;
80 int e;
81
82 if (!args) {
83 av_log(ctx, AV_LOG_ERROR,
84 "Filter expects 2 or 4 or 6 arguments, none provided\n");
85 return AVERROR(EINVAL);
86 }
87
88 e = sscanf(args, "%255[^:]:%d:%255[^:]:%d:%255[^:]:%d",
89 boxblur->luma_radius_expr, &boxblur->luma_param .power,
90 boxblur->chroma_radius_expr, &boxblur->chroma_param.power,
91 boxblur->alpha_radius_expr, &boxblur->alpha_param .power);
92
93 if (e != 2 && e != 4 && e != 6) {
94 av_log(ctx, AV_LOG_ERROR,
95 "Filter expects 2 or 4 or 6 params, provided %d\n", e);
96 return AVERROR(EINVAL);
97 }
98
99 if (e < 4) {
100 boxblur->chroma_param.power = boxblur->luma_param.power;
101 av_strlcpy(boxblur->chroma_radius_expr, boxblur->luma_radius_expr,
102 sizeof(boxblur->chroma_radius_expr));
103 }
104 if (e < 6) {
105 boxblur->alpha_param.power = boxblur->luma_param.power;
106 av_strlcpy(boxblur->alpha_radius_expr, boxblur->luma_radius_expr,
107 sizeof(boxblur->alpha_radius_expr));
108 }
109
110 return 0;
111 }
112
113 static av_cold void uninit(AVFilterContext *ctx)
114 {
115 BoxBlurContext *boxblur = ctx->priv;
116
117 av_freep(&boxblur->temp[0]);
118 av_freep(&boxblur->temp[1]);
119 }
120
121 static int query_formats(AVFilterContext *ctx)
122 {
123 enum PixelFormat pix_fmts[] = {
124 PIX_FMT_YUV444P, PIX_FMT_YUV422P, PIX_FMT_YUV420P,
125 PIX_FMT_YUV411P, PIX_FMT_YUV410P, PIX_FMT_YUVA420P,
126 PIX_FMT_YUV440P, PIX_FMT_GRAY8,
127 PIX_FMT_YUVJ444P, PIX_FMT_YUVJ422P, PIX_FMT_YUVJ420P,
128 PIX_FMT_YUVJ440P,
129 PIX_FMT_NONE
130 };
131
132 avfilter_set_common_formats(ctx, avfilter_make_format_list(pix_fmts));
133 return 0;
134 }
135
136 static int config_input(AVFilterLink *inlink)
137 {
138 const AVPixFmtDescriptor *desc = &av_pix_fmt_descriptors[inlink->format];
139 AVFilterContext *ctx = inlink->dst;
140 BoxBlurContext *boxblur = ctx->priv;
141 int w = inlink->w, h = inlink->h;
142 int cw, ch;
143 double var_values[VARS_NB], res;
144 char *expr;
145 int ret;
146
147 av_freep(&boxblur->temp[0]);
148 av_freep(&boxblur->temp[1]);
149 if (!(boxblur->temp[0] = av_malloc(FFMAX(w, h))))
150 return AVERROR(ENOMEM);
151 if (!(boxblur->temp[1] = av_malloc(FFMAX(w, h)))) {
152 av_freep(&boxblur->temp[0]);
153 return AVERROR(ENOMEM);
154 }
155
156 boxblur->hsub = desc->log2_chroma_w;
157 boxblur->vsub = desc->log2_chroma_h;
158
159 var_values[VAR_W] = inlink->w;
160 var_values[VAR_H] = inlink->h;
161 var_values[VAR_CW] = cw = w>>boxblur->hsub;
162 var_values[VAR_CH] = ch = h>>boxblur->vsub;
163 var_values[VAR_HSUB] = 1<<boxblur->hsub;
164 var_values[VAR_VSUB] = 1<<boxblur->vsub;
165
166 #define EVAL_RADIUS_EXPR(comp) \
167 expr = boxblur->comp##_radius_expr; \
168 ret = av_expr_parse_and_eval(&res, expr, var_names, var_values, \
169 NULL, NULL, NULL, NULL, NULL, 0, ctx); \
170 boxblur->comp##_param.radius = res; \
171 if (ret < 0) { \
172 av_log(NULL, AV_LOG_ERROR, \
173 "Error when evaluating " #comp " radius expression '%s'\n", expr); \
174 return ret; \
175 }
176 EVAL_RADIUS_EXPR(luma);
177 EVAL_RADIUS_EXPR(chroma);
178 EVAL_RADIUS_EXPR(alpha);
179
180 av_log(ctx, AV_LOG_DEBUG,
181 "luma_radius:%d luma_power:%d "
182 "chroma_radius:%d chroma_power:%d "
183 "alpha_radius:%d alpha_power:%d "
184 "w:%d chroma_w:%d h:%d chroma_h:%d\n",
185 boxblur->luma_param .radius, boxblur->luma_param .power,
186 boxblur->chroma_param.radius, boxblur->chroma_param.power,
187 boxblur->alpha_param .radius, boxblur->alpha_param .power,
188 w, cw, h, ch);
189
190 #define CHECK_RADIUS_VAL(w_, h_, comp) \
191 if (boxblur->comp##_param.radius < 0 || \
192 2*boxblur->comp##_param.radius > FFMIN(w_, h_)) { \
193 av_log(ctx, AV_LOG_ERROR, \
194 "Invalid " #comp " radius value %d, must be >= 0 and <= %d\n", \
195 boxblur->comp##_param.radius, FFMIN(w_, h_)/2); \
196 return AVERROR(EINVAL); \
197 }
198 CHECK_RADIUS_VAL(w, h, luma);
199 CHECK_RADIUS_VAL(cw, ch, chroma);
200 CHECK_RADIUS_VAL(w, h, alpha);
201
202 boxblur->radius[Y] = boxblur->luma_param.radius;
203 boxblur->radius[U] = boxblur->radius[V] = boxblur->chroma_param.radius;
204 boxblur->radius[A] = boxblur->alpha_param.radius;
205
206 boxblur->power[Y] = boxblur->luma_param.power;
207 boxblur->power[U] = boxblur->power[V] = boxblur->chroma_param.power;
208 boxblur->power[A] = boxblur->alpha_param.power;
209
210 return 0;
211 }
212
213 static inline void blur(uint8_t *dst, int dst_step, const uint8_t *src, int src_step,
214 int len, int radius)
215 {
216 /* Naive boxblur would sum source pixels from x-radius .. x+radius
217 * for destination pixel x. That would be O(radius*width).
218 * If you now look at what source pixels represent 2 consecutive
219 * output pixels, then you see they are almost identical and only
220 * differ by 2 pixels, like:
221 * src0 111111111
222 * dst0 1
223 * src1 111111111
224 * dst1 1
225 * src0-src1 1 -1
226 * so when you know one output pixel you can find the next by just adding
227 * and subtracting 1 input pixel.
228 * The following code adopts this faster variant.
229 */
230 const int length = radius*2 + 1;
231 const int inv = ((1<<16) + length/2)/length;
232 int x, sum = 0;
233
234 for (x = 0; x < radius; x++)
235 sum += src[x*src_step]<<1;
236 sum += src[radius*src_step];
237
238 for (x = 0; x <= radius; x++) {
239 sum += src[(radius+x)*src_step] - src[(radius-x)*src_step];
240 dst[x*dst_step] = (sum*inv + (1<<15))>>16;
241 }
242
243 for (; x < len-radius; x++) {
244 sum += src[(radius+x)*src_step] - src[(x-radius-1)*src_step];
245 dst[x*dst_step] = (sum*inv + (1<<15))>>16;
246 }
247
248 for (; x < len; x++) {
249 sum += src[(2*len-radius-x-1)*src_step] - src[(x-radius-1)*src_step];
250 dst[x*dst_step] = (sum*inv + (1<<15))>>16;
251 }
252 }
253
254 static inline void blur_power(uint8_t *dst, int dst_step, const uint8_t *src, int src_step,
255 int len, int radius, int power, uint8_t *temp[2])
256 {
257 uint8_t *a = temp[0], *b = temp[1];
258
259 if (radius && power) {
260 blur(a, 1, src, src_step, len, radius);
261 for (; power > 2; power--) {
262 uint8_t *c;
263 blur(b, 1, a, 1, len, radius);
264 c = a; a = b; b = c;
265 }
266 if (power > 1) {
267 blur(dst, dst_step, a, 1, len, radius);
268 } else {
269 int i;
270 for (i = 0; i < len; i++)
271 dst[i*dst_step] = a[i];
272 }
273 } else {
274 int i;
275 for (i = 0; i < len; i++)
276 dst[i*dst_step] = src[i*src_step];
277 }
278 }
279
280 static void hblur(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize,
281 int w, int h, int radius, int power, uint8_t *temp[2])
282 {
283 int y;
284
285 if (radius == 0 && dst == src)
286 return;
287
288 for (y = 0; y < h; y++)
289 blur_power(dst + y*dst_linesize, 1, src + y*src_linesize, 1,
290 w, radius, power, temp);
291 }
292
293 static void vblur(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize,
294 int w, int h, int radius, int power, uint8_t *temp[2])
295 {
296 int x;
297
298 if (radius == 0 && dst == src)
299 return;
300
301 for (x = 0; x < w; x++)
302 blur_power(dst + x, dst_linesize, src + x, src_linesize,
303 h, radius, power, temp);
304 }
305
306 static void draw_slice(AVFilterLink *inlink, int y0, int h0, int slice_dir)
307 {
308 AVFilterContext *ctx = inlink->dst;
309 BoxBlurContext *boxblur = ctx->priv;
310 AVFilterLink *outlink = inlink->dst->outputs[0];
311 AVFilterBufferRef *inpicref = inlink ->cur_buf;
312 AVFilterBufferRef *outpicref = outlink->out_buf;
313 int plane;
314 int cw = inlink->w >> boxblur->hsub, ch = h0 >> boxblur->vsub;
315 int w[4] = { inlink->w, cw, cw, inlink->w };
316 int h[4] = { h0, ch, ch, h0 };
317
318 for (plane = 0; inpicref->data[plane] && plane < 4; plane++)
319 hblur(outpicref->data[plane], outpicref->linesize[plane],
320 inpicref ->data[plane], inpicref ->linesize[plane],
321 w[plane], h[plane], boxblur->radius[plane], boxblur->power[plane],
322 boxblur->temp);
323
324 for (plane = 0; inpicref->data[plane] && plane < 4; plane++)
325 vblur(outpicref->data[plane], outpicref->linesize[plane],
326 outpicref->data[plane], outpicref->linesize[plane],
327 w[plane], h[plane], boxblur->radius[plane], boxblur->power[plane],
328 boxblur->temp);
329
330 avfilter_draw_slice(outlink, y0, h0, slice_dir);
331 }
332
333 AVFilter avfilter_vf_boxblur = {
334 .name = "boxblur",
335 .description = NULL_IF_CONFIG_SMALL("Blur the input."),
336 .priv_size = sizeof(BoxBlurContext),
337 .init = init,
338 .uninit = uninit,
339 .query_formats = query_formats,
340
341 .inputs = (AVFilterPad[]) {{ .name = "default",
342 .type = AVMEDIA_TYPE_VIDEO,
343 .config_props = config_input,
344 .draw_slice = draw_slice,
345 .min_perms = AV_PERM_READ },
346 { .name = NULL}},
347 .outputs = (AVFilterPad[]) {{ .name = "default",
348 .type = AVMEDIA_TYPE_VIDEO, },
349 { .name = NULL}},
350 };