2 * Copyright (c) 2002 Michael Niedermayer <michaelni@gmx.at>
3 * Copyright (c) 2011 Stefano Sabatini
5 * This file is part of Libav.
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.
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.
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.
24 * Apply a boxblur filter to the input video.
25 * Ported from MPlayer libmpcodecs/vf_boxblur.c.
28 #include "libavutil/avstring.h"
29 #include "libavutil/eval.h"
30 #include "libavutil/pixdesc.h"
34 static const char *const var_names[] = {
60 FilterParam luma_param;
61 FilterParam chroma_param;
62 FilterParam alpha_param;
63 char luma_radius_expr [256];
64 char chroma_radius_expr[256];
65 char alpha_radius_expr [256];
70 uint8_t *temp[2]; ///< temporary buffer used in blur_power()
78 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
80 BoxBlurContext *boxblur = ctx->priv;
84 av_log(ctx, AV_LOG_ERROR,
85 "Filter expects 2 or 4 or 6 arguments, none provided\n");
86 return AVERROR(EINVAL);
89 e = sscanf(args, "%255[^:]:%d:%255[^:]:%d:%255[^:]:%d",
90 boxblur->luma_radius_expr, &boxblur->luma_param .power,
91 boxblur->chroma_radius_expr, &boxblur->chroma_param.power,
92 boxblur->alpha_radius_expr, &boxblur->alpha_param .power);
94 if (e != 2 && e != 4 && e != 6) {
95 av_log(ctx, AV_LOG_ERROR,
96 "Filter expects 2 or 4 or 6 params, provided %d\n", e);
97 return AVERROR(EINVAL);
101 boxblur->chroma_param.power = boxblur->luma_param.power;
102 av_strlcpy(boxblur->chroma_radius_expr, boxblur->luma_radius_expr,
103 sizeof(boxblur->chroma_radius_expr));
106 boxblur->alpha_param.power = boxblur->luma_param.power;
107 av_strlcpy(boxblur->alpha_radius_expr, boxblur->luma_radius_expr,
108 sizeof(boxblur->alpha_radius_expr));
114 static av_cold void uninit(AVFilterContext *ctx)
116 BoxBlurContext *boxblur = ctx->priv;
118 av_freep(&boxblur->temp[0]);
119 av_freep(&boxblur->temp[1]);
122 static int query_formats(AVFilterContext *ctx)
124 enum PixelFormat pix_fmts[] = {
125 PIX_FMT_YUV444P, PIX_FMT_YUV422P, PIX_FMT_YUV420P,
126 PIX_FMT_YUV411P, PIX_FMT_YUV410P, PIX_FMT_YUVA420P,
127 PIX_FMT_YUV440P, PIX_FMT_GRAY8,
128 PIX_FMT_YUVJ444P, PIX_FMT_YUVJ422P, PIX_FMT_YUVJ420P,
133 ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
137 static int config_input(AVFilterLink *inlink)
139 const AVPixFmtDescriptor *desc = &av_pix_fmt_descriptors[inlink->format];
140 AVFilterContext *ctx = inlink->dst;
141 BoxBlurContext *boxblur = ctx->priv;
142 int w = inlink->w, h = inlink->h;
144 double var_values[VARS_NB], res;
148 av_freep(&boxblur->temp[0]);
149 av_freep(&boxblur->temp[1]);
150 if (!(boxblur->temp[0] = av_malloc(FFMAX(w, h))))
151 return AVERROR(ENOMEM);
152 if (!(boxblur->temp[1] = av_malloc(FFMAX(w, h)))) {
153 av_freep(&boxblur->temp[0]);
154 return AVERROR(ENOMEM);
157 boxblur->hsub = desc->log2_chroma_w;
158 boxblur->vsub = desc->log2_chroma_h;
160 var_values[VAR_W] = inlink->w;
161 var_values[VAR_H] = inlink->h;
162 var_values[VAR_CW] = cw = w>>boxblur->hsub;
163 var_values[VAR_CH] = ch = h>>boxblur->vsub;
164 var_values[VAR_HSUB] = 1<<boxblur->hsub;
165 var_values[VAR_VSUB] = 1<<boxblur->vsub;
167 #define EVAL_RADIUS_EXPR(comp) \
168 expr = boxblur->comp##_radius_expr; \
169 ret = av_expr_parse_and_eval(&res, expr, var_names, var_values, \
170 NULL, NULL, NULL, NULL, NULL, 0, ctx); \
171 boxblur->comp##_param.radius = res; \
173 av_log(NULL, AV_LOG_ERROR, \
174 "Error when evaluating " #comp " radius expression '%s'\n", expr); \
177 EVAL_RADIUS_EXPR(luma);
178 EVAL_RADIUS_EXPR(chroma);
179 EVAL_RADIUS_EXPR(alpha);
181 av_log(ctx, AV_LOG_DEBUG,
182 "luma_radius:%d luma_power:%d "
183 "chroma_radius:%d chroma_power:%d "
184 "alpha_radius:%d alpha_power:%d "
185 "w:%d chroma_w:%d h:%d chroma_h:%d\n",
186 boxblur->luma_param .radius, boxblur->luma_param .power,
187 boxblur->chroma_param.radius, boxblur->chroma_param.power,
188 boxblur->alpha_param .radius, boxblur->alpha_param .power,
191 #define CHECK_RADIUS_VAL(w_, h_, comp) \
192 if (boxblur->comp##_param.radius < 0 || \
193 2*boxblur->comp##_param.radius > FFMIN(w_, h_)) { \
194 av_log(ctx, AV_LOG_ERROR, \
195 "Invalid " #comp " radius value %d, must be >= 0 and <= %d\n", \
196 boxblur->comp##_param.radius, FFMIN(w_, h_)/2); \
197 return AVERROR(EINVAL); \
199 CHECK_RADIUS_VAL(w, h, luma);
200 CHECK_RADIUS_VAL(cw, ch, chroma);
201 CHECK_RADIUS_VAL(w, h, alpha);
203 boxblur->radius[Y] = boxblur->luma_param.radius;
204 boxblur->radius[U] = boxblur->radius[V] = boxblur->chroma_param.radius;
205 boxblur->radius[A] = boxblur->alpha_param.radius;
207 boxblur->power[Y] = boxblur->luma_param.power;
208 boxblur->power[U] = boxblur->power[V] = boxblur->chroma_param.power;
209 boxblur->power[A] = boxblur->alpha_param.power;
214 static inline void blur(uint8_t *dst, int dst_step, const uint8_t *src, int src_step,
217 /* Naive boxblur would sum source pixels from x-radius .. x+radius
218 * for destination pixel x. That would be O(radius*width).
219 * If you now look at what source pixels represent 2 consecutive
220 * output pixels, then you see they are almost identical and only
221 * differ by 2 pixels, like:
227 * so when you know one output pixel you can find the next by just adding
228 * and subtracting 1 input pixel.
229 * The following code adopts this faster variant.
231 const int length = radius*2 + 1;
232 const int inv = ((1<<16) + length/2)/length;
235 for (x = 0; x < radius; x++)
236 sum += src[x*src_step]<<1;
237 sum += src[radius*src_step];
239 for (x = 0; x <= radius; x++) {
240 sum += src[(radius+x)*src_step] - src[(radius-x)*src_step];
241 dst[x*dst_step] = (sum*inv + (1<<15))>>16;
244 for (; x < len-radius; x++) {
245 sum += src[(radius+x)*src_step] - src[(x-radius-1)*src_step];
246 dst[x*dst_step] = (sum*inv + (1<<15))>>16;
249 for (; x < len; x++) {
250 sum += src[(2*len-radius-x-1)*src_step] - src[(x-radius-1)*src_step];
251 dst[x*dst_step] = (sum*inv + (1<<15))>>16;
255 static inline void blur_power(uint8_t *dst, int dst_step, const uint8_t *src, int src_step,
256 int len, int radius, int power, uint8_t *temp[2])
258 uint8_t *a = temp[0], *b = temp[1];
260 if (radius && power) {
261 blur(a, 1, src, src_step, len, radius);
262 for (; power > 2; power--) {
264 blur(b, 1, a, 1, len, radius);
268 blur(dst, dst_step, a, 1, len, radius);
271 for (i = 0; i < len; i++)
272 dst[i*dst_step] = a[i];
276 for (i = 0; i < len; i++)
277 dst[i*dst_step] = src[i*src_step];
281 static void hblur(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize,
282 int w, int h, int radius, int power, uint8_t *temp[2])
286 if (radius == 0 && dst == src)
289 for (y = 0; y < h; y++)
290 blur_power(dst + y*dst_linesize, 1, src + y*src_linesize, 1,
291 w, radius, power, temp);
294 static void vblur(uint8_t *dst, int dst_linesize, const uint8_t *src, int src_linesize,
295 int w, int h, int radius, int power, uint8_t *temp[2])
299 if (radius == 0 && dst == src)
302 for (x = 0; x < w; x++)
303 blur_power(dst + x, dst_linesize, src + x, src_linesize,
304 h, radius, power, temp);
307 static void draw_slice(AVFilterLink *inlink, int y0, int h0, int slice_dir)
309 AVFilterContext *ctx = inlink->dst;
310 BoxBlurContext *boxblur = ctx->priv;
311 AVFilterLink *outlink = inlink->dst->outputs[0];
312 AVFilterBufferRef *inpicref = inlink ->cur_buf;
313 AVFilterBufferRef *outpicref = outlink->out_buf;
315 int cw = inlink->w >> boxblur->hsub, ch = h0 >> boxblur->vsub;
316 int w[4] = { inlink->w, cw, cw, inlink->w };
317 int h[4] = { h0, ch, ch, h0 };
319 for (plane = 0; inpicref->data[plane] && plane < 4; plane++)
320 hblur(outpicref->data[plane], outpicref->linesize[plane],
321 inpicref ->data[plane], inpicref ->linesize[plane],
322 w[plane], h[plane], boxblur->radius[plane], boxblur->power[plane],
325 for (plane = 0; inpicref->data[plane] && plane < 4; plane++)
326 vblur(outpicref->data[plane], outpicref->linesize[plane],
327 outpicref->data[plane], outpicref->linesize[plane],
328 w[plane], h[plane], boxblur->radius[plane], boxblur->power[plane],
331 avfilter_draw_slice(outlink, y0, h0, slice_dir);
334 AVFilter avfilter_vf_boxblur = {
336 .description = NULL_IF_CONFIG_SMALL("Blur the input."),
337 .priv_size = sizeof(BoxBlurContext),
340 .query_formats = query_formats,
342 .inputs = (AVFilterPad[]) {{ .name = "default",
343 .type = AVMEDIA_TYPE_VIDEO,
344 .config_props = config_input,
345 .draw_slice = draw_slice,
346 .min_perms = AV_PERM_READ },
348 .outputs = (AVFilterPad[]) {{ .name = "default",
349 .type = AVMEDIA_TYPE_VIDEO, },