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path: root/libavfilter/vf_find_rect.c (plain)
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1/*
2 * Copyright (c) 2014-2015 Michael Niedermayer <michaelni@gmx.at>
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (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
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License along
17 * with FFmpeg; if not, write to the Free Software Foundation, Inc.,
18 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
19 */
20
21/**
22 * @todo switch to dualinput
23 */
24
25#include "libavutil/avassert.h"
26#include "libavutil/imgutils.h"
27#include "libavutil/opt.h"
28#include "internal.h"
29
30#include "lavfutils.h"
31
32#define MAX_MIPMAPS 5
33
34typedef struct FOCContext {
35 AVClass *class;
36 float threshold;
37 int mipmaps;
38 int xmin, ymin, xmax, ymax;
39 char *obj_filename;
40 int last_x, last_y;
41 AVFrame *obj_frame;
42 AVFrame *needle_frame[MAX_MIPMAPS];
43 AVFrame *haystack_frame[MAX_MIPMAPS];
44} FOCContext;
45
46#define OFFSET(x) offsetof(FOCContext, x)
47#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
48static const AVOption find_rect_options[] = {
49 { "object", "object bitmap filename", OFFSET(obj_filename), AV_OPT_TYPE_STRING, {.str = NULL}, .flags = FLAGS },
50 { "threshold", "set threshold", OFFSET(threshold), AV_OPT_TYPE_FLOAT, {.dbl = 0.5}, 0, 1.0, FLAGS },
51 { "mipmaps", "set mipmaps", OFFSET(mipmaps), AV_OPT_TYPE_INT, {.i64 = 3}, 1, MAX_MIPMAPS, FLAGS },
52 { "xmin", "", OFFSET(xmin), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, FLAGS },
53 { "ymin", "", OFFSET(ymin), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, FLAGS },
54 { "xmax", "", OFFSET(xmax), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, FLAGS },
55 { "ymax", "", OFFSET(ymax), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, FLAGS },
56 { NULL }
57};
58
59AVFILTER_DEFINE_CLASS(find_rect);
60
61static int query_formats(AVFilterContext *ctx)
62{
63 static const enum AVPixelFormat pix_fmts[] = {
64 AV_PIX_FMT_YUV420P,
65 AV_PIX_FMT_YUVJ420P,
66 AV_PIX_FMT_NONE
67 };
68
69 return ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
70}
71
72static AVFrame *downscale(AVFrame *in)
73{
74 int x, y;
75 AVFrame *frame = av_frame_alloc();
76 uint8_t *src, *dst;
77 if (!frame)
78 return NULL;
79
80 frame->format = in->format;
81 frame->width = (in->width + 1) / 2;
82 frame->height = (in->height+ 1) / 2;
83
84 if (av_frame_get_buffer(frame, 32) < 0) {
85 av_frame_free(&frame);
86 return NULL;
87 }
88 src = in ->data[0];
89 dst = frame->data[0];
90
91 for(y = 0; y < frame->height; y++) {
92 for(x = 0; x < frame->width; x++) {
93 dst[x] = ( src[2*x+0]
94 + src[2*x+1]
95 + src[2*x+0 + in->linesize[0]]
96 + src[2*x+1 + in->linesize[0]]
97 + 2) >> 2;
98 }
99 src += 2*in->linesize[0];
100 dst += frame->linesize[0];
101 }
102 return frame;
103}
104
105static float compare(const AVFrame *haystack, const AVFrame *obj, int offx, int offy)
106{
107 int x,y;
108 int o_sum_v = 0;
109 int h_sum_v = 0;
110 int64_t oo_sum_v = 0;
111 int64_t hh_sum_v = 0;
112 int64_t oh_sum_v = 0;
113 float c;
114 int n = obj->height * obj->width;
115 const uint8_t *odat = obj ->data[0];
116 const uint8_t *hdat = haystack->data[0] + offx + offy * haystack->linesize[0];
117 int64_t o_sigma, h_sigma;
118
119 for(y = 0; y < obj->height; y++) {
120 for(x = 0; x < obj->width; x++) {
121 int o_v = odat[x];
122 int h_v = hdat[x];
123 o_sum_v += o_v;
124 h_sum_v += h_v;
125 oo_sum_v += o_v * o_v;
126 hh_sum_v += h_v * h_v;
127 oh_sum_v += o_v * h_v;
128 }
129 odat += obj->linesize[0];
130 hdat += haystack->linesize[0];
131 }
132 o_sigma = n*oo_sum_v - o_sum_v*(int64_t)o_sum_v;
133 h_sigma = n*hh_sum_v - h_sum_v*(int64_t)h_sum_v;
134
135 if (o_sigma == 0 || h_sigma == 0)
136 return 1.0;
137
138 c = (n*oh_sum_v - o_sum_v*(int64_t)h_sum_v) / (sqrt(o_sigma)*sqrt(h_sigma));
139
140 return 1 - fabs(c);
141}
142
143static int config_input(AVFilterLink *inlink)
144{
145 AVFilterContext *ctx = inlink->dst;
146 FOCContext *foc = ctx->priv;
147
148 if (foc->xmax <= 0)
149 foc->xmax = inlink->w - foc->obj_frame->width;
150 if (foc->ymax <= 0)
151 foc->ymax = inlink->h - foc->obj_frame->height;
152
153 return 0;
154}
155
156static float search(FOCContext *foc, int pass, int maxpass, int xmin, int xmax, int ymin, int ymax, int *best_x, int *best_y, float best_score)
157{
158 int x, y;
159
160 if (pass + 1 <= maxpass) {
161 int sub_x, sub_y;
162 search(foc, pass+1, maxpass, xmin>>1, (xmax+1)>>1, ymin>>1, (ymax+1)>>1, &sub_x, &sub_y, 1.0);
163 xmin = FFMAX(xmin, 2*sub_x - 4);
164 xmax = FFMIN(xmax, 2*sub_x + 4);
165 ymin = FFMAX(ymin, 2*sub_y - 4);
166 ymax = FFMIN(ymax, 2*sub_y + 4);
167 }
168
169 for (y = ymin; y <= ymax; y++) {
170 for (x = xmin; x <= xmax; x++) {
171 float score = compare(foc->haystack_frame[pass], foc->needle_frame[pass], x, y);
172 av_assert0(score != 0);
173 if (score < best_score) {
174 best_score = score;
175 *best_x = x;
176 *best_y = y;
177 }
178 }
179 }
180 return best_score;
181}
182
183static int filter_frame(AVFilterLink *inlink, AVFrame *in)
184{
185 AVFilterContext *ctx = inlink->dst;
186 FOCContext *foc = ctx->priv;
187 float best_score;
188 int best_x, best_y;
189 int i;
190
191 foc->haystack_frame[0] = av_frame_clone(in);
192 for (i=1; i<foc->mipmaps; i++) {
193 foc->haystack_frame[i] = downscale(foc->haystack_frame[i-1]);
194 }
195
196 best_score = search(foc, 0, 0,
197 FFMAX(foc->xmin, foc->last_x - 8),
198 FFMIN(foc->xmax, foc->last_x + 8),
199 FFMAX(foc->ymin, foc->last_y - 8),
200 FFMIN(foc->ymax, foc->last_y + 8),
201 &best_x, &best_y, 1.0);
202
203 best_score = search(foc, 0, foc->mipmaps - 1, foc->xmin, foc->xmax, foc->ymin, foc->ymax,
204 &best_x, &best_y, best_score);
205
206 for (i=0; i<MAX_MIPMAPS; i++) {
207 av_frame_free(&foc->haystack_frame[i]);
208 }
209
210 if (best_score > foc->threshold) {
211 return ff_filter_frame(ctx->outputs[0], in);
212 }
213
214 av_log(ctx, AV_LOG_DEBUG, "Found at %d %d score %f\n", best_x, best_y, best_score);
215 foc->last_x = best_x;
216 foc->last_y = best_y;
217
218 av_frame_make_writable(in);
219
220 av_dict_set_int(&in->metadata, "lavfi.rect.w", foc->obj_frame->width, 0);
221 av_dict_set_int(&in->metadata, "lavfi.rect.h", foc->obj_frame->height, 0);
222 av_dict_set_int(&in->metadata, "lavfi.rect.x", best_x, 0);
223 av_dict_set_int(&in->metadata, "lavfi.rect.y", best_y, 0);
224
225 return ff_filter_frame(ctx->outputs[0], in);
226}
227
228static av_cold void uninit(AVFilterContext *ctx)
229{
230 FOCContext *foc = ctx->priv;
231 int i;
232
233 for (i = 0; i < MAX_MIPMAPS; i++) {
234 av_frame_free(&foc->needle_frame[i]);
235 av_frame_free(&foc->haystack_frame[i]);
236 }
237
238 if (foc->obj_frame)
239 av_freep(&foc->obj_frame->data[0]);
240 av_frame_free(&foc->obj_frame);
241}
242
243static av_cold int init(AVFilterContext *ctx)
244{
245 FOCContext *foc = ctx->priv;
246 int ret, i;
247
248 if (!foc->obj_filename) {
249 av_log(ctx, AV_LOG_ERROR, "object filename not set\n");
250 return AVERROR(EINVAL);
251 }
252
253 foc->obj_frame = av_frame_alloc();
254 if (!foc->obj_frame)
255 return AVERROR(ENOMEM);
256
257 if ((ret = ff_load_image(foc->obj_frame->data, foc->obj_frame->linesize,
258 &foc->obj_frame->width, &foc->obj_frame->height,
259 &foc->obj_frame->format, foc->obj_filename, ctx)) < 0)
260 return ret;
261
262 if (foc->obj_frame->format != AV_PIX_FMT_GRAY8) {
263 av_log(ctx, AV_LOG_ERROR, "object image is not a grayscale image\n");
264 return AVERROR(EINVAL);
265 }
266
267 foc->needle_frame[0] = av_frame_clone(foc->obj_frame);
268 for (i = 1; i < foc->mipmaps; i++) {
269 foc->needle_frame[i] = downscale(foc->needle_frame[i-1]);
270 if (!foc->needle_frame[i])
271 return AVERROR(ENOMEM);
272 }
273
274 return 0;
275}
276
277static const AVFilterPad foc_inputs[] = {
278 {
279 .name = "default",
280 .type = AVMEDIA_TYPE_VIDEO,
281 .config_props = config_input,
282 .filter_frame = filter_frame,
283 },
284 { NULL }
285};
286
287static const AVFilterPad foc_outputs[] = {
288 {
289 .name = "default",
290 .type = AVMEDIA_TYPE_VIDEO,
291 },
292 { NULL }
293};
294
295AVFilter ff_vf_find_rect = {
296 .name = "find_rect",
297 .description = NULL_IF_CONFIG_SMALL("Find a user specified object."),
298 .priv_size = sizeof(FOCContext),
299 .init = init,
300 .uninit = uninit,
301 .query_formats = query_formats,
302 .inputs = foc_inputs,
303 .outputs = foc_outputs,
304 .priv_class = &find_rect_class,
305};
306
generated by cgit at 2024-05-17 06:12:09 (GMT)