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avfilter: add backgroundkey video filter

Paul B Mahol committed 4 years ago

Commit 5c2a29c1 parent 1dc8d826 files · +279 −2Browse files

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6 files
  1. Changelog +1 −0
  2. doc/filters.texi +19 −0
  3. libavfilter/Makefile +1 −0
  4. libavfilter/allfilters.c +1 −0
  5. libavfilter/version.h +2 −2
  6. libavfilter/vf_backgroundkey.c +255 −0
Changelog+1−0
@@ -18,6 +18,7 @@ version <next>: · 17 unmodified lines
1818 - Media 100i decoders
1919 - DTS to PTS reorder bsf
2020 - ViewQuest VQC decoder
21+- backgroundkey filter
2122
2223
2324 version 5.1:
doc/filters.texi+19−0
@@ -7987,6 +7987,25 @@ The command accepts the same syntax of the corresponding option. · 7986 unmodified lines
79877987 If the specified expression is not valid, it is kept at its current
79887988 value.
79897989
7990+@section backgroundkey
7991+
7992+Turns a static background into transparency.
7993+
7994+The filter accepts the following option:
7995+
7996+@table @option
7997+@item threshold
7998+Threshold for scene change detection.
7999+@item similarity
8000+Similarity percentage with the background.
8001+@item blend
8002+Set the blend amount for pixels that are not similar.
8003+@end table
8004+
8005+@subsection Commands
8006+
8007+This filter supports the all above options as @ref{commands}.
8008+
79908009 @section bbox
79918010
79928011 Compute the bounding box for the non-black pixels in the input frame
libavfilter/Makefile+1−0
@@ -191,6 +191,7 @@ OBJS-$(CONFIG_AVGBLUR_FILTER) += vf_avgblur.o · 190 unmodified lines
191191 OBJS-$(CONFIG_AVGBLUR_OPENCL_FILTER) += vf_avgblur_opencl.o opencl.o \
192192 opencl/avgblur.o boxblur.o
193193 OBJS-$(CONFIG_AVGBLUR_VULKAN_FILTER) += vf_avgblur_vulkan.o vulkan.o vulkan_filter.o
194+OBJS-$(CONFIG_BACKGROUNDKEY_FILTER) += vf_backgroundkey.o
194195 OBJS-$(CONFIG_BBOX_FILTER) += bbox.o vf_bbox.o
195196 OBJS-$(CONFIG_BENCH_FILTER) += f_bench.o
196197 OBJS-$(CONFIG_BILATERAL_FILTER) += vf_bilateral.o
libavfilter/allfilters.c+1−0
@@ -177,6 +177,7 @@ extern const AVFilter ff_vf_atadenoise; · 176 unmodified lines
177177 extern const AVFilter ff_vf_avgblur;
178178 extern const AVFilter ff_vf_avgblur_opencl;
179179 extern const AVFilter ff_vf_avgblur_vulkan;
180+extern const AVFilter ff_vf_backgroundkey;
180181 extern const AVFilter ff_vf_bbox;
181182 extern const AVFilter ff_vf_bench;
182183 extern const AVFilter ff_vf_bilateral;
libavfilter/version.h+2−2
@@ -31,8 +31,8 @@ · 30 unmodified lines
3131
3232 #include "version_major.h"
3333
34−#define LIBAVFILTER_VERSION_MINOR 49
35−#define LIBAVFILTER_VERSION_MICRO 101
34+#define LIBAVFILTER_VERSION_MINOR 50
35+#define LIBAVFILTER_VERSION_MICRO 100
3636
3737
3838 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
libavfilter/vf_backgroundkey.c+255−0
@@ -0,0 +1,255 @@
1+/*
2+ * This file is part of FFmpeg.
3+ *
4+ * FFmpeg is free software; you can redistribute it and/or
5+ * modify it under the terms of the GNU Lesser General Public
6+ * License as published by the Free Software Foundation; either
7+ * version 2.1 of the License, or (at your option) any later version.
8+ *
9+ * FFmpeg is distributed in the hope that it will be useful,
10+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
11+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12+ * Lesser General Public License for more details.
13+ *
14+ * You should have received a copy of the GNU Lesser General Public
15+ * License along with FFmpeg; if not, write to the Free Software
16+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17+ */
18+
19+#include "libavutil/opt.h"
20+#include "libavutil/imgutils.h"
21+#include "avfilter.h"
22+#include "formats.h"
23+#include "internal.h"
24+#include "video.h"
25+
26+typedef struct BackgroundkeyContext {
27+ const AVClass *class;
28+
29+ float threshold;
30+ float similarity;
31+ float blend;
32+ int max;
33+
34+ int nb_threads;
35+ int hsub_log2;
36+ int vsub_log2;
37+
38+ int64_t max_sum;
39+ int64_t *sums;
40+
41+ AVFrame *background;
42+
43+ int (*do_slice)(AVFilterContext *avctx, void *arg,
44+ int jobnr, int nb_jobs);
45+} BackgroundkeyContext;
46+
47+static int do_backgroundkey_slice(AVFilterContext *avctx, void *arg, int jobnr, int nb_jobs)
48+{
49+ BackgroundkeyContext *s = avctx->priv;
50+ AVFrame *frame = arg;
51+ const int slice_start = (frame->height * jobnr) / nb_jobs;
52+ const int slice_end = (frame->height * (jobnr + 1)) / nb_jobs;
53+ const int min_diff = (255 + 255 + 255) * s->similarity;
54+ const float blend = s->blend;
55+ const int hsub = s->hsub_log2;
56+ const int vsub = s->vsub_log2;
57+ int64_t sum = 0;
58+
59+ for (int y = slice_start; y < slice_end; y++) {
60+ const uint8_t *srcy = frame->data[0] + frame->linesize[0] * y;
61+ const uint8_t *srcu = frame->data[1] + frame->linesize[1] * (y >> vsub);
62+ const uint8_t *srcv = frame->data[2] + frame->linesize[2] * (y >> vsub);
63+ const uint8_t *bsrcy = s->background->data[0] + s->background->linesize[0] * y;
64+ const uint8_t *bsrcu = s->background->data[1] + s->background->linesize[1] * (y >> vsub);
65+ const uint8_t *bsrcv = s->background->data[2] + s->background->linesize[2] * (y >> vsub);
66+ uint8_t *dst = frame->data[3] + frame->linesize[3] * y;
67+ for (int x = 0; x < frame->width; x++) {
68+ const int xx = x >> hsub;
69+ const int diff = FFABS(srcy[x] - bsrcy[x]) +
70+ FFABS(srcu[xx] - bsrcu[xx]) +
71+ FFABS(srcv[xx] - bsrcv[xx]);
72+ int A;
73+
74+ sum += diff;
75+ if (blend > 0.f) {
76+ A = 255 - av_clipf((min_diff - diff) / blend, 0.f, 255.f);
77+ } else {
78+ A = (diff > min_diff) ? 255 : 0;
79+ }
80+
81+ dst[x] = A;
82+ }
83+ }
84+
85+ s->sums[jobnr] = sum;
86+
87+ return 0;
88+}
89+
90+static int do_backgroundkey16_slice(AVFilterContext *avctx, void *arg, int jobnr, int nb_jobs)
91+{
92+ BackgroundkeyContext *s = avctx->priv;
93+ AVFrame *frame = arg;
94+ const int slice_start = (frame->height * jobnr) / nb_jobs;
95+ const int slice_end = (frame->height * (jobnr + 1)) / nb_jobs;
96+ const int hsub = s->hsub_log2;
97+ const int vsub = s->vsub_log2;
98+ const int max = s->max;
99+ const int min_diff = s->similarity * (s->max + s->max + s->max);
100+ const float blend = s->blend;
101+ int64_t sum = 0;
102+
103+ for (int y = slice_start; y < slice_end; y++) {
104+ const uint16_t *srcy = (const uint16_t *)(frame->data[0] + frame->linesize[0] * y);
105+ const uint16_t *srcu = (const uint16_t *)(frame->data[1] + frame->linesize[1] * (y >> vsub));
106+ const uint16_t *srcv = (const uint16_t *)(frame->data[2] + frame->linesize[2] * (y >> vsub));
107+ const uint16_t *bsrcy = (const uint16_t *)(s->background->data[0] + s->background->linesize[0] * y);
108+ const uint16_t *bsrcu = (const uint16_t *)(s->background->data[1] + s->background->linesize[1] * (y >> vsub));
109+ const uint16_t *bsrcv = (const uint16_t *)(s->background->data[2] + s->background->linesize[2] * (y >> vsub));
110+ uint16_t *dst = (uint16_t *)(frame->data[3] + frame->linesize[3] * y);
111+ for (int x = 0; x < frame->width; x++) {
112+ const int xx = x >> hsub;
113+ const int diff = FFABS(srcy[x] - bsrcy[x] ) +
114+ FFABS(srcu[xx] - bsrcu[xx]) +
115+ FFABS(srcv[xx] - bsrcv[xx]);
116+ int A;
117+
118+ sum += diff;
119+ if (blend > 0.f) {
120+ A = max - av_clipf((min_diff - diff) / blend, 0.f, max);
121+ } else {
122+ A = (diff > min_diff) ? max : 0;
123+ }
124+
125+ dst[x] = A;
126+ }
127+ }
128+
129+ s->sums[jobnr] = sum;
130+
131+ return 0;
132+}
133+
134+static int filter_frame(AVFilterLink *link, AVFrame *frame)
135+{
136+ AVFilterContext *avctx = link->dst;
137+ BackgroundkeyContext *s = avctx->priv;
138+ int64_t sum = 0;
139+ int ret = 0;
140+
141+ if (!s->background) {
142+ s->background = ff_get_video_buffer(link, frame->width, frame->height);
143+ if (!s->background) {
144+ ret = AVERROR(ENOMEM);
145+ goto fail;
146+ }
147+ ret = av_frame_copy(s->background, frame);
148+ if (ret < 0)
149+ goto fail;
150+ }
151+
152+ if (ret = ff_filter_execute(avctx, s->do_slice, frame, NULL,
153+ FFMIN(frame->height, s->nb_threads)))
154+ goto fail;
155+
156+ for (int n = 0; n < s->nb_threads; n++)
157+ sum += s->sums[n];
158+ if (s->max_sum * s->threshold < sum) {
159+ ret = av_frame_copy(s->background, frame);
160+ if (ret < 0)
161+ goto fail;
162+ }
163+
164+ return ff_filter_frame(avctx->outputs[0], frame);
165+fail:
166+ av_frame_free(&frame);
167+ return ret;
168+}
169+
170+static av_cold int config_output(AVFilterLink *outlink)
171+{
172+ const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(outlink->format);
173+ AVFilterContext *avctx = outlink->src;
174+ AVFilterLink *inlink = avctx->inputs[0];
175+ BackgroundkeyContext *s = avctx->priv;
176+ int depth;
177+
178+ s->nb_threads = ff_filter_get_nb_threads(avctx);
179+ depth = desc->comp[0].depth;
180+ s->do_slice = depth <= 8 ? do_backgroundkey_slice : do_backgroundkey16_slice;
181+ s->max = (1 << depth) - 1;
182+ s->hsub_log2 = desc->log2_chroma_w;
183+ s->vsub_log2 = desc->log2_chroma_h;
184+ s->max_sum = (int64_t)(inlink->w) * inlink->h * s->max;
185+ s->max_sum += 2LL * (inlink->w >> s->hsub_log2) * (inlink->h >> s->vsub_log2) * s->max;
186+
187+ s->sums = av_calloc(s->nb_threads, sizeof(*s->sums));
188+ if (!s->sums)
189+ return AVERROR(ENOMEM);
190+
191+ return 0;
192+}
193+
194+static av_cold void uninit(AVFilterContext *ctx)
195+{
196+ BackgroundkeyContext *s = ctx->priv;
197+
198+ av_frame_free(&s->background);
199+ av_freep(&s->sums);
200+}
201+
202+static const AVFilterPad backgroundkey_inputs[] = {
203+ {
204+ .name = "default",
205+ .type = AVMEDIA_TYPE_VIDEO,
206+ .flags = AVFILTERPAD_FLAG_NEEDS_WRITABLE,
207+ .filter_frame = filter_frame,
208+ },
209+};
210+
211+static const AVFilterPad backgroundkey_outputs[] = {
212+ {
213+ .name = "default",
214+ .type = AVMEDIA_TYPE_VIDEO,
215+ .config_props = config_output,
216+ },
217+};
218+
219+#define OFFSET(x) offsetof(BackgroundkeyContext, x)
220+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
221+
222+static const AVOption backgroundkey_options[] = {
223+ { "threshold", "set the scene change threshold", OFFSET(threshold), AV_OPT_TYPE_FLOAT, { .dbl = 0.08}, 0.0, 1.0, FLAGS },
224+ { "similarity", "set the similarity", OFFSET(similarity), AV_OPT_TYPE_FLOAT, { .dbl = 0.1 }, 0.0, 1.0, FLAGS },
225+ { "blend", "set the blend value", OFFSET(blend), AV_OPT_TYPE_FLOAT, { .dbl = 0.0 }, 0.0, 1.0, FLAGS },
226+ { NULL }
227+};
228+
229+static const enum AVPixelFormat backgroundkey_fmts[] = {
230+ AV_PIX_FMT_YUVA420P,
231+ AV_PIX_FMT_YUVA422P,
232+ AV_PIX_FMT_YUVA444P,
233+ AV_PIX_FMT_YUVA420P9, AV_PIX_FMT_YUVA422P9, AV_PIX_FMT_YUVA444P9,
234+ AV_PIX_FMT_YUVA420P10, AV_PIX_FMT_YUVA422P10, AV_PIX_FMT_YUVA444P10,
235+ AV_PIX_FMT_YUVA422P12, AV_PIX_FMT_YUVA444P12,
236+ AV_PIX_FMT_YUVA420P16, AV_PIX_FMT_YUVA422P16, AV_PIX_FMT_YUVA444P16,
237+ AV_PIX_FMT_GBRAP,
238+ AV_PIX_FMT_GBRAP10, AV_PIX_FMT_GBRAP12, AV_PIX_FMT_GBRAP16,
239+ AV_PIX_FMT_NONE
240+};
241+
242+AVFILTER_DEFINE_CLASS(backgroundkey);
243+
244+const AVFilter ff_vf_backgroundkey = {
245+ .name = "backgroundkey",
246+ .description = NULL_IF_CONFIG_SMALL("Turns a static background into transparency."),
247+ .priv_size = sizeof(BackgroundkeyContext),
248+ .priv_class = &backgroundkey_class,
249+ .uninit = uninit,
250+ FILTER_INPUTS(backgroundkey_inputs),
251+ FILTER_OUTPUTS(backgroundkey_outputs),
252+ FILTER_PIXFMTS_ARRAY(backgroundkey_fmts),
253+ .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
254+ .process_command = ff_filter_process_command,
255+};

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