[FFmpeg-cvslog] avfilter: add backgroundkey video filter
Paul B Mahol
git at videolan.org
Sat Nov 5 11:50:02 EET 2022
ffmpeg | branch: master | Paul B Mahol <onemda at gmail.com> | Fri Oct 28 22:02:29 2022 +0200| [5c2a29cf7239e78db7dfa27182144f68da88ca5c] | committer: Paul B Mahol
avfilter: add backgroundkey video filter
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=5c2a29cf7239e78db7dfa27182144f68da88ca5c
---
Changelog | 1 +
doc/filters.texi | 19 +++
libavfilter/Makefile | 1 +
libavfilter/allfilters.c | 1 +
libavfilter/version.h | 4 +-
libavfilter/vf_backgroundkey.c | 255 +++++++++++++++++++++++++++++++++++++++++
6 files changed, 279 insertions(+), 2 deletions(-)
diff --git a/Changelog b/Changelog
index ec9de1bd85..b40118093a 100644
--- a/Changelog
+++ b/Changelog
@@ -18,6 +18,7 @@ version <next>:
- Media 100i decoders
- DTS to PTS reorder bsf
- ViewQuest VQC decoder
+- backgroundkey filter
version 5.1:
diff --git a/doc/filters.texi b/doc/filters.texi
index 006173ba47..721549c2c7 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -7987,6 +7987,25 @@ The command accepts the same syntax of the corresponding option.
If the specified expression is not valid, it is kept at its current
value.
+ at section backgroundkey
+
+Turns a static background into transparency.
+
+The filter accepts the following option:
+
+ at table @option
+ at item threshold
+Threshold for scene change detection.
+ at item similarity
+Similarity percentage with the background.
+ at item blend
+Set the blend amount for pixels that are not similar.
+ at end table
+
+ at subsection Commands
+
+This filter supports the all above options as @ref{commands}.
+
@section bbox
Compute the bounding box for the non-black pixels in the input frame
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index ff2a06c262..ace0e60ba1 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -191,6 +191,7 @@ OBJS-$(CONFIG_AVGBLUR_FILTER) += vf_avgblur.o
OBJS-$(CONFIG_AVGBLUR_OPENCL_FILTER) += vf_avgblur_opencl.o opencl.o \
opencl/avgblur.o boxblur.o
OBJS-$(CONFIG_AVGBLUR_VULKAN_FILTER) += vf_avgblur_vulkan.o vulkan.o vulkan_filter.o
+OBJS-$(CONFIG_BACKGROUNDKEY_FILTER) += vf_backgroundkey.o
OBJS-$(CONFIG_BBOX_FILTER) += bbox.o vf_bbox.o
OBJS-$(CONFIG_BENCH_FILTER) += f_bench.o
OBJS-$(CONFIG_BILATERAL_FILTER) += vf_bilateral.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index 119de40b25..e0598e9986 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -177,6 +177,7 @@ extern const AVFilter ff_vf_atadenoise;
extern const AVFilter ff_vf_avgblur;
extern const AVFilter ff_vf_avgblur_opencl;
extern const AVFilter ff_vf_avgblur_vulkan;
+extern const AVFilter ff_vf_backgroundkey;
extern const AVFilter ff_vf_bbox;
extern const AVFilter ff_vf_bench;
extern const AVFilter ff_vf_bilateral;
diff --git a/libavfilter/version.h b/libavfilter/version.h
index 4ccbf5641c..436c2b8b17 100644
--- a/libavfilter/version.h
+++ b/libavfilter/version.h
@@ -31,8 +31,8 @@
#include "version_major.h"
-#define LIBAVFILTER_VERSION_MINOR 49
-#define LIBAVFILTER_VERSION_MICRO 101
+#define LIBAVFILTER_VERSION_MINOR 50
+#define LIBAVFILTER_VERSION_MICRO 100
#define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
diff --git a/libavfilter/vf_backgroundkey.c b/libavfilter/vf_backgroundkey.c
new file mode 100644
index 0000000000..8c7c289d0b
--- /dev/null
+++ b/libavfilter/vf_backgroundkey.c
@@ -0,0 +1,255 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/opt.h"
+#include "libavutil/imgutils.h"
+#include "avfilter.h"
+#include "formats.h"
+#include "internal.h"
+#include "video.h"
+
+typedef struct BackgroundkeyContext {
+ const AVClass *class;
+
+ float threshold;
+ float similarity;
+ float blend;
+ int max;
+
+ int nb_threads;
+ int hsub_log2;
+ int vsub_log2;
+
+ int64_t max_sum;
+ int64_t *sums;
+
+ AVFrame *background;
+
+ int (*do_slice)(AVFilterContext *avctx, void *arg,
+ int jobnr, int nb_jobs);
+} BackgroundkeyContext;
+
+static int do_backgroundkey_slice(AVFilterContext *avctx, void *arg, int jobnr, int nb_jobs)
+{
+ BackgroundkeyContext *s = avctx->priv;
+ AVFrame *frame = arg;
+ const int slice_start = (frame->height * jobnr) / nb_jobs;
+ const int slice_end = (frame->height * (jobnr + 1)) / nb_jobs;
+ const int min_diff = (255 + 255 + 255) * s->similarity;
+ const float blend = s->blend;
+ const int hsub = s->hsub_log2;
+ const int vsub = s->vsub_log2;
+ int64_t sum = 0;
+
+ for (int y = slice_start; y < slice_end; y++) {
+ const uint8_t *srcy = frame->data[0] + frame->linesize[0] * y;
+ const uint8_t *srcu = frame->data[1] + frame->linesize[1] * (y >> vsub);
+ const uint8_t *srcv = frame->data[2] + frame->linesize[2] * (y >> vsub);
+ const uint8_t *bsrcy = s->background->data[0] + s->background->linesize[0] * y;
+ const uint8_t *bsrcu = s->background->data[1] + s->background->linesize[1] * (y >> vsub);
+ const uint8_t *bsrcv = s->background->data[2] + s->background->linesize[2] * (y >> vsub);
+ uint8_t *dst = frame->data[3] + frame->linesize[3] * y;
+ for (int x = 0; x < frame->width; x++) {
+ const int xx = x >> hsub;
+ const int diff = FFABS(srcy[x] - bsrcy[x]) +
+ FFABS(srcu[xx] - bsrcu[xx]) +
+ FFABS(srcv[xx] - bsrcv[xx]);
+ int A;
+
+ sum += diff;
+ if (blend > 0.f) {
+ A = 255 - av_clipf((min_diff - diff) / blend, 0.f, 255.f);
+ } else {
+ A = (diff > min_diff) ? 255 : 0;
+ }
+
+ dst[x] = A;
+ }
+ }
+
+ s->sums[jobnr] = sum;
+
+ return 0;
+}
+
+static int do_backgroundkey16_slice(AVFilterContext *avctx, void *arg, int jobnr, int nb_jobs)
+{
+ BackgroundkeyContext *s = avctx->priv;
+ AVFrame *frame = arg;
+ const int slice_start = (frame->height * jobnr) / nb_jobs;
+ const int slice_end = (frame->height * (jobnr + 1)) / nb_jobs;
+ const int hsub = s->hsub_log2;
+ const int vsub = s->vsub_log2;
+ const int max = s->max;
+ const int min_diff = s->similarity * (s->max + s->max + s->max);
+ const float blend = s->blend;
+ int64_t sum = 0;
+
+ for (int y = slice_start; y < slice_end; y++) {
+ const uint16_t *srcy = (const uint16_t *)(frame->data[0] + frame->linesize[0] * y);
+ const uint16_t *srcu = (const uint16_t *)(frame->data[1] + frame->linesize[1] * (y >> vsub));
+ const uint16_t *srcv = (const uint16_t *)(frame->data[2] + frame->linesize[2] * (y >> vsub));
+ const uint16_t *bsrcy = (const uint16_t *)(s->background->data[0] + s->background->linesize[0] * y);
+ const uint16_t *bsrcu = (const uint16_t *)(s->background->data[1] + s->background->linesize[1] * (y >> vsub));
+ const uint16_t *bsrcv = (const uint16_t *)(s->background->data[2] + s->background->linesize[2] * (y >> vsub));
+ uint16_t *dst = (uint16_t *)(frame->data[3] + frame->linesize[3] * y);
+ for (int x = 0; x < frame->width; x++) {
+ const int xx = x >> hsub;
+ const int diff = FFABS(srcy[x] - bsrcy[x] ) +
+ FFABS(srcu[xx] - bsrcu[xx]) +
+ FFABS(srcv[xx] - bsrcv[xx]);
+ int A;
+
+ sum += diff;
+ if (blend > 0.f) {
+ A = max - av_clipf((min_diff - diff) / blend, 0.f, max);
+ } else {
+ A = (diff > min_diff) ? max : 0;
+ }
+
+ dst[x] = A;
+ }
+ }
+
+ s->sums[jobnr] = sum;
+
+ return 0;
+}
+
+static int filter_frame(AVFilterLink *link, AVFrame *frame)
+{
+ AVFilterContext *avctx = link->dst;
+ BackgroundkeyContext *s = avctx->priv;
+ int64_t sum = 0;
+ int ret = 0;
+
+ if (!s->background) {
+ s->background = ff_get_video_buffer(link, frame->width, frame->height);
+ if (!s->background) {
+ ret = AVERROR(ENOMEM);
+ goto fail;
+ }
+ ret = av_frame_copy(s->background, frame);
+ if (ret < 0)
+ goto fail;
+ }
+
+ if (ret = ff_filter_execute(avctx, s->do_slice, frame, NULL,
+ FFMIN(frame->height, s->nb_threads)))
+ goto fail;
+
+ for (int n = 0; n < s->nb_threads; n++)
+ sum += s->sums[n];
+ if (s->max_sum * s->threshold < sum) {
+ ret = av_frame_copy(s->background, frame);
+ if (ret < 0)
+ goto fail;
+ }
+
+ return ff_filter_frame(avctx->outputs[0], frame);
+fail:
+ av_frame_free(&frame);
+ return ret;
+}
+
+static av_cold int config_output(AVFilterLink *outlink)
+{
+ const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(outlink->format);
+ AVFilterContext *avctx = outlink->src;
+ AVFilterLink *inlink = avctx->inputs[0];
+ BackgroundkeyContext *s = avctx->priv;
+ int depth;
+
+ s->nb_threads = ff_filter_get_nb_threads(avctx);
+ depth = desc->comp[0].depth;
+ s->do_slice = depth <= 8 ? do_backgroundkey_slice : do_backgroundkey16_slice;
+ s->max = (1 << depth) - 1;
+ s->hsub_log2 = desc->log2_chroma_w;
+ s->vsub_log2 = desc->log2_chroma_h;
+ s->max_sum = (int64_t)(inlink->w) * inlink->h * s->max;
+ s->max_sum += 2LL * (inlink->w >> s->hsub_log2) * (inlink->h >> s->vsub_log2) * s->max;
+
+ s->sums = av_calloc(s->nb_threads, sizeof(*s->sums));
+ if (!s->sums)
+ return AVERROR(ENOMEM);
+
+ return 0;
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+ BackgroundkeyContext *s = ctx->priv;
+
+ av_frame_free(&s->background);
+ av_freep(&s->sums);
+}
+
+static const AVFilterPad backgroundkey_inputs[] = {
+ {
+ .name = "default",
+ .type = AVMEDIA_TYPE_VIDEO,
+ .flags = AVFILTERPAD_FLAG_NEEDS_WRITABLE,
+ .filter_frame = filter_frame,
+ },
+};
+
+static const AVFilterPad backgroundkey_outputs[] = {
+ {
+ .name = "default",
+ .type = AVMEDIA_TYPE_VIDEO,
+ .config_props = config_output,
+ },
+};
+
+#define OFFSET(x) offsetof(BackgroundkeyContext, x)
+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
+
+static const AVOption backgroundkey_options[] = {
+ { "threshold", "set the scene change threshold", OFFSET(threshold), AV_OPT_TYPE_FLOAT, { .dbl = 0.08}, 0.0, 1.0, FLAGS },
+ { "similarity", "set the similarity", OFFSET(similarity), AV_OPT_TYPE_FLOAT, { .dbl = 0.1 }, 0.0, 1.0, FLAGS },
+ { "blend", "set the blend value", OFFSET(blend), AV_OPT_TYPE_FLOAT, { .dbl = 0.0 }, 0.0, 1.0, FLAGS },
+ { NULL }
+};
+
+static const enum AVPixelFormat backgroundkey_fmts[] = {
+ AV_PIX_FMT_YUVA420P,
+ AV_PIX_FMT_YUVA422P,
+ AV_PIX_FMT_YUVA444P,
+ AV_PIX_FMT_YUVA420P9, AV_PIX_FMT_YUVA422P9, AV_PIX_FMT_YUVA444P9,
+ AV_PIX_FMT_YUVA420P10, AV_PIX_FMT_YUVA422P10, AV_PIX_FMT_YUVA444P10,
+ AV_PIX_FMT_YUVA422P12, AV_PIX_FMT_YUVA444P12,
+ AV_PIX_FMT_YUVA420P16, AV_PIX_FMT_YUVA422P16, AV_PIX_FMT_YUVA444P16,
+ AV_PIX_FMT_GBRAP,
+ AV_PIX_FMT_GBRAP10, AV_PIX_FMT_GBRAP12, AV_PIX_FMT_GBRAP16,
+ AV_PIX_FMT_NONE
+};
+
+AVFILTER_DEFINE_CLASS(backgroundkey);
+
+const AVFilter ff_vf_backgroundkey = {
+ .name = "backgroundkey",
+ .description = NULL_IF_CONFIG_SMALL("Turns a static background into transparency."),
+ .priv_size = sizeof(BackgroundkeyContext),
+ .priv_class = &backgroundkey_class,
+ .uninit = uninit,
+ FILTER_INPUTS(backgroundkey_inputs),
+ FILTER_OUTPUTS(backgroundkey_outputs),
+ FILTER_PIXFMTS_ARRAY(backgroundkey_fmts),
+ .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
+ .process_command = ff_filter_process_command,
+};
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