[FFmpeg-devel] [PATCH v2 1/3] avfilter/vf_scenechangedetect: add filter to detect scene change
Limin Wang
lance.lmwang at gmail.com
Mon Oct 7 18:10:02 EEST 2019
ping, please give comments.
On Sun, Sep 29, 2019 at 09:25:12PM +0800, lance.lmwang at gmail.com wrote:
> From: Limin Wang <lance.lmwang at gmail.com>
>
> Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> ---
> Please provide a comment to add a new filter for scene change detection to avoid
> multiple calculations of mafd in the filter chain. The filter can avoid duplication
> code also for I am writing a new filter to synchronize frames that require scene
> change information. If the detect metadata can get, the code will be simple.
>
> In addition, I'm trying to add a reduced size before scene change detection to improve
> the performance. From the initial test, we can only get 10-20% improvement, but some
> scene change aren't detected after that. Therefore, I think that should not be done.
>
> This version, I removed the version change for it's easy to cause code conflict,
> please the committer help to update it if review done.
>
> configure | 1 +
> doc/filters.texi | 35 +++++
> libavfilter/Makefile | 1 +
> libavfilter/allfilters.c | 1 +
> libavfilter/vf_scenechangedetect.c | 220 +++++++++++++++++++++++++++++
> 5 files changed, 258 insertions(+)
> create mode 100644 libavfilter/vf_scenechangedetect.c
>
> diff --git a/configure b/configure
> index 8413826f9e..909a77b9cf 100755
> --- a/configure
> +++ b/configure
> @@ -3520,6 +3520,7 @@ sab_filter_deps="gpl swscale"
> scale2ref_filter_deps="swscale"
> scale_filter_deps="swscale"
> scale_qsv_filter_deps="libmfx"
> +scenechangedetect_filter_select="scene_sad"
> select_filter_select="scene_sad"
> sharpness_vaapi_filter_deps="vaapi"
> showcqt_filter_deps="avcodec avformat swscale"
> diff --git a/doc/filters.texi b/doc/filters.texi
> index e6f8bf0ee9..f9247643cb 100644
> --- a/doc/filters.texi
> +++ b/doc/filters.texi
> @@ -15642,6 +15642,41 @@ Scale a logo to 1/10th the height of a video, while preserving its display aspec
> @end example
> @end itemize
>
> + at anchor{scenechangedetect}
> + at section scenechangedetect
> +
> +Detect video scene change.
> +
> +This filter sets frame metadata with mafd between frame, the scene score, and
> +forward the frame to the next filter, so they can use these metadata to detect
> +scene change or others.
> +
> +In addition, this filter logs a message and sets frame metadata when it detects
> +a scene change by @option{threshold}.
> +
> + at code{lavfi.scd.mafd} metadata keys are set with mafd for every frame.
> +
> + at code{lavfi.scd.score} metadata keys are set with scene change score for every frame
> +to detect scene change.
> +
> + at code{lavfi.scd.time} metadata keys are set with current filtered frame time which
> +detect scene change with @option{threshold}.
> +
> +The filter accepts the following options:
> +
> + at table @option
> + at item threshold, t
> +Set the scene change detection threshold as a percentage of maximum change. Good
> +values are in the @code{[8.0, 14.0]} range. The range for @option{threshold} is
> + at code{[0., 100.]}.
> +
> +Default value is @code{10.}.
> +
> + at item sc_pass, s
> +Set the scene change pass the frame to the next filter or not. Default value is @code{0}
> +You can enable it if you want to get snapshot of scene change frames.
> + at end table
> +
> @anchor{selectivecolor}
> @section selectivecolor
>
> diff --git a/libavfilter/Makefile b/libavfilter/Makefile
> index b99ecc8c26..f6c6ba5d45 100644
> --- a/libavfilter/Makefile
> +++ b/libavfilter/Makefile
> @@ -356,6 +356,7 @@ OBJS-$(CONFIG_SCALE_NPP_FILTER) += vf_scale_npp.o scale.o
> OBJS-$(CONFIG_SCALE_QSV_FILTER) += vf_scale_qsv.o
> OBJS-$(CONFIG_SCALE_VAAPI_FILTER) += vf_scale_vaapi.o scale.o vaapi_vpp.o
> OBJS-$(CONFIG_SCALE2REF_FILTER) += vf_scale.o scale.o
> +OBJS-$(CONFIG_SCENECHANGEDETECT_FILTER) += vf_scenechangedetect.o
> OBJS-$(CONFIG_SELECT_FILTER) += f_select.o
> OBJS-$(CONFIG_SELECTIVECOLOR_FILTER) += vf_selectivecolor.o
> OBJS-$(CONFIG_SENDCMD_FILTER) += f_sendcmd.o
> diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
> index 788652ab1e..69a4d5e8e5 100644
> --- a/libavfilter/allfilters.c
> +++ b/libavfilter/allfilters.c
> @@ -338,6 +338,7 @@ extern AVFilter ff_vf_scale_npp;
> extern AVFilter ff_vf_scale_qsv;
> extern AVFilter ff_vf_scale_vaapi;
> extern AVFilter ff_vf_scale2ref;
> +extern AVFilter ff_vf_scenechangedetect;
> extern AVFilter ff_vf_select;
> extern AVFilter ff_vf_selectivecolor;
> extern AVFilter ff_vf_sendcmd;
> diff --git a/libavfilter/vf_scenechangedetect.c b/libavfilter/vf_scenechangedetect.c
> new file mode 100644
> index 0000000000..269fa399d0
> --- /dev/null
> +++ b/libavfilter/vf_scenechangedetect.c
> @@ -0,0 +1,220 @@
> +/*
> + * 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
> + */
> +
> +/**
> + * @file
> + * video scene change detection filter
> + */
> +
> +#include "libavutil/avassert.h"
> +#include "libavutil/imgutils.h"
> +#include "libavutil/opt.h"
> +#include "libavutil/pixdesc.h"
> +#include "libavutil/timestamp.h"
> +
> +#include "avfilter.h"
> +#include "filters.h"
> +#include "scene_sad.h"
> +
> +typedef struct SceneChangeDetectContext {
> + const AVClass *class;
> +
> + ptrdiff_t width[4];
> + ptrdiff_t height[4];
> + int nb_planes;
> + int bitdepth;
> + ff_scene_sad_fn sad;
> + double prev_mafd;
> + double scene_score;
> + AVFrame *prev_picref;
> + double threshold;
> + int sc_pass;
> +} SceneChangeDetectContext;
> +
> +#define OFFSET(x) offsetof(SceneChangeDetectContext, x)
> +#define V AV_OPT_FLAG_VIDEO_PARAM
> +#define F AV_OPT_FLAG_FILTERING_PARAM
> +
> +static const AVOption scenechangedetect_options[] = {
> + { "threshold", "set scene change detect level", OFFSET(threshold), AV_OPT_TYPE_DOUBLE, {.dbl = 10.}, 0, 100., V|F },
> + { "t", "set scene change detect level", OFFSET(threshold), AV_OPT_TYPE_DOUBLE, {.dbl = 10.}, 0, 100., V|F },
> + { "sc_pass", "set scene change frame pass", OFFSET(sc_pass), AV_OPT_TYPE_BOOL, {.dbl = 0 }, 0, 1., V|F },
> + { "s", "set scene change frame pass", OFFSET(sc_pass), AV_OPT_TYPE_BOOL, {.dbl = 0 }, 0, 1., V|F },
> + {NULL}
> +};
> +
> +AVFILTER_DEFINE_CLASS(scenechangedetect);
> +
> +static int query_formats(AVFilterContext *ctx)
> +{
> + static const enum AVPixelFormat pix_fmts[] = {
> + AV_PIX_FMT_RGB24, AV_PIX_FMT_BGR24, AV_PIX_FMT_RGBA,
> + AV_PIX_FMT_ABGR, AV_PIX_FMT_BGRA, AV_PIX_FMT_GRAY8,
> + AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUVJ420P,
> + AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUVJ422P,
> + AV_PIX_FMT_YUV420P10,
> + AV_PIX_FMT_NONE
> + };
> +
> + AVFilterFormats *fmts_list = ff_make_format_list(pix_fmts);
> + if (!fmts_list)
> + return AVERROR(ENOMEM);
> + return ff_set_common_formats(ctx, fmts_list);
> +}
> +
> +static int config_input(AVFilterLink *inlink)
> +{
> + AVFilterContext *ctx = inlink->dst;
> + SceneChangeDetectContext *s = ctx->priv;
> + const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
> + int is_yuv = !(desc->flags & AV_PIX_FMT_FLAG_RGB) &&
> + (desc->flags & AV_PIX_FMT_FLAG_PLANAR) &&
> + desc->nb_components >= 3;
> +
> + s->bitdepth = desc->comp[0].depth;
> + s->nb_planes = is_yuv ? 1 : av_pix_fmt_count_planes(inlink->format);
> +
> + for (int plane = 0; plane < 4; plane++) {
> + ptrdiff_t line_size = av_image_get_linesize(inlink->format, inlink->w, plane);
> + s->width[plane] = line_size >> (s->bitdepth > 8);
> + s->height[plane] = inlink->h >> ((plane == 1 || plane == 2) ? desc->log2_chroma_h : 0);
> + }
> +
> + s->sad = ff_scene_sad_get_fn(s->bitdepth == 8 ? 8 : 16);
> + if (!s->sad)
> + return AVERROR(EINVAL);
> +
> + return 0;
> +}
> +
> +static av_cold void uninit(AVFilterContext *ctx)
> +{
> + SceneChangeDetectContext *s = ctx->priv;
> +
> + av_frame_free(&s->prev_picref);
> +}
> +
> +static double get_scene_score(AVFilterContext *ctx, AVFrame *frame)
> +{
> + double ret = 0;
> + SceneChangeDetectContext *s = ctx->priv;
> + AVFrame *prev_picref = s->prev_picref;
> +
> + if (prev_picref && frame->height == prev_picref->height
> + && frame->width == prev_picref->width) {
> + uint64_t sad = 0;
> + double mafd, diff;
> + uint64_t count = 0;
> +
> + for (int plane = 0; plane < s->nb_planes; plane++) {
> + uint64_t plane_sad;
> + s->sad(prev_picref->data[plane], prev_picref->linesize[plane],
> + frame->data[plane], frame->linesize[plane],
> + s->width[plane], s->height[plane], &plane_sad);
> + sad += plane_sad;
> + count += s->width[plane] * s->height[plane];
> + }
> +
> + emms_c();
> + mafd = (double)sad * 100. / count / (1ULL << s->bitdepth);
> + diff = fabs(mafd - s->prev_mafd);
> + ret = av_clipf(FFMIN(mafd, diff), 0, 100.);
> + s->prev_mafd = mafd;
> + av_frame_free(&prev_picref);
> + }
> + s->prev_picref = av_frame_clone(frame);
> + return ret;
> +}
> +
> +static int set_meta(SceneChangeDetectContext *s, AVFrame *frame, const char *key, const char *value)
> +{
> + return av_dict_set(&frame->metadata, key, value, 0);
> +}
> +
> +static int activate(AVFilterContext *ctx)
> +{
> + int ret;
> + AVFilterLink *inlink = ctx->inputs[0];
> + AVFilterLink *outlink = ctx->outputs[0];
> + SceneChangeDetectContext *s = ctx->priv;
> + AVFrame *frame;
> +
> + FF_FILTER_FORWARD_STATUS_BACK(outlink, inlink);
> +
> + ret = ff_inlink_consume_frame(inlink, &frame);
> + if (ret < 0)
> + return ret;
> +
> + if (frame) {
> + char buf[64];
> + s->scene_score = get_scene_score(ctx, frame);
> + snprintf(buf, sizeof(buf), "%0.3f", s->prev_mafd);
> + set_meta(s, frame, "lavfi.scd.mafd", buf);
> + snprintf(buf, sizeof(buf), "%0.3f", s->scene_score);
> + set_meta(s, frame, "lavfi.scd.score", buf);
> +
> + if (s->scene_score > s->threshold) {
> + av_log(s, AV_LOG_INFO, "lavfi.scd.score: %.3f, lavfi.scd.time: %s\n",
> + s->scene_score, av_ts2timestr(frame->pts, &inlink->time_base));
> + set_meta(s, frame, "lavfi.scd.time",
> + av_ts2timestr(frame->pts, &inlink->time_base));
> + }
> + if (s->sc_pass) {
> + if (s->scene_score > s->threshold)
> + return ff_filter_frame(outlink, frame);
> + else {
> + av_frame_free(&frame);
> + }
> + } else
> + return ff_filter_frame(outlink, frame);
> + }
> +
> + FF_FILTER_FORWARD_STATUS(inlink, outlink);
> + FF_FILTER_FORWARD_WANTED(outlink, inlink);
> +
> + return FFERROR_NOT_READY;
> +}
> +
> +static const AVFilterPad scenechangedetect_inputs[] = {
> + {
> + .name = "default",
> + .type = AVMEDIA_TYPE_VIDEO,
> + .config_props = config_input,
> + },
> + { NULL }
> +};
> +
> +static const AVFilterPad scenechangedetect_outputs[] = {
> + {
> + .name = "default",
> + .type = AVMEDIA_TYPE_VIDEO,
> + },
> + { NULL }
> +};
> +
> +AVFilter ff_vf_scenechangedetect = {
> + .name = "scenechangedetect",
> + .description = NULL_IF_CONFIG_SMALL("Detect video scene change"),
> + .priv_size = sizeof(SceneChangeDetectContext),
> + .priv_class = &scenechangedetect_class,
> + .uninit = uninit,
> + .query_formats = query_formats,
> + .inputs = scenechangedetect_inputs,
> + .outputs = scenechangedetect_outputs,
> + .activate = activate,
> +};
> --
> 2.21.0
>
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