[FFmpeg-devel] [PATCH v2 1/3] avfilter/vf_scenechangedetect: add filter to detect scene change

Limin Wang lance.lmwang at gmail.com
Tue Oct 8 03:50:00 EEST 2019


On Mon, Oct 07, 2019 at 09:00:10PM +0200, Paul B Mahol wrote:

> Too long filter name.
Yes, the name is too long, how about to use scdetect?  If it's OK, I'll
update the patch.

> 
> On 10/7/19, Limin Wang <lance.lmwang at gmail.com> wrote:
> >
> > 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
> >>
> > _______________________________________________
> > ffmpeg-devel mailing list
> > ffmpeg-devel at ffmpeg.org
> > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> >
> > To unsubscribe, visit link above, or email
> > ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> 
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".


More information about the ffmpeg-devel mailing list