avfilter/vf_freezedetect: add filter to detect frozen input

Signed-off-by: Marton Balint <cus@passwd.hu>

Changelog

@@ -6,6 +6,7 @@ version <next>:
 - AV1 decoding support through libdav1d
 - dedot filter
 - chromashift and rgbashift filters
+- freezedetect filter
 
 
 version 4.1:

configure

@@ -3403,6 +3403,7 @@ firequalizer_filter_deps="avcodec"
 firequalizer_filter_select="rdft"
 flite_filter_deps="libflite"
 framerate_filter_select="scene_sad"
+freezedetect_filter_select="scene_sad"
 frei0r_filter_deps="frei0r libdl"
 frei0r_src_filter_deps="frei0r libdl"
 fspp_filter_deps="gpl"

doc/filters.texi

@@ -10069,6 +10069,35 @@ Select frame after every @code{step} frames.
 Allowed values are positive integers higher than 0. Default value is @code{1}.
 @end table
 
+@section freezedetect
+
+Detect frozen video.
+
+This filter logs a message and sets frame metadata when it detects that the
+input video has no significant change in content during a specified duration.
+Video freeze detection calculates the mean average absolute difference of all
+the components of video frames and compares it to a noise floor.
+
+The printed times and duration are expressed in seconds. The
+@code{lavfi.freezedetect.freeze_start} metadata key is set on the first frame
+whose timestamp equals or exceeds the detection duration and it contains the
+timestamp of the first frame of the freeze. The
+@code{lavfi.freezedetect.freeze_duration} and
+@code{lavfi.freezedetect.freeze_end} metadata keys are set on the first frame
+after the freeze.
+
+The filter accepts the following options:
+
+@table @option
+@item noise, n
+Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
+specified value) or as a difference ratio between 0 and 1. Default is -60dB, or
+0.001.
+
+@item duration, d
+Set freeze duration until notification (default is 2 seconds).
+@end table
+
 @anchor{frei0r}
 @section frei0r
 

libavfilter/Makefile

@@ -238,6 +238,7 @@ OBJS-$(CONFIG_FPS_FILTER)                    += vf_fps.o
 OBJS-$(CONFIG_FRAMEPACK_FILTER)              += vf_framepack.o
 OBJS-$(CONFIG_FRAMERATE_FILTER)              += vf_framerate.o
 OBJS-$(CONFIG_FRAMESTEP_FILTER)              += vf_framestep.o
+OBJS-$(CONFIG_FREEZEDETECT_FILTER)           += vf_freezedetect.o
 OBJS-$(CONFIG_FREI0R_FILTER)                 += vf_frei0r.o
 OBJS-$(CONFIG_FSPP_FILTER)                   += vf_fspp.o
 OBJS-$(CONFIG_GBLUR_FILTER)                  += vf_gblur.o

libavfilter/allfilters.c

@@ -224,6 +224,7 @@ extern AVFilter ff_vf_fps;
 extern AVFilter ff_vf_framepack;
 extern AVFilter ff_vf_framerate;
 extern AVFilter ff_vf_framestep;
+extern AVFilter ff_vf_freezedetect;
 extern AVFilter ff_vf_frei0r;
 extern AVFilter ff_vf_fspp;
 extern AVFilter ff_vf_gblur;

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   7
-#define LIBAVFILTER_VERSION_MINOR  45
+#define LIBAVFILTER_VERSION_MINOR  46
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

libavfilter/vf_freezedetect.c

@@ -0,0 +1,236 @@
+/*
+ * 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 freeze 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 FreezeDetectContext {
+    const AVClass *class;
+
+    ptrdiff_t width[4];
+    ptrdiff_t height[4];
+    ff_scene_sad_fn sad;
+    int bitdepth;
+    AVFrame *reference_frame;
+    int64_t n;
+    int64_t reference_n;
+    int frozen;
+
+    double noise;
+    int64_t duration;            ///< minimum duration of frozen frame until notification
+} FreezeDetectContext;
+
+#define OFFSET(x) offsetof(FreezeDetectContext, x)
+#define V AV_OPT_FLAG_VIDEO_PARAM
+#define F AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption freezedetect_options[] = {
+    { "n",                   "set noise tolerance",                       OFFSET(noise),  AV_OPT_TYPE_DOUBLE,   {.dbl=0.001},     0,       1.0, V|F },
+    { "noise",               "set noise tolerance",                       OFFSET(noise),  AV_OPT_TYPE_DOUBLE,   {.dbl=0.001},     0,       1.0, V|F },
+    { "d",                   "set minimum duration in seconds",        OFFSET(duration),  AV_OPT_TYPE_DURATION, {.i64=2000000},   0, INT64_MAX, V|F },
+    { "duration",            "set minimum duration in seconds",        OFFSET(duration),  AV_OPT_TYPE_DURATION, {.i64=2000000},   0, INT64_MAX, V|F },
+
+    {NULL}
+};
+
+AVFILTER_DEFINE_CLASS(freezedetect);
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum AVPixelFormat pix_fmts[] = {
+        AV_PIX_FMT_YUV420P, AV_PIX_FMT_YUYV422, AV_PIX_FMT_RGB24,
+        AV_PIX_FMT_BGR24, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUV444P,
+        AV_PIX_FMT_YUV410P, AV_PIX_FMT_YUV411P, AV_PIX_FMT_GRAY8,
+        AV_PIX_FMT_YUVJ420P, AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ444P,
+        AV_PIX_FMT_UYVY422, AV_PIX_FMT_NV12, AV_PIX_FMT_NV21, AV_PIX_FMT_ARGB,
+        AV_PIX_FMT_RGBA, AV_PIX_FMT_ABGR, AV_PIX_FMT_BGRA, AV_PIX_FMT_GRAY16,
+        AV_PIX_FMT_YUV440P, AV_PIX_FMT_YUVJ440P, AV_PIX_FMT_YUVA420P,
+        AV_PIX_FMT_YUV420P16, AV_PIX_FMT_YUV422P16, AV_PIX_FMT_YUV444P16,
+        AV_PIX_FMT_YA8, AV_PIX_FMT_YUV420P9, AV_PIX_FMT_YUV420P10,
+        AV_PIX_FMT_YUV422P10, AV_PIX_FMT_YUV444P9, AV_PIX_FMT_YUV444P10,
+        AV_PIX_FMT_YUV422P9, AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRP9,
+        AV_PIX_FMT_GBRP10, AV_PIX_FMT_GBRP16, 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_YUVA420P16, AV_PIX_FMT_YUVA422P16,
+        AV_PIX_FMT_YUVA444P16, AV_PIX_FMT_NV16, AV_PIX_FMT_YVYU422,
+        AV_PIX_FMT_GBRAP, AV_PIX_FMT_GBRAP16, AV_PIX_FMT_YUV420P12,
+        AV_PIX_FMT_YUV420P14, AV_PIX_FMT_YUV422P12, AV_PIX_FMT_YUV422P14,
+        AV_PIX_FMT_YUV444P12, AV_PIX_FMT_YUV444P14, AV_PIX_FMT_GBRP12,
+        AV_PIX_FMT_GBRP14, AV_PIX_FMT_YUVJ411P, AV_PIX_FMT_YUV440P10,
+        AV_PIX_FMT_YUV440P12, AV_PIX_FMT_GBRAP12, AV_PIX_FMT_GBRAP10,
+        AV_PIX_FMT_GRAY12, AV_PIX_FMT_GRAY10, AV_PIX_FMT_GRAY9,
+        AV_PIX_FMT_GRAY14,
+        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;
+    FreezeDetectContext *s = ctx->priv;
+    const AVPixFmtDescriptor *pix_desc = av_pix_fmt_desc_get(inlink->format);
+
+    s->bitdepth = pix_desc->comp[0].depth;
+
+    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) ? pix_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)
+{
+    FreezeDetectContext *s = ctx->priv;
+    av_frame_free(&s->reference_frame);
+}
+
+static int is_frozen(FreezeDetectContext *s, AVFrame *reference, AVFrame *frame)
+{
+    uint64_t sad = 0;
+    uint64_t count = 0;
+    double mafd;
+    for (int plane = 0; plane < 4; plane++) {
+        if (s->width[plane]) {
+            uint64_t plane_sad;
+            s->sad(frame->data[plane], frame->linesize[plane],
+                   reference->data[plane], reference->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 / count / (1ULL << s->bitdepth);
+    return (mafd <= s->noise);
+}
+
+static int set_meta(FreezeDetectContext *s, AVFrame *frame, const char *key, const char *value)
+{
+    av_log(s, AV_LOG_INFO, "%s: %s\n", key, 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];
+    FreezeDetectContext *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) {
+        int frozen = 0;
+        s->n++;
+
+        if (s->reference_frame) {
+            int64_t duration;
+            if (s->reference_frame->pts == AV_NOPTS_VALUE || frame->pts == AV_NOPTS_VALUE || frame->pts < s->reference_frame->pts)     // Discontinuity?
+                duration = inlink->frame_rate.num > 0 ? av_rescale_q(s->n - s->reference_n, av_inv_q(inlink->frame_rate), AV_TIME_BASE_Q) : 0;
+            else
+                duration = av_rescale_q(frame->pts - s->reference_frame->pts, inlink->time_base, AV_TIME_BASE_Q);
+
+            frozen = is_frozen(s, s->reference_frame, frame);
+            if (duration >= s->duration) {
+                if (frozen) {
+                    if (!s->frozen)
+                        set_meta(s, frame, "lavfi.freezedetect.freeze_start", av_ts2timestr(s->reference_frame->pts, &inlink->time_base));
+                } else {
+                    set_meta(s, frame, "lavfi.freezedetect.freeze_duration", av_ts2timestr(duration, &AV_TIME_BASE_Q));
+                    set_meta(s, frame, "lavfi.freezedetect.freeze_end", av_ts2timestr(frame->pts, &inlink->time_base));
+                }
+                s->frozen = frozen;
+            }
+        }
+
+        if (!frozen) {
+            av_frame_free(&s->reference_frame);
+            s->reference_frame = av_frame_clone(frame);
+            s->reference_n = s->n;
+            if (!s->reference_frame) {
+                av_frame_free(&frame);
+                return AVERROR(ENOMEM);
+            }
+        }
+        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 freezedetect_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .config_props = config_input,
+    },
+    { NULL }
+};
+
+static const AVFilterPad freezedetect_outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+    },
+    { NULL }
+};
+
+AVFilter ff_vf_freezedetect = {
+    .name          = "freezedetect",
+    .description   = NULL_IF_CONFIG_SMALL("Detects frozen video input."),
+    .priv_size     = sizeof(FreezeDetectContext),
+    .priv_class    = &freezedetect_class,
+    .uninit        = uninit,
+    .query_formats = query_formats,
+    .inputs        = freezedetect_inputs,
+    .outputs       = freezedetect_outputs,
+    .activate      = activate,
+};