avfilter: add vfrdet filter

Signed-off-by: Paul B Mahol <onemda@gmail.com>

Changelog

@@ -53,6 +53,7 @@ version <next>:
 - bitstream filter for extracting E-AC-3 core
 - Haivision SRT protocol via libsrt
 - segafilm muxer
+- vfrdet filter
 
 
 version 3.4:

doc/filters.texi

@@ -16248,6 +16248,17 @@ For example, to vertically flip a video with @command{ffmpeg}:
 ffmpeg -i in.avi -vf "vflip" out.avi
 @end example
 
+@section vfrdet
+
+Detect variable frame rate video.
+
+This filter tries to detect if the input is variable or constant frame rate.
+
+At end it will output number of frames detected as having variable delta pts,
+and ones with constant delta pts.
+If there was frames with variable delta, than it will also show min and max delta
+encountered.
+
 @anchor{vignette}
 @section vignette
 

libavfilter/Makefile

@@ -353,6 +353,7 @@ OBJS-$(CONFIG_USPP_FILTER)                   += vf_uspp.o
 OBJS-$(CONFIG_VAGUEDENOISER_FILTER)          += vf_vaguedenoiser.o
 OBJS-$(CONFIG_VECTORSCOPE_FILTER)            += vf_vectorscope.o
 OBJS-$(CONFIG_VFLIP_FILTER)                  += vf_vflip.o
+OBJS-$(CONFIG_VFRDET_FILTER)                 += vf_vfrdet.o
 OBJS-$(CONFIG_VIDSTABDETECT_FILTER)          += vidstabutils.o vf_vidstabdetect.o
 OBJS-$(CONFIG_VIDSTABTRANSFORM_FILTER)       += vidstabutils.o vf_vidstabtransform.o
 OBJS-$(CONFIG_VIGNETTE_FILTER)               += vf_vignette.o

libavfilter/allfilters.c

@@ -343,6 +343,7 @@ extern AVFilter ff_vf_uspp;
 extern AVFilter ff_vf_vaguedenoiser;
 extern AVFilter ff_vf_vectorscope;
 extern AVFilter ff_vf_vflip;
+extern AVFilter ff_vf_vfrdet;
 extern AVFilter ff_vf_vidstabdetect;
 extern AVFilter ff_vf_vidstabtransform;
 extern AVFilter ff_vf_vignette;

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   7
-#define LIBAVFILTER_VERSION_MINOR  14
+#define LIBAVFILTER_VERSION_MINOR  15
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

libavfilter/vf_vfrdet.c

+/*
+ * Copyright (C) 2017 Paul B Mahol
+ *
+ * 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/common.h"
+#include "libavutil/opt.h"
+#include "internal.h"
+
+typedef struct VFRDETContext {
+    const AVClass *class;
+
+    int64_t prev_pts;
+    int64_t delta;
+    int64_t min_delta;
+    int64_t max_delta;
+
+    uint64_t vfr;
+    uint64_t cfr;
+} VFRDETContext;
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *in)
+{
+    AVFilterContext *ctx = inlink->dst;
+    VFRDETContext *s = ctx->priv;
+
+    if (s->prev_pts != AV_NOPTS_VALUE) {
+        int64_t delta = in->pts - s->prev_pts;
+
+        if (s->delta == AV_NOPTS_VALUE) {
+            s->delta = delta;
+        }
+
+        if (s->delta != delta) {
+            s->vfr++;
+            s->delta = delta;
+            s->min_delta = FFMIN(delta, s->min_delta);
+            s->max_delta = FFMAX(delta, s->max_delta);
+        } else {
+            s->cfr++;
+        }
+    }
+
+    s->prev_pts = in->pts;
+
+    return ff_filter_frame(ctx->outputs[0], in);
+}
+
+static av_cold int init(AVFilterContext *ctx)
+{
+    VFRDETContext *s = ctx->priv;
+
+    s->prev_pts = AV_NOPTS_VALUE;
+    s->delta    = AV_NOPTS_VALUE;
+    s->min_delta = INT64_MAX;
+    s->max_delta = INT64_MIN;
+
+    return 0;
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    VFRDETContext *s = ctx->priv;
+
+    av_log(ctx, AV_LOG_INFO, "VFR:%f (%"PRIu64"/%"PRIu64")", s->vfr / (float)(s->vfr + s->cfr), s->vfr, s->cfr);
+    if (s->vfr)
+        av_log(ctx, AV_LOG_INFO, " min: %"PRId64" max: %"PRId64")", s->min_delta, s->max_delta);
+    av_log(ctx, AV_LOG_INFO, "\n");
+}
+
+static const AVFilterPad vfrdet_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .filter_frame = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad vfrdet_outputs[] = {
+    {
+        .name = "default",
+        .type = AVMEDIA_TYPE_VIDEO,
+    },
+    { NULL }
+};
+
+AVFilter ff_vf_vfrdet = {
+    .name        = "vfrdet",
+    .description = NULL_IF_CONFIG_SMALL("Variable frame rate detect filter."),
+    .priv_size   = sizeof(VFRDETContext),
+    .init        = init,
+    .uninit      = uninit,
+    .inputs      = vfrdet_inputs,
+    .outputs     = vfrdet_outputs,
+};