[FFmpeg-devel] avfilter: add tdisplace filter

diff --git a/doc/filters.texi b/doc/filters.texi
index 5cebb26cbd..5d3a36e49f 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -17233,6 +17233,27 @@  the position in the file of the input frame, NAN if unknown
 @section swapuv
 Swap U & V plane.
 
+@section tdisplace
+
+Displace pixels temporally as indicated by second stream.
+
+It takes two input streams and outputs one stream, the first input is the
+source, and second input in temporal displacement map.
+
+The second input specifies how much to displace pixels along the
+time-axis.
+If temporal displacement map stream terminates, last frame from that stream
+will be used.
+
+This filter accepts the following options:
+
+@table @option
+@item edge
+Set temporal displacement radius. Any value present in temporal displacement
+map which is higher/lower than this one will be clipped.
+Allowed range is from 1 to 127. Default is 127.
+@end table
+
 @section telecine
 
 Apply telecine process to the video.
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index e9ac54daee..a76347af45 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -394,6 +394,7 @@  OBJS-$(CONFIG_SUPER2XSAI_FILTER)             += vf_super2xsai.o
 OBJS-$(CONFIG_SWAPRECT_FILTER)               += vf_swaprect.o
 OBJS-$(CONFIG_SWAPUV_FILTER)                 += vf_swapuv.o
 OBJS-$(CONFIG_TBLEND_FILTER)                 += vf_blend.o framesync.o
+OBJS-$(CONFIG_TDISPLACE_FILTER)              += vf_tdisplace.o framesync.o
 OBJS-$(CONFIG_TELECINE_FILTER)               += vf_telecine.o
 OBJS-$(CONFIG_THRESHOLD_FILTER)              += vf_threshold.o framesync.o
 OBJS-$(CONFIG_THUMBNAIL_FILTER)              += vf_thumbnail.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index a7a165e0d8..a04dcfbf5b 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -375,6 +375,7 @@  extern AVFilter ff_vf_super2xsai;
 extern AVFilter ff_vf_swaprect;
 extern AVFilter ff_vf_swapuv;
 extern AVFilter ff_vf_tblend;
+extern AVFilter ff_vf_tdisplace;
 extern AVFilter ff_vf_telecine;
 extern AVFilter ff_vf_threshold;
 extern AVFilter ff_vf_thumbnail;
diff --git a/libavfilter/vf_tdisplace.c b/libavfilter/vf_tdisplace.c
new file mode 100644
index 0000000000..abf4beba11
--- /dev/null
+++ b/libavfilter/vf_tdisplace.c
@@ -0,0 +1,234 @@ 
+/*
+ * Copyright (c) 2019 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/opt.h"
+#include "libavutil/pixdesc.h"
+#include "avfilter.h"
+#include "filters.h"
+#include "formats.h"
+#include "framesync.h"
+#include "internal.h"
+#include "video.h"
+
+#define MAX_RADIUS 127
+#define MAX_FRAMES (MAX_RADIUS * 2 + 1)
+
+typedef struct TDisplaceContext {
+    const AVClass *class;
+    int radius;
+
+    int max_frames;
+
+    int planewidth[4], planeheight[4];
+    int nb_planes;
+
+    AVFrame *frames[MAX_FRAMES];
+    int nb_frames;
+
+    FFFrameSync fs;
+} TDisplaceContext;
+
+#define OFFSET(x) offsetof(TDisplaceContext, x)
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+
+static const AVOption tdisplace_options[] = {
+    { "radius", "set temporal radius", OFFSET(radius), AV_OPT_TYPE_INT, {.i64=MAX_RADIUS}, 1, MAX_RADIUS, FLAGS },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(tdisplace);
+
+static int tdisplace_frame(FFFrameSync *fs)
+{
+    AVFilterContext *ctx = fs->parent;
+    AVFilterLink *outlink = ctx->outputs[0];
+    TDisplaceContext *s = ctx->priv;
+    AVFrame *in, *tmap, *out;
+    int ret;
+
+    ret = ff_framesync_dualinput_get(fs, &in, &tmap);
+    if (ret < 0)
+        return ret;
+
+    if (s->nb_frames < s->max_frames) {
+        s->frames[s->nb_frames] = in;
+        if (s->frames[s->nb_frames])
+            s->nb_frames++;
+    } else {
+        av_frame_free(&s->frames[0]);
+        memmove(&s->frames[0], &s->frames[1], (s->nb_frames - 1) * sizeof(s->frames[0]));
+        s->frames[s->max_frames - 1] = in;
+        if (!s->frames[s->max_frames - 1])
+            s->nb_frames--;
+    }
+
+    out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
+    if (!out)
+        return AVERROR(ENOMEM);
+    av_frame_copy_props(out, in);
+
+    for (int p = 0; p < s->nb_planes; p++) {
+        uint8_t *dst = out->data[p];
+        const uint8_t *tsrc = tmap->data[p];
+        const int tlinesize = tmap->linesize[p];
+        const int dlinesize = out->linesize[p];
+        const int half = (s->nb_frames + 1) >> 1;
+
+        for (int y = 0; y < s->planeheight[p]; y++) {
+            for (int x = 0; x < s->planewidth[p]; x++) {
+                const int frame = tsrc[x] - s->max_frames / 2;
+                const int index = av_clip(half + frame, 0, s->nb_frames - 1);
+                const int linesize = s->frames[index]->linesize[p];
+
+                dst[x] = s->frames[index]->data[p][linesize * y + x];
+            }
+
+            tsrc += tlinesize;
+            dst += dlinesize;
+        }
+    }
+
+    return ff_filter_frame(outlink, out);
+}
+
+static av_cold int init(AVFilterContext *ctx)
+{
+    TDisplaceContext *s = ctx->priv;
+
+    s->max_frames  = s->radius * 2 + 1;
+    s->fs.on_event = tdisplace_frame;
+
+    return 0;
+}
+
+static int query_formats(AVFilterContext *ctx)
+{
+    static const enum AVPixelFormat pix_fmts[] = {
+        AV_PIX_FMT_YUVA444P, AV_PIX_FMT_YUV444P, AV_PIX_FMT_YUV440P,
+        AV_PIX_FMT_YUVJ444P, AV_PIX_FMT_YUVJ440P,
+        AV_PIX_FMT_YUVA422P, AV_PIX_FMT_YUV422P, AV_PIX_FMT_YUVA420P, AV_PIX_FMT_YUV420P,
+        AV_PIX_FMT_YUVJ422P, AV_PIX_FMT_YUVJ420P,
+        AV_PIX_FMT_YUVJ411P, AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV410P,
+        AV_PIX_FMT_GBRP, AV_PIX_FMT_GBRAP,
+        AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE
+    };
+
+    return ff_set_common_formats(ctx, ff_make_format_list(pix_fmts));
+}
+
+static int config_output(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    TDisplaceContext *s = ctx->priv;
+    AVFilterLink *srclink = ctx->inputs[0];
+    AVFilterLink *tlink = ctx->inputs[1];
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(outlink->format);
+    int ret, vsub, hsub;
+
+    if (srclink->format != tlink->format) {
+        av_log(ctx, AV_LOG_ERROR, "inputs must be of same pixel format\n");
+        return AVERROR(EINVAL);
+    }
+    if (srclink->w != tlink->w ||
+        srclink->h != tlink->h) {
+        av_log(ctx, AV_LOG_ERROR, "First input link %s parameters "
+               "(size %dx%d) do not match the corresponding "
+               "second input link %s parameters (%dx%d)\n",
+               ctx->input_pads[0].name, srclink->w, srclink->h,
+               ctx->input_pads[1].name, tlink->w, tlink->h);
+        return AVERROR(EINVAL);
+    }
+
+    outlink->w = srclink->w;
+    outlink->h = srclink->h;
+    outlink->time_base = srclink->time_base;
+    outlink->sample_aspect_ratio = srclink->sample_aspect_ratio;
+    outlink->frame_rate = srclink->frame_rate;
+
+    s->nb_planes = av_pix_fmt_count_planes(outlink->format);
+
+    hsub = desc->log2_chroma_w;
+    vsub = desc->log2_chroma_h;
+
+    s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(outlink->h, vsub);
+    s->planeheight[0] = s->planeheight[3] = outlink->h;
+    s->planewidth[1]  = s->planewidth[2]  = AV_CEIL_RSHIFT(outlink->w, hsub);
+    s->planewidth[0]  = s->planewidth[3]  = outlink->w;
+
+    if ((ret = ff_framesync_init_dualinput(&s->fs, ctx)) < 0)
+        return ret;
+
+    ret = ff_framesync_configure(&s->fs);
+    outlink->time_base = s->fs.time_base;
+
+    return ret;
+}
+
+static int activate(AVFilterContext *ctx)
+{
+    TDisplaceContext *s = ctx->priv;
+    return ff_framesync_activate(&s->fs);
+}
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    TDisplaceContext *s = ctx->priv;
+
+    ff_framesync_uninit(&s->fs);
+
+    for (int i = 0; i < s->nb_frames; i++) {
+        av_frame_free(&s->frames[i]);
+    }
+    s->nb_frames = 0;
+}
+
+static const AVFilterPad tdisplace_inputs[] = {
+    {
+        .name         = "in",
+        .type         = AVMEDIA_TYPE_VIDEO,
+    },
+    {
+        .name         = "tmap",
+        .type         = AVMEDIA_TYPE_VIDEO,
+    },
+    { NULL }
+};
+
+static const AVFilterPad tdisplace_outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+        .config_props  = config_output,
+    },
+    { NULL }
+};
+
+AVFilter ff_vf_tdisplace = {
+    .name          = "tdisplace",
+    .description   = NULL_IF_CONFIG_SMALL("Temporal pixel displacement."),
+    .priv_size     = sizeof(TDisplaceContext),
+    .priv_class    = &tdisplace_class,
+    .query_formats = query_formats,
+    .init          = init,
+    .uninit        = uninit,
+    .activate      = activate,
+    .inputs        = tdisplace_inputs,
+    .outputs       = tdisplace_outputs,
+};