avfilter: add weave filter

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

Changelog

@@ -24,6 +24,7 @@ version <next>:
 - yuvtestsrc filter
 - vaguedenoiser filter
 - added threads option per filter instance
+- weave filter
 
 
 version 3.1:

doc/filters.texi

@@ -14104,6 +14104,27 @@ Set scale used for displaying graticule.
 Default is digital.
 @end table
 
+@section weave
+
+The @code{weave} takes a field-based video input and join
+each two sequential fields into single frame, producing a new double
+height clip with half the frame rate and half the frame count.
+
+It accepts the following option:
+
+@table @option
+@item first_field
+Set first field. Available values are:
+
+@table @samp
+@item top, t
+Set the frame as top-field-first.
+
+@item bottom, b
+Set the frame as bottom-field-first.
+@end table
+@end table
+
 @section xbr
 Apply the xBR high-quality magnification filter which is designed for pixel
 art. It follows a set of edge-detection rules, see

libavfilter/Makefile

@@ -295,6 +295,7 @@ OBJS-$(CONFIG_VIGNETTE_FILTER)               += vf_vignette.o
 OBJS-$(CONFIG_VSTACK_FILTER)                 += vf_stack.o framesync.o
 OBJS-$(CONFIG_W3FDIF_FILTER)                 += vf_w3fdif.o
 OBJS-$(CONFIG_WAVEFORM_FILTER)               += vf_waveform.o
+OBJS-$(CONFIG_WEAVE_FILTER)                  += vf_weave.o
 OBJS-$(CONFIG_XBR_FILTER)                    += vf_xbr.o
 OBJS-$(CONFIG_YADIF_FILTER)                  += vf_yadif.o
 OBJS-$(CONFIG_ZMQ_FILTER)                    += f_zmq.o

libavfilter/allfilters.c

@@ -311,6 +311,7 @@ void avfilter_register_all(void)
     REGISTER_FILTER(VSTACK,         vstack,         vf);
     REGISTER_FILTER(W3FDIF,         w3fdif,         vf);
     REGISTER_FILTER(WAVEFORM,       waveform,       vf);
+    REGISTER_FILTER(WEAVE,          weave,          vf);
     REGISTER_FILTER(XBR,            xbr,            vf);
     REGISTER_FILTER(YADIF,          yadif,          vf);
     REGISTER_FILTER(ZMQ,            zmq,            vf);

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   6
-#define LIBAVFILTER_VERSION_MINOR  58
+#define LIBAVFILTER_VERSION_MINOR  59
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

libavfilter/vf_weave.c

@@ -0,0 +1,143 @@
+/*
+ * Copyright (c) 2013 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/imgutils.h"
+#include "libavutil/opt.h"
+#include "libavutil/pixdesc.h"
+#include "avfilter.h"
+#include "internal.h"
+
+typedef struct WeaveContext {
+    const AVClass *class;
+    int first_field;
+    int nb_planes;
+    int planeheight[4];
+    int linesize[4];
+
+    AVFrame *prev;
+} WeaveContext;
+
+#define OFFSET(x) offsetof(WeaveContext, x)
+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
+
+static const AVOption weave_options[] = {
+    { "first_field", "set first field", OFFSET(first_field), AV_OPT_TYPE_INT,   {.i64=0}, 0, 1, FLAGS, "field"},
+        { "top",     "set top field first",               0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, "field"},
+        { "t",       "set top field first",               0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, FLAGS, "field"},
+        { "bottom",  "set bottom field first",            0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, FLAGS, "field"},
+        { "b",       "set bottom field first",            0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, FLAGS, "field"},
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(weave);
+
+static int config_props_output(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    WeaveContext *s = ctx->priv;
+    AVFilterLink *inlink = ctx->inputs[0];
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(inlink->format);
+    int ret;
+
+    outlink->time_base.num = inlink->time_base.num * 2;
+    outlink->time_base.den = inlink->time_base.den;
+    outlink->frame_rate.num = inlink->frame_rate.num;
+    outlink->frame_rate.den = inlink->frame_rate.den * 2;
+    outlink->w = inlink->w;
+    outlink->h = inlink->h * 2;
+
+    if ((ret = av_image_fill_linesizes(s->linesize, inlink->format, inlink->w)) < 0)
+        return ret;
+
+    s->planeheight[1] = s->planeheight[2] = AV_CEIL_RSHIFT(inlink->h, desc->log2_chroma_h);
+    s->planeheight[0] = s->planeheight[3] = inlink->h;
+
+    s->nb_planes = av_pix_fmt_count_planes(inlink->format);
+
+    return 0;
+}
+
+static int filter_frame(AVFilterLink *inlink, AVFrame *in)
+{
+    AVFilterContext *ctx = inlink->dst;
+    WeaveContext *s = ctx->priv;
+    AVFilterLink *outlink = ctx->outputs[0];
+    AVFrame *out;
+    int i;
+
+    if (!s->prev) {
+        s->prev = in;
+        return 0;
+    }
+
+    out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
+    if (!out) {
+        av_frame_free(&in);
+        av_frame_free(&s->prev);
+        return AVERROR(ENOMEM);
+    }
+    av_frame_copy_props(out, in);
+
+    for (i = 0; i < s->nb_planes; i++) {
+        av_image_copy_plane(out->data[i] + out->linesize[i] * s->first_field,
+                            out->linesize[i] * 2,
+                            in->data[i], in->linesize[i],
+                            s->linesize[i], s->planeheight[i]);
+        av_image_copy_plane(out->data[i] + out->linesize[i] * !s->first_field,
+                            out->linesize[i] * 2,
+                            s->prev->data[i], s->prev->linesize[i],
+                            s->linesize[i], s->planeheight[i]);
+    }
+
+    out->pts = in->pts / 2;
+    out->interlaced_frame = 1;
+    out->top_field_first = !s->first_field;
+
+    av_frame_free(&in);
+    av_frame_free(&s->prev);
+    return ff_filter_frame(outlink, out);
+}
+
+static const AVFilterPad weave_inputs[] = {
+    {
+        .name             = "default",
+        .type             = AVMEDIA_TYPE_VIDEO,
+        .filter_frame     = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad weave_outputs[] = {
+    {
+        .name          = "default",
+        .type          = AVMEDIA_TYPE_VIDEO,
+        .config_props  = config_props_output,
+    },
+    { NULL }
+};
+
+AVFilter ff_vf_weave = {
+    .name          = "weave",
+    .description   = NULL_IF_CONFIG_SMALL("Weave input video fields into frames."),
+    .priv_size     = sizeof(WeaveContext),
+    .priv_class    = &weave_class,
+    .inputs        = weave_inputs,
+    .outputs       = weave_outputs,
+};