[FFmpeg-devel,09/16] lavfi/vf_blend: convert to framesync2.

diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 75a73c4cc0..13c0c2dbd2 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -136,7 +136,7 @@  OBJS-$(CONFIG_BENCH_FILTER)                  += f_bench.o
 OBJS-$(CONFIG_BITPLANENOISE_FILTER)          += vf_bitplanenoise.o
 OBJS-$(CONFIG_BLACKDETECT_FILTER)            += vf_blackdetect.o
 OBJS-$(CONFIG_BLACKFRAME_FILTER)             += vf_blackframe.o
-OBJS-$(CONFIG_BLEND_FILTER)                  += vf_blend.o dualinput.o framesync.o
+OBJS-$(CONFIG_BLEND_FILTER)                  += vf_blend.o framesync2.o
 OBJS-$(CONFIG_BOXBLUR_FILTER)                += vf_boxblur.o
 OBJS-$(CONFIG_BWDIF_FILTER)                  += vf_bwdif.o
 OBJS-$(CONFIG_CHROMAKEY_FILTER)              += vf_chromakey.o
@@ -307,7 +307,7 @@  OBJS-$(CONFIG_SUBTITLES_FILTER)              += vf_subtitles.o
 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 dualinput.o framesync.o
+OBJS-$(CONFIG_TBLEND_FILTER)                 += vf_blend.o framesync2.o
 OBJS-$(CONFIG_TELECINE_FILTER)               += vf_telecine.o
 OBJS-$(CONFIG_THRESHOLD_FILTER)              += vf_threshold.o framesync2.o
 OBJS-$(CONFIG_THUMBNAIL_FILTER)              += vf_thumbnail.o
diff --git a/libavfilter/vf_blend.c b/libavfilter/vf_blend.c
index 9bde3b22a1..24f8729892 100644
--- a/libavfilter/vf_blend.c
+++ b/libavfilter/vf_blend.c
@@ -25,8 +25,8 @@ 
 #include "avfilter.h"
 #include "bufferqueue.h"
 #include "formats.h"
+#include "framesync2.h"
 #include "internal.h"
-#include "dualinput.h"
 #include "video.h"
 #include "blend.h"
 
@@ -35,7 +35,7 @@ 
 
 typedef struct BlendContext {
     const AVClass *class;
-    FFDualInputContext dinput;
+    FFFrameSync fs;
     int hsub, vsub;             ///< chroma subsampling values
     int nb_planes;
     char *all_expr;
@@ -114,12 +114,10 @@  typedef struct ThreadData {
 
 static const AVOption blend_options[] = {
     COMMON_OPTIONS,
-    { "shortest",    "force termination when the shortest input terminates", OFFSET(dinput.shortest), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, FLAGS },
-    { "repeatlast",  "repeat last bottom frame", OFFSET(dinput.repeatlast), AV_OPT_TYPE_BOOL, {.i64=1}, 0, 1, FLAGS },
     { NULL }
 };
 
-AVFILTER_DEFINE_CLASS(blend);
+FRAMESYNC_DEFINE_CLASS(blend, BlendContext, fs);
 
 #define COPY(src)                                                            \
 static void blend_copy ## src(const uint8_t *top, ptrdiff_t top_linesize,    \
@@ -405,13 +403,28 @@  static AVFrame *blend_frame(AVFilterContext *ctx, AVFrame *top_buf,
     return dst_buf;
 }
 
+static int blend_frame_for_dualinput(FFFrameSync *fs)
+{
+    AVFilterContext *ctx = fs->parent;
+    AVFrame *top_buf, *bottom_buf, *dst_buf;
+    int ret;
+
+    ret = ff_framesync2_dualinput_get(fs, &top_buf, &bottom_buf);
+    if (ret < 0)
+        return ret;
+    if (!bottom_buf)
+        return ff_filter_frame(ctx->outputs[0], top_buf);
+    dst_buf = blend_frame(ctx, top_buf, bottom_buf);
+    return ff_filter_frame(ctx->outputs[0], dst_buf);
+}
+
 static av_cold int init(AVFilterContext *ctx)
 {
     BlendContext *s = ctx->priv;
 
     s->tblend = !strcmp(ctx->filter->name, "tblend");
 
-    s->dinput.process = blend_frame;
+    s->fs.on_event = blend_frame_for_dualinput;
     return 0;
 }
 
@@ -439,7 +452,7 @@  static av_cold void uninit(AVFilterContext *ctx)
     BlendContext *s = ctx->priv;
     int i;
 
-    ff_dualinput_uninit(&s->dinput);
+    ff_framesync2_uninit(&s->fs);
     av_frame_free(&s->prev_frame);
 
     for (i = 0; i < FF_ARRAY_ELEMS(s->params); i++)
@@ -539,7 +552,7 @@  static int config_output(AVFilterLink *outlink)
     s->nb_planes = av_pix_fmt_count_planes(toplink->format);
 
     if (!s->tblend)
-        if ((ret = ff_dualinput_init(ctx, &s->dinput)) < 0)
+        if ((ret = ff_framesync2_init_dualinput(&s->fs, ctx)) < 0)
             return ret;
 
     for (plane = 0; plane < FF_ARRAY_ELEMS(s->params); plane++) {
@@ -566,32 +579,24 @@  static int config_output(AVFilterLink *outlink)
         }
     }
 
-    return 0;
+    return s->tblend ? 0 : ff_framesync2_configure(&s->fs);
 }
 
 #if CONFIG_BLEND_FILTER
 
-static int request_frame(AVFilterLink *outlink)
+static int activate(AVFilterContext *ctx)
 {
-    BlendContext *s = outlink->src->priv;
-    return ff_dualinput_request_frame(&s->dinput, outlink);
-}
-
-static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
-{
-    BlendContext *s = inlink->dst->priv;
-    return ff_dualinput_filter_frame(&s->dinput, inlink, buf);
+    BlendContext *s = ctx->priv;
+    return ff_framesync2_activate(&s->fs);
 }
 
 static const AVFilterPad blend_inputs[] = {
     {
         .name          = "top",
         .type          = AVMEDIA_TYPE_VIDEO,
-        .filter_frame  = filter_frame,
     },{
         .name          = "bottom",
         .type          = AVMEDIA_TYPE_VIDEO,
-        .filter_frame  = filter_frame,
     },
     { NULL }
 };
@@ -601,7 +606,6 @@  static const AVFilterPad blend_outputs[] = {
         .name          = "default",
         .type          = AVMEDIA_TYPE_VIDEO,
         .config_props  = config_output,
-        .request_frame = request_frame,
     },
     { NULL }
 };
@@ -609,10 +613,12 @@  static const AVFilterPad blend_outputs[] = {
 AVFilter ff_vf_blend = {
     .name          = "blend",
     .description   = NULL_IF_CONFIG_SMALL("Blend two video frames into each other."),
+    .preinit       = blend_framesync_preinit,
     .init          = init,
     .uninit        = uninit,
     .priv_size     = sizeof(BlendContext),
     .query_formats = query_formats,
+    .activate      = activate,
     .inputs        = blend_inputs,
     .outputs       = blend_outputs,
     .priv_class    = &blend_class,