avfilter/vf_w3fdif: add support for commands

doc/filters.texi

@@ -20922,6 +20922,9 @@ Only deinterlace frames marked as interlaced.
 Default value is @samp{all}.
 @end table
 
+@subsection Commands
+This filter supports same @ref{commands} as options.
+
 @section waveform
 Video waveform monitor.
 

libavfilter/vf_w3fdif.c

@@ -49,7 +49,7 @@ typedef struct W3FDIFContext {
 } W3FDIFContext;
 
 #define OFFSET(x) offsetof(W3FDIFContext, x)
-#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
+#define FLAGS AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
 #define CONST(name, help, val, unit) { name, help, 0, AV_OPT_TYPE_CONST, {.i64=val}, 0, 0, FLAGS, unit }
 
 static const AVOption w3fdif_options[] = {
@@ -602,4 +602,5 @@ AVFilter ff_vf_w3fdif = {
     .inputs        = w3fdif_inputs,
     .outputs       = w3fdif_outputs,
     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL | AVFILTER_FLAG_SLICE_THREADS,
+    .process_command = ff_filter_process_command,
 };