avfilter/vf_colorkey: add support for commands

doc/filters.texi

@@ -7378,6 +7378,13 @@ ffmpeg -i background.png -i video.mp4 -filter_complex "[1:v]colorkey=0x3BBD1E:0.
 @end example
 @end itemize
 
+@subsection Commands
+This filter supports same @ref{commands} as options.
+The command accepts the same syntax of the corresponding option.
+
+If the specified expression is not valid, it is kept at its current
+value.
+
 @section colorhold
 Remove all color information for all RGB colors except for certain one.
 
@@ -7396,6 +7403,13 @@ Blend percentage. 0.0 makes pixels fully gray.
 Higher values result in more preserved color.
 @end table
 
+@subsection Commands
+This filter supports same @ref{commands} as options.
+The command accepts the same syntax of the corresponding option.
+
+If the specified expression is not valid, it is kept at its current
+value.
+
 @section colorlevels
 
 Adjust video input frames using levels.

libavfilter/vf_colorkey.c

@@ -199,7 +199,7 @@ static const AVFilterPad colorkey_outputs[] = {
 };
 
 #define OFFSET(x) offsetof(ColorkeyContext, x)
-#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
 
 #if CONFIG_COLORKEY_FILTER
 
@@ -222,6 +222,7 @@ AVFilter ff_vf_colorkey = {
     .inputs        = colorkey_inputs,
     .outputs       = colorkey_outputs,
     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
+    .process_command = ff_filter_process_command,
 };
 
 #endif /* CONFIG_COLORKEY_FILTER */
@@ -246,6 +247,7 @@ AVFilter ff_vf_colorhold = {
     .inputs        = colorkey_inputs,
     .outputs       = colorkey_outputs,
     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
+    .process_command = ff_filter_process_command,
 };
 
 #endif /* CONFIG_COLORHOLD_FILTER */