avfilter/avfilter: mark enable as runtime option too

libavfilter/avfilter.c

@@ -620,11 +620,12 @@ static const AVClass *filter_child_class_iterate(void **iter)
 
 #define OFFSET(x) offsetof(AVFilterContext, x)
 #define FLAGS AV_OPT_FLAG_FILTERING_PARAM
+#define TFLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
 static const AVOption avfilter_options[] = {
     { "thread_type", "Allowed thread types", OFFSET(thread_type), AV_OPT_TYPE_FLAGS,
         { .i64 = AVFILTER_THREAD_SLICE }, 0, INT_MAX, FLAGS, "thread_type" },
         { "slice", NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AVFILTER_THREAD_SLICE }, .flags = FLAGS, .unit = "thread_type" },
-    { "enable", "set enable expression", OFFSET(enable_str), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = FLAGS },
+    { "enable", "set enable expression", OFFSET(enable_str), AV_OPT_TYPE_STRING, {.str=NULL}, .flags = TFLAGS },
     { "threads", "Allowed number of threads", OFFSET(nb_threads), AV_OPT_TYPE_INT,
         { .i64 = 0 }, 0, INT_MAX, FLAGS },
     { "extra_hw_frames", "Number of extra hardware frames to allocate for the user",

libavfilter/internal.h

@@ -368,6 +368,8 @@ int ff_filter_get_nb_threads(AVFilterContext *ctx);
 /**
  * Generic processing of user supplied commands that are set
  * in the same way as the filter options.
+ * NOTE: 'enable' option is handled separately, and not by
+ * this function.
  */
 int ff_filter_process_command(AVFilterContext *ctx, const char *cmd,
                               const char *arg, char *res, int res_len, int flags);