+int avfilter_process_command(AVFilterContext *filter, const char *cmd, const char *arg, char *res, int res_len, int flags)
+{
+ if(!strcmp(cmd, "ping")){
+ av_strlcatf(res, res_len, "pong from:%s %s\n", filter->filter->name, filter->name);
+ return 0;
+ }else if(filter->filter->process_command) {
+ return filter->filter->process_command(filter, cmd, arg, res, res_len, flags);
+ }
+ return AVERROR(ENOSYS);
+}
+