diff --git a/libavfilter/avfiltergraph.c b/libavfilter/avfiltergraph.c
index 1ff69fb346..0101d650a6 100644
--- a/libavfilter/avfiltergraph.c
+++ b/libavfilter/avfiltergraph.c
@@ -23,6 +23,7 @@
 #include <string.h>
 
 #include "libavutil/avassert.h"
+#include "libavutil/avstring.h"
 #include "libavutil/bprint.h"
 #include "libavutil/channel_layout.h"
 #include "libavutil/opt.h"
@@ -340,11 +341,11 @@ static int query_formats(AVFilterGraph *graph, AVClass *log_ctx)
 
                     snprintf(inst_name, sizeof(inst_name), "auto-inserted scaler %d",
                              scaler_count++);
-                    if (graph->scale_sws_opts)
-                        snprintf(scale_args, sizeof(scale_args), "0:0:%s", graph->scale_sws_opts);
-                    else
-                        snprintf(scale_args, sizeof(scale_args), "0:0");
-
+                    av_strlcpy(scale_args, "0:0", sizeof(scale_args));
+                    if (graph->scale_sws_opts) {
+                        av_strlcat(scale_args, ":", sizeof(scale_args));
+                        av_strlcat(scale_args, graph->scale_sws_opts, sizeof(scale_args));
+                    }
                     if ((ret = avfilter_graph_create_filter(&convert, filter,
                                                             inst_name, scale_args, NULL,
                                                             graph)) < 0)
diff --git a/libavfilter/graphparser.c b/libavfilter/graphparser.c
index 8d2fffc194..a1e1b37fc9 100644
--- a/libavfilter/graphparser.c
+++ b/libavfilter/graphparser.c
@@ -122,8 +122,8 @@ static int create_filter(AVFilterContext **filt_ctx, AVFilterGraph *ctx, int ind
         return ret;
     }
 
-    if (!strcmp(filt_name, "scale") && args && !strstr(args, "flags")
-        && ctx->scale_sws_opts) {
+    if (!strcmp(filt_name, "scale") && args && !strstr(args, "flags") &&
+        ctx->scale_sws_opts) {
         snprintf(tmp_args, sizeof(tmp_args), "%s:%s",
                  args, ctx->scale_sws_opts);
         args = tmp_args;