avfilter/af_join: use av_asprintf()

libavfilter/af_join.c

@@ -25,6 +25,7 @@
  */
 
 #include "libavutil/avassert.h"
+#include "libavutil/avstring.h"
 #include "libavutil/channel_layout.h"
 #include "libavutil/common.h"
 #include "libavutil/opt.h"
@@ -185,12 +186,10 @@ static av_cold int join_init(AVFilterContext *ctx)
         return ret;
 
     for (i = 0; i < s->inputs; i++) {
-        char name[32];
         AVFilterPad pad = { 0 };
 
-        snprintf(name, sizeof(name), "input%d", i);
         pad.type           = AVMEDIA_TYPE_AUDIO;
-        pad.name           = av_strdup(name);
+        pad.name           = av_asprintf("input%d", i);
         if (!pad.name)
             return AVERROR(ENOMEM);