diff --git a/libavformat/mux.c b/libavformat/mux.c
index 6847ec342b..7b4f7c77d3 100644
--- a/libavformat/mux.c
+++ b/libavformat/mux.c
@@ -334,7 +334,7 @@ static int init_muxer(AVFormatContext *s, AVDictionary **options)
         if (of->priv_class) {
             *(const AVClass **)s->priv_data = of->priv_class;
             av_opt_set_defaults(s->priv_data);
-            if ((ret = av_opt_set_dict(s->priv_data, &tmp)) < 0)
+            if ((ret = av_opt_set_dict2(s->priv_data, &tmp, AV_OPT_SEARCH_CHILDREN)) < 0)
                 goto fail;
         }
     }