diff --git a/misc/json.c b/misc/json.c
index d1b2afddb6..d25e0f55c8 100644
--- a/misc/json.c
+++ b/misc/json.c
@@ -299,9 +299,11 @@ static int json_append(bstr *b, const struct mpv_node *src, int indent)
     case MPV_FORMAT_INT64:
         bstr_xappend_asprintf(NULL, b, "%"PRId64, src->u.int64);
         return 0;
-    case MPV_FORMAT_DOUBLE:
-        bstr_xappend_asprintf(NULL, b, "%f", src->u.double_);
+    case MPV_FORMAT_DOUBLE: {
+        const char *px = isfinite(src->u.double_) ? "" : "\"";
+        bstr_xappend_asprintf(NULL, b, "%s%f%s", px, src->u.double_, px);
         return 0;
+    }
     case MPV_FORMAT_STRING:
         write_json_str(b, src->u.string);
         return 0;