diff --git a/panda/src/pgraph/nodePath.cxx b/panda/src/pgraph/nodePath.cxx
index 1159a5d1d1..a05cd287da 100644
--- a/panda/src/pgraph/nodePath.cxx
+++ b/panda/src/pgraph/nodePath.cxx
@@ -6831,7 +6831,7 @@ find_net_python_tag(const string &key) const {
 //               error.
 ////////////////////////////////////////////////////////////////////
 bool NodePath::
-write_bam_file(const string &filename) const {
+write_bam_file(const Filename &filename) const {
   nassertr_always(!is_empty(), false);
 
   BamFile bam_file;
diff --git a/panda/src/pgraph/nodePath.h b/panda/src/pgraph/nodePath.h
index 78477654ec..39f029b48b 100644
--- a/panda/src/pgraph/nodePath.h
+++ b/panda/src/pgraph/nodePath.h
@@ -904,7 +904,7 @@ PUBLISHED:
   INLINE void set_name(const string &name);
   INLINE string get_name() const;
 
-  BLOCKING bool write_bam_file(const string &filename) const;
+  BLOCKING bool write_bam_file(const Filename &filename) const;
   BLOCKING bool write_bam_stream(ostream &out) const;
 
   INLINE string encode_to_bam_stream() const;