diff --git a/src/drawbot_skia/document.py b/src/drawbot_skia/document.py
index 7da6971..523c4d1 100644
--- a/src/drawbot_skia/document.py
+++ b/src/drawbot_skia/document.py
@@ -122,7 +122,7 @@ def _saveImage_mp4(self, path, codec="libx264", **kwargs):
                 singlePage=False,
             )
             imagesTemplate = os.fspath(tempDir / "frame_%d.png")
-            generateMP4(imagesTemplate, path, frameRate, codec=codec)
+            generateMP4(imagesTemplate, os.fspath(path), frameRate, codec=codec)
 
 
 def _savePixelImages(pictures, path, format, whiteBackground=False, singlePage=None):