Add a warning

libmat2/video.py

@@ -84,6 +84,12 @@ class MP4Parser(AbstractFFmpegParser):
         'TrackVolume': '0.00%',
     }
 
+    def remove_all(self) -> bool:
+        logging.warning('The format of "%s" (video/mp4) has some mandatory '
+                        'metadata fields; mat2 filled them with standard data.',
+                        self.filename)
+        return super().remove_all()
+
     def get_meta(self) -> Dict[str, Union[str, dict]]:
         meta = super().get_meta()
 

mat2

@@ -20,6 +20,8 @@ __version__ = '0.5.0'
 assert Tuple
 assert Union
 
+logging.basicConfig(format='%(levelname)s: %(message)s', level=logging.WARNING)
+
 
 def __check_file(filename: str, mode: int=os.R_OK) -> bool:
     if not os.path.exists(filename):