alignments tool - Don't re-analyze video if metadata in alignments

tools/alignments/jobs.py

@@ -405,13 +405,30 @@ def __init__(self, alignments, arguments):
         self._is_legacy = self._alignments.version == 1.0  # pylint:disable=protected-access
         self._mask_pipeline = None
         self._faces_dir = arguments.faces_dir
-        self._frames = Frames(arguments.frames_dir)
+
+        self._frames = Frames(arguments.frames_dir, self._get_count())
         self._extracted_faces = ExtractedFaces(self._frames,
                                                self._alignments,
                                                size=arguments.size)
         self._saver = None
         logger.debug("Initialized %s", self.__class__.__name__)
 
+    def _get_count(self):
+        """ If the alignments file has been run through the manual tool, then it will hold video
+        meta information, meaning that the count of frames in the alignment file can be relied
+        on to be accurate.
+
+        Returns
+        -------
+        int or ``None``
+        For video input which contain video meta-data in the alignments file then the count of
+        frames is returned. In all other cases ``None`` is returned
+        """
+        has_meta = all(val is not None for val in self._alignments.video_meta_data.values())
+        retval = len(self._alignments.video_meta_data["pts_time"]) if has_meta else None
+        logger.debug("Frame count from alignments file: (has_meta: %s, %s", has_meta, retval)
+        return retval
+
     def process(self):
         """ Run the re-extraction from Alignments file process"""
         logger.info("[EXTRACT FACES]")  # Tidy up cli output

tools/alignments/media.py

@@ -72,11 +72,14 @@ class MediaLoader():
     ----------
     folder: str
         The folder of images or video file to load images from
+    count: int or ``None``, optional
+        If the total frame count is known it can be passed in here which will skip
+        analyzing a video file. If the count is not passed in, it will be calculated.
     """
-    def __init__(self, folder):
+    def __init__(self, folder, count=None):
         logger.debug("Initializing %s: (folder: '%s')", self.__class__.__name__, folder)
         logger.info("[%s DATA]", self.__class__.__name__.upper())
-        self._count = None
+        self._count = count
         self.folder = folder
         self.vid_reader = self.check_input_folder()
         self.file_list_sorted = self.sorted_items()
@@ -188,7 +191,7 @@ def stream(self, skip_list=None):
         numpy.ndarray
             The image that has been loaded from disk
         """
-        loader = ImagesLoader(self.folder, queue_size=32)
+        loader = ImagesLoader(self.folder, queue_size=32, count=self._count)
         if skip_list is not None:
             loader.add_skip_list(skip_list)
         for filename, image in loader.load():