          logger.trace("Processed landmarks: %s", retval)
          return retval
  
      # <<< FACE NORMALIZATION METHODS >>> #
      def normalize_face(self, feed_dict):
          """ Normalize the face for feeding into model """
          if self.normalize_method is None:
              return
          logger.trace("Normalizing face")
          meth = getattr(self, "normalize_{}".format(self.normalize_method.lower()))
          feed_dict["image"] = meth(feed_dict["image"])
 
</s> remove             return
        logger.trace("Normalizing face")
        meth = getattr(self, "normalize_{}".format(self.normalize_method.lower()))
        feed_dict["image"] = meth(feed_dict["image"])
        logger.trace("Normalized face")
 </s> add             return faces
        logger.trace("Normalizing faces")
        meth = getattr(self, "_normalize_{}".format(self.normalize_method.lower()))
        faces = [meth(face) for face in faces]
        logger.trace("Normalized faces")
        return faces </s> remove             cvt_image = image.copy()
        return cvt_image

    def process_landmarks(self, image, detected_faces):
        """ Align image and process landmarks """
        logger.trace("Processing landmarks")
        retval = list()
        for detected_face in detected_faces:
            feed_dict = self.align_image(detected_face, image)
            self.normalize_face(feed_dict)
            landmarks = self.predict_landmarks(feed_dict)
            retval.append(landmarks)
        logger.trace("Processed landmarks: %s", retval)
        return retval
 </s> add             logger.trace(item)
        return exhausted, batch

    def _collect_item(self, queue):
        """ Collect the item from the _rollover dict or from the queue
            Add face count per frame to self._faces_per_filename for joining
            batches back up in finalize """
        if self._rollover:
            logger.trace("Getting from _rollover: (filename: `%s`, faces: %s)",
                         self._rollover["filename"], len(self._rollover["detected_faces"]))
            item = self._rollover
            self._rollover = dict()
        else:
            item = self._get_item(queue)
            if item != "EOF":
                logger.trace("Getting from queue: (filename: %s, faces: %s)",
                             item["filename"], len(item["detected_faces"]))
                self._faces_per_filename[item["filename"]] = len(item["detected_faces"])
        return item

    # <<< FINALIZE METHODS >>> #
    def finalize(self, batch):
        """ Finalize the output from Aligner

        This should be called as the final task of each `plugin`.

        It strips unneeded items from the :attr:`batch` ``dict`` and pairs the detected faces back
        up with their original frame before yielding each frame.

        Outputs items in the format:

        >>> {'image': [<original frame>],
        >>>  'filename': [<frame filename>),
        >>>  'detected_faces': [<lib.faces_detect.DetectedFace objects>]}

        Parameters
        ----------
        batch : dict
            The final ``dict`` from the `plugin` process. It must contain the `keys`:
            ``detected_faces``, ``landmarks``, ``filename``, ``image``

        Yields
        ------
        dict
            A ``dict`` for each frame containing the ``image``, ``filename`` and list of
            :class:`lib.faces_detect.DetectedFace` objects.

        """

        for face, landmarks in zip(batch["detected_faces"], batch["landmarks"]):
            face.landmarks_xy = [(int(round(pt[0])), int(round(pt[1]))) for pt in landmarks]

        self._remove_invalid_keys(batch, ("detected_faces", "filename", "image"))
        logger.trace("Item out: %s", {key: val
                                      for key, val in batch.items()
                                      if key != "image"})
        for filename, image, face in zip(batch["filename"],
                                         batch["image"],
                                         batch["detected_faces"]):
            self._output_faces.append(face)
            if len(self._output_faces) != self._faces_per_filename[filename]:
                continue
            retval = dict(filename=filename, image=image, detected_faces=self._output_faces)

            self._output_faces = []
            logger.trace("Yielding: (filename: '%s', image: %s, detected_faces: %s)",
                         retval["filename"], retval["image"].shape, len(retval["detected_faces"]))
            yield retval

    # <<< PROTECTED METHODS >>> #
    # <<< PREDICT WRAPPER >>> #
    def _predict(self, batch):
        """ Just return the aligner's predict function """
        return self.predict(batch) </s> remove     def normalize_mean(face):
 </s> add     def _normalize_mean(face): </s> remove     # <<< OVERRIDE METHODS >>> #
    # These methods must be overriden when creating a plugin
    def initialize(self, *args, **kwargs):
        """ Inititalize the aligner
            Tasks to be run before any alignments are performed.
            Override for specific detector """
        logger.debug("_base initialize %s: (PID: %s, args: %s, kwargs: %s)",
                     self.__class__.__name__, os.getpid(), args, kwargs)
        self.init = kwargs["event"]
        self.error = kwargs["error"]
        self.queues["in"] = kwargs["in_queue"]
        self.queues["out"] = kwargs["out_queue"]

    def align_image(self, detected_face, image):
        """ Align the incoming image for feeding into aligner
            Override for aligner specific processing """
        raise NotImplementedError

    def predict_landmarks(self, feed_dict):
        """ Predict the 68 point landmarks
            Override for aligner specific landmark prediction """
        raise NotImplementedError

    # <<< GET MODEL >>> #
    @staticmethod
    def get_model(git_model_id, model_filename):
        """ Check if model is available, if not, download and unzip it """
        if model_filename is None:
            logger.debug("No model_filename specified. Returning None")
            return None
        if git_model_id is None:
            logger.debug("No git_model_id specified. Returning None")
            return None
        cache_path = os.path.join(os.path.dirname(__file__), ".cache")
        model = GetModel(model_filename, cache_path, git_model_id)
        return model.model_path

    # <<< ALIGNMENT WRAPPER >>> #
    def run(self, *args, **kwargs):
        """ Parent align process.
            This should always be called as the entry point so exceptions
            are passed back to parent.
            Do not override """
        try:
            self.align(*args, **kwargs)
        except Exception:  # pylint:disable=broad-except
            logger.error("Caught exception in child process: %s", os.getpid())
            # Display traceback if in initialization stage
            if not self.init.is_set():
                logger.exception("Traceback:")
            tb_buffer = StringIO()
            traceback.print_exc(file=tb_buffer)
            exception = {"exception": (os.getpid(), tb_buffer)}
            self.queues["out"].put(exception)
            exit(1)

    def align(self, *args, **kwargs):
        """ Process landmarks """
        if not self.init:
            self.initialize(*args, **kwargs)
        logger.debug("Launching Align: (args: %s kwargs: %s)", args, kwargs)

        for item in self.get_item():
 </s> add     # << QUEUE METHODS >>> #
    def get_batch(self, queue):
        """ Get items for inputting into the aligner from the queue in batches

        Items are returned from the ``queue`` in batches of
        :attr:`~plugins.extract._base.Extractor.batchsize`

        To ensure consistent batchsizes for aligner the items are split into separate items for
        each :class:`lib.faces_detect.DetectedFace` object.

        Remember to put ``'EOF'`` to the out queue after processing
        the final batch

        Outputs items in the following format. All lists are of length
        :attr:`~plugins.extract._base.Extractor.batchsize`:

        >>> {'filename': [<filenames of source frames>],
        >>>  'image': [<source images>],
        >>>  'detected_faces': [[<lib.faces_detect.DetectedFace objects]]}

        Parameters
        ----------
        queue : queue.Queue()
            The ``queue`` that the plugin will be fed from.

        Returns
        -------
        exhausted, bool
            ``True`` if queue is exhausted, ``False`` if not
        batch, dict
            A dictionary of lists of :attr:`~plugins.extract._base.Extractor.batchsize`:
        """
        exhausted = False
        batch = dict()
        idx = 0
        while idx < self.batchsize:
            item = self._collect_item(queue) </s> remove     def set_parallel_processing(self, multiprocess):
        """ Set whether to run detect and align together or separately """
        detector_vram = self.detector.vram
        aligner_vram = self.aligner.vram
 </s> add         Parameters
        ----------
        plugin_type: {'aligner', 'detector'}
            The plugin_type to be overriden
        batchsize: int
            The batchsize to use for this plugin type
        """
        logger.debug("Overriding batchsize for plugin_type: %s to: %s", plugin_type, batchsize)
        plugin = getattr(self, "_{}".format(plugin_type))
        plugin.batchsize = batchsize

    def launch(self):
        """ Launches the plugin(s)

        This launches the plugins held in the pipeline, and should be called at the beginning
        of each :attr:`phase`. To ensure VRAM is conserved, It will only launch the plugin(s)
        required for the currently running phase

        Example
        -------
        >>> for phase in extractor.passes:
        >>>     extractor.launch():
        >>>         <do processing>
        """

        if self._is_parallel:
            self._launch_aligner()
            self._launch_detector()
        elif self.phase == "detect":
            self._launch_detector()
        else:
            self._launch_aligner()

    def detected_faces(self):
        """ Generator that returns results, frame by frame from the extraction pipeline

        This is the exit point for the extraction pipeline and is used to obtain the output
        of any pipeline :attr:`phase`

        Yields
        ------
        faces: dict
            regardless of phase, the returned dictinary will contain, exclusively, ``filename``:
            the filename of the source image, ``image``: the ``numpy.array`` of the source image
            in BGR color format, ``detected_faces``: a list of
            :class:`~lib.faces_detect.Detected_Face` objects.

        Example
        -------
        >>> for face in extractor.detected_faces():
        >>>     filename = face["filename"]
        >>>     image = face["image"]
        >>>     detected_faces = face["detected_faces"]
        """
        logger.debug("Running Detection. Phase: '%s'", self.phase)
        # If not multiprocessing, intercept the align in queue for
        # detection phase
        out_queue = self._output_queue
        while True:
            try:
                if self._check_and_raise_error():
                    break
                faces = out_queue.get(True, 1)
                if faces == "EOF":
                    break
            except QueueEmpty:
                continue

            yield faces
        self._join_threads()
        if self.final_pass:
            # Cleanup queues
            for q_name in self._queues.keys():
                queue_manager.del_queue(q_name)
            logger.debug("Detection Complete")
        else:
            logger.debug("Switching to align phase")
            self.phase = "align"

    # <<< INTERNAL METHODS >>> #
    @property
    def _output_queue(self):
        """ Return the correct output queue depending on the current phase """
        qname = "extract_align_out" if self.final_pass else "extract_align_in"
        retval = self._queues[qname]
        logger.trace("%s: %s", qname, retval)
        return retval

    @property
    def _active_plugins(self):
        """ Return the plugins that are currently active based on pass """
        if self.passes == 1:
            retval = [self._detector, self._aligner]
        elif self.passes == 2 and not self.final_pass:
            retval = [self._detector]
        else:
            retval = [self._aligner]
        logger.trace("Active plugins: %s", retval)
        return retval

    def _add_queues(self):
        """ Add the required processing queues to Queue Manager """
        queues = dict()
        for task in ("extract_detect_in", "extract_align_in", "extract_align_out"):
            # Limit queue size to avoid stacking ram
            self._queue_size = 32
            if task == "extract_detect_in" or (not self._is_parallel
                                               and task == "extract_align_in"):
                self._queue_size = 64
            queue_manager.add_queue(task, maxsize=self._queue_size)
            queues[task] = queue_manager.get_queue(task)
        logger.debug("Queues: %s", queues)
        return queues
    def _normalize_faces(self, faces):
        """ Normalizes the face for feeding into model

        The normalization method is dictated by the cli argument:
            -nh (--normalization)
        """
          logger.trace("Processed landmarks: %s", retval)
          return retval
  
      # <<< FACE NORMALIZATION METHODS >>> #
    def _normalize_faces(self, faces):
        """ Normalizes the face for feeding into model

        The normalization method is dictated by the cli argument:
            -nh (--normalization)
        """
    def _normalize_faces(self, faces):
        """ Normalizes the face for feeding into model

        The normalization method is dictated by the cli argument:
            -nh (--normalization)
        """
          if self.normalize_method is None:
              return
          logger.trace("Normalizing face")
          meth = getattr(self, "normalize_{}".format(self.normalize_method.lower()))
          feed_dict["image"] = meth(feed_dict["image"])
keep keep keep keep replace replace keep keep keep keep keep
 De-Multiprocess Extract (#871)

* requirements.txt: - Pin opencv to 4.1.1 (fixes cv2-dnn error)

* lib.face_detect.DetectedFace: change LandmarksXY to landmarks_xy. Add left, right, top, bottom attributes

* lib.model.session: Session manager for loading models into different graphs (for Nvidia + CPU)

* plugins.extract._base: New parent class for all extract plugins

* plugins.extract.pipeline. Remove MultiProcessing. Dynamically limit batchsize for Nvidia cards. Remove loglevel input

* S3FD + FAN plugins. Standardise to Keras version for all backends

* Standardize all extract plugins to new threaded codebase

* Documentation. Start implementing Numpy style docstrings for Sphinx Documentation

* Remove s3fd_amd. Change convert OTF to expect DetectedFace object

* faces_detect - clean up and documentation

* Remove PoolProcess

* Migrate manual tool to new extract workflow

* Remove AMD specific extractor code from cli and plugins

* Sort tool to new extract workflow

* Remove multiprocessing from project

* Remove multiprocessing queues from QueueManager

* Remove multiprocessing support from logger

* Move face_filter to new extraction pipeline

* Alignments landmarksXY > landmarks_xy and legacy handling

* Intercept get_backend for sphinx doc build

# Add Sphinx documentation 
plugins/extract/align/_base.py