def _construct_loader()

in slowfast/datasets/ssv2.py [0:0]

• 70 lines of code
• 9 McCabe index (conditional complexity)

    def _construct_loader(self):
        """
        Construct the video loader.
        """
        # Loading label names.
        with PathManager.open(
            os.path.join(
                self.cfg.DATA.PATH_TO_DATA_DIR,
                "something-something-v2-labels.json",
            ),
            "r",
        ) as f:
            label_dict = json.load(f)

        # Loading labels.
        label_file = os.path.join(
            self.cfg.DATA.PATH_TO_DATA_DIR,
            "something-something-v2-{}.json".format(
                "train" if self.mode == "train" else "validation"
            ),
        )
        with PathManager.open(label_file, "r") as f:
            label_json = json.load(f)

        self._video_names = []
        self._labels = []
        for video in label_json:
            video_name = video["id"]
            template = video["template"]
            template = template.replace("[", "")
            template = template.replace("]", "")
            label = int(label_dict[template])
            self._video_names.append(video_name)
            self._labels.append(label)

        path_to_file = os.path.join(
            self.cfg.DATA.PATH_TO_DATA_DIR,
            "{}.csv".format("train" if self.mode == "train" else "val"),
        )
        assert PathManager.exists(path_to_file), "{} dir not found".format(
            path_to_file
        )

        self._path_to_videos, _ = utils.load_image_lists(
            path_to_file, self.cfg.DATA.PATH_PREFIX
        )

        assert len(self._path_to_videos) == len(self._video_names), (
            len(self._path_to_videos),
            len(self._video_names),
        )

        # From dict to list.
        new_paths, new_labels = [], []
        for index in range(len(self._video_names)):
            if self._video_names[index] in self._path_to_videos:
                new_paths.append(self._path_to_videos[self._video_names[index]])
                new_labels.append(self._labels[index])

        self._labels = new_labels
        self._path_to_videos = new_paths

        # Extend self when self._num_clips > 1 (during testing).
        self._path_to_videos = list(
            chain.from_iterable(
                [[x] * self._num_clips for x in self._path_to_videos]
            )
        )
        self._labels = list(
            chain.from_iterable([[x] * self._num_clips for x in self._labels])
        )
        self._spatial_temporal_idx = list(
            chain.from_iterable(
                [
                    range(self._num_clips)
                    for _ in range(len(self._path_to_videos))
                ]
            )
        )
        logger.info(
            "Something-Something V2 dataloader constructed "
            " (size: {}) from {}".format(
                len(self._path_to_videos), path_to_file
            )
        )