def _compute_frame_pts(self) -> None:
        """Retrieve the number of frames in each video."""
        self.video_pts = []
        for video_path in self.video_paths:
            n_frames = len(list(Path(video_path).glob("*.jpg")))
            self.video_pts.append(torch.Tensor(range(n_frames)))

        # fps information cannot be inferred from folder structure
        self.video_fps = [None] * len(self.video_paths)
Retrieve the number of frames in each video.
src/anomalib/data/datasets/video/shanghaitech.py