scripts/build_webdataset.py

#!/usr/bin/env python
r"""
Builds a WebDataset from the Cityscapes Video dataset.
"""

import argparse
import tarfile

from pathlib import Path
from tqdm import tqdm


def parse_args():
    p = argparse.ArgumentParser(
        description="Build a WebDataset from the Cityscapes Video dataset."
    )
    p.add_argument("--prefix", default="csvps", help="Prefix for the tar files.")
    p.add_argument("data", type=Path, help="Path to the Cityscapes Video dataset.")
    p.add_argument("output", type=Path, help="Path to the output directory.")

    return p.parse_args()


def build_dataset(split: str, data_dir: Path, out_dir: Path, *, prefix: str = ""):
    data_dir = data_dir / split
    name = f"{split}.tar"
    if prefix and prefix != "":
        name = f"{prefix}-{name}"
    tar_path = out_dir / name

    if tar_path.exists():
        print(f"Error: Tar archive already exists: {tar_path}")

    with tarfile.open(tar_path, "w") as tar:
        # Add the files to the tar archive
        for file in tqdm(sorted(data_dir.glob("**/*")), desc=f"Building {tar_path}"):
            tar.add(file, arcname=file.relative_to(data_dir))


def main():
    args = parse_args()

    # For each split, build a tar archive containing the sorted files
    for split in ("train", "val", "test"):
        build_dataset(split, args.data, args.output, prefix=args.prefix)


if __name__ == "__main__":
    main()