examples/inspect_tar.py

import argparse
import io
import json
import tarfile
from pathlib import Path

from PIL import Image


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(description="Inspect one Camera Motion tar shard.")
    parser.add_argument("--tar", type=Path, required=True, help="Path to a tar shard.")
    parser.add_argument("--limit", type=int, default=2, help="Number of sample ids to inspect.")
    return parser.parse_args()


def main() -> None:
    args = parse_args()

    with tarfile.open(args.tar, "r") as tar:
        members = tar.getnames()
        sample_ids = []
        for name in members:
            if name.endswith(".json"):
                sample_ids.append(name.rsplit(".", 1)[0])
            if len(sample_ids) >= args.limit:
                break

        print(json.dumps({"tar": str(args.tar), "num_members": len(members), "sample_ids": sample_ids}, indent=2))

        for sample_id in sample_ids:
            metadata = json.loads(tar.extractfile(f"{sample_id}.json").read().decode("utf-8"))
            frame_members = [f"{sample_id}.jpg-{i:02d}" for i in range(8)]
            first_frame = Image.open(io.BytesIO(tar.extractfile(frame_members[0]).read()))
            print(
                json.dumps(
                    {
                        "sample_id": sample_id,
                        "frame_members": frame_members,
                        "metadata": metadata,
                        "first_frame_size": first_frame.size,
                        "first_frame_mode": first_frame.mode,
                    },
                    indent=2,
                )
            )


if __name__ == "__main__":
    main()