File size: 2,603 Bytes
1bb0b8a | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 | #!/usr/bin/env python3
"""Unpack the frame archives of this dataset and (optionally) write a parquet with absolute frame paths.
python extract_frames.py # unzip frames_zip/*.zip -> ./frames/<frame_dir>/000.jpg ... 031.jpg
python extract_frames.py --abs # also write train.abs.parquet (frame paths made absolute; needs pyarrow)
python extract_frames.py --out /data # extract somewhere else (frames end up in /data/frames)
`train.parquet` stores frame paths relative to the extraction root (`frames/<frame_dir>/NNN.jpg`).
"""
import argparse
import glob
import hashlib
import json
import os
import zipfile
HERE = os.path.dirname(os.path.abspath(__file__))
def sha256(path):
h = hashlib.sha256()
with open(path, "rb") as f:
for blk in iter(lambda: f.read(1 << 24), b""):
h.update(blk)
return h.hexdigest()
def main():
ap = argparse.ArgumentParser()
ap.add_argument("--out", default=HERE, help="extraction root (default: the dataset folder)")
ap.add_argument("--abs", action="store_true", help="write train.abs.parquet with absolute frame paths")
ap.add_argument("--no-verify", action="store_true", help="skip the sha256 check of the zip files")
args = ap.parse_args()
out = os.path.abspath(args.out)
manifest = json.load(open(os.path.join(HERE, "manifest.json")))
want = {z["file"]: z for z in manifest["zips"]}
zips = sorted(glob.glob(os.path.join(HERE, "frames_zip", "frames-*.zip")))
assert len(zips) == len(want), f"expected {len(want)} zip files, found {len(zips)}"
for zp in zips:
rel = "frames_zip/" + os.path.basename(zp)
if not args.no_verify:
assert sha256(zp) == want[rel]["sha256"], f"sha256 mismatch: {rel} (re-download it)"
with zipfile.ZipFile(zp) as z:
z.extractall(out)
print("extracted", rel, flush=True)
n = len(glob.glob(os.path.join(out, "frames", "*", "*.jpg")))
assert n == manifest["frame_files"], f"expected {manifest['frame_files']} frames, found {n}"
print(f"ok: {n} frames in {os.path.join(out, 'frames')}")
if args.abs:
import pyarrow as pa
import pyarrow.parquet as pq
t = pq.read_table(os.path.join(HERE, "train.parquet"))
rows = t.to_pylist()
for r in rows:
r["videos"][0]["video"] = [os.path.join(out, f) for f in r["videos"][0]["video"]]
dst = os.path.join(out, "train.abs.parquet")
pq.write_table(pa.Table.from_pylist(rows, schema=t.schema), dst)
print("wrote", dst)
if __name__ == "__main__":
main()
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