CamxTime / preprocess_gt_videos.py
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#!/usr/bin/env python3
"""
eval/preprocess_gt_videos.py
Apply the same spatial preprocessing used by SpaceTimePilot to the GT videos
in camxtime_evaluation_gt, so they match the network output format exactly.
Pipeline (mirrors spacetimepilot/dataset/utils.py):
1. Load up to 81 frames at stride=1
2. crop_and_resize: aspect-ratio preserving scale so image covers 832×480
3. CenterCrop to exactly 832×480
4. Pad with last frame if shorter than 81 frames
5. Write as 30fps H264 MP4
For 1080×1080 source: scale to 832×832, then crop 176px top/bottom → 832×480.
Usage (run from repo root):
python eval/preprocess_gt_videos.py \\
--input camxtime_evaluation_gt \\
--output camxtime_evaluation_gt_preprocessed
"""
import argparse
import multiprocessing
import shutil
from concurrent.futures import ProcessPoolExecutor, as_completed
from pathlib import Path
import imageio.v2 as imageio
import numpy as np
from PIL import Image
from tqdm import tqdm
TARGET_W = 832
TARGET_H = 480
NUM_FRAMES = 81
FPS = 30
def crop_and_resize(img: Image.Image) -> Image.Image:
w, h = img.size
scale = max(TARGET_W / w, TARGET_H / h)
return img.resize((round(w * scale), round(h * scale)), Image.BILINEAR)
def center_crop(img: Image.Image) -> Image.Image:
w, h = img.size
return img.crop(((w - TARGET_W) // 2, (h - TARGET_H) // 2,
(w - TARGET_W) // 2 + TARGET_W, (h - TARGET_H) // 2 + TARGET_H))
def preprocess_frame(arr: np.ndarray) -> np.ndarray:
img = Image.fromarray(arr).convert("RGB")
return np.array(center_crop(crop_and_resize(img)))
def process_video(src: Path, dst: Path) -> None:
reader = imageio.get_reader(str(src))
total = reader.count_frames()
frames = [preprocess_frame(reader.get_data(i)) for i in range(min(NUM_FRAMES, total))]
reader.close()
while len(frames) < NUM_FRAMES:
frames.append(frames[-1].copy())
writer = imageio.get_writer(str(dst), fps=FPS, codec="libx264", quality=8)
for f in frames:
writer.append_data(f)
writer.close()
def process_scene(args):
scene_dir, out_dir = Path(args[0]), Path(args[1])
out_scene = out_dir / scene_dir.name
out_scene.mkdir(parents=True, exist_ok=True)
n_built = n_skipped = 0
for vid in sorted(scene_dir.glob("*.mp4")):
out_vid = out_scene / vid.name
if out_vid.exists():
n_skipped += 1
else:
process_video(vid, out_vid)
n_built += 1
for ext in (".json", ".txt"):
src = vid.with_suffix(ext)
if src.exists():
dst = out_scene / src.name
if not dst.exists():
shutil.copy2(src, dst)
cam_json = scene_dir / "camera_data.json"
if cam_json.exists() and not (out_scene / "camera_data.json").exists():
shutil.copy2(cam_json, out_scene / "camera_data.json")
return scene_dir.name, n_built, n_skipped
def main():
parser = argparse.ArgumentParser(
description="Preprocess GT videos to 832×480 / 81 frames to match network output."
)
parser.add_argument("--input", required=True,
help="camxtime_evaluation_gt root")
parser.add_argument("--output", required=True,
help="Output root (camxtime_evaluation_gt_preprocessed)")
parser.add_argument("--scenes", nargs="+")
parser.add_argument("--workers", type=int,
default=min(32, multiprocessing.cpu_count()))
args = parser.parse_args()
input_dir = Path(args.input)
output_dir = Path(args.output)
output_dir.mkdir(parents=True, exist_ok=True)
scenes = ([input_dir / s for s in args.scenes] if args.scenes
else sorted(p for p in input_dir.iterdir() if p.is_dir()))
print(f"CPUs: {multiprocessing.cpu_count()} | workers: {args.workers} "
f"| target: {TARGET_W}×{TARGET_H}, {NUM_FRAMES}f @ {FPS}fps "
f"| scenes: {len(scenes)}\n")
tasks = [(s, output_dir) for s in scenes]
n_done = n_errors = 0
with ProcessPoolExecutor(max_workers=args.workers) as pool:
futures = {pool.submit(process_scene, t): Path(t[0]).name for t in tasks}
with tqdm(total=len(futures), desc="Overall", unit="scene",
dynamic_ncols=True) as pbar:
for fut in as_completed(futures):
name = futures[fut]
try:
_, built, skipped = fut.result()
n_done += 1
tqdm.write(f" OK {name:<12s} {built} preprocessed, {skipped} skipped")
except Exception as exc:
n_errors += 1
tqdm.write(f" ERR {name:<12s} {exc}")
pbar.set_postfix(done=n_done, err=n_errors)
pbar.update(1)
print(f"\nFinished — {n_done} scenes done, {n_errors} errors")
print(f"Output: {output_dir}")
if __name__ == "__main__":
main()