| from pathlib import Path |
| import io |
| import cv2 |
| import numpy as np |
| from PIL import Image |
| from ..io import atomic_bytes, sha256 |
|
|
| def loaded_frame_count(available, requested=101): |
| n = min(int(available), int(requested)) |
| return (n - 1) // 4 * 4 + 1 |
|
|
| def frame_indices(n, count=24): |
| if n < 1: raise ValueError("Empty video") |
| return np.linspace(0, n - 1, count).astype(int).tolist() |
|
|
| def video_info(path): |
| cap = cv2.VideoCapture(str(path)) |
| result = {"frames": int(cap.get(cv2.CAP_PROP_FRAME_COUNT)), "fps": cap.get(cv2.CAP_PROP_FPS), "width": int(cap.get(cv2.CAP_PROP_FRAME_WIDTH)), "height": int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))} |
| cap.release() |
| if result["frames"] < 1 or result["fps"] <= 0: raise ValueError(f"Unreadable video: {path}") |
| return result |
|
|
| def read_frames(path, n=None): |
| cap = cv2.VideoCapture(str(path)); frames = [] |
| while n is None or len(frames) < n: |
| ok, frame = cap.read() |
| if not ok: break |
| frames.append(Image.fromarray(cv2.cvtColor(frame, cv2.COLOR_BGR2RGB))) |
| cap.release() |
| if n is not None and len(frames) != n: raise ValueError("Video ended early") |
| return frames |
|
|
| def jpeg_asset(image, path, max_side=832, quality=90): |
| image = image.convert("RGB"); scale = min(1, max_side / max(image.size)) |
| if scale < 1: image = image.resize(tuple(max(1, round(x * scale)) for x in image.size), Image.Resampling.LANCZOS) |
| stream = io.BytesIO(); image.save(stream, format="JPEG", quality=quality) |
| atomic_bytes(path, stream.getvalue()) |
| return {"path": str(Path(path).resolve()), "sha256": sha256(path), "width": image.width, "height": image.height, "mode": "RGB"} |
|
|
| def extract_assets(video, root, count=24, max_side=832, quality=90): |
| info = video_info(video); indices = frame_indices(info["frames"], count); frames = read_frames(video) |
| return [{**jpeg_asset(frames[index], root / f"{j:02d}.jpg", max_side, quality), "index": index, "timestamp": index / info["fps"]} for j, index in enumerate(indices)] |
|
|
