# -*- coding: utf-8 -*-
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import logging
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import subprocess
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from typing import Optional, Tuple
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import cv2
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import numpy as np
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from app.video_io import get_ffmpeg_cmd
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logger = logging.getLogger(__name__)
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def laplacian_score(image_path: str) -> float:
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img = cv2.imread(image_path, cv2.IMREAD_GRAYSCALE)
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if img is None:
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return 0.0
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return float(cv2.Laplacian(img, cv2.CV_64F).var())
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def refine_time_in_window(
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video_path: str,
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center_sec: float,
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window_sec: float = 2.0,
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step: float = 0.5,
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) -> Tuple[float, float]:
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"""在 [center-window, center+window] 内选清晰度最高帧，返回 (best_sec, score)。"""
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import os
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import tempfile
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best_t = center_sec
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best_score = 0.0
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ffmpeg = get_ffmpeg_cmd("ffmpeg")
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t = max(0.0, center_sec - window_sec)
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end = center_sec + window_sec
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tmp = tempfile.NamedTemporaryFile(suffix=".jpg", delete=False)
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tmp.close()
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try:
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while t <= end:
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cmd = [
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ffmpeg, "-y", "-ss", f"{t:.3f}", "-i", video_path,
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"-frames:v", "1", "-q:v", "2", tmp.name,
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]
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subprocess.run(cmd, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
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if os.path.isfile(tmp.name) and os.path.getsize(tmp.name) > 0:
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score = laplacian_score(tmp.name)
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if score > best_score:
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best_score = score
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best_t = t
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t += step
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finally:
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if os.path.isfile(tmp.name):
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os.remove(tmp.name)
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return round(best_t, 2), best_score
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