Splittend in several files

src/river_annotation_tool/video_loader.py

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+import os
+import tempfile
+import zipfile
+from pathlib import Path
+
+import cv2
+
+from .config import Config
+
+
+def load_frames(zip_path: Path, max_frames: int):
+    video_bytes = zipfile.ZipFile(zip_path).read("left.mp4")
+
+    with tempfile.NamedTemporaryFile(suffix=".mp4", delete=False) as f:
+        f.write(video_bytes)
+        tmp_path = f.name
+
+    cap = cv2.VideoCapture(tmp_path)
+    fps = cap.get(cv2.CAP_PROP_FPS) or Config.FPS_FALLBACK
+
+    frames = []
+    while len(frames) < max_frames:
+        ok, frame = cap.read()
+        if not ok:
+            break
+        frames.append(cv2.cvtColor(frame, cv2.COLOR_BGR2RGB))
+
+    cap.release()
+    os.unlink(tmp_path)
+
+    if not frames:
+        raise RuntimeError(f"No frames found in {zip_path}")
+
+    h, w = frames[0].shape[:2]
+    scale = Config.DISPLAY_MAX / max(h, w)
+    dh, dw = int(h * scale), int(w * scale)
+
+    frames = [cv2.resize(f, (dw, dh)) for f in frames]
+
+    return frames, fps, dh, dw, h, w