capture.release()
writer.release()

if frame_count == 0:
    raise SystemExit(f"No frames were read from: {args.input_video}")
if peak_mask is None:
    peak_mask = foreground_mask
if not cv.imwrite(str(preview_path), peak_mask):
    raise SystemExit(f"Could not write preview image: {preview_path}")

print(f"input={args.input_video}")
print(f"frames={frame_count} size={width}x{height} fps={fps:.2f}")
print(f"warmup_frames={min(args.warmup, frame_count)}")
print(f"active_frames={active_frames} peak_foreground_pixels={peak_pixels}")
print(f"wrote_video={mask_path}")
print(f"wrote_preview={preview_path}")