fix: no null check after cv2.imread can crash on bad files

[andrewwhitecdw]

This PR addresses the following issue in scripts/images_to_video.py: no null check after cv2.imread can crash on bad files.

Changes

• scripts/images_to_video.py: no null check after cv2.imread can crash on bad files.

Details

Before:

    # Read first image to get dimensions
    first_img = cv2.imread(str(image_files[0]))
    height, width = first_img.shape[:2]

    # Initialize video writer
    fourcc = cv2.VideoWriter_fourcc(*'mp4v')
    out = cv2.VideoWriter(args.output_path, fourcc, args.fps, (width, height))

    # Process each frame
    for image_file in image_files:
        # Read image
        frame = cv2.imread(str(image_file))
        
        # Write frame to video
        out.write(frame)

After:

    # Read first image to get dimensions
    first_img = cv2.imread(str(image_files[0]))
    if first_img is None:
        raise ValueError(f"Could not read image: {image_files[0]}")
    height, width = first_img.shape[:2]

    # Initialize video writer
    fourcc = cv2.VideoWriter_fourcc(*'mp4v')
    out = cv2.VideoWriter(args.output_path, fourcc, args.fps, (width, height))
    if not out.isOpened():
        raise RuntimeError(f"Could not open video writer: {args.output_path}")

    # Process each frame
    for image_file in image_files:
        # Read image
        frame = cv2.imread(str(image_file))
        if frame is None:
            raise ValueError(f"Could not read image: {image_file}")
        
        # Write frame to video
        out.write(frame)