AutoCrop-Vertical is a Python-based video processing tool that automatically converts horizontal videos into vertical formats optimized for social media platforms. It uses computer vision techniques and AI models such as YOLOv8 to analyze each frame, detect subjects, and dynamically adjust cropping decisions. Instead of applying a static center crop, the system intelligently tracks people or key objects to preserve visual focus and composition. When cropping would degrade the scene, it can switch to alternative layouts such as letterboxing to maintain context. The tool integrates FFmpeg for encoding and rendering, ensuring efficient processing and compatibility with standard video workflows. It supports multiple output aspect ratios and quality settings, allowing customization for different platforms. Designed as a lightweight script, it runs locally and provides a cost-free alternative to commercial video reframing tools.