MIDIVisualizer is a cross-platform application that renders real-time visualizations of MIDI files using OpenGL. Inspired by the look of rhythm games and piano roll editors, it offers smooth animations and customizable themes to turn MIDI sequences into captivating graphical performances. It works as both a live visualizer and a tool to export visuals into video, making it ideal for musicians, VJs, and creators who want to produce visually engaging content synced to their compositions.