Short, four-letter alphanumeric strings like "xdut" are common naming conventions for videos saved from platforms like Telegram , Discord , or certain TikTok downloaders.
The (5) suggests this is the fifth copy of a file named "xdut" downloaded to the same folder. xdut (5).mp4
Look at your recently used apps. Did you save a video from a group chat or a specific website right before this appeared? xdut (5).mp4