Many older or budget-friendly MP4 players used "VM" as a model prefix. These typically feature basic video playback, FM radio, and voice recording. Reviewers often find them simple but limited by modern smartphone standards.
If you have a file named VM-01.mp4 , it is likely a system recording or a sample video from a specific camera model (like a dashcam or security camera). VM-01mp4
If you are referring to a specific device or file, here are the most likely possibilities based on common naming conventions: Many older or budget-friendly MP4 players used "VM"