It can store video, audio, subtitles, and even still images.
Using hashes helps prevent users from easily guessing the names of other private files on a server. The MP4 Format: A Universal Container
The term "Erox" in your search query could refer to several distinct entities:
The string does not correspond to a known software version, hardware serial number, or a widely documented viral video. In the context of an .mp4 file, this specific alphanumeric string most likely represents a unique internal identifier or a CDN (Content Delivery Network) hash generated by a file-hosting platform or video-sharing site.