The code format (Letter-Letter-Letter-Number) is the standard industrial format for Japanese media production. The Story:
Often, this denotes a part number or a specific version/edit of the file. In this case, it might be the fourth segment of a larger series. FHD-ARCHIVE-SONE-466 -4-.mp4
If SONE-466 represents copyrighted commercial media, you must understand your jurisdiction's laws regarding backup copies and "archival" use. FHD-ARCHIVE-SONE-466 -4-.mp4