The hyphen before .av (i.e., Part1-.av ) indicates a possible filename corruption during a transfer from a FAT32 filesystem, where special characters or long names were truncated.
Many users from that era used or Ulead VideoStudio which sometimes saved project files with temporary extensions ( .av as an active video capture temp file). If this file is only 10–50MB, it may be a low-resolution WMV preview. If it’s 200MB–2GB, it’s likely a full AVI. The hyphen before
This likely refers to the production series or the agency name responsible for the content. The hyphen before .av (i.e.