those VCD dat file are MPEG , not avi - avi is a container format

Audio Video Interleave (also Audio Video Interleaved), known by its acronym AVI, is a multimedia container format introduced by Microsoft in November 1992 as part of its Video for Windows technology. AVI files can contain both audio and video data in a file container that allows synchronous audio-with-video playback.
Audio Video Interleave - Wikipedia, the free encyclopedia