Tony Crowther developed the Gremlin Digital Video (GDV) standard that was used on many of Gremlin’s releases in the late 90s. On many games it powered the introductions and cutscene videos, but in Realms of the Haunting it drove the Full Motion Video embedded within the title. It was another example of Gremlin leading the games industry having its own video compression technology.
Tony has recently dug out the Windows version, developed for a native port of his True3D games that never happened. It should run under most modern Windows systems including Windows 10. Just find a Gremlin CD-ROM with the GDV files intact, download the ZIP and extract it somewhere and RUN ….