Complex sentence: The Laserfilm format was originally based off an earlier videodisc called ARDEV, originally developed by ARDEV Inc. ARDEV was originally a subsidiary of Atlantic Richfield until 1981, when ARDEV and all of its videodisc technologies were acquired by McDonnell-Douglas.
Split into simpler sentences: The Laserfilm format was originally based off an earlier videodisc format called ARDEV, developed by a company of the same name ARDEV which was originally a subsidiary of Atlantic Richfield until 1981. At that time, ARDEV and all of its videodisc technologies were acquired by McDonnell-Douglas.