Complex sentence: Previews of movies and events were shortened trailers of the program provided to cable/satellite operators regularly on laserdisc, and would feature information on the bottom of the screen and a date/time on the top left that would serve as a countdown to start time.
Split into simpler sentences: Previews of movies and events were shortened trailers of the programs, provided to cable/satellite operators regularly on laserdisc. These short trailers would feature digitally-overlaid information on the bottom of the screen and a date/time on the top left serving as a countdown to start time.