Complex sentence: Before 1998, the company was primarily known as Channel Four Films and/or FilmFour International, but it was changed to FilmFour, to coincide with the launch of a new Digital TV channel of the same name.
Split into simpler sentences: Before 1998, the company was identified as Channel Four Films or FilmFour International. Later, the outfit was re-branded as FilmFour, to coincide with the launch of a new Digital TV channel of the same name.