Complex sentence: The race film or race movie was a film type produced entirely in the United States between about 1915 and the early 1950s, consisting of films produced for an all-black audience, featuring black casts.
Split into simpler sentences: The race film or race movie was a film genre which existed in the United States between about 1915 and 1950. It consisted of films produced for an all-black audience, featuring black casts.