Film captioning services provide a visual aid to moviegoers and audiences in regards to the actor's dialogue, notations for music, sound effects, and other background noises, particularly when these components are central to the on-screen exploit. A caption is a central tenet of modern cinema, because of the assistance it provides towards people with hearing disability, and speakers of a foreign language. The role of captioning in inclusivity has even been recognized by government institutions - Final Rule in ADA Title III mandates movie theaters and cinemas to provide closed captioning.
Subtitles have been defined varyingly. Subtitles are sometimes defined as translated captions. While at other times they are defined as “minimalistic captions”. At other times - they are assumed to be aimed at an audience who can hear a movie. Whatever may be the definition of subtitles, one theme seems to be common among subtitles - details of sound effects aren't incorporated, and the source of off-screen speakers is not elaborated.