The answer to this question really lies in two parts.
If you mean largest in terms of film output, then India is by far the world’s largest producer of cinema, with some 1300 films made annually (although most of these are never screened outside the country). Reasonably close behind is the USA with around 800 films.
If on the other hand you mean which country exports the most cinema, then of course the USA is a clear winner, with Hong Kong a surprisingly close second.