For film screenings in theatres or film festivals, you will not receive any royalties from Sabam as the screenwriter/director has assigned all rights on these works to the producer, and Sabam only collects royalties for the music that is featured in the work.
In the agreement between the producer and the director, the latter is presumed to have assigned to the producer his author’s rights for exploitations in theatres and festivals.
So, it is up to the producer to directly remunerate the screenwriters and directors.
In a nutshell, screenwriters/directors cannot receive any remuneration from their authors’ society when their works are screened in theatres or film festivals. All the same, Sabam is collecting and distributing music royalties, i.e. the royalties coming to the composer(s) of the film music.