The noises in the background of a film that are not part of the main soundtrack or intentional sound effects are typically referred to as "ambient sounds" or "ambient audio." These sounds are often added during post-production to enhance the realism and atmosphere of a scene. They can include background chatter, footsteps, traffic noise, birds chirping, wind blowing, or any other sounds that occur naturally in the environment being portrayed in the film. Ambient sounds help create a sense of immersion and contribute to the overall audio experience of a movie.