From the sound source, there are two main types. The first category is the sound in the natural environment, large to wind and rain, mountain call tsunami, fine bird language. The second category is the sound in the social environment, compared to the natural environment sound, it is more complicated, in addition to the sound of the items such as cars, doors and windows, etc., including voices and music appearing as a background audio.
From the technical point of view, it is divided into "same period recording" in shooting on-site synchronization and the simulation and reproduction of manual methods and utensils in the production of manual methods and appliances are also called "quasin". The former is more real, and it is used in a lot of adoption in movie production, and the latter is used to complete some sounds that are difficult to include and reality.
Environmental sound is the first as a means of building real hearing spaces, which is also the most basic role of environmental sound.
Environmental audio can also participate in the narrative of the film, mainly as a painted eucalyptus, suggesting to the audience, what happened outside the picture. Don't see its shape, but smell, so that the audience will trigger the audience's imagination of the space, this technique is often more fun than the direct watch scene, or more intricate.
More time, the role of environmental sound is to create an atmosphere, and the emotional tone of a scene is created. At this time, the environmental sound invisible is an important emotional expression technique, which promotes the development of the human psychology, and also touches the soul of the audience.