While theatrical folk may perhaps use the term “Rhubarb” the film industry in the US and Australasia, influenced by our North American colleagues, use the word “Walla” more frequently.

Usually background extras are required to appear more or less animated during the shooting of a scene, but remain as quiet as possible so that the principal actors’ dialogue may be clearly recorded.

For various reasons a scene may be shot “MOS” (“mit out sound”--a legacy of one of those European directors who came to Hollywood in the Golden Age) as well, and the whole track including Walla has to be built from scratch.

“Walla” is usually recorded later in a sound studio as part of post production and generated by a “loop group” of actors, who very often have played no previous part in the film and usually require some direction to acquaint them with the nature of the scene. It’s common, too, to add further information from unspecified extras by recording “wild lines” which have written content but vaguely defined speakers.

The film industry has a rich jargon, it’s not just about “best boys”.

Ross