Auro-3D is an immersive 3D audio format. It is designed along three layers of sound (surround, height and overhead ceiling), building on the single horizontal layer used in the 5.1 sound format. Auro-3D creates a spatial sound field by adding a height layer around the audience on top of the traditional 2D surround sound system. This additional layer reveals both localized sounds and height reflections complementing the sounds that exist in the lower surround layer. The height information that is captured during recording is mixed into a standard 5.1 surround PCM carrier, and during playback the Auro-3D decoder extracts the originally recorded height channels from this stream.