New Concepts in Parametric Coding of Spatial Audio: From SAC to SAOC

In the area of low bitrate audio coding, the emergence of "spatial audio coding" (SAC) technology is one of the most remarkable innovations during the recent years. By exploiting the human perception of spatial sound, these coding schemes are capable of transmitting high quality surround sound using bitrates that have been used so far for carrying traditional two-channel stereo audio. After the recent finalization of the MPEG surround (MPS) specification, a next technology generation is envisaged for standardization within ISO/MPEG allowing bitrate-efficient and backward compatible coding of several sound objects. On the receiving side, such a "spatial audio object coding" (SAOC) system renders the objects interactively into a sound scene on a reproduction setup of choice. The paper reviews the principles and current status of SAC schemes and discusses their evolution towards SAOC.