An expanded Mid/Side coding for 3D audio signal compression

Three dimensional (3D) audio technologies are booming with the success of 3D video technology. The sharply increased audio channels make its huge data unacceptable for transmitting bandwidth and storage media. This paper investigates the conventional Mid/Side (M/S) coding method, and expands it to a Three-channel Dependent M/S coding (3D-M/S) method. 3D-M/S perform sum and difference coding based on three channels instead of conventional two channels, and corresponding transform matrixes are presented. Furthermore, a framework is proposed to enable 3D-M/S compress any number of audio channels. Experiment shows proposed method obtains 25.4% objective quality improvement comparing with independent channel coding, and only increases 11.3% complexity comparing with the 29.9% of PCA method.