Multi-step Coding Structure of Spatial Audio Object Coding

The spatial audio object coding (SAOC) is an effective method which compresses multiple audio objects and provides flexibility for personalized rendering in interactive services. It divides each frame signal into 28 sub-bands and extracts one set object spatial parameters for each sub-band. Objects can be coded into a downmix signal and a few parameters by this way. However, using same parameters in one sub-band will cause frequency aliasing distortion, which seriously impacts listening experience. Existing studies to improve SAOC cannot guarantee that all audio objects can be decoded well. This paper describes a new multi-step object coding structure to efficient calculate residual of each object as additional side information to compensate the aliasing distortion of each object. In this multi-step structure, a sorting strategy based on sub-band energy of each object is proposed to determine which audio object should be encoded in each step, because the object encoding order will affect the final decoded quality. The singular value decomposition (SVD) is used to reduce the increasing bit-rate due to the added side information. From the experiment results, the performance of proposed method is better than SAOC and SAOC-TSC, and each object can be decoded well with respect to the bit-rate and the sound quality.