Temporal quantization of spatial information using directional clustering for multichannel audio coding

Binaural cue coding, which is a representing low bit-rate coding of multichannel audio, generates large distortion when the audio data have complex spatial image, such as symphony. Such distortion caused by the low frequency resolution of spatial information because BCC quantizes the parameters of localization. In this paper we propose a new coding framework by quantizing the spatial information temporally. The single-channel sum signal is panned to the multiple channels by selecting the prototypes of the spatial filter. Optimization of the prototypes with minimum coding error is given by a k-means-like clustering of the angles whose centroids are given by the first principal components of the covariances in the classes. The efficiency of the proposed coding with high quality is verified both in the objective and subjective evaluations.