Analysis and Synthesis of Spatial Parameters Using MDCT

We present a method of analyzing and synthesizing spatial parameters using only modified discrete cosine transform (MDCT). Combing it with modified discrete sine transform (MDST) enables spatial parameters representation. And instead of direct transforming, MDST spectra can be perfectly built from neighboring MDCT spectra by a conversion matrix, which is highly diagonal and can be approximated by a small number of its sub-diagonals. With MDCT based core coders, like advanced audio coding (AAC), we need no separate transforming for spatial coding, cutting down significant computational complexity.