Patent ID: 8818764

Claim:
A downmixing device comprising: a memory; and a processor, the processor configured to execute instructions stored in the memory, the instructions including: an input receiving instruction configured to receive an input signal including a plurality of channels; a matrix conversion instruction configured to perform a matrix operation for the input signal using a matrix D and output a plurality of signals applied with the matrix operation; a rotation correction instruction configured to provide different phase rotations with each of at least two signals of the plurality of signals outputted the matrix conversion instruction based on vectors of the plurality of channels when each of phases of the at least two signals is the same; a spatial information extraction instruction configured to extract spatial information from output signals of the rotation correction instruction; an inverse matrix conversion instruction configured to perform an inverse matrix operation for the output signals of the rotation correction instruction and for a signal generated based on the spatial information using an inverse matrix D −1 , which is an inverse of the matrix D used for the matrix operation by the matrix conversion instruction; and an error calculation instruction configured to calculate an error amount between the input signal and a result of the inverse matrix conversion instruction, wherein: the rotation correction instruction determines the different phase rotations based on the error amount; and the spatial information extraction instruction determines final spatial information based on the error amount.