Patent ID: 8612239

Claim:
An apparatus for coding audio signals based on signal distribution characteristics of each channel, comprising: a down-mixer for receiving multi-channel audio signals and down-mixing the multi-channel audio signals into mono signals; a coder for coding the mono signals; an input channel correlation analyzer for receiving the multi-channel audio signals, deciding whether to give stereo effect to the multi-channel audio signals based on signal distribution characteristics of the multi-channel audio signals for each channel, and outputting a control signal indicating whether to perform stereo representation process; and a stereo representation unit for performing stereo representation process onto the multi-channel audio signals when the control signal indicating to perform stereo representation process, wherein the input channel correlation analyzer includes: an auto-correlation calculator for calculating and outputting auto-correlation for the multi-channel audio signals; a cross-correlation calculator for calculating and outputting cross-correlation for the multi-channel audio signals; a correlation ratio calculator for receiving the auto-correlation and the cross-correlation, calculating a ratio between the auto-correlation and the cross-correlation, and outputting a correlation ratio; and a stereo coding decider for comparing the correlation ratio with a predetermined threshold and deciding whether to inactivate operation of a stereo representation unit, wherein the stereo coding decider generates and outputs a control signal including information for inactivating operation of the stereo representation unit when the correlation ratio is smaller than the threshold, and the stereo coding decider generates and outputs a control signal including information for operating the stereo representation unit when the correlation ratio is not smaller than the threshold.