17. A non-transitory computer readable recording medium storing instruction for encoding a multi-channel audio signal, the instructions comprising: determining semantic information for at least two channels of the multi-channel audio signal; determining degree of similarity between the at least two channels based on the determined semantic information using similar channels so as to enhance a channel separation on a decoder; and if the degree of similarity exceed a predetermined threshold, extract spatial parameters between the at least two channels and down-mix audio signals of the at least two channels: wherein the determining the degree of similarity comprises comparing a degree of similarity between the at least two channels with a predetermined threshold.
17. A non-transitory computer readable recording medium storing instruction for encoding a multi-channel audio signal, the instructions comprising: determining semantic information for at least two channels of the multi-channel audio signal; determining degree of similarity between the at least two channels based on the determined semantic information using similar channels so as to enhance a channel separation on a decoder; and if the degree of similarity exceed a predetermined threshold, extract spatial parameters between the at least two channels and down-mix audio signals of the at least two channels: wherein the determining the degree of similarity comprises comparing a degree of similarity between the at least two channels with a predetermined threshold. 18. The non-transitory computer readable recording medium of claim 17 , further comprising if the degree of similarity does not a exceed a predetermined threshold, encoding the audio signals of the at least two channels without down-mixing the audio signals.