Patent ID: 8422688

Claim:
An apparatus for decoding an audio signal, comprising: an audio signal receiving device configured to receive the audio signal as an input, the audio signal having a plurality of channel signals each including an ambient component signal and a source component signal, wherein the ambient component signal corresponds to a component signal of the audio signal for enabling a listener to sense a feeling for a currently located space; an ambient component signal extracting device configured to extract the ambient component signal of each of the channel signals based on correlation between the channel signals; an ambient component signal modifying device configured to modify the ambient component signal using surround effect information; a source component signal extracting device configured to extract the source component signal of each of the channel signals based on the correlation between the channel signals; a first signal output device configured to output the modified ambient component signal; and a second signal output device configured to output the audio signal or the source component signal, wherein the ambient component signal extracting device is further configured to: estimate a power of a first channel signal of the received audio signal, a power of a second channel signal of the received audio signal, and correlation between the first and second channel signal, calculate a power of the source component signal and a power of the ambient component signal using the estimated power of the first channel signal, the estimated power of the second channel signal and the correlation between the first and second channel signal, and extract the ambient component signal using the calculated power of the source component signal and the calculated power of the ambient component signal.