Method and Apparatus for Decoding an Audio Signal

Abstract

An apparatus for decoding an audio signal and method thereof are disclosed. The present invention includes receiving the audio signal and spatial information, identifying a type of modified spatial information, generating the modified spatial information using the spatial information, and decoding the audio signal using the modified spatial information, wherein the type of the modified spatial information includes at least one of partial spatial information, combined spatial information and expanded spatial information. Accordingly, an audio signal can be decoded into a configuration different from a configuration decided by an encoding apparatus. Even if the number of speakers is smaller or greater than that of multi-channels before execution of downmixing, it is able to generate output channels having the number equal to that of the speakers from a downmix audio signal.

1 . A method of decoding an audio signal, comprising:
 receiving spatial information;   generating combined spatial information using the spatial information; and   decoding the audio signal using the combined spatial information,   wherein the combined spatial information is generated by combining spatial parameters included in the spatial information.   
     
     
         2 . The method of  claim 1 , wherein the combined spatial parameters are generated by inputting the spatial parameters to a conversion formula. 
     
     
         3 . The method of  claim 2 , further comprising deciding the conversion formula according to tree configuration information for the audio signal. 
     
     
         4 . The method of  claim 2 , further comprising deciding the conversion formula according to output channel information. 
     
     
         5 . The method of  claim 1 , wherein the audio signal is a downmix audio signal generated from downmixing a multi-channel audio signal, and the spatial parameters are decided in the course of downmixing the multi-channel audio signal according to a predetermined tree configuration. 
     
     
         6 . The method of  claim 1 , wherein the audio signal is a signal generated from downmixing a multi-channel audio signal, the spatial parameters include an inter-channel level difference of the multi-channel audio signal, and an inter-channel level difference of combined spatial parameters is calculated by combining the inter-channel level difference of the multi-channel audio signal entirely or partially. 
     
     
         7 . The method of  claim 1 , wherein the audio signal is a signal generated from downmixing a multi-channel audio signal, the spatial parameters include at least one of an inter-channel correlation of the multi-channel audio signal, and an inter-channel correlation of combined spatial parameters are calculated by combining the inter-channel correlation of the multi-channel audio signal. 
     
     
         8 . The method of  claim 7 , wherein the spatial parameters further include an inter-channel level difference of the multi-channel audio signal, and the inter-channel correlation of the combined spatial parameters are calculated by combining at least one of the inter-channel level difference of the multi-channel audio signal and at least one of the inter-channel level difference of the multi-channel audio signal. 
     
     
         9 . The method of  claim 1 , wherein modified spatial information including the combined spatial information is generated using the spatial information and the modified spatial information includes at least one of partial spatial information and expanded spatial information.