Patent ID: 7720231

Claim:
An encoder for encoding audio signals, the encoder comprising means ( 1 ) for generating a monaural signal (MAS) comprising a combination of at least two input audio signals (x(n), y(n)), and means ( 10 ) for generating a set of spatial parameters (IPDi; ICi) indicative of spatial properties of the at least two input audio signals (x(n),y(n)), wherein the set of spatial parameters (IPDi; ICi) at least comprises an inter-channel coherence value (ICi) and/or an inter-channel phase difference value (IPDi), and wherein the means ( 10 ) for generating the set of spatial parameters (IPDi; ICi) comprises means ( 106 ; 106 , 107 ) for generating a cross-correlation function (Ri; Pi) of the at least two input audio signals (x(n), y(n)), means ( 111 ) for determining a complex coherence value (Qi) by summing values of the cross-correlation function (Ri; Pi), and means ( 112 ) for determining an absolute value of the complex coherence value (Qi) to obtain an estimate of the inter-channel coherence value (ICi), and/or means ( 113 ) for determining an argument of the complex coherence value (Qi) to obtain an estimate of the inter-channel phase difference value (IPDi).