An Audio Coding Technique Employing the Inter-channel Phase Difference Skip

!"#$%&'(/')*+,-.(USAC)$/01MPEG %23$% (IPD) 456/789&$:; ?@$%& A3?IPD BCDEFGH$IJK4LM9NJO<. PGH*;QR5STUVWX<. IPD ?YM'T/Z[I4\]9N^_`G$%a 9ab9&#cdef9\, #cdgh? 4iUjI38% fI? p[564qWX\, MUSHRA ^_rs*;t0?'u9vw'x<.AbstractThis paper deals with an efficient method for skipping inter-channel phase differences (IPD) in the MPEG surround of the unified speech and audio coding (USAC). Based on the psycho-acoustic sensitivity on the IPD, we estimate a threshold on IPD, below which we can not notice degradation in spatial cue. We propose an IPD skip method, in which any IPDs within the threshold are set to zero and are not transmitted. The proposed IPD skip method gives about 38% savings in terms of bit amount for IPD. Nevertheless, in the MUSHRA test, the proposed method does not show any noticeable degradation in the decoded audio quality. Keyword : MPEG Surround(MPS), Unified speech and audio coding(USAC), Inter-channel phase difference(IPD), Overall phase difference(OPD)