The new nADPCMB⊥MLT coding scheme: from non linear fullband toward non linear subband prediction coding of speech signal

This paper focuses on a newly developed transparent nADPCMB⊥MLT speech coding algorithm. Our coder first decomposes the narrowband speech signal in subbands, a nonlinear ADPCM scheme is then performed in each subband. The signal subband decomposition is piloted by the equivalent Modulated Lapped Transform (MLT) filter bank. The novelty of this algorithm is the nonlinear approach, based on neural networks, to subband prediction coding. The nADPCMB⊥MLT coding algorithm derives from our preceding nonlinear speech coding algorithm and our ADPCMB⊥MLT linear subband coding scheme. The nADPCMB⊥MLT coding algorithm also reveals transparent coding of a multi-talker speech signal at the rate of 24 kbps.