Scalable innovation coding

Low-complexity scalable methods are of importance to achieve multi-rate and variable rate speech coding. Adopting the CELP concept, we focus on the innovation coding, suggesting an adaptive companding VQ. We present a scheme having essentially no increase in complexity as the rate is increased, yet having a competitive distortion performance. This is acheived by avoiding an explicit perceptual filtering step in the coding, still utilizing close to optimal VQ techniques in a perceptual domain. Subjective and objective distortion performance is better than, or in parity with, that of conventional white noise excitation methods or multipulse structures.