A 16 kb/s APC system with adaptive postfilter and evaluation of its performance

Abstract

An adaptive predictive coder (APC) with backward adaptive short-term predictor is presented for operation at 16 kb/s. Adaptive postfiltering is applied in the output of the decoder. The performance of the coder is evaluated both objectively and subjectively for fixed and switched degrees of postfiltering. Based on a stimulus-response model for the subjective testing method the performance of the coder is expressed in terms of Q-equivalent values.<>