A rerceptual weighting filter on cepstrum domain for wideband speech codecs

A novel perceptual weighting filter for improving the perceptual quality of wideband speech codecs (such as ITU-T G.722.2 Adaptive Multi-rate Wideband codec AMR-WB) is proposed.The perceptual processing is based on the cepstral difference of ISP multiplied-polynomial cepstrum and LPC cepstral coefficients. The paper introduces the concepts of ISP pseudo-cepstrum, deduces the ISP pseudo-cepstrum and ISP multiplied-polynomial cepstrum.The spectral tilt is more pronounced in wideband signals due to the wide dynamic range between low and high frequencies. The proposed filter significantly compensates the spectral tilt of wideband signals that codec does not require an additional tilt compensation as traditional technique.The frequency response of proposed perceptual weighting filter is consistent with the auditory masking theory. Simulation results indicate that the objective assessment scores obtained using wideband Perceptual Evaluation of Speech Quality (w-PESQ) can be improved significantly by the proposed method.