New algorithm of perceptual weighting filter used in CELP wideband speech codec.
Yang Wen · Journal of Zhejiang University(Science Edition) · 2009
The psychoacoustic model has been successfully applied in wideband audio coding.By incorporating the psychoacoustic model into CELP speech codec and constructing a new perceptual weighting filter,the quality of synthesized speech can be effectively improved.The fundamental obstacle to the application of the psychoacoustic model lays its complexity.This paper tried to solve the problem by designing new schemes for the application of the psychoacoustic model.Instead of computing and converting the masking curve,LSP coefficients or filter coefficients were interpolated for the psychoacoustic model in each sub-frame to greatly reduce its complexity.The average coding time was thus decreased by 18% and 53% respectively,with little impact on the speech quality.The improved scheme achieves a high generality and it could be integrated into the psychoacoustic models applied to other CELP coders.