New LSP encoding method based on two-dimensional linear prediction

A new line spectrum pair (LSP) encoding method, two-dimensional differential LSP (2DdLSP) coding, is proposed. This 2DdLSP approach simultaneously takes advantage of strong interframe and intraframe correlation of LSP parameters. The parameters to be quantised are the prediction residuals which possess the property of smaller variance than LSP parameters. This is the key point for the success of the 2DdLSP method. Three quantisation schemes, a scalar quantisation and two vector quantisations (VQs), are presented. The best result in simulation is achieved by using the product codebook VQ. A spectral distortion of 1 dB ² at 19 bits per frame can be obtained when the frame period is 10 ms. Both within-training and out-of-training tests have demonstrated the robustness of the proposed method to data variation.<>