Speech coding with the ACELP paradigm is based on a least squares algorithm in a perceptual domain, where the perceptual domain is specified by a filter. This article shows that the computational complexity of this conventional definition of the least squares problem can be reduced by taking into account the impact of the zero impulse response into the next frame. The proposed modification introduces a Toeplitz structure to a correlation matrix appearing in the objective function, which simplifies the structure and reduces computations. It is shown that the proposed method reduces computational complexity up to 17% without reducing perceptual quality.
Bibliographic reference. Bäckström, Tom (2013): "Computationally efficient objective function for algebraic codebook optimization in ACELP", In INTERSPEECH-2013, 3434-3438.