Efficient quantization of LSF by utilizing dynamic interpolation

Utilizing the ordering property of LSF (Line Spectral Frequency) parameters, we propose a new quantization method for scalar quantization of LSF coefficients, which uses a new set of quantization parameters called LSFI instead of direct LSF or Differential LSF (LSFD). Based on the experimental analysis the new quantization method is further improved by combining with LSFD parameters (we call this improved version an LSFID scheme). The experimental results have shown that the proposed methods are effective in decreasing quantization distortion. Compared with LSFD, the LSFID quantizer can save at least 1 bit per frame to achieve 1dB quantization