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About MSVQ design codebook

Started by mouloud Djamah July 28, 2008
Hi

I have questions and I hope that someone will reply me.
- I Know that for SVQ (Split vector quantization) design codebook for LSF (line spectral frequencies) quantization, the centroid of each cell is calculated as the mean of all vectors (belong to this cell) even if the weighted Euclidean distance is used while designing the codebook. This is to ensure that the LSF parameters are sorted (lsf0
-But the design algorithms (sequential and joint design algorithms) for MSVQ (from reference [1] see below) take into account the weighted Euclidean distance while computing the centroid. Hence the LSF parameters may be not sorted !!!!!. Note that in FS MELP quantizer (which is MSVQ quantizer), if we check the codevectors of the first stage, we will see that the LSF parameters are perfectly sorted !!!!!!.

I hope that someone will reply me.

thanks[1]- W. P. LeBlanc, B. Bhattacharya, S. A. Mahmoud, and V. Cuperman, Efficient Search and Design Procedures for Robust Multi-stage VQ of LPC Parameters for 4 kb/s Speech Coding, IEEE Trans. Speech and Audio Processing, vol. 1, pp. 373-385, Oct 1993.