Recursive coding of spectrum parameters
- 20 January 2003
- conference paper
- Published by Institute of Electrical and Electronics Engineers (IEEE)
Abstract
Estimates of optimal performance in terms of spectral distortion (SD) for first order time-recursive spectrum coders are presented. Extensions of high rate theory provides us with the formulas to calculate estimates and also tells us how to design coders with optimal VQ point density. For this purpose, the PDF of the current spectrum parameter vector, given the previous, is needed. This conditional PDF is obtained analytically from a model PDF for pairs of consecutive parameter vectors, based on Gaussian mixtures. The theory gives a lower bound of 16 bits to achieve 1 dB SD. Practical coders must base the adaptive codebook design on quantized previous vectors and experiments suggest that another 2-3 bits is needed to achieve 1 dB SD. Informal subjective tests indicate that transparent quality may be maintained at even lower rates.Keywords
This publication has 5 references indexed in Scilit:
- Single stage spectral quantization at 20 bitsPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2002
- Interframe LSF quantization for noisy channelsIEEE Transactions on Speech and Audio Processing, 1999
- Performance bounds for LPC spectrum quantizationPublished by Institute of Electrical and Electronics Engineers (IEEE) ,1999
- Efficient vector quantization of LPC parameters at 24 bits/frameIEEE Transactions on Speech and Audio Processing, 1993
- Robust and efficient quantization of speech LSP parameters using structured vector quantizersPublished by Institute of Electrical and Electronics Engineers (IEEE) ,1991