Interspeech'2005 - Eurospeech

Lisbon, Portugal
September 4-8, 2005

Using Dynamic Codebook Re-Ordering to Exploit Inter-Frame Correlation in MELP Coders

Venkatesh Krishnan, Thomas P. Barnwell III, David V. Anderson

Georgia Institute of Technology, Atlanta, GA, USA

Model based speech coders such as the mixed-excitation linear prediction (MELP) coder encode parameters of the autoregressive model for short-duration frames of the speech signal. Typically, parameters extracted from successive frames by the MELP coder exhibit strong correlation. Reduction in the transmitted data-rates can be achieved if the encoders for these parameters effectively exploit this inter-frame correlation. In this paper, we apply a procedure, called dynamic codebook re-ordering (DCR) to reduce the entropy in the distribution of the symbols generated by the vector quantization encoders used in coding the MELP parameters. The entropy reduction is achieved by exploiting the correlation between the vectors of MELP parameters derived from successive speech frames. The advantages of the DCR procedure over other techniques that exploit inter-frame correlation stem from the fact that it significantly reduces the data-rates without introducing any additional coding delays or increasing the distortion and it is simple and elegant.

Full Paper

Bibliographic reference.  Krishnan, Venkatesh / Barnwell III, Thomas P. / Anderson, David V. (2005): "Using dynamic codebook re-ordering to exploit inter-frame correlation in MELP coders", In INTERSPEECH-2005, 2717-2720.