This paper presents an efficient codebook design for treestructured vector quantization (TSVQ), which is embedded in nature. The federal standard MELP (mixed excitation linear prediction) speech coder is modified by replacing the original single stage vector quantizer for Fourier magnitudes with a TSVQ and the original multistage vector quantizer (MSVQ) for line spectral frequencies (LSF’s) with a multistage TSVQ (MTVQ). The modified coder is fine-granular bit-rate scalable with gradual change in quality for the synthetic speech when the number of bits available for LSF and Fourier magnitudes decoding is decremented bit-by-bit.
Bibliographic reference. Djamah, Mouloud / O'Shaughnessy, Douglas (2009): "Fine-granular scalable MELP coder based on embedded vector quantization", In INTERSPEECH-2009, 2603-2606.