Novel technique for tonal language speech compression based on a bit rate scalable MP-CELP coder

This paper proposes a modification of the flexible multi-pulse based code excited linear predictive (MP-CELP) coder with bit rate scalabilities for tonal language speech in multimedia applications. The coder consists of a core coder and bit rate scalable tools. The high pitch delay resolutions are applied to the adaptive codebook of the core coder for tonal language speech quality improvement. The bit rate scalable tool employs multi-stage excitation coding based on an embedded-coding approach. The multi-pulse excitation codebook at each stage is adaptively produced depending on the selected excitation signal ut the previous stage. The experimental results show that the speech quality of the proposed coder is improved compared to that of the conventional coder without pitch-resolution adaptation.