Speech analysis and synthesis methods developed at ECL in NTT-From LPC to LSP-
Speech Communication - Special issue: Speech research in Japan
Vector quantization and signal compression
Vector quantization and signal compression
A Multi-Band CELP Wideband Speech Coder
ICASSP '97 Proceedings of the 1997 IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP '97)-Volume 2 - Volume 2
Wideband CELP speech coding at 16 kbits/sec
ICASSP '91 Proceedings of the Acoustics, Speech, and Signal Processing, 1991. ICASSP-91., 1991 International Conference
Efficient product code vector quantisation using the switched split vector quantiser
Digital Signal Processing
16 kbit/s wideband speech coding based on unequal subbands
ICASSP '96 Proceedings of the Acoustics, Speech, and Signal Processing, 1996. on Conference Proceedings., 1996 IEEE International Conference - Volume 01
Transform predictive coding of wideband speech signals
ICASSP '96 Proceedings of the Acoustics, Speech, and Signal Processing, 1996. on Conference Proceedings., 1996 IEEE International Conference - Volume 01
A 16, 24, 32 kbit/s wideband speech codec based on ATCELP
ICASSP '99 Proceedings of the Acoustics, Speech, and Signal Processing, 1999. on 1999 IEEE International Conference - Volume 01
Immittance spectral pairs (ISP) for speech encoding
ICASSP'93 Proceedings of the 1993 IEEE international conference on Acoustics, speech, and signal processing: speech processing - Volume II
Low-complexity predictive trellis-coded quantization of speech line spectral frequencies
IEEE Transactions on Signal Processing
High-resolution quantization theory and the vector quantizer advantage
IEEE Transactions on Information Theory
Optimum switched split vector quantization of LSF parameters
Signal Processing
Reduced complexity two stage vector quantization
Digital Signal Processing
A Perceptual Weighting Filter Based on ISP Pseudo-cepstrum and Its Application in AMR-WB
ISNN 2009 Proceedings of the 6th International Symposium on Neural Networks: Advances in Neural Networks - Part III
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In this paper, we provide a review of LPC parameter quantisation for wideband speech coding as well as evaluate our contributions, namely the switched split vector quantiser (SSVQ) and multi-frame GMM-based block quantiser. We also compare the performance of various quantisation schemes on the two popular LPC parameter representations: line spectral frequencies (LSFs) and immittance spectral pairs (ISPs). Our experimental results indicate that ISPs are superior to LSFs by 1 bit/frame in independent quantiser schemes, such as scalar quantisers; while LSFs are the superior representation for joint vector quantiser schemes. We also derive informal lower bounds, 35 and 36 bits/frame, for the transparent coding of LSFs and ISPs, respectively, via the extrapolation of the operating distortion-rate curve of the unconstrained vector quantiser. Finally, we report and discuss the results of applying the SSVQ with dynamically-weighted distance measure and the multi-frame GMM-based block quantiser, which achieve transparent coding at 42 and 37 bits/frame, respectively, for LSFs. ISPs were found to be inferior to the LSFs by 1 bit/frame. In our comparative study, other quantisation schemes that were investigated include PDF-optimised scalar quantisers, the memoryless Gaussian mixture model-based block quantiser, the split vector quantiser, and the split-multistage vector quantiser with MA predictor from the AMR-WB (ITU-T G.722.2) speech coder.