Backward adaptation for low delay vector excitation coding of speech at 16 kbit/s

Cuperman, V.; Gersho, A.; Pettigrew, R.; Shynk, J.J.; Yao, Jey-Hsin

doi:10.1109/glocom.1989.64153

Cited by 24 publications

(10 citation statements)

References 7 publications

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“…For codebook based systems like LD-CELP and LD-VXC, the WMSE is computed for each entry in the excitation codebook and M is the vector dimension. Codebook design algorithms are discussed in [7,83. For tree coding, all possible path map sequences to depth M are considered for computing the reconstructed speech y ( n ) and the path giving the minimum distortion is chosen.…”

Section: Excitation Sequence Optimization the Weighted Mean-square Errormentioning

confidence: 99%

“…The update of the coefficients k r ) may be done using the LMS algorithm with leakage factors for improving noisy channel performance. However, a significant reduction in the computational complexity may be obtained by using the so-called sign algorithm [8] which avoids the division operations required by the standard LMS algorithm: kp+')-, -(l-p)kr)+ hsign(ej(n))sign(rj(n-l)) (7) where l<$.IM. A good choice for the constants is…”

Section: Fig 2 Lattice Short-term Predictormentioning

confidence: 99%

“…In block adaptation, the pitch prediction coefficients, ai, may be calculated from the previous frame of predictor output, w ( n ) , using the autocorrelation [7,15,161 or the covariance methods [4,5,14].…”

Section: The Pitch Predictor Tor Is Given Bymentioning

confidence: 99%

“…A system based on recursive backward adaptation and analysis-by-synthesis codebook excitation quantization called Vector ADPCM was introduced in [6]. Vector ADPCM, which appears to be the first application of backward adaptation to analysis-bysynthesis excitation coding, evolved into Low-Delay Vector Excitation Coding (LD-VXC) [7]. Lattice LD-VXC (LLD-VXC) achieved toll quality at 16 kbls with a delay lower than 2 ms [SI.…”

Section: Introductionmentioning

confidence: 99%

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Low delay speech coding

Cuperman

[1991] Conference Record of the Twenty-Fifth Asilomar Conference on Signals, Systems &Amp; Computers

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Good speech quality with low-delay coding at 8-16 kb/s has been obtained using backward adaptive analysis-by-synthesis codecs, such as Low-Delay CELP (future 16 kb/s standard), Low-Delay Vector Excitation Coding (LD-VXC), and backward adaptive tree/trellis codecs. This paper presents design and performance trade-offs for the low-delay analysis-by-synthesis codecs at rates of 8-16 kb/s. A number of approaches for improving the speech quality at 8 kb/s are discussed. Backward pitch prediction configuration is compared to a closed-loop forward configuration similar to that used in the conventional forward CELP for the adaptive codebook. Finally, the robustness to transmission errors is discussed and a number of trade-offs for reducing the sensitivity to transmission errors are presented.

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Section: Excitation Sequence Optimization the Weighted Mean-square Errormentioning

confidence: 99%

Section: Fig 2 Lattice Short-term Predictormentioning

confidence: 99%

Section: The Pitch Predictor Tor Is Given Bymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Low delay speech coding

Cuperman

[1991] Conference Record of the Twenty-Fifth Asilomar Conference on Signals, Systems &Amp; Computers

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“…The recursive adaptive algorithms used to update the predictor coefficients are similar to those used in the CCITT 32 kb/s algorithm [5,71. This solution leads to relatively low computational complexity; however, it has the disadvantage of a rough spectral modeling of the speech signal.…”

Section: Introductionmentioning

confidence: 99%