Fast methods for the CELP speech coding algorithm

Kleijn, W. Bastiaan; Krasinski, D. J.; Ketchum, R. H.

doi:10.1109/29.57568

Cited by 75 publications

(10 citation statements)

References 26 publications

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“…We can rewrite the speech synthesis equation in (5) in order to include the analysis matrix rather than the synthesis matrix [14][15][16]. Thus, (5) becomes:…”

Section: Alternative Formulationmentioning

confidence: 99%

Revisiting the Linear Prediction Analysis-by-Synthesis Speech Coding Paradigm Using Real-Time Convex Optimization

Giacobello¹,

Murthi

Jensen

et al. 2018

2018 52nd Asilomar Conference on Signals, Systems, and Computers

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In this work, we propose a novel approach to speech coding by rewriting the nonlinear analysis-by-synthesis linear prediction scheme as a convex problem. This allows for determining trade-offs between, on one hand, the reconstruction error and, on the other, the sparsity of the predictor and the residual used to parametrize the speech signal. Differently from traditional coding schemes where the parameters are chosen throughout multiple optimization stages, our scheme produces a one-shot parametrization of a speech segment that intrinsically takes into consideration the voiced or unvoiced nature of a speech segment providing a better balance between residual and predictor and, consequently, a more appropriate bit allocation.

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“…We can rewrite the speech synthesis equation in (5) in order to include the analysis matrix rather than the synthesis matrix [14][15][16]. Thus, (5) becomes:…”

Section: Alternative Formulationmentioning

confidence: 99%

Revisiting the Linear Prediction Analysis-by-Synthesis Speech Coding Paradigm Using Real-Time Convex Optimization

Giacobello¹,

Murthi

Jensen

et al. 2018

2018 52nd Asilomar Conference on Signals, Systems, and Computers

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show abstract

“…In the last few years, several computational reduction methods have been studied [3], and some of them, using structured stochastic codebooks, have been reported to give a good compromise between complexity and performance [4-71. We have also proposed a hexagonal lattice codebook [8] and a sparse-delta codebook [91 effective for reducing the com-…”

Section: Codebook Structurementioning

confidence: 99%

Tree-structured delta codebook for an efficient implementation of CELP

Taniguchi

Tanaka

Ohta

1992

[Proceedings] ICASSP-92: 1992 IEEE International Conference on Acoustics, Speech, and Signal Processing

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In this paper, we present a new structured codebook for reducing the complexity and memory of a CELP stochastic codebook search. The tree-structured delta codebook, whose code vectors are generated from a small number of delta vectors, can be searched efficiently by calculating the vector correlations recursively. The complexity was reduced to 1/70 that of a conventional full-gaussian codebook, and the memory for codebook storage was reduced to 1/100.Another excellent feature of this codebook is the feasibility of changing the distribution of code vectors adaptively. The codebook adaptation method (delta vector sorting) provides an SNRseg improvement of 0.6 dB, and consistent improvement in perceptual quality, by changing the order of delta vectors according to fit the input speech.plexity. As an extension of the delta codebook, we propose a tree-structured delta codebook which not only reduces the complexity but reduces the memory requirements of CELP. We will also investigate a method for adapting the distribution of the tree-structured delta codebook based on the input speech signal for improved CELP performance.In the following section, we will first introduce the treestructured delta codebook, and discuss how it can reduce the complexity of the CELP stochastic codebook search. In section 3, we will describe the codebook adaptation method which controls the distribution of code vectors adaptively based on the input speech, using the special nature of the treestructured delta codebook. Then, in section 4, we will analyze the performance of a CELP coder which uses the tree-structured delta codebook, and the codebook adaptation method. TREE-STRUCTURED DELTA CODEBOOK 1. INTRODUCTION Codebook structureSince it was first introduced in 1984, Code Excited Linear Prediction (CELP) [ 1,2] has been intensively investigated as a promising coding algorithm to provide good quality speech at low bit rates. CELP is a name for the class of coding algorithms which employ vector quantization (VQ) using a perceptually weighted error criterion measured in an Analysis-by-Synthesis loop. Although this process gives an efficient representation of the excitation signal, and exhibits better performance than conventional coding methods, the codebook search requires a huge computational load. This was a major drawback of CELP in its practical implementation. In particular, in the area of digital cellular communication, which is considered the biggest application area for lowbit-rate speech coding, reducing the complexity of CELP is important for small hardware size and low power consumption.In the last few years, several computational reduction methods have been studied [3], and some of them, using structured stochastic codebooks, have been reported to give a good compromise between complexity and performance [4-71. We have also proposed a hexagonal lattice codebook [8] and a sparse-delta codebook [91 effective for reducing the com-The tree-structured delta codebook is a variation on the delta codebook which we proposed in [9]. In the d...

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“…Pulse code modulation (PCM) techniques such as G.726 (ADPCM) yield much better hearing quality over LPC-10E but demand higher bit rates of 32 or 16Kbps [1]. The CELP coding algorithm is the improved version of the LPC algorithm which produces high quality speech at 8Kbps [2][3] but below this rate speech quality is degraded significantly.…”

Section: Introductionmentioning

confidence: 99%

A new speech coding algorithm using zero cross and phoneme based SYMPES

Şişman

Güz

Gürkan

et al. 2013

International Symposium on Signals, Circuits and Systems ISSCS2013

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In this work, a new low bit rate hybrid speech coding approach which combines the benefits of the SYMPES (Systematic Procedure for Predefined Envelope and Signature Sequences) and zero cross and phoneme based segmentation is proposed. In the new approach, the SYMPES structure is developed in the phoneme based fashion. In order to achieve lower bit rates, some drawbacks such as computational complexity, relatively high encoding times etc. of the SYMPES are also eliminated in the new version. Experimental results show that in almost same bit rates very promising speech quality is obtained compared to the other conventional methods such as CELP (Code Excited Linear Predictive) coding algorithm.

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Fast methods for the CELP speech coding algorithm

Cited by 75 publications

References 26 publications

Revisiting the Linear Prediction Analysis-by-Synthesis Speech Coding Paradigm Using Real-Time Convex Optimization

Revisiting the Linear Prediction Analysis-by-Synthesis Speech Coding Paradigm Using Real-Time Convex Optimization

Tree-structured delta codebook for an efficient implementation of CELP

A new speech coding algorithm using zero cross and phoneme based SYMPES

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