Linear predictive coding

About: Linear predictive coding is a research topic. Over the lifetime, 6565 publications have been published within this topic receiving 142991 citations. The topic is also known as: Linear predictive coding, LPC.

A new speech coding model based on a least-squares sinusoidal representation

Abstract: In recent years the concept of analysis-by-synthesis has been applied very successfully to improving the performance of LPC based models At the same time, new speech models have been introduced based on representing speech by a sum of amplitude and frequency-modulated sinusoids which have been shown to successfully represent the non-linear, time-varying and quasi-periodic nature of speech In this paper we present an approach to applying the analysis-by-synthesis technique to sinusoidal speech modelling in an attempt to increase the ability of the model to accurately represent the speech waveform

eX-CELP: a speech coding paradigm

Abstract: This paper presents the core technology of novel enhancements to achieve toll quality at 4 kbps, our experiments and test results traditional CELP coding, coined eXtended CELP (eX-CELP). It is showed that this technology is also successful and suitable for centered on a combined and selective usage of closed-loop/open-both high and medium bit rates. Fig. I and Fig.2 illustrate the basic loop approach, and variant algorithm structure concept. The above structure of the eX-CELP encoder and decoder. two concepts are complemented by new features and refined One of the main themes of the eX-CELP technology is the existing technologies. The eX-CELP paradigm was used in judicious combination of the closed-loop approach and the open-several speech coding systems. It is the core technology of the loop approach, together with a careful selective usage of them. recently chosen candidate for the 3G-CDMA speech codec This mechanism is coined COLA, and its main objective is to standard. It was the best candidate for ITU-T 4 kbps codec intelligently employ the most appropriate approach for different qualification test, and became the basis technology for a types of input signals in order to preserve the perceptually consortium candidate to the ITU-T 4 kbps speech coding important contents. Another important feature in the eX-CELP competition.

Robust predictive coding and the Wyner-Ziv problem

Abstract: The problem of robust communication of predictive encoded video in a joint source-channel setting is addressed. Specifically, the problem of predictive mismatch, where there is a drift between the state of the encoder and the decoder is addressed as a variant of the Wyner-Ziv problem. A video encoding algorithm based on the H.26L video codec, which presents the propagation of error in predictively encoded video in the event of predictive mismatch (or drift) between the encoder and the decoder, is proposed. One of the main advantages of the proposed approach is that there is minimal loss in performance over the standard H.26L encoder during error-free transmission, while simultaneously allowing error recovery in the event of errors. Using turbo codes as coset codes, the performance of the proposed codec is evaluated and the efficacy of the proposed framework is demonstrated. The performance of the proposed approach can only improve with the use of superior coset codes.

Fundamental frequency generation for whisper-to-audible speech conversion

Abstract: In this work, we address the issues involved in whisper-to-audible speech conversion. Spectral mapping techniques using Gaussian mixture models or Artificial Neural Networks borrowed from voice conversion have been applied to transform whisper spectral features to normally phonated audible speech. However, the modeling and generation of fundamental frequency ($F_0$) and its contour in the converted speech is a major issue. Whispered speech does not contain explicit voicing characteristics and hence it is hard to derive a suitable $F_0$, making it difficult to generate a natural prosody after conversion. Our work addresses the $F_0$ modeling in whisper-to-speech conversion. We show that $F_0$ contours can be derived from the mapped spectral vectors, which can be used for the synthesis of a speech signal. We also present a hybrid unit selection approach for whisper-to-speech conversion. Unit selection is performed on the spectral vectors, where $F_0$ and its contour can be obtained as a byproduct without any additional modeling.

The optimization of perceptually-based features for speaker identification

Abstract: Results of an experimental study and the optimization of features for a conventional vector-quantization codebook-based automatic speaker identification (ASI) system are presented. Standard LPC (linear predictive coding) and a perceptually weighted feature termed PLP (perceptually based linear prediction) are compared using appropriate distance measures, namely, the log-likelihood, and three cepstral variants: constant weighting, the robot-power-sum, and the inverse variance. PLP features combined with a weighted cepstral measure are found to be consistently the best in a number of different digit-independent ASI experiments. Results support the hypothesis that the higher orders of PLP (>5) contain significant speaker-specific information, with ASI performance improving rapidly up to order 8, and then far more slowly yet consistently up to order 16. A similar pattern is seen for codebook size, with fast improvements up to size 64, with more gradual gains thereafter. >