Proceedings ArticleDOI
Code-excited linear prediction(CELP): High-quality speech at very low bit rates
Manfred R. Schroeder,B. S. Atal +1 more
- Vol. 10, pp 937-940
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TLDR
A code-excited linear predictive coder in which the optimum innovation sequence is selected from a code book of stored sequences to optimize a given fidelity criterion, indicating that a random code book has a slight speech quality advantage at low bit rates.Abstract:
We describe in this paper a code-excited linear predictive coder in which the optimum innovation sequence is selected from a code book of stored sequences to optimize a given fidelity criterion. Each sample of the innovation sequence is filtered sequentially through two time-varying linear recursive filters, one with a long-delay (related to pitch period) predictor in the feedback loop and the other with a short-delay predictor (related to spectral envelope) in the feedback loop. We code speech, sampled at 8 kHz, in blocks of 5-msec duration. Each block consisting of 40 samples is produced from one of 1024 possible innovation sequences. The bit rate for the innovation sequence is thus 1/4 bit per sample. We compare in this paper several different random and deterministic code books for their effectiveness in providing the optimum innovation sequence in each block. Our results indicate that a random code book has a slight speech quality advantage at low bit rates. Examples of speech produced by the above method will be played at the conference.read more
Citations
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Journal ArticleDOI
Vector quantization in speech coding
John Makhoul,S. Roucos,H. Gish +2 more
TL;DR: This tutorial review presents the basic concepts employed in vector quantization and gives a realistic assessment of its benefits and costs when compared to scalar quantization, and focuses primarily on the coding of speech signals and parameters.
Book
Survey of the State of the Art in Human Language Technology
TL;DR: In this article, the authors present a glossary for language analysis and understanding in the context of spoken language input and output technologies, and evaluate their work with a set of annotated corpora.
PatentDOI
Variable rate vocoder
Jacobs Paul E,Gardner William R,Lee Chong U,Gilhousen Klein S,Lam S Katherine,Ming-Chang Tsai +5 more
TL;DR: In this paper, a variable rate coding of frames of digitized speech samples is proposed, comprising the steps of determining a level of speech activity for a frame of digitised speech samples, selecting an encoding rate from a set of rates based upon the determined level of activity within said frame, and coding said frame according to a predetermined coding format for said selected rate wherein each rate has a corresponding different coding format.
Journal ArticleDOI
Vocal quality factors: analysis, synthesis, and perception.
TL;DR: A new voice source model that accounted for certain physiological aspects of vocal fold motion was developed and tested using speech synthesis, and applications include synthesis of natural sounding speech, synthesis and modeling of vocal disorders, and the development of speaker independent (or adaptive) speech recognition systems.
Journal ArticleDOI
Speech coding: a tutorial review
TL;DR: The objective of this paper is to provide a tutorial overview of speech coding methodologies with emphasis on those algorithms that are part of the recent low-rate standards for cellular communications.
References
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Journal ArticleDOI
Predictive Coding of Speech at Low Bit Rates
TL;DR: A new class of speech coders are described which allow one to realize the precise optimum noise spectrum which is crucial to achieving very low bit rates, but also represent the important first step in bridging the gap between waveform coders and vocoders without suffering from their limitations.
Proceedings ArticleDOI
Improving performance of multi-pulse LPC coders at low bit rates
Sharad Singhal,B. S. Atal +1 more
TL;DR: This paper focuses on problems encountered in attempting to maintain speech quality while synthesizing speech using multi-pulse excitation at lower bit rates.
Journal ArticleDOI
Stochastic coding of speech signals at very low bit rates: The importance of speech perception
TL;DR: A new stochastic model for generating speech signals suitable for coding at low bit rates is described, in which the speech waveform is represented as a zero mean Gaussian process with slowly-varying power spectrum.
Journal ArticleDOI
Multipath Search Coding of Stationary Signals with Applications to Speech
TL;DR: The paper reports also on results of MSC coding of speech, where both the strategy of adaptive quantization and of adaptive prediction were included in coder design.
Proceedings ArticleDOI
Speech coding using efficient block codes
Manfred R. Schroeder,B. Atal +1 more
TL;DR: This paper considers and reports on non-instantaneous digital speech coders using tree-search procedures to determine the optimal innovation sequence and discusses both random and special block codes based on optimum packing of Voronoi regions on unit spheres in multi-dimensional spaces.