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Proceedings ArticleDOI

Improving performance of multi-pulse LPC coders at low bit rates

Sharad Singhal, +1 more
- Vol. 9, pp 9-12
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TLDR
This paper focuses on problems encountered in attempting to maintain speech quality while synthesizing speech using multi-pulse excitation at lower bit rates.
Abstract: 
The multi-pulse excitation model provides a method for producing natural-sounding speech at medium to low bit rates. Multi-pulse analysis obtains the all-pole filter excitation by minimizing a spectrally-weighted mean-squared error between the original and synthetic speech signals. Although the method provides high quality speech around 10 kbits/sec, speech quality suffers if the bit rate is lowered. In this paper, we focus on problems encountered in attempting to maintain speech quality while synthesizing speech using multi-pulse excitation at lower bit rates.

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Citations
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Proceedings ArticleDOI

Code-excited linear prediction(CELP): High-quality speech at very low bit rates

Manfred R. Schroeder, +1 more
TL;DR: 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.
Journal ArticleDOI

Efficient vector quantization of LPC parameters at 24 bits/frame

Kuldip K. Paliwal, +1 more
- 01 Jan 1993 - 
TL;DR: It is shown that the split vector quantizer can quantize LPC information in 24 bits/frame with an average spectral distortion of 1 dB and less than 2% of the frames having spectral distortion greater than 2 dB.
PatentDOI

Variable rate vocoder

Jacobs Paul E, +5 more
- 03 Jun 1992 - 
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

Advances in speech and audio compression

Allen Gersho
TL;DR: Current activity in speech compression is dominated by research and development of a family of techniques commonly described as code-excited linear prediction (CELP) coding, which offer a quality versus bit rate tradeoff that significantly exceeds most prior compression techniques.
Journal ArticleDOI

Regular-pulse excitation--A novel approach to effective and efficient multipulse coding of speech

P. Kroon, +2 more
- 01 Oct 1986 - 
TL;DR: Using the generalized baseband coder formulation, it is demonstrated that under reasonable assumptions concerning the weighting filter, an attractive low-complexity/high-quality coder can be obtained.
References
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Proceedings ArticleDOI

A new model of LPC excitation for producing natural-sounding speech at low bit rates

B. Atal, +1 more
TL;DR: This paper describes a new approach to the excitation problem that does not require a priori knowledge of either the voiced-unvoiced decision or the pitch period, and minimizes a perceptual-distance metric representing subjectively-important differences between the waveforms of the original and the synthetic speech signals.
Journal ArticleDOI

Predictive Coding of Speech at Low Bit Rates

Bishnu S. Atal
- 01 Apr 1982 - 
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.
Journal ArticleDOI

LPC prediction error--Analysis of its variation with the position of the analysis frame

Lawrence R. Rabiner, +2 more
- 01 Oct 1977 - 
TL;DR: It is shown that a fairly substantial variation in the prediction error is obtained within a single frame, independent of the analysis method (i.e., the covariance, autocorrelation, or lattice method), suggesting that standard methods of LPC analysis may be inadequate for some applications.