Journal ArticleDOI
Predictive Coding of Speech at Low Bit Rates
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TLDR
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.Abstract:
Predictive coding is a promising approach for speech coding. In this paper, we review the recent work on adaptive predictive coding of speech signals, with particular emphasis on achieving high speech quality at low bit rates (less than 10 kbits/s). Efficient prediction of the redundant structure in speech signals is obviously important for proper functioning of a predictive coder. It is equally important to ensure that the distortion in the coded speech signal be perceptually small. The subjective loudness of quantization noise depends both on the short-time spectrum of the noise and its relation to the short-time spectrum of the Speech signal. The noise in the formant regions is partially masked by the speech signal itself. This masking of quantization noise by speech signal allows one to use low bit rates while maintaining high speech quality. This paper will present generalizations of predictive coding for minimizing subjective distortion in the reconstructed speech signal at the receiver. The quantizer in predictive coders quantizes its input on a sample-by-sample basis. Such sample-by-sample (instantaneous) quantization creates difficulty in realizing an arbitrary noise spectrum, particularly at low bit rates. We will describe a new class of speech coders in this paper which could be considered to be a generalization of the predictive coder. These new coders not only 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.read more
Citations
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Proceedings ArticleDOI
On noise propagation in closed-loop linear predictive coding
TL;DR: A new noise production and propagation model for open- and closed loop linear predictive coding (LPC) is proposed and allows to accurately predict the overall SNR even at lower bit rates where the conventional high rate theory fails.
Journal ArticleDOI
Transmission noise eliminations in BDPCM image
TL;DR: In order to improve the median filter that reduces impulse noise with blurring, adaptive filtering for the differences is proposed by means of the difference range, transmission impulse noises are detected and corrected by the filtering.
Proceedings ArticleDOI
Scalable decomposition of speech waveforms
J. Lukasiak,Ian Burnett +1 more
TL;DR: This paper proposes a technique that requires only a single frame of speech and produces a scalable decomposition, which allows reconstruction accuracy to be varied according to the bit rate available.
Proceedings ArticleDOI
Performance of a low complexity CELP speech coder under mobile channel fading conditions
TL;DR: Different block coding and convolutional coding techniques have been applied to improve the performance of the coder in the presence of burst errors, and novel methods to quantize the residual and the long- and short-term model filters are presented.
Book ChapterDOI
Analog-to-Digital Conversion Techniques
TL;DR: Explains the overall design, performance, and applications of analog-to-digital conversion techniques, including the basic principles of vocoding techniques and hybrid coders.
References
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Journal ArticleDOI
Speech analysis and synthesis by linear prediction of the speech wave.
B. S. Atal,Suzanne L. Hanauer +1 more
TL;DR: Application of this method for efficient transmission and storage of speech signals as well as procedures for determining other speechcharacteristics, such as formant frequencies and bandwidths, the spectral envelope, and the autocorrelation function, are discussed.
Journal ArticleDOI
Predictive coding--I
TL;DR: Part II will give the mathematical criterion for the best predictor for use in the predictive coding of particular messages, will give examples of such messages, and will show that the error term which is transmitted in predictive coding may always be coded efficiently.
Journal ArticleDOI
Optimizing digital speech coders by exploiting masking properties of the human ear
TL;DR: New results of masking and loudness reduction of noise are reported and the design principles of speech coding systems exploiting auditory masking are described.
Journal ArticleDOI
Predictive coding of speech signals and subjective error criteria
TL;DR: Improved speech quality is obtained by efficient removal of formant and pitch-related redundant structure of speech before quantizing, and by effective masking of the quantizer noise by the speech signal.
Journal ArticleDOI
Adaptive predictive coding of speech signals
Bishnu S. Atal,M. R. Schroeder +1 more
TL;DR: Preliminary studies suggest that the binary difference signal and the predictor parameters together can be transmitted at approximately 10 kilobits/second which is several times less than the bit rate required for log-PCM encoding with comparable speech quality.