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
Predictive coding of speech using analysis-by-synthesis techniques
TL;DR: Different excitation signals are discussed, as well as procedures for determining the various coder parametsrs, which are based on analysis-by-synthesis techniques.
Proceedings ArticleDOI
Optimizing LPC filter parameters for multi-pulse excitation
Sharad Singhal,B. Atal +1 more
TL;DR: The possibility that multi-pulse excitation can approximate the all-pole filter excitation sufficiently closely and obtain the optimum filter parameters for this excitation is examined.
Proceedings ArticleDOI
Analysis-by-synthesis method for whisper-speech reconstruction
TL;DR: This approach uses a template of a speakerpsilas normal phonated speech for extraction of excitation parameters such as pitch and gain, and then injects these estimated excitations into whispered signal to synthesize normal-sounding speech through the CELP codec.
Book
Speech and Audio Processing: A MATLAB®-based Approach
TL;DR: This pragmatic and application driven focus, and concise explanations, are an essential resource for anyone who wants to rapidly gain a practical understanding of speech and audio processing and technology.
Patent
Multi-state speech encoder and decoder
John M. Turner,Dana J. Redington +1 more
TL;DR: In this paper, the original signal state, over a short-term interval of samples (packet) is defined as one of four states: Silence, Hiss, Sigma, or Peaky.
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.