Topic
Speech coding
About: Speech coding is a research topic. Over the lifetime, 14245 publications have been published within this topic receiving 271964 citations.
Papers published on a yearly basis
Papers
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05 Jun 2000TL;DR: Both the objective and subjective test results shows that the proposed algorithm outperforms the conventional codebook mapping method.
Abstract: Reconstruction of wideband speech from its narrowband version is an attractive issue, since it can enhance the speech quality without modifying the existing communication networks. This paper proposes a new recovery method of wideband speech from narrowband speech. In the proposed method, the narrowband spectral envelope of input speech is transformed to a wideband spectral envelope based on the Gaussian mixture model (GMM), whose parameters are calculated by a joint density estimation technique. Then the lowband and highband speech signal is reconstructed by the LPC synthesizer using the reconstructed spectral envelope. This paper also proposes a codeword-dependent power estimation method. Both the objective and subjective test results shows that the proposed algorithm outperforms the conventional codebook mapping method.
197 citations
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TL;DR: A statistical approach based on a hidden Markov model (HMM) is used, which takes into account several features of the band-limited speech, and enhanced speech exhibits a significantly improved quality without objectionable artifacts.
197 citations
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TL;DR: The speech produced by most audio response units is noticeably artifical and mechanical sounding as discussed by the authors, which makes it difficult to distinguish between real speech and synthesized speech. But the response units can select speech sounds, stored in analog or coded digital form, as the excitation for a speech synthesizer, for example in telephone audio announcement terminals.
Abstract: Audio response units that select speech sounds, stored in analog or coded digital form, as the excitation for a speech synthesizer are widely used, for example in telephone audio announcement terminals. The speech produced by most units is noticeably artifical and mechanical sounding.
196 citations
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TL;DR: A novel two-dimensional subband coding technique is presented that can be applied to images as well as speech and has a performance that is comparable to that of more complex coding techniques.
Abstract: A novel two-dimensional subband coding technique is presented that can be applied to images as well as speech. A frequency-band decomposition of the image is carried out by means of 2D separable quadrature mirror filters, which split the image spectrum into 16 equal-rate subbands. These 16 parallel subband signals are regarded as a 16-dimensional vector source and coded as such using vector quantization. In the asymptotic case of high bit rates, a theoretical analysis yields that a lower bound to the gain is attainable by choosing this approach over scalar quantization of each subband with an optimal bit allocation. It is shown that vector quantization in this scheme has several advantages over coding the subbands separately. Experimental results are given, and it is shown the scheme has a performance that is comparable to that of more complex coding techniques. >
196 citations
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01 Apr 1987TL;DR: The paper describes a related scheme, which allows real time implementation on current DSP chips, and the very efficient search procedure in the codebook is achieved by means of a new technique called "backward filtering" and the use of algebraic codes.
Abstract: Code-Excited Linear Prediction (CELP) produces high quality synthetic speech at low bit rate. However the basic scheme leads to huge computational loads. The paper describes a related scheme, which allows real time implementation on current DSP chips. The very efficient search procedure in the codebook is achieved by means of a new technique called "backward filtering" and the use of algebraic codes. RSB performances are reported for a variety of conditions.
196 citations